FR2489386A1 - Oxidn. of sulphur dyes of fibres - using oxygen enriched, esp. supersaturated water - Google Patents

Abstract

In the oxidn. of sulphur dyes on natural or synthetic fibres, the oxidn. bath is enriched in oxygen, esp. by water supersatd. with oxygen. Esp. the oxidn. is at an acid pH and 30-70 deg.C using a treatment bath contg. at least 20 mg. per l. oxygen; esp. pH 3.5, 70 deg.C and oxygen concn. 30 mg. per ml. Pref. the oxygen-enriched water is injected into the oxidn. compartment at 1-2 cu.m. per hr., using 1-2 cu.m. per ton of material being dyed. Alternatively, the enriched soln. is supplied in counter-current at 5 cu.m. per ton of material. The process avoids pollution of water by chromium salts and problems of over-oxidn. (as caused by hydrogen peroxide), and is cheaper than usual oxidn. processes. Colour yields are at least as good as those achieved by bichromate and fastness to light and washing generally superior.

Description

"PROCESS FOR OXIDATION OF SULFUR COLORANTS ON TEXTILE FIBERS
NATURAL AND SYNTHETIC ".

 The present invention relates to the oxidation of sulfur dyes to natural and synthetic textile fibers.

The sulfur dyes used at present are mainly "solubilized" dyes in the form of thiosulphonate R - S SO 3 Na, where R is the chromophore residue. They are supplied in the form of a liquid preparation in the presence of sodium sulphide as the reducing agent from which the following equilibrium

These dyes are applied to the textile fibers in the reduced state by impregnating the fabric and squeezing followed by vaporization to disperse the dye into the fibers for which it has affinity only to the fiber. Reduced state. After rinsing, rinses remove the excess sodium sulphide before proceeding to the actual oxidation phase.
2R-S + (OX) # RSS-R + 2e
This oxidation of the dye in the fiber causes its insolubilization and consequently guarantees the fixation in the internal structure of the fibers
The oxidation takes place in a machine tank to be washed off continuously in which the fabric, guided by a set of diverting wheels, passes into the "reactive" medium (oxidizing medium) and into the air.

 This oxidation is usually carried out using a solution of dichromate, the use of which tends to be suppressed given the toxic nature of this pollutant, the presence of which inhibits the activity of the bacterial flora.

 Alternatives have been proposed for using hydrogen peroxide or sodium iodate.

Hydrogen peroxide has the disadvantage of over-oxidizing the dyes, which causes poorer use.

Iodate, for its part, does not have this disadvantage, but, in addition to its high price, may be subject to supply problems.

 It has been found a simple process of oxidation of sulfur dyes on natural or synthetic textile fibers, allowing the removal of chromium salt rejections, without overoxidation phenomenon compared to hydrogen peroxide, for a lower treatment cost. , compared to all the usual oxidants.

 The new process, characterized by the use of oxygen conveyed by the treatment bath which makes it possible to avoid the risks of each of the solutions mentioned above, is not only an alternative solution since it is very efficient in the improvement in the level of certain textile fastnesses such as the lightfastness of dyed fabrics or their fastness to washing.

 The oxygen enrichment of the treatment bath is carried out by means of water supersaturated with oxygen. Virtually the oxidation of sulfur dyes on textile fibers such as cotton, linen, viscose, etc. or in mixture with other fibers is carried out by means of water supersaturated with oxygen.

 At a determined temperature and pH, it was noted that the dye yield increases in all cases with the dissolved oxygen concentration of the feed bath.

 The pH value has a significant importance on the dye yield, and an acidic medium promotes the oxidation of sulfur dyes.

 The increase in temperature generally improves the dye yield.

 It has been found advantageous to carry out the oxidation of sulfur dyestuffs on teitile fibers at an acidic pH of between 3.5 and 7, with a bath temperature of between 30 and 700.degree. C., and at a dissolved oxygen concentration of bath at least equal to 20 mg / l of oxygen.

 The use of water at 10 mg / l of oxygen does not lead to satisfactory results, especially for red dyes. A dissolved oxygen concentration of 20 mg / l sometimes requires a temperature above SOU C.

 On the other hand, at a pH of 3.5 and in a temperature range of between 30 and 700 ° C., a dissolved oxygen concentration of 30 mg / l of the oxidation bath makes it possible to obtain dye yields higher than those obtained in FIG. means of dichromate.

Oxygen oxidation of sulfur dyes can be considered in two different ways
or by injecting the aqueous solution enriched in oxygen at the level of the oxidation compartment alone.

 The aqueous solution enriched with oxygen is introduced at a flow rate of between 1 and 2 m 3 / hour, ie 1 to 2 m 3 per ton of treated fabric.

 or by working countercurrently from the oxidation compartment to the first rinsing tank after steaming, at the rate of a few cubic meters of oxygen-enriched water per ton of treated fabric, advantageously about 5 m 3 of enriched water.

 The oxygen consumption is of the order of 30 to 150 g per ton of treated fabric, in continuous operation. To this is added the quantity necessary for filling the vats of the different compartments for each dyeing pass. in laboratory tests, the amount of available oxygen in the oxidation compartment is 300 g per tonne of tissue, which can be considered an upper limit.

