Aqueous liquid composition of vinylsulfone type reactive dyes in lithium salt form and buffer

An aqueous liquid dye composition comprising a dye represented by the following formula in a free acid form, ##STR1## wherein Y is --CH.dbd.CH.sub.2 or --CH.sub.2 CH.sub.2 X in which X is a group splittable by the action of an alkali, and a pH buffer, the dye being in the form of a lithium salt, and the liquid dye composition having a pH value of from 3 through 7 and a dye content of from 5 through 50% by weight based on the weight of the liquid dye composition, which can be stored stably for a long period of time even at a low temperature such as 0.degree. C. or lower, and a high temperature such as 40.degree. C. or higher.

The present invention relates to an aqueous liquid composition of an 
anionic dye. More specifically, the present invention relates to an 
aqueous liquid composition of a vinylsulfone type reactive dye excellent 
in storage stability. 
Industrial dyeing or printing of fiber materials with anionic dyes has been 
carried out usually in an aqueous medium. Therefore, the anionic dyes 
commercially available in the form of powder or granule must be dissolved 
in the aqueous medium using hot water, when used for the dyeing or 
printing. 
In recent years, dyeing or printing systems in a dye house have been 
eagerly required to be made into a form suitable for an automatic weighing 
and dispensing system. 
An aqueous liquid composition of the dye is now considered to be very 
favorable, because it is suitable for the automatic weighing and 
dispensing system and causes no powder-scattering on the handling, 
resulting in no pollution of a working environment, and moreover it can 
serve saving energy and labor. Thus, it has been increasingly required to 
manufacture an aqueous liquid dye composition without any problem from 
industrial point of view. 
As well known, the aqueous liquid dye composition can be relatively easily 
manufactured, where the dye has a high solubility in water. However, there 
are many anionic dyes insufficient in the solubility. In order to improve 
the solubility of such dyes, there have heretofore been proposed to use a 
hydrotropic agent as disclosed in Published Examined Japanese Patent 
Application No. 8369/1984, and to effect demineralization by passing an 
aqueous dye solution through a reverse osmotic membrane as disclosed in 
Published Unexamined Japanese Patent Application No. 16522/1972. 
Meanwhile, vinylsulfone type reactive dyes having the following formula (I) 
in a free acid form, 
##STR2## 
where Y is --CH.dbd.CH.sub.2 or --CH.sub.2 CH.sub.2 X in which X is a 
group splittable by the action of an alkali or a halogen atom, which are 
known as C.I. Reactive Orange 7, C.I. Reactive Orange 16 and the like, 
have been manufactured industrially in the form of a sodium or potassium 
salt, and widely used for dyeing or printing fiber materials, particularly 
cellulose fiber materials. However, all of said reactive dyes are low in 
the solubility, so that an aqueous liquid dye composition having a low 
content of the dye, which is therefore of no value from industrial 
viewpoint, can only be obtained even in the conventional manners such as 
addition of hydrotropic agents or demineralization. Moreover, the aqueous 
liquid dye composition obtained in such manners has drawbacks such that it 
is easy to precipitate the dye crystals at a relatively low temperature 
such as 10.degree. C. or lower, under conditions of which the dye 
composition may often be shipped or stored, or it is easy to deteriorate 
the dye contained therein or change the liquid state at a relatively high 
temperature such as 40.degree. C. or higher, even though such liquid dye 
composition is stable at ordinary temperature. 
The present inventors have undertaken extensive studies to solve the 
problems as described above, and found that the problems can be solved by 
providing an aqueous liquid composition comprising the dye of the formula 
(I) in the form of a lithium salt and a pH buffer, the composition being 
controlled within a specific pH range. 
The present invention provides an aqueous liquid dye composition comprising 
the dye represented by the aforesaid formula (I) in a free acid form and a 
pH buffer, the dye being in the form of a lithium salt, and the liquid dye 
composition having a pH value of from 3 through 7 and a dye content of 
from 5 through 50% by weight based on the weight of the liquid dye 
composition. 
In the present invention, the dye of the formula (I) in the form of a 
lithium salt can be used in each alone or preferably in a mixture of two 
or more. 
Examples of the dye usable in the present invention are as follows. 
