The Dyeing of Cotton Fabrics Part 14

_Dark Chestnut._--Dye with 2-1/2 lb. Dianil brown 3 G O, 13 oz. Dianil brown R, 13 oz. Dianil brown B D, 1 lb. soda and 20 lb. salt, fixing with 3 lb. copper sulphate and 1 lb. acetic acid.

_Brown._--Dye with 2-1/4 lb. Chrysophenine G, 1-1/4 lb. Diamine brown G, 1-1/4 lb. Chicago blue R W, 3 lb. soda and 20 lb. Glauber's salt; fix with 3 lb. sulphate of copper and 2 lb. acetic acid.

_Nut Brown._--Dye with 3 lb. Chromanil brown 2 G, 3 lb. soda and 20 lb.

Glauber's salt; fix with 1 lb. b.i.+.c.hromate of potash, 3 lb. sulphate of copper and 2 lb. acetic acid.

_Dark Grey._--Dye at the boil for one hour with 1 lb. Zambesi black F, 3 lb. soda and 10 lb. Glauber's salt; fix in a fresh boiling bath with 3 lb. sulphate of copper, 1 lb. b.i.+.c.hromate of potash and 10 lb. Glauber's salt.

_Dark Grey._--Dye with 3 lb. Chromanil black 4 R F, 3 lb. soda and 10 lb. Glauber's salt; fix with 1 lb. b.i.+.c.hromate of potash, 3 lb. sulphate of copper and 2 lb. acetic acid.

_Dark Grey._--Use in the dye-bath 1 lb. Diamine blue R W, 1/2 lb.

Diamine orange B, 1/4 lb. Diamine new blue R, 2 lb. soda and 20 lb.

Glauber's salt, fixing with 4 lb. sulphate of copper and 2 lb. acetic acid.

_Pale Greenish Grey._--Dye with 1/4 oz. Diamine orange B, 3 oz. Diamine blue R W, 1/2 lb. soda, 2 lb. soap and 5 lb. Glauber's salt, fixing with 1 lb. sulphate of copper and 1/2 lb. acetic acid.

_Slate Blue._--Dye with 1/4 lb. Diamine dark blue B, 2 oz. Diamine new blue R, 1 lb. soda and 10 lb. Glauber's salt; fix with 2 lb. sulphate of copper and 1 lb. acetic acid.

_Grey._--Prepare the dye-bath with 2 lb. Cross-dye black 2 B, 5 lb. soda ash, 15 lb. common salt; after rinsing leave the cotton in the air to age overnight, rinse again and work for half to three-quarters of an hour at from 150 to 160 F. in a bath containing 5 lb. b.i.+.c.hromate of potash and 5 lb. sulphuric acid, then thoroughly rinse and dry.

_Dark Grey._--Dye with 1 lb. Diamine jet black Cr, 1 lb. soda and 10 lb.

Glauber's salt, fixing with 1 lb. b.i.+.c.hromate of potash and 1/2 lb.

acetic acid.

_Green Grey._--Dye with 1 lb. Diamine dark blue B, 2 oz. Diamine orange B, 4 oz. Diamine fast yellow B, 1 lb. soda and 10 lb. Glauber's salt, fixing with 3 lb. sulphate of copper and 1 lb. acetic acid.

_Grey._--Dye with 4 oz. Dianil black N, 1 lb. soda and 10 lb. salt, fixing with 1 lb. copper sulphate and 1/2 lb. acetic acid.

_Black._--Prepare the dye-bath with 5-1/2 lb. Diamine jet black R B, 1 lb. Diamine dark blue B, 20 lb. Glauber's salt; dye at the boil for one hour, rinse and then treat the goods simmering for twenty minutes with 4 lb. b.i.+.c.hromate of potash.

_Black._--Prepare the dye-bath with 8 lb. Chromanil black R F and 20 lb.

Glauber's salt; dye at the boil for one hour, then treat boiling hot for about thirty minutes in a fresh bath with 1 lb. b.i.+.c.hromate of potash and 3 lb. sulphate of copper. Add 6 lb. only of the dye-stuff to the bath for a second batch.

_Black._--Use 5 lb. Dianil black N, 5 lb. soda and 20 lb. salt; then fix with 3 lb. copper sulphate, 3 lb. b.i.+.c.hromate of potash and 2 lb. acetic acid.

_Black._--Use in the dye-bath 5 lb. Dianil black C R. 3 lb. caustic soda, 36 Tw. and 20 lb. salt, fixing with 3 lb. copper sulphate, 3 lb.

b.i.+.c.hromate of potash and 2 lb. acetic acid.