 The oxidation tests of the sulfur dyes using oxygen conveyed by the treatment bath indicated that coloristic yields at least identical to those obtained using dichromate or oxidation agent could be discounted in the case of the majority of dyes.

 the fastness to light and washing are in most cases improved by the use of oxygen. It thus appears that oxidation with oxygen represents a valid solution for the dyeing process with sulfur dyes.

 The advantage of this oxygen process lies mainly in the absence of pollution (compared with bichronate), the absence of overoxidation phenomena (compared with hydrogen peroxide) and finally at a lower cost (compared to to all usual oxidants and especially to sodium iodate).

 The oxidation study of sulfur dyes in the presence of oxygen was carried out in a laboratory installation simulating the industrial conditions, in particular at the level of the oxidation compartment.

 The dyes are made by impregnating on a BENZ laboratory scarf followed by a WIRA vaporizer treatment at 100 ° C. in the presence of saturated steam. After steaming, rinses are carried out in solutions of decreasing concentrations of sodium sulphide before carrying out the oxidation in a cell specially designed for this purpose and making it possible to treat alternately submerged phase and gaseous tissue samples.

 The saturated oxygen solution is prepared in a tank of 90 liters capacity by bubbling oxygen introduced into a porous stainless steel. This solution is introduced at a constant flow and known in the oxidation compartment after having been previously brought to the desired temperature in a liquid heater (power 3 kW).

The oxidation chamber, placed in a thermoset chamber, is provided at its upper part with an airlock allowing the introduction of the tissue sample without modification of the gaseous atmosphere.

 The liquid phase represents one-third of the volume of the compartment, the remaining two-thirds being the gaseous sky. Prior to oxidation, the tissue sample is rapidly attached to a support secured to a reciprocating device which, after passage of the airlock, provides reciprocating movement of the tissue sample in the immersed phase and in the the gaseous sky is analogous to what happens in an industrial machine, the detour rollers put aside. The duration of a passage (aLler and return) was fixed 9 3 seconds, so that 10 back and forth correspond to 30 seconds of treatment, duration of use in practice.

The temperature is controlled in the oxidation tank by means of two platinum probes placed one in the gaseous sky, the other in the aqueous solution. The dissolved oxygen concentrations are monitored after inlet sampling (before reheating) and at the outlet of the oxidation tank, using an OX 439 oximeter from WTW. The percentage of oxygen in the gas phase is evaluated by means of a measurement probe connected to an oxygen analyzer
PO2meter of Tacussel.

 Examples which illustrate the invention are given below.

Example 1
The definition of oxygen contents was investigated in dynamic tests.

In order to define the time necessary to obtain the dynamic equilibrium at a given temperature, solutions are prepared at 10 mg / l of dissolved oxygen (purified water at 110 ° C.) and at 30 and 30 mg / l. by bubbling oxygen, and this at the two pH values considered (3,5 and 7). The feeding of the oxidation tank is carried out using these solutions with a flow rate of 50 l / n. The oxygen concentrations measured in the liquid and gaseous phases as a function of time are recorded for three temperatures 30, 50 and 700 C. The results obtained are recorded in Table I. TABLE I @ Approximate duration

Concentration <SEP> [O2] <SEP> eq <SEP> [O2] <SEP> eq <SEP> Duration <SEP> of <SEP> setting
<tb> feed <SEP> Temperature <SEP> pH <SEP> (phase <SEP> gaseous) <SEP> (phase <SEP> liquid) <SEP> in <SEP> balance <SEP>#
<tb><SEP> O2 (mg / l) <SEP> (C)
<tb> (%) <SEP> (mg / l) <SEP> (min)
<tb> 3.5 <SEP> 19 <SEP> 7.7 <SEP> 55
<tb> 30
<tb> 7 <SEP> 19.5 <SEP> 7.5 <SEP> 60
<tb> 3.5 <SEP> 18.3 <SEP> 7 <SEP> 60
<tb> 10 <SEP> 50
<tb> 7 <SEP> 18.8 <SEP> 6.5-7 <SEP> 60
<tb> 3.5 <SEP> 11 <SEP> 4.5 <SEP> 80
<tb> 70
<tb> 7 <SEP> 16.5 <SEP> 3.3 <SEP> 60
<tb> 3.5 <SEP> 21 <SEP> 15 <SEP> 90
<tb> 30
<tb> 7 <SEP> 21.8 <SEP> 13.5 <SEP> 90
<tb> 3.5 <SEP> 24.5 <SEP> 12 <SEP> 90
<tb> 20 <SEP> 50
<tb> 7 <SEP> 31 <SEP> 7 <SEP> 90
<tb> 3.5 <SEP> 29 <SEP> 6 <SEP> 100
<tb> 70
<tb> 7 <SEP> 37.5 <SEP> 4.5 <SEP> 100
<tb> 3.5 <SEP> 21.6 <SEP> 20.5 <SEP> 80
<tb> 30
<tb> 7 <SEP> 21.7 <SEP> 17.5 <SEP> 80
<tb> 3.5 <SEP> 25.5 <SEP> 14 <SEP> 110
<tb> 30 <SEP> 50
<tb> 7 <SEP> 35.5 <SEP> 13 <SEP> 90
<tb> 3.5 <SEP> 32.5 <SEP> 11 <SEP> 90
<tb> 70
<tb> 7 <SEP> 45 <SEP> 9.5 <SEP> 100
<Tb>
The equilibration time varies between about 60 and 100 minutes for the fixed flow rate. With regard to the equilibrium oxygen contents, these increase in the gaseous phase, especially as the temperature is high, with the exception of the case where the concentration of feed is low (10 mg / l 02) due to the enrichment of the gaseous water with water vapor while the oxygen degassing is relatively low. The oxygen content in the gaseous phase also increases with the feed concentration, but it is lower. in an acid medium in a neutral medium.