##STR3## 
Of these dyes, the sulfuric acid ester type dyes of the formula (I-1) and 
(I-2) are preferably used in each alone or preferably in a mixture of the 
two. The ester type dyes (I-1) and (I-2) may contain their corresponding 
vinylsulfone type dyes (I-3) and (I-4), respectively. In the present 
invention, a mixture of the ester type dyes (I-1) and (I-2) and the 
vinylsulfone types dyes (I-3) and (I-4) is preferably used. In this case, 
the weight ratio of the ester type dyes to the vinylsulfone types dyes 
ranges from 98:2 to 70:30, preferably from 95:5 to 75:25. 
The dye represented by the formula (I) in a free acid form is already known 
and can be produced in a conventional manner such as coupling between a 
diazonium salt of an amine represented by the following formula (II), 
##STR4## 
wherein Y is as defined above, and a coupler represented by the following 
formula (III) 
##STR5## 
which is hereinafter referred to as acetyl .gamma.-acid. 
In preparing a lithium salt of the dye, a lithium salt of acetyl 
.gamma.-acid can be used for the coupling reaction, or the dye once 
produced in the form of a sodium or potassium salt in a conventional 
manner can be subjected to salt exchange using a lithium compound such as 
lithium hydroxide, lithium carbonate and the like. 
In producing the aqueous liquid dye composition of the present invention, a 
dye-containing reaction mixture obtainable through the production process 
of the dye can be used as it is. Alternatively, a wet cake obtainable by 
salting out the dye-containing reaction mixture, followed by filtration, 
or a powder obtainable by drying the web cake, followed by pulverization, 
can be used in the form of its aqueous solution prepared by dissolving it 
in water. 
The content of the lithium salt of the dye ranges from 5 to 50% by weight, 
preferably from 15 to 40% by weight based on the weight of the aqueous 
liquid composition. 
The pH buffers usable in the present invention are at least one member 
selected from those derived from carboxylic acids and phosphoric acids. 
Particularly preferred are those derived from carboxylic acids. Examples 
of those derived from carboxylic acids are sodium, potassium and lithium 
salts of acetic acid, citric acid, oxalic acid, malic acid, malonic acid, 
phthalic acid and the like. The content of the buffer including those 
by-produced, if any, in the production process of the dye ranges from 0.1 
to 10% by weight, preferably from 0.5 to 5% by weight, based on the weight 
of the liquid dye composition. 
The pH of the aqueous liquid dye composition can be controlled with a range 
of from 3 through 7, preferably from 4 through 6, by the addition of usual 
alkalis or acids after or before incorporation of the buffer. 
The aqueous liquid dye composition in accordance with the present invention 
can additionally comprise a lactam such as .epsilon.-caprolactum, 
.gamma.-caprolactam, .delta.-caprolactam, .gamma.-valerolactam, 
.gamma.-butyrolactam and the like. Of these lactams, particularly 
preferred is .epsilon.-caprolactam. The content of the lactam ranges from 
0.1 to 20% by weight, preferably from 1 to 5% by weight, based on the 
weight of the dye composition. 
The thus prepared aqueous liquid dye composition of the present invention 
can be subjected to removal of inorganic salts which are by-products 
produced in the course of production process of the reactive dyes and/or 
the aqueous liquid dye composition (the removal being hereinafter referred 
to as demineralization). The demineralization can be carried out 
preferably by passing the liquid dye composition through a reverse osmotic 
membrane to lower the content of inorganic salts. The reverse osmotic 
membrane usable in the present invention is the one capable of permeating 
water and low molecular weight solutes such as inorganic salts including 
sodium chloride, sodium sulfate, lithium chloride, lithium sulfate and the 
like, and of rejecting the permeation of relatively high molecular weight 
solutes such as dyes and their isomeric substances. Such membrane is 
preferably asymmetric, and has 1 to 500 .ANG. in its pore size and 25 to 
95%, preferably 60 to 90%, in a rejection percent of a 0.5% aqueous sodium 
chloride solution, and is made up of cellolose acetate, polyvinylalcohol, 
polyacrylonitrile and the like. Of these, preferred is the one made up of 
polyacrylonitrile. 
In order to improve the solubility and particularly the low temperature 
storage stability of the present liquid dye composition much more, it is 
preferred to effect the demineralization so as to make each content of 
inorganic salts in the form of sodium chloride, lithium chloride, sodium 
sulfate and lithium sulfate 1% by weight or less, respectively. More 
preferably, the demineralization is effected to make the total content of 
the inorganic salts 1% by weight or less. 
