US1661606A - Dyeing process - Google Patents

Description

Patented Mar. 6, 1928.

UNITED *STATES v 1,661,606 PATENT OFFICE.

AUGUSTE ESCAICH AND JEAN PAUL WOIBIMS,- OF IABIS, FRANCE.

Drama rnocnss.

No Drawing. bpplication flled November 20, 1928,. Serial No. 675,956. and in Germany November 25, 1922.

This invention relates to a dyeing process applicable to all fibres, leathers, hairs and the like which consists in causing reducing agents to actin either the hot or. cold state in an acid medium on ferri and ferrocyanides and in the presence of traces of catalyzing salts or of metallic oxides. By ferro and ferricyanides, we means in this specification the double cyanides of iron and of analkali metal, sodium or potassium.

These substances can furnish various colors. They have, moreover, been used for a long time, for giving-blue (Raymond,

Prussian, French blue etc.).

It is well known that for obtaining these blues one generally uses somewhat considerable amounts of minerals acids, in a first operation, .and tin salts which are relatively of a high price, in a subsequent operation.

In the present process use is made of the fact that POtB-SSIUIII ferricyanide, in the presence of various reducing agents will dye any fibres very easily if the medium is slightly acid and contains traces of catalyzing mercury compounds.

The best results are obtained by acid mercury sulphate, known as Deniges reagent consisting of yellow'mercu oxide; 50 gr.,

sulphuric acid 200 c. c., dist ed water 1000 c. c. the amount of mercury oxide may however be increased.

The reducers suitable for use are numerous and will be enumerated hereinafter, for instance, ordinary sugar'may be employed as as follows 20 ,litres of water +50 0. c. of a solution of sugar, at 10% +40 0. c. of a solution sulphate; is brought to the invert the sugar, and then 40 40 c. c. of a solution of 10 potassium ferri cyanide for 100 water is added; fabrics of any kind immersed at the beginning or at the end in the bath, will be colored blue. With the .above proportions, the color is very marked on wool, less intense on silk and cotton, but is suflicient for light shades.

It is thus possible to develop very interesting colors with very reduced quantities of alkali metal ferro or ferricyanides and of mineral acid. a

The composition of the bath remaining otherwise'the same, by doubling the ferncyanide, that is to say, 80 0. cm. at 10% for 20 litres of water; a blue which is deep 58 on wool and very decided 011 silk is obof acid mercury boil in order to The same results are obtained with cold treatment in about 24 hours. 7

With hot treatment, the first stage of coloring of the fabrics results below. boilnag-point temperature in greens. If desired, with a view to shading, the operation can be stopped at this point before proceeding to the blue sta e.

In the absence 0 sugar, the mercury sulphate and the ferricyanide "give a blue of' less depth. 7

The sugar can be replaced by equivalent quantities of glucose.

If, theoretically, in an alkaline medium, the reduction oftwo molecules of ferricy anide is obtained with a molecule of glucose, in practice practially equal quantities of these two substances can be used. In acid medium'the proportions hereinbefore indicated give excellent results.

Ferrocyanide substituted for lferricyanide gives lighter colors. With a view to producing a shade or tint, these two substances can be mixed at the rate of 1 part of ferricyanide and of 1 to 10 parts of ferrocyanide. With these proportions the addition of ferric chloride or sulphate gives very fine blues.

Instead of sugar, various reducers can be employed and usedin an amount equal to that of .the ferricyanide or to a smaller amount if the conditions of solubility or of economy are in favour of a decrease.

In a quantity equal to that of the ferrocyanide use can be made of commercial formic acid, hydroquinone, resorcin, formaldehyde, dextrine, soluble starch, aniline salts, and tannins; in a smaller quantity one will use the naphthols (0.50 gr. per liter of bath), I

the pyrocatechin of saponin (0.50 gr..for 1 liter).

The colors are especially good when formic acid, naphthols, hydroquinone or re- Panama wood may be substituted for the sugar and has the advantage of drawing,

very uniformly. Further it must -be borne in mind that the saponin seems to adhere to the fibre like a tannic mordant and under the same conditions, which allows of dyeing blue after washing the fabric by immersion in the bath. Hence only two reagents will be required in the bath, the acid mercury sulphate and the ferricyanide, the reducer being carried by the saponified fibre.

If the reducer employed is itself a chromogen (tannin, na hthols) and is fixed as a mordant on the fi re, it will be possible to alter the blue tint obtained by passing a. previously tanned blue fibre into a bath of molybdate or a blue fibre previously naphtholated into a bath of nitrous acid.

We claim- 1. Method of dyeing any fibres with the aid of a double cyanide of iron and of an alkali metal, consisting in causing to act on the fibres a slightly acid bath containing a double cyanide of iron and of an alkali metal, an organic reducing agent and traces of a mercury compound.

2. Method of dyeing any fibres with the aid of a double cyanide of iron and of an alkali metal, consisting in causing to act on the fibres a slightly acid Fat-h containing a ferricyanide of an alkal metal, a ferrocyanide of an alkali metal, an organic reducing agent and traces of a mercury compound.

In testimony, that we claim the foregoing as our invention, we have signed our names.

AUGUSTE nsoAIoH. JEAN PAUL WORMS.