 The oxygen content in the liquid phase is the reverse all the more important as the temperature decreases and the medium is more acidic. As a function of time, the concentration of dissolved oxygen generally decreases sharply under the effect of the temperature causing degassing.

It then tends to rise before stabilizing. Other things being equal, the dissolved oxygen content increases with the feed concentration.

Example 2
These tests were carried out with two solubilized sulfur dyes - yellow Sodyesul MCF gold (difficult to oxidize in the air,
metallisable) - Red Sodyesul 2B (easily oxidizable).

These two dyes were applied on whitened velvet whose characteristics are as follows - weight per square meter: 300 g - composition by elements
channe: 50/50 cotton / polyester blend
weft: 100% cotton
pompoms: 100% cotton - overall composition
cotton: 85 7.

 polyester 15 7.

The dyes are carried out on the laboratory installation previously described. The procedure is as follows - Foulardage (Impregnation - Exprimage) in a bath
100 g / l of dye and 10 g / l of sodium sulphide,
at 600 C and with an expression rate of 65%.

- Vaporization of one minute at 100 C in saturated steam.

- Successive pre-rinsing with intermediate expressions in
three baths containing sodium sulphide in quantities
decreasing, ie 2 g / L for the first bath, 0.5 g / l
in the second and O g / l in the third Each rinse
is carried out for 20 seconds at 70 ° C. Oxidation with oxygen in the device described in FIG.
paragraph 3. The bath and atmosphere of the oxidation tank
are prepared 90 minutes before use by circulating
the aqueous phase more or less rich in oxygen with a
flow rate of 50 l / h, and this in order to be in dynamic balancing behaviors such as those defined in
paragraph 4.

 The treatment parameters studied are the supply of dissolved oxygen (10, 20 and 30 mg / l), the temperature (30, 50 and 700 G) and the pH (3.5 or 7). ).

The oxidation time is 30 seconds decomposed back and forth for 3 seconds each. One-third of the time corresponds to the submerged state of the sample, while the other two-thirds relate to the passage of the wet sample into the gas phase.

 By way of comparison, the oxidations were also carried out for 30 seconds at 700 ° C. in a bath containing 6 g / l of sodium dichromate at pH = 3.5, which corresponds to the conditions customarily used for these dyes.

- Soaping for 20 seconds at 95 C in a bath
2 g / l of Sunaptol MB (alcohol-based surfactant
linear ethoxylated PCUK).

- Post-rinsing in three successive baths in water a
950 C, each rinse being carried out for 20 seconds.

The samples thus treated are monitored spectrophotometrically on a Spectromat FS 3A
Pretema using magnesium oxide as a reference. The reflectance values R have thus been determined for the wavelength corresponding to the absorption maximum (# max).

From these reflectance values, we can deduce the K / S color output according to the Kubeika-
(1-R) 2
Munck: K / S =
2R
The results obtained, expressed in K / S, are summarized in Tables II and III.

TABLE II
COLOR: YELLOW GOLD SODYESUL MCF - #max = 420 nm

<tb><SEP> Yield <SEP> K / S: <SEP><SEP> Feed Concentration <SEP> Oxidation
<tb><SEP> in <SEP> oxygen <SEP> (mg / l) <SEP> at
<tb> bichromate
<tb> of <SEP> sodium
<tb> pH <SEP> Temperature
<tb><SEP> 10 <SEP> 20 <SEP> 30
<tb><SEP> (C)
<tb><SEP> 30 <SEP> 19.42 <SEP> 19.67 <SE> 20.11 <SEP>
<tb><SEP> 3.5 <SEP> 50 <SEP> 20.11 <SEP> 20.38 <SEP> 20.47 <SEP>
<tb><SEP> 70 <SEP> 20.02 <SEP> 20.66 <SEP> 21.14 <SEP> 19.67
<tb><SEP> 30 <SEP> 18.54 <SEP> 18.70 <SE> 19.34 <SEP>
<tb><SEP> 7 <SEP> 50 <SEP> 18.70 <SEP> 18.93 <SE> 19.42 <SEP>
<tb><SEP> 70 <SEP> 19.09 <SEP> 19.42 <SEP> 20.02
<Tb>
TABLE III
COLOR: RED SODYESUL 2B - # max = 500 nm

<tb><SEP> Yield <SEP> K / S <SEP> Feed Concentration <SEP>
<tb> Oxidation
<tb><SEP> in <SEP> oxygen <SEP> (mg / l)
<tb><SEP> dichromate
<tb> Temperature <SEP> of <SEP> sodium
<tb><SEP> pH
<tb><SEP> (C) <SEP> 10 <SEP> 20 <SEP> 30
<tb><SEP> 30 <SEP> 5.69 <SEP> 5.96 <SEP> 6.52 <SEP> 3.5 <SEP> 50 <SEP> 5.89 <SEP> 6.29 <SEP> 6.45 <SEP>
<SEP> 70 <SEP> 6.07 <SEP> 6.49 <SEP> 6.72 <SEP> 6.38
<tb><SEP> 30 <SEP> 5.34 <SEP> 5.94 <SEP> 6.53 <SEP>
<SEP> 7 <SEP> 50 <SEP> 5.61 <SEP> 5.78 <SEP> 6.14 <SEP>
<tb> 70 <SEP> 5.36 <SEP> 6.53 <SEP> 6.70 <SEP>
Example 3
A series of tests were carried out with 26 solubilized sulfur dyes referenced in the list below.

