JPS6259148B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the heat resistance of a water-insoluble benzothiazole azo dye used for dyeing polyester fibers or blended products of polyester fibers and other fibers. More specifically, a mixture of 2-amino-5,6-dichlorobenzothiazole and 2-amino-6,7-dichlorobenzothiazole is diazotized to N-ethyl-
A wet cake of thermally unstable crystalline azo dyes obtained by coupling with N-β-cyanoethylaniline or 2-amino-5,6-dichlorobenzothiazole and 2-amino-6,7-dichlorobenzo The mixture with thiazole is diazotized to N-ethyl-
A wet cake of thermally unstable crystalline azo dye obtained by coupling with N-β-cyanoethyl metatoluidine is added with an anionic dispersant or an anionic dispersant and a nonionic surfactant, respectively. 80-100℃ in aqueous medium
The present invention relates to a method for producing a benzothiazole-based azo dye, which is characterized by converting it into a crystalline azo dye with excellent heat resistance by heating the dye to

The dye obtained by the method of the invention has the formula and expression The mixture of dyes represented by and also the dyes obtained by the method of formula and expression It is a mixture of dyes shown in

These mixtures can be obtained in any mixing ratio to achieve the desired hue or fastness. For example, in the dye, 60 to 45% by weight of the dye of the formula (A) and 40 to 55% by weight of the dye of the formula (B), and in the case of the dye, 60 to 45% by weight of the dye of the formula (C) and the formula (b) Dye 40
Obtained as a mixture with ~55 wt. Among these, CI Dispersed Red 153 is a mixture of 55% by weight of the dye of formula (a) and 45% by weight of the dye of formula (b).
Also, 55% by weight of the dye of formula (c) and 45% of the dye of formula (d)
The mixture in weight percent is known as CI Dispersed Red 152, and has been produced in large quantities in recent years as a high-grade red disperse dye, and is used for dyeing synthetic fibers, especially polyester fibers.

The azo dye of the present invention before crystal conversion is prepared by preparing a mixture of 2-amino-5,6-dichlorobenzothiazole and 2-amino-6,7-dichlorobenzothiazole with sodium nitrite, preferably in sulfuric acid. Alternatively, it can be obtained as an aqueous wet cake by diazotizing with nitrosyl sulfuric acid, coupling with N-ethyl-N-β-cyanoethylaniline or N-ethyl-N-β-cyanoethyl metatoluidine, preferably under acidic conditions, and washing with water. The dyes produced by these methods are amorphous or consist of crystals designated as β-type, and in some cases may include some crystals designated as α-type. To this aqueous wet cake is added a dispersant, such as the formaldehyde condensate sodium salt of naphthalene sulfonic acid and the lignin sulfonic acid sodium salt in general;
The dye product is obtained by grinding into fine particles of about 1 μm in a ball mill or sand mill, followed by sprue drying. However, the products obtained in this way are unstable to heat, especially at temperatures of 95 to 135 °C, which is the temperature at which polyester fibers are dyed.
At a temperature of , crystal transformation and exchange occur, and at this time, fine particles agglomerate and expand. These enlarged dye particles interfere with uniform dyeing, and especially in jet dyeing such as Obermeyer dyeing, cheese dyeing, and beam dyeing, the dye passes through the fiber layer, causing clogging and internal penetration. This is extremely inconvenient as it causes defects, casing spots, etc. Therefore, it is necessary to maintain the fine particle dispersion of the dye even at high temperatures.

The present inventors conducted research on improving the high-temperature dispersibility of the above dyes and arrived at the present invention.

Methods generally employed to improve high-temperature dispersibility include making the dye into fine particles and selecting a dispersant, but this method alone often fails to achieve the objective. Furthermore, obtaining heat-stable crystals by heat treatment is unique depending on the structure of the dye, and cannot be widely applied. Therefore, for a limited range of similar dyes, it is currently necessary to find economical ways to obtain heat-stable dyes.

The present inventors have discovered a new technology that is commonly applied to obtain heat-stable benzothiazole azo dyes. That is, the β-type crystals of the above-mentioned dye can be obtained by heat treatment with the addition of an anionic dispersant, and
It was discovered that the β-form crystals of the dye can be efficiently transformed into heat-stable α-form crystals by heat treatment in the presence of an anionic dispersant and a nonionic activator, respectively.

The α-type crystals obtained in this way are made into fine particles and are a dye with excellent high-temperature dispersibility.

As the anionic dispersant used in the present invention, for example, β-naphthalenesulfonic acid formalin condensate sodium salt and ligninsulfonic acid sodium salt are generally used. Common nonionic surfactants include, for example, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol ethers, and polyoxyethylene alkyl amides.

As for the heat treatment conditions, heating to 80 to 100°C and stirring for about 3 hours is sufficient. However, there is no problem in lengthening the processing time.

Next, the difference in crystal form before and after treatment by the method of the present invention will be explained.

CI Dispersed, one of the dyes of
According to X-ray diffraction, the β-type crystal of 153 has a diffraction angle of 26.1
The α-form crystals of the dye obtained by the treatment method of the present invention have strong diffraction lines at angles of 19.4°, 14.5°, and 12.0°.
It has a strong diffraction line at °, and there is a clear difference in crystal form.

