JP2628382B2 - Thermally stable crystal modification of dye and its production method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a heat-stable dye crystal modification and a method for producing the same.

Conventional technology Formula (I) The dye represented by is known from JP-B-44-13389.

The dyes of the formula (I) are known to dye synthetic fibers, for example polyethylene terephthalate fibers, with a bluish red color.

In recent years, in the dyeing industry, the rationalization of dyeing methods and energy saving measures have been advanced, and the bath ratio has been reduced. In order to prevent spotting due to a filter effect, dyes having excellent dispersion stability at high temperatures are strongly desired.

Problems to be Solved by the Invention When a dye represented by the formula (I) produced by an ordinary method is used for dyeing at a high temperature, there is a disadvantage that the dispersion state of the dye particles in a dye bath is reduced, and therefore, a uniform It is difficult to obtain a stain with a staining concentration.

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention
In the powder X-ray diffraction method using Cu-Kα ray, the diffraction angle (2
θ) [°] Strong peak at 25.8, diffraction angle (2θ) [°] 4.
Formula (I) characterized by an X-ray diffraction diagram (FIG. 1) having somewhat strong peaks at 2,12.9,13.5,14.2 The present invention provides a thermally stable crystal modification of the dye represented by the formula (hereinafter referred to as β-type crystal) and a method for producing the same. (A normal error range (± 0.3) is allowed for the diffraction angle.) In the present invention, the formula (I) before being converted into the β-type crystal is used.
The thermally unstable crystal modification of the dye represented by
According to a known method, 2-amino-
It is obtained by diazotizing 6-nitrobenzothiazole and coupling to N-ethyl-N-acinoethyl-m-toluidine in acidic medium. This α-type crystal is a so-called amorphous type having a gentle undulating peak as shown in FIG. 2, for example, in a Cu-Kα ray diffraction method.
The α-type crystal dye is mechanically micronized with a dispersant, for example, a soda salt of a formalin condensate of naphthalenesulfonic acid or a sodium ligninsulfonate by a sand mill or the like, according to a usual method of commercialization, and then polyester is formed. In the case of dyeing a fiber woven fabric or a blended woven fabric of polyester fiber and acrylic fiber or cotton, this α
Since the type crystal is unstable to heat, the conversion of the crystal occurs at a temperature of 95 to 135 ° C. at which the polyester fiber is dyed, and the dye particles are tarred or aggregates are formed. Such tar compounds and coarse dye particles hinder uniform dyeing. Especially over Meyer dyeing, cheese dyeing,
In bead dyeing, liquid flow dyeing, etc., aggregated particles are passed through the fiber layer, causing clogging, poor internal penetration, casing spots, etc., and not only do not give uniform dyeing, but also the fastness of dyeing It causes inconvenience such as decline.

As a result of investigations to improve such drawbacks and to meet the demands of the market, they have found that the β-type crystal characterized by the above-mentioned X-ray diffraction pattern is extremely excellent in dyeing stability at high temperatures. It is completed.

Further, the present invention will be described in detail.

Β of the dyestuff of the formula (I), which is stable at high temperatures
The type crystal is obtained by heating a wet cake or a dry cake of the α type crystal obtained by known diazotization followed by coupling in water at a temperature of 40 ° C. or more.
The processing time can be lengthened or shortened as required.

For example, by heating at 40 ° C. or more and 200 ° C. or less, preferably 50 ° C. or more and 100 ° C. or less for about 1 hour to 3 hours, α-type crystals are converted to β-type crystals. At this time, maintaining the temperature at 100 ° C. or higher or increasing the processing time may be acceptable, but is economically disadvantageous.

After the coupling reaction, the crystal conversion from α-form crystal to β-form crystal is carried out using a wet cake obtained by over-washing, washing with water, or by drying it, or the coupling reaction is completed without going through an over-process. The reaction is performed by heating the reaction solution.

Whether or not the desired crystal conversion is completed in the present invention can be easily confirmed by measuring an X-ray diffraction spectrum.