<tb> References <SEP><SEPName> Commercial <SEP> N <SEP> Color <SEP> In
<tb><SEP> dex <SEP> (CILeuco
<tb><SEP> Manufacturer
<tb><SEP> Yellow <SEP> 1 <SEP> Yellow <SEP> Gold <SEP> Sodyesul <SEP> MCF <SEP> 53120-Yellow <SEP> 2 <SEP> Sodyeco
<tb><SEP> Red <SEP> 1 <SEP> Red <SEP>'I<SEP> 2B <SEP> Red <SEP> 14 <SEP> (S)
<tb><SEP> Yellow <SEP> 2 <SEP> Yellow <SEP><SEP> GLCF <SEP> 53040-Yellow <SEP> 1
<tb><SEP> 80%
<tb> Orange <SEP> 1 <SEP> Orange <SEP><SEP> RDCF <SEP> 53320-Brown <SEP> 52
<tb> Brown <SEP> 1 <SEP> Brown <SEP>"<SEP> GFL <SEP> 53280-Brown <SEP> 31 <SEP>"<SEP>
<tb> Brown <SEP> 2 <SEP>"<SEP>"<SEP> GNCF <SEP> 53000-Brown <SEP> 1 <SEP>"
<tb> Brown <SEP> 3 <SEP>"<SEP>"<SEP> CRCF <SEP> 53228-Red <SEP> 10 <SEP>"
<tb> Brown <SEP> 4 <SEP> n <SEP> n <SEP> 5RCF <SEP> 53228-Red <SEP> 10 <SEP><SEP> n <SEP>
<tb> Brown <SEP> 5 <SEP>"<SEP>"<SEP> AFCF <SEP> - <SEP>"
<tb><SEP> Green <SEP> 1 <SEP> Green <SEP>"<SEP> 4YCF <SEP> Green <SEP> 35 <SEP> (S) <SEP> n
<tb><SEP> Green <SEP> 2 <SEP>"<SEP>"<SEP> NYCF <SEP> 53571-Green <SEP> 2
<tb> Green <SEP> 3 <SEP> n <SEP> n <SEP> BLCF <SEP> Green <SEP> 16 <SEP> n
<tb> Green <SEP> 4 <SEP> n <SEP> t <SEP><SEP> B <SEP> 53570-Green <SEP> 3 <SEP><SEP> n <SEP>
<tb> Brown <SEP> 6 <SEP> n <SEP> n <SEP> FCF <SEP> Brown <SEP> 37 <SEP>
<tb> Brown <SEP> 7 <SEP> Olive <SEP> yellow <SEP> n <SEP> RFCF <SEP> Brown <SEP> 95 <SEP> (S) <SEP> n
<tb> Blue <SEP> 1 <SEP> Blue <SEP>"<SEP> 2GBCF <SEP> 53450-Blue <SEP> 13 <SEP> n
<tb> Blue <SEP> 2 <SEP>"<SEP>"<SEP> 8RCF <SEP> 53440-Blue <SEP> 7 <SEP>"
<tb><SEP> Blue <SEP> 3 <SEP> Blue <SEP> dark <SEP>"<SEP> QL <SEP> n <SEP>
<tb> Blue <SEP> 4 <SEP> Navy <SEP>"<SEP> GFCF <SEP> Blue <SEP> 19 <SEP>"
<tb> Blue <SEP> 5 <SEP> n <SEP> n <SEP> GICF <SEP> 53440-Blue <SEP> 7 <SEP><SEP> n <SEP>
<tb> Blue <SEP> 6 <SEP> n <SEP> Sulphol <SEP> QR <SEP> - <SEP> J.Robinson <SEP>
<tb> Gray <SEP> 1 <SEP> Gray <SEP> Sodyesul <SEP> 3BFL <SEP> Black <SEP> L8 <SEP> (S) <SEP> Sodyeco <SEP>
<tb> Black <SEP> 1 <SEP> Black <SEP> Sulphol <SEP> HQ <SEP> 53185-Black <SEP><SEP> 1 <SEP> J.Robinson <SEP>
<tb> Black <SEP> 2 <SEP>"<SEP>"<SEP> QR <SEP> 53195-Black <SEP> 2
<tb><SEP> Black <SEP> 3 <SEP> n <SEP> Sulfanol <SEP> SBR <SEP> 53195-B <SEP> lack <SEP> 2 <SEP> PCUK <SEP>
<tb><SEP> Black <SEP> 4 <SEP><SEP> Sodyesul <SEP> 2RCF <SEP> 53195-Black <SEP> 2 <SEP> Sodyeco
<Tb>
The dyes were carried out under the described conditions and by comparing two oxidation treatment modes with a solution of 6 g / i of chromium dichromate.
sodium, pH 3.5 for 30 seconds at 700 C - treatment with water enriched with oxygen at pH 3.5 and 700 C.

