JPH06212084A - Dry leuco sulfur dye - Google Patents

Abstract

(57) [Summary] [Object] To provide a method for producing a water-soluble dry leuco sulfur dye. [Structure] At a temperature of 60 ° C. or higher in an aqueous medium, a sulfur dye (S) and an effective amount of (A) a reducing carbonyl compound,
A method comprising reacting in the presence of (B) an alkali metal hydroxide and optionally (C) an alkali metal sulfite and / or an alkali metal hydrogen sulfite and drying by spray drying with a drying time of less than 4 minutes.

Description

Detailed Description of the Invention

GB-A-2255981 (corresponding to Japanese Examined Patent Publication No. 5-140469) British Patent Application No. 92 10931.3 discloses a sulfur dye as an effective amount of a reducing carbonyl compound at a temperature of 60 ° C. or higher in an aqueous medium. Dry water solubility by reacting in the presence of an alkali metal hydroxide, and optionally an alkali metal sulfite and / or an alkali metal hydrogen sulfite, and drying (wherein this reaction and drying may be at least partly simultaneous) The production of leuco sulfur dyes is disclosed.

It has been found that when the reaction mixture is dried by spray drying, especially by hot gas spray drying, the drying, preferably the reaction and the drying, can be carried out in a very short time of less than 4 minutes, in particular of a few seconds.

The present invention relates to this spray-drying process, its dry product and its use in dyeing.

The present invention comprises a sulfur dye (S) in an aqueous medium at a temperature of 60 ° C. or higher, an effective amount of (A) a reducing carbonyl compound, (B) an alkali metal hydroxide and optionally (C).
Provided is a method for producing a water-soluble dry leuco sulfur dye (L), which comprises reacting in the presence of an alkali metal sulfite and / or an alkali metal hydrogen sulfite and drying by spray drying with a drying time of less than 4 minutes.

The components (S), (A), (B) and (C) and their amounts, and the reaction conditions when the reaction and the drying are carried out independently, are defined in the above GB-A-2255981. (S) may be any commercially available sulfur dye or may be an optionally oxidised and / or acidified vulcanization reaction product, preferably a wet, preferably washed filter cake Is the shape of. (A) is a monomeric or oligomeric keto or aldosaccharide or hydroxyacetone, preferably a monomeric aldopentose or hexose. As (B) and (C), lithium, sodium or potassium compounds may be used, and of these, sodium compounds are preferable. (A) is
It is preferably used in an amount of 1 to 40% by weight, more preferably 5 to 15% by weight, based on the weight of (L), and the weight ratio (A) / (S) is preferably 5/100 to 40/100, More preferably 10 / 100-20
/ 100. The weight ratio (B) / (S) is preferably in excess of (B)
Is present in the final product, preferably 0.5-20, more preferably 3-10% by weight, based on the weight of (L).
Is. (C) is advantageously used in an amount of 1 to 40% by weight, preferably 2 to 24% by weight, more preferably 5 to 10% by weight, based on the weight of (L), the weight ratio (C) / (S ) Is preferably 5/10
It is 0 to 40/100, more preferably 10/100 to 20/100. The weight ratio (A) / (C) is preferably 1/5 to 5/1, more preferably 2/1 to 1/2. The amount of water in the composition to be dried, i.e. the total water content of the reaction mixture at the beginning of the drying, is at least such that the mixture can be easily sprayed and the aqueous phase shows a continuous phase, preferably 95 % Or less, preferably 10 to 90% by weight, more preferably 20 to 80% by weight, as shown in GB-A-2255981 above.

Drying may be carried out by conventional spray-drying systems, for example by spray freeze-drying (if the reaction has been terminated before drying) or preferably by hot gas (G).