_Jet Black._--Dye with 5 lb. Diamine jet black Cr, 1 lb. soda and 20 lb.

Glauber's salt, fixing with 4 lb. b.i.+.c.hromate of potash and 2 lb. acetic acid.

It will be convenient here to deal with a small but growing and important cla.s.s of dye-stuffs which contain sulphur in their composition, and which, therefore, are named:--

=Sulphur or Sulphyl Colours.=

The original type of this group is Cachou de laval, sent out a good many years ago, but of late years Vidal black, St. Dennis black, Cross-dye blacks and drab, Immedial blacks, blues and browns, Amidazol blacks, browns and olives, Sulfaniline black and brown, Katigen blacks, greens and browns, etc., have been added, and the group is likely to become a very numerous one in the future.

All these colours are dyed on to the cotton or linen from baths containing soda and salt, while some require the addition of sodium sulphide or caustic soda in order to have the dye-stuff properly dissolved. They are very weak dyes compared with the direct colours, and require from 20 to 60 per cent. to produce full shades, although of this fully one-third remains in the bath unabsorbed by the cotton. It is, therefore, important in order to work as economically as possible to retain the bath, bringing it up to strength by the addition of fresh dye-stuffs, etc.

Most of the dyes require the dyed goods to pa.s.s through a second bath of some reagent, b.i.+.c.hromate of potash, sulphate of copper, etc., in order to fully develop and fix the dye on the fabric.

The best method of using the various dyes of this group will be given in the form of formulae. Two points of importance are to use as strong a dye liquor as possible, and to expose the cotton as little as possible to the air during the dyeing operation. The dye-stuffs when exposed to the air readily become oxidised, and are thereby converted into insoluble products which become fixed on the fibre in a loose form, and in that case the dyed fibre rubs rather badly.

_Pale Brown._--Prepare a dye-bath with 15 lb. Cachou de laval, 10 lb. of soda, and 10 lb. salt. The bath is not exhausted of colouring matter, and by adding one-half of the above quant.i.ties of dye-stuff and salt may be used again for another lot of cotton. After the dyeing the cotton is pa.s.sed into a fixing bath of 2 lb. b.i.+.c.hromate of potash and 1 lb. acetic acid, working at 180 F. ten to fifteen minutes.

_Black._--Prepare the dye-bath with 200 gallons of water, 10 lb. soda, 10 lb. sulphide of sodium, 60 lb. salt and 16 lb. Immedial black V extra. Work at the boil for one hour, keeping the cotton well under the surface during the operation, in the case of yarns this is effected by using bent iron rods on which to hang the hanks in the vat, in the case of pieces by working with vats the guide rollers of which are below the surface of the dye liquor. After the dyeing the yarn or pieces are squeezed, well rinsed in water, then pa.s.sed into the fixing bath, which contains 2 lb. sulphate of copper, 2 lb. b.i.+.c.hromate of potash and 3 lb.

of acetic acid, for half an hour at 170 to 180 F. b.i.+.c.hromate of potash used alone gives a reddish shade of black, sulphate of copper a greenish shade, a mixture of the two gives a greenish shade.

There are three brands of Immedial black, _viz._, V extra, G extra and F F, which vary a little in the tone of black they produce. The method of using is identical for all three. The dye-bath is not exhausted of colour and so should be kept standing, for each subsequent lot of cotton add 8 lb. Immedial black and 3 lb. sulphide of soda, and to every 10 gallons of water added to bring the bath up to volume 1/2 lb. soda and 3 lb. salt.

These blacks are very fast to was.h.i.+ng, light, etc. By using smaller quant.i.ties of dye-stuff good greys can be dyed.

_Black._--Prepare the dye-bath with 10 lb. soda, 10 lb. sulphide of sodium, 60 lb. salt and 25 lb. Vidal black, work at the boil for one hour, then rinse and fix with 3 lb b.i.+.c.hromate of potash and 2 lb.

sulphuric acid.

_Black._--Prepare the dye-bath with 30 lb. Cross-dye black B, 10 lb.

soda, 150 lb. salt. Dissolve the dye-stuff in boiling water, then add the soda crystals and finally the salt. Enter the previously well-boiled cotton at about 175 F. After a few turns raise the temperature to the boil as quickly as possible, and work for one hour (just at the boil).

Lift and thoroughly rinse without delay. (The better the cotton is washed the clearer the ultimate shade.) After was.h.i.+ng, wring up and let air age for about one hour; the intensity of the black is thereby increased.