The aqueous liquid dye composition in accordance with the present invention 
is improved in the solubility in water to a great degree, so that the 
liquid dye composition can be stored for a long period of time, preferably 
in a closed vessel, even at a lower temperature such as 0.degree. C. or 
lower, or a high temperature such as 40.degree. C. or higher without 
chemical and physical changes. Even after the storage, the present liquid 
dye composition can be used for dyeing or printing natural or synthetic 
fiber materials, particularly such as paper, cellulose fibers, polyamide 
fibers, wools and the like in a conventional manner, thereby giving dyed 
or printed products which are equal to those obtained using the reactive 
dye in the form of powder or granule. 
The present invention is illustrated in more detail with reference to the 
following Examples, which are only illustrative and not intended to limit 
the scope of the present invention. In Examples, parts and % are by weight 
.

EXAMPLE 1 
Into water (400 parts) of 20.degree. C. was added .gamma.-acid (119 parts), 
and then lithium hydroxide (12 parts) was added thereto to adjust the pH 
within 7 to 8, thereby forming a clear solution. Thereafter, acetic 
anhydride (58 parts) was slowly added to the solution over 1 hour, and the 
mixture was stirred for 1 hour. 
On the other hand, into water (500 parts) of 20.degree. C. were added 
4-.beta.-sulfatoethylsulfonyl-aniline (140 parts) and 35% hydrochloric 
acid (52 parts). 35% Aqueous sodium nitrite solution (99 parts) was 
dropwise added thereto over 30 minutes at 5.degree. to 10.degree. C., and 
the mixture was stirred for 1 hour at that temperature to perform 
diazotization. 
The resulting diazonium solution was added to the above acetyl 
.gamma.-acid-containing reaction mixture over 1 hour, while controlling 
the temperature within 5.degree. to 10.degree. C. Thereafter, the reaction 
mixture was adjusted to pH 5.0 using lithium hydroxide to obtain a liquid 
composition (1850 parts) containing the dye of the formula (I-1) described 
above. 
Sodium acetate (1 part) was added, and then water was added to the 
composition to make the dye content 15%. Thus, a desired liquid dye 
composition was obtained. 
The liquid dye composition was found to be stable for 6 months or more at 
20.degree. C., 1 month or more at 0.degree. C., and 2 weeks at 60.degree. 
C., respectively. 
Using the liquid dye composition which had been stored for 6 months at 
40.degree. C., a dyeing bath, padding liquor and printing paste having 
each predetermined dye concentration were prepared in each conventional 
manner respectively. Using them, cotton was dyed to obtain each dyed 
product of an orange color with a good dyeing affinity, which was not 
different from those dyed using a dye bath, padding liquor and printed 
paste having the same dye concentration as above which were prepared using 
the pulverulent dye of the formula (I-1). 
EXAMPLE 2 
Example 1 was repeated, provided that an aqueous liquid composition 
containing the dye of the formula (I-2) described above was prepared using 
3-.beta.-sulfato-ethylsulfonyl-aniline. 
The liquid composition was subjected to demineralization and concentration 
using an asymmetric reverse osmotic membrane having 80% in the rejection 
percent of 0.5% aqueous sodium chloride solution, then obtaining a liquid 
composition having less than 0.1, 0.2, 0.1 and 0.3% in the content of 
NaCl, Na.sub.2 SO.sub.4, LiCl and Li.sub.2 SO.sub.4, respectively. 
.epsilon.-Caprolactum (5 parts) and sodium malonate (2 parts) were added 
thereto, and the liquid composition was adjusted to pH 5.5 using lithium 
carbonate to obtain a desired aqueous liquid dye composition having 20% in 
the dye content. 
The liquid dye composition was found to be stable in a closed vessel for 6 
months or more at 20.degree. C., 1 month or more at 0.degree. C. and 6 
months or more at 40.degree. C., respectively, 
Using the liquid dye composition which had been stored for 6 months at 
40.degree. C., cotton was dyed in a conventional manner to obtain a dyed 
product of an orange color with a good dyeing affinity, which was not 
different from that dyed using a pulverulent dye of the formula (I-2). 