The initial oxygen concentration was 30 mg / l and
the oxidation of the dyes was carried out at equilibrium
dynamic (ie after 90 minutes at a rate of 50 l / h).

The oxygen concentrations measured at the time of milking
vary between 10 and 13 mg / l in the aqueous phase, and
between 28 and 35% in the gaseous sky. Treatments
oxidation were carried out for 30 seconds following
3 seconds back and forth in the device described in
paragraph 3.

After dyeing, the samples dyed according to the two oxidation modes were checked from the point of view of the following parameters coloristic yield (measurement of reflectance R% for the
wavelength tmax corresponding to the absorption maximum
and calculation of K / S) wash fastness at 600 C (method C2 of the standard
NF G07-200 fastness to light (standard NF G07-067) fastness to dry and wet friction (standard NF G07-016)
TABLE IV
COMPARISON OF COLORISTIC YIELDS

<tb> Reference <SEP> of <SEP> Oxidation <SEP> to <SEP> dichromate <SEP> Oxidation <SEP> a <SEP> oxygen
<tb><SEP> dyes
<tb><SEP>#<SEP><SEP> max <SEP> Reflect <SEP> Yield <SEP>#max<SEP> Reflect <SEP> Yield
<tb><SEP> (nm) <SEP> tance <SEP>% <SEP> K / S <SEP> (nm) <SEP> tance <SEP>% <SEP> K / S
<tb> Yellow <SEP> 1 <SEP> 420 <SEP> 2.42 <SEP> 19.67 <SEQ> 440 <SEP> 2.26 <SEP> 21.14
<tb> Red <SEP> 1 <SEP> 500 <SEP> 6.81 <SEP> 6.38 <SEP> 500 <SEP> 6.50 <SEP> 6.72
<tb> Yellow <SEP> 2 <SEP> 400 <SEP> 2.39 <SEP> 19.93 <SEP> 400 <SEP> 2.25 <SEP> 21.23
<tb> Orange <SEP> 1 <SEP> 460 <SEP> 2.34 <SEP> 20.37 <SEP> 460 <SE> 2.37 <SEP> 20.10
<tb> Brown <SEP> 1 <SEP> 400 <SEP> 3.36 <SE> 13.90 <SEP> 400 <SE> 2.78 <SE> 17.00
<tb> Brown <SEP> 2 <SEP> 400 <SEP> 2.61 <SEP> 18.17 <SEP> 400 <SEP> 2.27 <SEP> 21.04
<tb> Brown <SEP> 3 <SEP> 420 <SEP> 2.13 <SEP> 22.48 <SEP> 420 <SEP> 2.07 <SEP> 23.16
<tb> Brown <SEP> 4 <SEP> 520 <SEP> 5,17 <SEP> 8.70 <SEP> 520 <SEP> 6.17 <SEP> 7.13
<tb> Brown <SEP> 5 <SEP> 420 <SEQ> 1.97 <SEP> 24.39 <SEP> 420 <SEP> 2.02 <SEP> 23.76
<tb> green <SEP> 1 <SEP> 400 <SEP> 2.43 <SEP> 19.59 <SEP> 400 <SEP> 2.28 <SEP> 20.94
<tb> Green <SEP> 2 <SEP> 640 <SEQ> 4.74 <SEP> 9.57 <SEP> 640 <SEP> 5.71 <SEP> 7.79
<tb> Green <SEP> 3 <SEP> 400 <SEP> 2.83 <SEP> 16.68 <SEP> 400 <SEP> 2.47 <SEP> 19.26
<tb> Green <SEP> 4 <SEP> 680 <SEP> 3.08 <SEP> 15.24 <SEP> 400 <SEP> 4.49 <SEP> 10.15
<tb> Brown <SEP> 6 <SEP> 400 <SEP> 2.91 <SEP> 16.25 <SEP> 400 <SEP> 2.84 <SEP> 16.62
<tb> Brown <SEP> 7 <SEP> 400 <SEP> 2.52 <SEP> 18.85 <SEP> 400 <SEP> 2.49 <SEP> 19.09
<tb> Blue <SEP> 1 <SEP> 640 <SEP> 1.69 <SEP> 28.59 <SEP> 640 <SE> 1.75 <SEP> 27.58
<tb> Blue <SEP> 2 <SEP> 580 <SE> 1.84 <SEP> 26.18 <SEP> 580 <SE> 1.95 <SEP> 24.65
<tb> Blue <SEP> 3 <SEP> 640 <SEP> 2.29 <SEP> 20.89 <SEP> 640 <SEP> 2.43 <SEP> 19.58
<tb> Blue <SEP> 4 <SEP> 600 <SEP> 1.65 <SEP> 29.31 <SEP> 600 <SEP> 2.02 <SEP> 23.76
<tb> Blue <SEP> 5 <SEP> 600 <SEP> 1.61 <SEP> 30.06 <SEP> 600 <SE> 1.76 <SEP> 27.41
<tb> Blue <SEP> 6 <SEP> 560 <SEP> 2.09 <SEP> 22.93 <SEP> 520 <SEP> 2.35 <SEP> 20.28
<tb> Gray <SEP> 1 <SEP> 700 <SEP> 3.70 <SEP> 12.53 <SEP> 700 <SEP> 3.58 <SEP> 12.98
<tb> Black <SEP> 1 <SEP> 600 <SEP> 2.58 <SEP> 18.39 <SEP> 700 <SEP> 2.48 <SEP> 19.17
<tb> Black <SEP> 2 <SEP> 600 <SEP> 2.44 <SEP> 19.50 <SEP> 700 <SEP> 2.32 <SEP> 20.56
<tb> Black <SEP> 3 <SEP> 600 <SEP> 2.63 <SEP> 18.02 <SEP> 700 <SEP> 2.33 <SEP> 20.47
<tb> Black <SEP> 4 <SEP> 600 <SEP> 2.49 <SEP> 19.09 <SEP> 700 <SEP> 2.36 <SEP> 20.20
<Tb>
If we consider a relative difference in color yield equal to 5% to be perceptible, we can classify the dyestuffs tested as follows: - Dyes whose yield is significantly improved
by oxidation at
Yellow 1 - Red 1 - Yellow 2 - Brown 1 - Brown 2 - Green 1
Green 3 - Black 2 - Black 3 - Black 4.