As the gas (G), under spray drying conditions
Gases which are substantially inert to (L), ie do not undergo chemical modification of the product (L) during spray drying, are considered. As (G), nitrogen, superheated steam and / or air are considered, for example. For the production of leuco sulfur dyes (L) which are easily oxidized by hot air, this gas is preferably a substantially oxygen-free inert gas, preferably nitrogen or a blend of air and nitrogen, in a spray dryer. For leuco sulfur dyes that are more resistant to air oxidation so that they are not degraded by short hot air treatments at low temperatures, such as those with a high limit of initial oxidation by hot air (eg, Color Index Leuco Sulfide Black 1 and 2), ) May be hot air. The use of hot air is usually preferred for economic reasons. The suitability for a given dye (S) and (L) in spray drying is confirmed by preliminary tests. Most preferably (G) is nitrogen.

Particularly preferably, the drying is carried out with the hot gas (G) at least partly simultaneously with the reduction reaction, most preferably the reduction reaction and the drying are carried out simultaneously and the water content of the reaction mixture is dried. Equivalent to the water content of.

Drying may be carried out at temperatures as indicated in GB-A-2255981 or higher, depending on the drying system in the spray dryer. The hot gas (G) inlet temperature to the dryer (ie, the temperature at which (G) enters the spray dryer) should be a convenient temperature, especially 70 ° C.
Higher, advantageously above 105 ° C., preferably above 150 ° C., the upper limit of the inflow temperature of (G) mainly depends on the characteristics and size of the dryer, advantageously below 300 ° C., preferably
It is 280 ℃ or less. The preferred temperature range for the inflow of (G) into the spray dryer is 150 to 300 ° C, especially 165 to 300 ° C.
Preferably, (G) is introduced into the dryer at a temperature (D) above the boiling point of water at which the drying is carried out, in particular from 105 to 300 ° C, most preferably from 150 to 280 ° C, especially above 200 ° C.

The gas (G) is introduced into the dryer at a suitable pressure, for example 2 to 50, preferably 2.5 to 25, more preferably 3 to 12 kg / cm ² .

The mixture to be dried is preferably introduced at elevated temperature into the spray dryer, which temperature is below the boiling point of the mixture,
It is preferably from 50 to 100 ° C, advantageously from 70 to 98 ° C, most preferably from 85 to 98 ° C. Drying in a spray drier is preferably such that the temperature of the effluent gas (G) (ie the temperature at which (G) exits the spray drier) is preferably between 60 and 180 for hot air and / or nitrogen. ℃, preferably 100 ~ 150 ℃, for superheated steam 105 ~ 250 ℃, preferably 150 ~ 240
The conditions and parameters are such that the temperature is ° C. The dryer is preferably increased in temperature between the orbits of the sprayed particles in the dryer and the temperature at which the mixture to be dried flows into the dryer, preferably 10 to 60 ° C.,
More preferably the particles dried at a temperature of 15-40 ° C. higher are operated to leave the dryer.

The spray dryer may be conventional, such that the liquid composition to be spray dried is sprayed onto the dryer by spraying, in particular nozzle spraying, rotary spraying or ultrasonic spraying. Hot gas (G) is supplied to the atomized particles in cocurrent or countercurrent. According to one preferred method, spray drying is carried out by injection spray. Another preferred method is by rotary atomization, especially vertical rotary atomization (eg by turbine).

Nozzles or other feed devices (eg cups, disks, turbines) for spraying the composition onto the dryer are selected to suit the composition introduced. In particular, when the composition to be sprayed is a (S) -containing dispersion, the type, shape and size of the spraying device are chosen to be compatible with the dispersion to be sprayed. Due to the preferred features of this process, (S) -containing aqueous compositions, especially those containing a sulfur dye (S) not yet reduced by (A), are advantageously
In the presence of at least a part of (B), preferably
Without (A) and (B), it is preheated to a suitable temperature to make a liquid or fluid for atomization. This suitable temperature is below 100 ° C, especially 50 to 98 ° C, preferably 60 to 95 ° C.
Is. This is preferably done so that (S) does not react with (L) at this stage, but is solubilized by (B). Suitably (A) and optionally (C) is a preheated aqueous mixture of (S) and (B) just before being fed to the spray dryer, where (S) is preferably by (B). Is melted).