The β-type crystal of CI Dispersed Red 152, which is one of the dyes, has strong diffraction lines at diffraction angles of 26.4°, 25.3°, and 12.6°. The α-form crystals of the dye thus obtained had strong diffraction lines at diffraction angles of 24.0°, 18.8°, 15.1°, 14.7°, and 7.3°, and there was clearly a difference in crystal form.

The α-type benzothiazole azo dye obtained by the method of the present invention, which is made into fine particles by a conventional method, has good high-temperature dispersibility, and can be used to make hydrophobic fibers such as polyester. When dyed, a uniformly dyed product is obtained.

The present invention will be explained below with reference to specific examples. In the text, parts mean parts by weight.

Example 1 790 parts of 15.3% sulfuric acid was prepared in a glass-lined reaction vessel, and 55% by weight of 2-amino-5,6-dichlorobenzothiazole, 2-amino-6,
70 parts of a mixture consisting of 45% by weight of 7-dichlorobenzothiazole is charged and dissolved at 55-60°C. Next, 740 parts of 98% sulfuric acid was charged, and at -4 to 0°C, 30 parts of sodium nitrite was added little by little to carry out diazotization.

Meanwhile, in a rubber-lined tank, add 600 parts of water and 125 parts of denitrified sulfuric acid.
part, N-ethyl-N-βcyanoethylaniline 57
18 parts of sulfamic acid were dissolved therein, and the diazo solution was added dropwise thereto at 0 to 5°C (using ice) over about 1 hour, and the mixture was stirred for 5 hours. Next, pass through a filter press, wash with water and hot water until the liquid becomes neutral (approximately 30,000 parts at 50 to 60°C), and press cake 700
(116 parts of dry dye) is obtained. The Dispersed Thread 153 bulk powder thus obtained has a β-type crystal form.

To 905 parts of the above press cake (150 parts of dry dye), 150 parts of Demol T (dispersant manufactured by Kao Atlas) was added and heat treated at 95°C for 3 hours while stirring. Next, 500 parts of water, 150 parts of Demol T, and Demol SC-30.
% (dispersant manufactured by Kao Atlas) was added, and the mixture was ground with a sand grinder to an average particle diameter of about 1 μm, and then spray-dried to obtain 640 parts of bulk.
Load this bulk into a compounding machine and use Sun Extract P-252.
(Dispersant manufactured by Sanyo Kokusaku Pulp) 200 parts, anhydrous sodium sulfate 150
990 parts of dye product was obtained.

Dyeing example: 20 parts of the dye obtained in Example 1 was dissolved in 1000 parts of water, and the pH was adjusted to 5 with acetic acid. This dye solution was circulated through a beam made of 500 parts of Tetoron taffeta wrapped in 160 layers, and the temperature was raised from 80°C at a rate of 1.5°C/min to 130°C.
Stained for 60 minutes.

The dyed product obtained was uniformly dyed to the inside, and no dye aggregates were observed.
In addition, even in a dyebath heating test (Note 1) in which no dyed material was used, no aggregates were observed and good dispersibility was demonstrated.

On the other hand, in the case of a β-type crystalline dye, the dyeing was extremely uneven, and a large amount of dye aggregates were generated in the dye bath heating test.

(Note 1) Disperse 0.5 g of dye in 100 c.c. of water, stir at 130°C for 60 minutes, and then mix at 95-100°C with Toyo Roshi No. 5A (diameter 7
A test method that uses suction filtration (cm) and visually evaluates the amount of residue. In the case of dyes with poor high-temperature dispersibility, there is a large amount of residue, and in the case of dyes with excellent high-temperature dispersibility, almost no residue is observed.

Example 2 In Example 1, N-ethyl-N-β was substituted for 57 parts of N-ethyl-N-β-cyanoethylaniline.
-By using 65 parts of cyanoethyl metatoluidine, 152 parts of CI dispersion thread and 750 parts of powder presscake (119 parts of dry dye) are obtained.
This bulk powder has a β-type crystal form. Demol for 1134 parts of the above press cake (180 parts of dry dye)
45 parts of TWEEN and 30 parts of TWEEN80 (polyoxyethylene sorbitan monooleate manufactured by Kao Atlas Co., Ltd.) are mixed, stirred, and heat-treated at 90 to 95°C for 3 hours.

Next, Demol T255 part, Demol SC - 30%
667 parts of anhydrous sodium sulfate, 300 parts of anhydrous sodium sulfate, and 500 parts of water were ground to an average particle size of 1 μm using a sand grinder and spray dried to obtain 980 parts of dye.

This dye was dyed according to the dyeing example of Example 1, and a uniformly dyed product could be obtained.

On the other hand, in the case of a β-type crystalline dye that was not subjected to heat treatment, the finished dyeing was extremely uneven.

Claims (1)

[Claims] 1. Diazotizing a mixture of 2-amino-5,6-dichlorobenzothiazole and 2-amino-6,7-dichlorobenzothiazole and coupling it with N-ethyl-N-β-cyanoethylaniline. A wet cake of the thermally unstable crystalline azo dye obtained by -ethyl-
A wet cake of thermally unstable crystalline azo dye obtained by coupling with N-β-cyanoethyl metatoluidine is added with an anionic dispersant or an anionic dispersant and a nonionic surfactant, respectively. 80-100℃ in aqueous medium
A method for producing a benzothiazole-based azo dye, which is characterized by heating it to convert it into a crystalline azo dye with excellent heat resistance.