- Colorants whose yield is not significantly modified:
Orange 1 - Brown 3 - Brown 5 - Brown 6 - Brown 7 - Blue 1
Gray 1 - Black.

- dyes whose yield decreases significantly by
ratio to the oxidized dichromate control 6.2. Solidity analysis
The results concerning the solidities tested are summarized in Tables V and VI, respectively for dichromate oxidation and oxygen oxidation.

 The washing and rubbing fastnesses are rated 1 to 5 with respect to the normalized gray scale, with the corresponding upper rating being X no degradation or disgorging.

 The light fastnesses are rated from 1 to 8 in the range of blues simultaneously exposed to the samples for 220 hours on Original Hanau Xenotest apparatus (the rating of 8 represents the maximum score for this type of test).

TABLE V
SOLIDITIES: BICHROMATE OXIDE SAMPLES

Solidity <SEP> at <SEP> wash <SEP> at <SEP> 60 C <SEP> Strength <SEP> at
<tb> Reference <SEP> of <SEP> Solidity <SEP> friction
<tb> Dega <SEP> the <SEP> Disgorging
<tb><SEP> dyes <SEP> dation
<tb> light
<tb><SEP> Cotton <SEP> Viscose <SEP> Dry <SEP> Wet <SEP>
<tb> Yellow <SEP> 1 <SEP> 3 <SEP> 2 <SEP> 2 <SEP> 2-3 <SEP> 4-5 <SEP> 2
<tb> Red <SEP> 1 <SEP> 3-4 <SEP> 3-4 <SEP> 3-4 <SEP> 4 <SEP> 4-5 <SEP> 2-3
<tb> Yellow <SEP> 2 <SEP> 2-3 <SEP> 2 <SEP> 2 <SEP> 2-3 <SEP> 4-5 <SEP> 2
<tb> Orange <SEP> 1 <SEP> 3-4 <SEP> 2-3 <SEP> 2 <SEP> 2 <SEP> 4-5 <SEP> 2
<tb> Brown <SEP> 1 <SEP>><SEP><SEP> 6 <SEP> 3 <SEP> 2-3 <SEP> 2-3 <SEP> 4-5 <SEP> 2
<tb> Brown <SEP> 2 <SEP> 4 <SEP> 1-2 <SEP> 2 <SEP> 2 <SEP> 4-5 <SEP> 2-3
<tb> Brown <SEP> 3 <SEP>: <SEP><SEP> 6 <SEP> 3-4 <SEP> 3 <SEP> 4 <SEP> 3 <SEP> 1 <SEP>
<tb> Brown <SEP> 4 <SEP> 5 <SEP> 3-4 <SEP> 3-4 <SEP> 4 <SEP> 4-5 <SEP> 2-3
<tb> Brown <SEP> 5 <SEP># 6 <SEP><SEP> 4 <SEP> 2-3 <SEP> 3-4 <SEP> 4-5 <SEP> 2
<tb> Green <SEP> 1 <SEP> || <SEP>#<SEP>#<SEP> 6 <SEP> 2-3 <SEP> 2 <SEP> 2-3 <SEP> 4-5 <SEP> 2
<tb> Green <SEP> 2 <SEP> 5 <SEP> 2-3 <SEP> 2-3 <SEP> 3 <SEP> 4-5 <SEP> 3-4
<tb> Green <SEP> 3 <SEP>#<SEP><SEP> 6 <SEP> 3-4 <SEP> 2-3 <SEP> 3-4 <SEP> 4-5 <SEP> 1-2
<tb> Green <SEP> 4 <SEP> 5 <SEP> 2-3 <SEP> 3 <SEP> 3-4 <SEP> 4-5 <SEP> 2
<tb><SEP> Brown <SEP> 6 <SEP> 4 <SEP> 3 <SEP> 2-3 <SEP> 3-4 <SEP> 4-5 <SEP> 2
<tb><SEP> Brown <SEP> 7 <SEP> 1 <SEP> 2-3 <SEP> 2 <SEP> 3 <SEP> 4-5 <SEP> | <SEP> 2
<tb><SEP> Blue <SEP> 1 <SEP> 5-6 <SEP> 3 <SEP> 3 <SEP> 3-4 <SEP> 4-5 <SEP> 1-2
<tb> Blue <SEP> 2 <SEP> 4-5 <SEP> 4 <SEP> 3 <SEP> 3 <SEP> 3-4 <SEP> 1 <SEP>
<tb> Blue <SEP> 3 <SEP> 4 <SEP> 3 <SEP> 2 <SEP> 2-3 <SEP> 4-5 <SEP> 1-2
<tb> Blue <SEP> 4 <SEP> 4-5 <SEP> 3-4 <SEP> 3 <SEP> 4 <SEP> 4 <SEP> 1-2
<tb> Blue <SEP> 5 <SEP>#<SEP> 6 <SEP> 3-4 <SEP> 2-3 <SEP> 3 <SEP> 4-5 <SEP> 2
<tb> Blue <SEP> 6 <SEP> 5-6 <SEP> 3 <SEP> 2-3 <SEP> 3-4 <SEP> 3 <SEP> 1-2
<tb> Gray <SEP> 1 <SEP>#<SEP> 6 <SEP> 6 <SEP><SEP> 2-3 <SEP> 2 <SEP> 2 <SEP> 3-4 <SEP> 1-2
<tb> Black <SEP> 1 <SEP>#<SEP><SEP> 6 <SEP> 3 <SEP> 2-3 <SEP> 3 <SEP> 3 <SEP> 1-2
<tb> Black <SEP> 2 <SEP>#<SEP><SEP> 6 <SEP> 6 <SEP> 3 <SEP> 3 <SEP> 3-4 <SEP> 4 <SEP> 1-2
<tb><SEP> Black <SEP> 3 <SEP>#<SEP> 6 <SEP> 6 <SEP> 3-4 <SEP> 2-3 <SEP> 3 <SEP> 3 <SEP> 1-2
<tb> Black <SEP> 4 <SEP> 7/6 <SEP> 3-4 <SEP> 2-3 <SEP> 3 <SEP> 4 <SEP> 1-2
<Tb>
TABLE VI
SOLIDITIES: OXYGEN OXIDE SAMPLES