The drying time, in particular the reaction and drying time, is advantageously less than 2 minutes, preferably 1-60 seconds, more preferably 2 minutes.
~ 30 seconds. The feed rate of the composition to be dried depends on other parameters and the water content of the composition, but is for example 100 to 10,000, preferably 200 to 5000 liters / hour, for example about 4 m ³ / h, and the capacity of the dryer. It also depends on

When the reaction in the hot gas (G) and the spray drying are carried out at least in part simultaneously, more preferably, the mixture of reactants which has not yet reacted is sprayed into the dryer and the reduction reaction is carried out in the dryer. (B) and if desired
The reaction of (S) and (A) in the presence of (C) occurs on each atomized particle during the drying process of atomized droplets, drying the water soluble leuco sulfur dye (L) in seconds. Give the particles that have been treated. Especially when the composition contains unreacted sulfur dye (S), the sulfur dye (S) gradually becomes a more soluble reaction product (L) during the drying process of the particles passing through the hot gas (G). , Which is at least partially dissolved in the water present in the particles, but this water evaporates during the drying process, causing the concentration of (L) to occur outside the particles during drying, The water present inside the particles facilitates the further reaction of the existing (S), and at the end of the drying of the particles the reaction of (S) to (L) within each particle is virtually complete.

The reaction takes place surprisingly completely and the product obtained is a granular water-soluble dry leuco sulfur dye (L), preferably of castable particle size.

The dry product, in particular the dry product (L), has a water content of not more than 5% by weight, preferably not more than 2% by weight, based on the weight of the product (L), obtained by the above drying process. It means a solid leuco sulfur dye, and more preferably has a residual water content of 0.5% by weight or less.

Depending on the system and structure of the spray dryer and the operating parameters used, the shape, size and consistency of the dry particles obtained will vary, eg hard porous particles and / or hollow particles and / or crushed particles and And / or dented particles or flakes or other shapes. Depending on the structure and operating conditions of the spray dryer,
Dried products are obtained in various sizes, especially 1 μm
.About.2 mm, for example 1 to 20 .mu.m in the preferred spray system. If the dried product is of very small size, especially if it is a fine powder with a particle size of less than 5 μm or less than 10 μm, a larger, preferably 0.01-
10 mm, more preferably 0.01-4 mm, especially 0.05-4 mm
It is advantageous to agglomerate into agglomerates of particles, so that a substantially non-dusting product is obtained, for example in the form of flakes or particles, most preferably a size of 0.2 to 2 mm.

If desired, a suitable agglomeration system may be installed directly at the outlet of the dryer so that the fine powder is sent directly to the agglomerator. This is a conventional suitable system such as a mixer, granulator, spheronizer (sph).
eronizer) or other system suitable for providing particles of the desired size. For aggregating fine powder into larger particles, suitable, preferably non-aqueous, water-soluble additive ones, was particularly known as dusting preventing additive, such as glycerin, C ₂ - ₄ alkylene glycol, oligo - (C _2-4 alkylene) -glycol ether and its C
_1-4 alkyl monoethers, preferably mono or dipropylene glycol monomethyl ether are used. These anti-dust additives are very small, especially (L)
0.5 to 8, preferably 1 to 4 parts by weight of the additive per 100 parts by weight of. Selection of the optimum amount depends on the size and shape of the powder particles, as well as the desired size and consistency of the agglomerated product, as well as the system used.

Due to the subsequent agglomeration by the anti-dusting additive, the dried powder at the outlet of the spray dryer is preferably cooled to a temperature below 100 ° C., for example 50 to 100 ° C.

The dried product (L) obtained is virtually free of inorganic sulphides, stable to air oxidation and, moreover, rapidly converted to water even at temperatures below 40 ° C., for example between 5 and 25 ° C. It dissolves and is therefore suitable for direct use in dyeing, in particular cold dyeing and the production of stock solutions.