EXAMPLE 3 
Into water (400 parts) of 20.degree. C. was added .gamma.-acid (119 parts), 
and then lithium carbonate (37 parts) was added thereto to adjust the pH 
within 7 to 8, thereby forming a clear solution. Thereafter, acetic 
anhydride (58 parts) was slowly added to the solution over 1 hour, and the 
mixture was stirred for additional 1 hour. 
On the other hand, into water (500 parts) of 20.degree. C. were added 
4-.beta.-sulfatoethylsulfonyl-aniline (126 parts), 
3-.beta.-sulfatoethylsulfonyl-aniline (14 parts), and then 35% 
hydrochloric acid (52 parts). 35% Aqueous sodium nitrite solution (99 
parts) was dropwise added thereto at 5.degree. to 10.degree. C., and the 
mixture was stirred for 1 hour to perform diazotization. 
The resulting diazonium solution was dropwise added to the above acetyl 
.gamma.-acid-containing reaction mixture over 1 hour, while controlling 
the temperature within 5.degree. to 10.degree. C., and the mixture was 
stirred for 1 hour at that temperature. Thereafter, lithium carbonate was 
added to the reaction mixture to adjust the pH 5.3 to obtain a liquid 
composition. 
The liquid composition was subjected to salting out using lithium chloride 
(400 parts), followed by demineralization using an asymmetric reverse 
osmotic membrane made up of polyacrylonitrile having 90% in the rejection 
percent of a 0.5% aqueous sodium chloride solution, obtaining a liquid 
composition having less than 0.1, 0.1 and 0.1% in the content of NaCl, 
Na.sub.2 SO.sub.4 and LiCl, respectively, 
Sodium citrate (3 parts) was added thereto and the liquid composition was 
adjusted to pH 5.1 using lithium carbonate, obtaining a desired aqueous 
liquid dye composition having 15% in the dye content. 
The liquid dye composition was found to be stored stably in a closed vessel 
for 6 months or more at 20.degree. C., 1 month or more at 0.degree. C., 
and 6 months or more at 40.degree. C. 
Using the liquid dye composition which had been stored for 6 months at 
40.degree. C., cotton was dyed in a conventional manner to obtain a dyed 
product of an orange color with a good dyeing affinity, which was not 
different from that dyed using the corresponding dye in the pulverulent 
form. 
EXAMPLES 4 TO 14 AND COMATIVE EXAMPLES 1 TO 3 
In a manner similar to that of Example 1, each aqueous liquid dye 
composition was obtained, provided that sodium citrate (3 parts) as the 
buffer and .epsilon.-caprolactum (2.5 parts) were added, the pH was 
adjusted to 5.3, and the treatment with the membrane was applied in a 
manner similar to that of Example 3. 
The test of storage stability and the dyeing after the storage were carried 
out in a manner similar to that of Example 3. 
Results are shown in the following table, in which the marks of - and o in 
the column of treatment with membrane denote no-treatment and treatment, 
respectively, the marks of o, .DELTA. and x in the column of storage 
stability, denote a good storage stability, some precipitates and marked 
precipitates, respectively, and the marks of o and - in the column of 
dyeing after the storage denote a favorable result and no testing, 
respectively. 
TABLE 
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Alkali used 
for salt 
Salt used 
Treatment 
formation 
for salt- 
with Storage stability 
Dyeing after 
Example 
Dye used 
of dye 
ing out 
membrane 
0.degree. C. 
40.degree. C. 
storage 
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4 I-3 LiOH -- -- o o o 
5 I-3 LiOH LiCl o o o o 
6 I-3 Li.sub.2 CO.sub.3 
-- o o o o 
7 I-4 Li.sub.2 CO.sub.3 
LiCl o o o o 
8 I-4 Li.sub.2 CO.sub.3 
-- o o o o 
9 I-5 LiOH LiCl o o o o 
10 I-5 Li.sub.2 CO.sub.3 
-- o o o o 
11 I-6 LiOH LiCl o o o o 
12 I-6 Li.sub.2 CO.sub.3 
-- o o o o 
13 Same as 
LiOH LiCl o o o o 
in Exp. 3 
14 Same as 
LiOH -- o o o o 
in Exp. 3 
Compar- 
I-1 NaOH NaCl o x x -- 
ative 
Same as 
example 1 
in Exp. 3 
Compar- 
I-1 Na.sub.2 CO.sub.3 
NaCl o x .DELTA. 
-- 
ative 
example 2 
Compar- 
I-2 NaOH NaCl o x x -- 
ative 
example 3 
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