<tb><SEP> Strength <SEP> at <SEP> wash <SEP> at <SEP> 60 C
<tb> Solidity <SEP> Solidity <SEP> to
<tb> Reference <SEP> of
<tb><SEP> to <SEP> the <SEP> friction
<tb> Disgorging
<tb><SEP> dyes <SEP> light <SEP> Degradation
<tb><SEP> Cotton <SEP> Viscose <SEP> Dry <SEP> Humid @
<tb><SEP> Yellow <SEP> 1 <SEP> 4 <SEP> 2 <SEP> 3 <SEP> 3 <SEP> 3 <SEP> 1-2
<tb><SEP> Red <SEP> 1 <SEP> 3-4 <SEP> 4 <SEP> 4 <SEP> 4-5 <SEP> 4-5 <SEP> 3
<tb><SEP> Yellow <SEP> 2 <SEP> 3-4 <SEP> 1-2 <SEP> 3 <SEP> 3 <SEP> 3-4 <SEP> 2
<tb> Orange <SEP> 1 <SEP> 4-5 <SEP> 3 <SEP> 3-4 <SEP> 3-4 <SEP> 3 <SEP> 2
<tb> Brown <SEP> 1 <SEP>#<SEP><SEP> 6 <SEP> 3-4 <SEP> 3-4 <SEP> 3-4 <SEP> 4 <SEP> 2
<tb> Brown <SEP> 2 <SEP> 4-5 <SEP> 2-3 <SEP> 3 <SEP> 3 <SEP> 3-4 <SEP> 2
<tb> Brown <SEP> 3 <SEP> 6 <SEP> | <SEP> 4-5 <SEP> 3-4 <SEP> 4 <SEP> 3 <SEP> 1
<tb> Brown <SEP> 4 <SEP> 5-6 <SEP> 3-4 <SEP> 4 <SEP> 4-5 <SEP> 4 <SEP> 2-3
<tb> Brown <SEP> 5 <SEP>;<SEP><SEP> 6 <SEP> 4 <SEP> 3 <SEP> 3-4 <SEP> 4-5 <SEP> 2
<tb> Green <SEP> 1 <SEP>#<SEP><SEP> 6 <SEP> 2-3 <SEP> 2-3 <SEP> 3 <SEP> 3 <SEP> 2
<tb> Green <SEP> 2 <SEP> 5-6 <SEP> 3 <SEP> 3 <SEP> 3-4 <SEP> 4-5 <SEP> 3-4
<tb> Green <SEP> 3 <SEP>#<SEP><SEP> 6 <SEP> 3-4 <SEP> 4 <SEP> 4-5 <SEP> 4-5 <SEP> 2
<tb> Green <SEP> 4 <SEP> 5-6 <SEP> 2-3 <SEP> 3-4 <SEP> 4 <SEP> 3-4 <SEP> 2-3
<tb> Brown <SEP> 6 <SEP> 4 <SEP> 3 <SEP> 3-4 <SEP> 4 <SEP> 3-4 <SEP> 2
<tb> Brown <SEP> 7 <SEP> 3-4 <SEP> 2-3 <SEP> 3 <SEP> 3-4 <SEP> 3-4 <SEP> 2
<tb><SEP> Blue <SEP> 1 <SEP> 6 <SEP> 4 <SEP> 3-4 <SEP> 3-4 <SEP> 4-5 <SEP> 1-2
<tb> Blue <SEP> 2 <SEP> 5-6 <SEP> 4 <SEP> 4 <SEP> 3-4 <SEP> 4 <SEP> 1-2
<tb> Blue <SEP> 3 <SEP> 5-6 <SEP> 3-4 <SEP> 3 <SEP> 3 <SEP> 4-5 <SEP> 2
<tb> Blue <SEP> 4 <SEP> 5-6 <SEP> 4 <SEP> 4 <SEP> 4 <SEP> 4-5 <SEP> 1-2
<tb> Blue <SEP> 5 <SEP>#<SEP><SEP> 6 <SEP> 3-4 <SEP> 3-4 <SEP> 3-4 <SEP> 4-5 <SEP> 2
<tb> Blue <SEP> 6 <SEP> 5-6 <SEP> 3-4 <SEP> 3 <SEP> 3 <SEP> 4-5 <SEP> 1-2
<tb><SEP> Gray <SEP> 1 <SEP>#<SEP> 6 <SEP> 4 <SEP> 3-4 <SEP> 4 <SEP> 4-5 <SEP> 1-2
<tb><SEP> Black <SEP> 1 <SEP>#<SEP> 6 <SEP> 4 <SEP> 3-4 <SEP> 4-5 <SEP> 4-5 <SEP> 1-2
<tb><SEP> Black <SEP> 2 <SEP> 6 <SEP> 4 <SEP> 4 <SEP> 4-5 <SEP> 4-5 <SEP> 1-2
<tb><SEP> Black <SEP> 3 <SEP>#<SEP> 6 <SEP> 4-5 <SEP> 3-4 <SEP> 4-5 <SEP> 4-5 <SEP> 1-2
<tb><SEP> Black <SEP> 4 <SEP> 7 <SEP> 6 <SEP> 4 <SEP> 3-4 <SEP> 4-5 <SEP> 4-5 <SEP> 1-2
<Tb>
From the point of view of light fastness, the oxygen-oxidized samples have a level generally higher by + 1 point than that of the dichromate-oxidized samples. In the case of the Brown 7 and Blue 3 dyes, the improvement provided by the oxygen oxidation method can respectively reach 2.5 and 1.5 points.