Leuco sulfur dye (L) obtained by the present invention
Is suitable for dyeing any base material that can be dyed with a sulfur dye using the leuco form of the sulfur dye, especially a cellulose base material, and since there is no sulfide and the solubility is good, a polyamide base material, It is particularly suitable for dyeing fibrous substrates, such as synthetic polyamide, wool and leather (for example skins containing wool) fibrous substrates, of which wool is particularly preferred. Dyeing is carried out by conventional methods, in particular by impregnation with an impregnation composition containing (L), preferably by heat treatment of the impregnated substrate (eg by superheated steam).
And by final oxidation from the leuco stage to the sulfur dye stage or by discharge from the (L) -containing liquid (advantageously in the presence of the electrolyte, eg sodium sulphate) and oxidation from the leuco stage to the sulfur dye stage. . The dye liquor preferably contains antioxidants such as reducing sugars, hydroxyacetone, thiourea dioxide, sodium bisulfite and / or formaldehyde sulfoxylate. Dyeing of a polyamide substrate is carried out in an aqueous medium under mildly acidic to weakly basic conditions, for example, 6 to
At a pH of 8.5, preferably 6.5 to 8.5, it is carried out under suitable temperature conditions, advantageously below 100 ° C., preferably 40 to 90 ° C., especially 70 to 85 ° C., and after washing the leuco shape is on the substrate. With an oxidizing agent, preferably H ₂ O ₂ , at mildly acidic conditions (eg with acetic acid), preferably at a temperature of 30-60 ° C., more preferably 35-50 ° C., for a short time, eg 10
Oxidation to sulfur dye form is carried out by treatment for seconds to 10 minutes, preferably 30 seconds to 4 minutes. The leuco sulfur dye (L) is used in a concentration suitable for the substrate and the desired color strength. Leuco sulfur dye
(L) gives, for example, an aqueous solution with a concentration of 50 to 100 g / l or higher.

Dyeings with strong shades and outstanding fastnesses, in particular light and wet fastnesses, are obtained. Dried product (L)
Is substantially free of inorganic sulfides, so no sensory perceptible H ₂ S is generated during dyeing. The discharged mother liquor is further reused for dyeing, and / or the residual (L) in the residual liquor (eg from washing) is precipitated and separated by known methods, for example by desolvation with polyvalent metal ions or mineral acids. To be done.

The stock solution is stable for several hours without forming an oxide film. This dyeing method can be performed without substantially forming oxidized deposits on the dyeing machine.

The following examples illustrate the invention, in which percentages are percentages by weight and temperatures are in degrees Celsius.

Example 1 200 g of 2,4-dinitrochlorobenzene were reacted with 169 g of 50% aqueous sodium hydroxide solution at 100 ° C. for 2 hours.
The product obtained is added to a mixture of a solution of 200 g of sodium sulphide in 200 g of water and 200 g of sulfur and this mixture is added to
Heat to 120 ° C. and reflux at this temperature for 10-15 hours. The mixture was then diluted with 200 g of water and aerated by bubbling air through the solution until the dye had precipitated.
The resulting mixture is then filtered, washed with water, 40-60%
A filter cake of black dye having a water content of was obtained. The filter cake obtained is mixed with 120 g of 50% aqueous sodium hydroxide solution and the mixture is heated to 90 ° C.
G of glucose and 28 g of sodium bisulfite were added and the resulting mixture was immediately injected at a feed rate of 445 liters / hour through an injection spray nozzle into a hot air spray dryer. Air was introduced at an overpressure of 4-7 lg / cm ² and a temperature of 165 ° C. Outflow air was 118 ° C. Drying is complete after 5 to 15 minutes and the temperature of the dried product at the outlet is 105-110 ° C.
Met. The product exiting the drier was a fine powder with a particle size of 5-10 μm.

Example 2 Example 1 was repeated with 100 times the amount (particularly the components and feed ratios) under industrial scale conditions with an inlet air temperature of 220 ° C and an outlet air temperature of 120 ° C.