Meanwhile prepare a bath with 5 lb. b.i.+.c.hromate of potash, 4 lb.

sulphuric acid (168 Tw.). Enter at 150 to 160 F., and work at this for about ten minutes. After chroming, wash thoroughly to remove all traces of acid. At this stage, the usual softening may take place if desirable, and finally dry at a low temperature.

The bath is kept up for further lots, and three-fourths the quant.i.ty of colouring matter, and about half soda and one fourth salt are used.

Wood, or iron cisterns are most suitable, and copper pans or pipes must be avoided.

The dye-bath should be kept as short as possible, about twelve to fifteen times the amount of water on the weight of cotton is advisable.

The cotton when in the dye-bath should be exposed as little as possible to the air.

There are several brands of these Cross-dye blacks varying in the tone of black they give.

_Black._--Prepare the dye-bath with 5 lb. soda ash, 200 lb. salt and 20 lb. Amidazol black G, this is heated to 150 F., the cotton is entered, the heat raised to the boil, and the dyeing done for an hour at that heat. Lift, rinse well, then pa.s.s into a chroming bath, made from 5 lb.

b.i.+.c.hromate of potash and 3 lb. sulphuric acid, used at 160 F. for twenty minutes, then lift, wash well and dry. The bath may be kept standing and used for other lots of cotton by replenis.h.i.+ng with about two-thirds of the original weight of dye-stuff and a little soda. There are four brands of these Amidazol blacks which dye from a jet black with the G to a deep blue black with the 6 G brand. The G, 2 G, and 4 G, used in small quant.i.ties, 2-1/2 to 3 lb., dye good greys of a bluish tone, the 6 G gives a dull blue, the 4 G and 6 G, used in the proportions of 7-1/2 to 10 per cent., give dark blues.

All these blacks may be combined with aniline black with good results as shown in the following recipe:--

_Black._--Prepare the dye-bath with 10 lb. Amidazol black 2 G, 5 lb.

soda and 100 lb. salt. Work at the boil for an hour, then rinse, pa.s.s into a cold bath made from 2-1/2 lb. aniline oil, 2-1/2 lb. hydrochloric acid, 6-1/2 lb. sulphuric acid, 7-1/2 lb. b.i.+.c.hromate of potash, and 5-1/2 lb. perchloride of iron, 66 Tw. This is used cold for an hour, then the heat is slowly raised to 160 F., when the operation is finished, and the cotton is taken out well rinsed and finished as usual.

Any of this cla.s.s of black may be so topped with aniline black if thought necessary A very fast black is thus got.

_Black._--Make the dye-bath with 15 lb. Sulfaniline black G, 60 lb.

salt, 10 lb. soda, and 5 lb. sulphide of sodium. Work at a little under the boil, then lift, rinse well and pa.s.s into a hot bath of 3 lb.

b.i.+.c.hromate of potash, 3 lb. sulphate of copper, and 4 lb. acetic acid for half an hour, then lift, rinse well and dry.

It has been observed in the practical application on a large scale of these sulphur blacks that the cotton is liable to become tendered on being stored, although there are few signs of such after the dyeing is finished. The exact cause of this is somewhat uncertain, the most probable reason is that during the process of dyeing a deposit of sulphur in a fine state of division has been thrown down on the cotton by decomposition of the dye-stuff, and that this sulphur has in time become oxidised to sulphuric acid which then exerts its well-known tendering action on the cotton.

The remedy for this evil lies partly with the dye manufacturer and chiefly with the dyer. The dye manufacturer should see that his product is made as free from sulphur as possible, while the dyer by careful attention to thorough was.h.i.+ng, thorough fixation in the chrome, etc.

baths, tends to eliminate all sulphur from the goods, and so prevent all possibility of the cotton becoming affected.

_Blue._--Make the dye-bath with 22 lb. Immedial blue C, 13 lb. sulphide of sodium, 50 lb. salt and 15 lb. caustic soda lye at 70 Tw. Work at just under the boil for one hour, keeping the goods well under the surface of the liquor. After the dyeing the goods are well rinsed in the water and then pa.s.sed into a vat which contains 1 lb. peroxide of sodium and 1 lb. sulphuric acid. This is started cold, after about fifteen minutes heat slowly to about 150, work for twenty minutes, then lift, wash and dry. For subsequent lots of cotton there only need be used 7 lb. Immedial blue C. 2 lb. sulphide of sodium, 3 lb. salt and 1-1/2 lb.