With regard to the washing fastnesses b 60 C, and more particularly with regard to the degradation of the colors, the solidity levels of the samples oxidized with oxygen are at least equal. those obtained by oxidation in dichromate, and even generally superior by a + point to 1.5 points (case of the dye Gray 1), and that except for a single dye (yellow 2) whose degradation drops half a point if the oxidation is carried out with oxygen. From the point of view of disgorging, and apart from the case of the dye
Blue 6 (disgorging on viscose), the levels of solidities obtained with oxygen are systematically superior to those obtained with the dichromate, the difference being sometimes very important and being able to reach 1,5 to 2 points in particular in the case of certain dyes blue and gray and black dyes.

 From the point of view of frictional fastnesses and if these are carried out in the dry state, different behaviors can be observed depending on whether the oxidation is carried out using oxygen or dichromate: Oxygen causes a decrease in the solidities of yellow, brown and green dyes, while improving the fastness of blue and black dyes. In the wet state, on the other hand, the solidities obtained are identical in both cases.

Claims (7)

 1. Process for the oxidation of sulfur dyes on natural and synthetic textile fibers, characterized in that an oxygen enrichment of the oxidation bath is carried out.  2. Process for oxidation of sulfur dyes according to claim 1 characterized in that the oxidation is carried out by means of water supersaturated with oxygen.  3. Process for oxidation of sulfur dyestuffs according to claim 1 or 2, characterized in that the oxidation treatment is carried out at acidic pH, in a temperature range between about 30 and about 700 ° C., the concentration of dissolved oxygen of the treatment bath being at least 20 mg / l of oxygen.  4. Process for oxidation of sulfur dyes according to claim 3, characterized in that the oxidation treatment is conducted at pH 3.5, at a temperature of 700 C, with a dissolved oxygen concentration of 30 mg / liter.  5, Process for oxidation of sulfur dyes according to any one of claims 1 to 4, characterized in that the oxygen-enriched aqueous solution is injected into the oxidation compartment,  6. Process for oxidation of sulfur dyes according to claim 5, characterized in that the enriched oxygen solution is introduced with a flow rate of between 1 z 2 m3 / hour.  7. Process for oxidation of sulfur dyes according to any one of claims 1 9 4, characterized in that the solution enriched with oxygen is sent against the current from the oxidation bath to rinsing.  8. Oxidation process according to claim 7, characterized in that the oxygen-enriched solution is sent at a rate of 5 m3 per ton of treated fabric.  9. Oxidation process according to claim 5 or 6, carat térise in that the oxygen-enriched solution is introduced at 1 to 2 m3 per tonne of treated fabric.