Example 3 Example 2 was repeated except that hot nitrogen was used instead of hot air as the hot gas (G).

Example 4 Example 3 was repeated except that the nitrogen inlet temperature was 280 ° C and the nitrogen outlet temperature was 105 ° C.

Example 5 Example 3 was repeated except that the nitrogen inlet temperature was 300 ° C and the nitrogen outlet temperature was 110 ° C. The reaction mixture used in the above example was GB-A 2255981.
9 is an undried mixture of Example 8. The other undried mixtures exemplified in GB-A 2255981 in each of Examples 1-7, 9-14 and 8-2-4 are dried in the same manner as in Examples 1-5 above.

Example 6 The powders obtained in Examples 1-5 are mixed with 2% of dipropylene glycol monomethyl ether in a mixer to give 0.2-2.
A particle size aggregate of mm was obtained. All the products obtained were readily soluble in water and contained no inorganic sulfides.

Application Example A 5 g of the dry product obtained in Example 1 was dissolved in 90 g of water for 5 minutes and 2.5 g of glucose and 2 g of 50% aqueous sodium hydroxide solution were added. Dip a piece of cotton cloth in this solution and
% Soaked, steamed at 102 ° C. for 1 minute and then washed. Due to oxidation, this cloth was treated with 5 g / l at 40 ° C for 1 minute.
Treated with an aqueous solution containing 30% H ₂ O ₂ and 80% acetic acid 5 g / l,
It was then washed and dried. A deep black dyeing is obtained.

Application Example B 0.7 g of the black dry product of Example 1 was mixed with 4 g of sodium sulphate and
Dissolved in 200 g water containing 0.5 g thiourea dioxide. Ten
g cotton cloth in this liquid at 75-80 ° C, pH 6.5-8.
Stain for 1 hour at 5 (adjusted with acetic acid if necessary). The treated wool was then washed and oxidized as in Application Example A. Finally, the dyed wool was washed and dried.
A deep black wool dyeing having outstanding wetness and light fastness is obtained.

Similar to the dried product of Example 1, the dried product of each of Examples 2, 3, 4, 5 or 6 above, or GB
-A 2255981, the respective products obtained by drying the non-dried mixture illustrated in each of Examples 1-7, 9-14 and 8-2 by the drying method according to Example 3 or 4 above. Used in A and B, dyeings of corresponding hue and fastness were obtained.

Claims (12)

[Claims] 1. A process for producing a water-soluble dry leuco sulfur dye (L), which comprises adding an effective amount of a sulfur-containing dye (S) to a reducing carbonyl compound (A) at a temperature of 60 ° C. or higher in an aqueous medium.
A method comprising reacting in the presence of (B) an alkali metal hydroxide and optionally (C) an alkali metal sulfite and / or an alkali metal hydrogen sulfite and drying by spray drying with a drying time of less than 4 minutes. 2. The method according to claim 1, wherein the spray drying is carried out with hot gas (G). 3. The method according to claim 2, wherein the hot gas (G) is hot air or hot nitrogen. 4. A process according to claim 1, wherein the aqueous mixture is sprayed on the dryer by atomization. 5. The gas (G) inflow temperature is less than 150 ° C.,
The method according to claim 2. 6. The method according to claim 1, wherein the drying is performed at least partially at the same time as the reduction reaction. 7. The method according to claim 1, wherein the reduction reaction and the drying are performed in less than 2 minutes. 8. The method according to claim 1, wherein the obtained dry particles are agglomerated into particle agglomerates having a size of 0.01 to 4 mm. 9. A dry leuco sulfur dye (L) obtained by the method according to any one of claims 1 to 8. 10. Treated with a leuco form of a sulfur dye,
A method for dyeing a substrate which can be dyed with a sulfur dye by oxidizing the leuco dye to a sulfur dye dye, wherein the leuco sulfur dye (L) according to claim 9 is used as the leuco sulfur dye. 11. A method according to claim 10 for dyeing a polyamide fiber substrate. 12. A method according to claim 11 for dyeing wool.