Examples of the fibers that can be dyed with the dye having a β-type crystal of the present invention include polyethylene terephthalate fibers or a blend thereof with natural fibers such as cotton, silk, and wool,
Mixed woven products.

In order to dye a fiber using a dye having a structure of the formula (I) of the present invention and having a β-type crystal, a dispersant such as a naphthalenesulfonic acid formalin condensate, a higher alcohol sulfate or a higher alkylbenzene sulfonate is usually used. The dye cake of β-form crystals is finely dispersed in an aqueous medium in the presence of a dye bath to prepare a dyeing bath or printing paste, which can be used for permeation or printing.

In the case of dip dyeing, it can be applied to dyeing methods such as high temperature dyeing, carrier dyeing and thermosol dyeing.

In the present invention, the dye of formula (I) of the β-type crystal may be used in combination with another dye, and various additives may be added in the step of preparing the disperse dye.

Examples Hereinafter, the present invention will be described specifically with reference to examples.

Example 1. 22.5 g of 2-amino-6-nitrobenzothiazole was suspended in 316.8 g of 60% sulfuric acid, cooled, 51.3 g of 43% nitrosyl sulfuric acid was added at 0 ° C, and the mixture was stirred at the same temperature for 3 hours. A diazo solution of 2-amino-6-nitrobenzothiazole was obtained.
Separately, 21.5 g of N-ethyl-N-dianoethyl-m-toluidine was dissolved in 480 g of an 8% by weight aqueous sulfuric acid solution, and then cooled to 0 ° or lower, and the diazo solution was added dropwise to perform coupling. After the reaction is completed, neutralize Congo Red to neutral with sodium carbonate, wash with water, and wash with 37.3 g of dye cake.
(Equivalent to drying) was collected.

The X-ray diffraction pattern of a part of this cake was an amorphous α-type crystal as shown in FIG.

This dye cake is then dispersed in 500 ml of water and stirred
Heat treatment was performed at 0 to 75 ° C for 1 hour. After the treatment, the cake was passed, and a part thereof was analyzed according to the X-ray diffraction method.
It was a β-type crystal having an X-ray diffraction pattern as shown in the figure.

Example 2 Coupling was carried out in the same manner as in Example 1, and then the coupling solution was stirred at 70 to 75 ° C. for 1 hour. The dye crystals obtained by washing with water exhibited β-form.

<Comparative test> 21 g of each of the dyes exhibiting α-type or β-type, 21 g of naphthalenesulfonic acid formalin condensate, naphthalenesulfonic acid
After wet pulverization with a sand grind mill together with 28 g of cresol sulfonic acid formalin condensate, they were vacuum-dried to prepare respective disperse dye compositions.

In order to compare the heat stability of each of the obtained dye compositions, 1) a heat cohesion test and 2) a casing pot test were performed.

The details of each test method are as follows.

1) Thermal aggregation test 0.5 g of the disperse dye composition was dispersed in 100 ml of water, and the pH of the dye bath was adjusted to 4.5 with acetic acid and sodium acetate (without immersing the fiber = blank bath). Over 130
C., and kept at the same temperature for 10 minutes, cooled to 95 ° C. in 5 minutes, suctioned using quantitative paper (Toyo No. 5A), and judged from the amount and state of the residue on the paper.

Class 5 (good) to class 1 (poor) based on 5 levels.

2) Casing spot test 0.6 g of the disperse dye composition was dispersed in 180 ml of water, and tetron jersey 1 was placed in a dye bath adjusted to pH 4.5 with acetic acid and sodium acetate.
0g is immersed from 60 ° C to 130 ° C over 40 minutes (using a color pet dyeing machine), kept at the same temperature for 10 minutes, cooled to 60 ° C, and the area where the object is inscribed in the object holder It was determined from the state of the attached aggregate.

Class 5 (good) to class 1 (poor) based on 5 levels.

Effect of the Invention A thermally stable crystal modification (β-type crystal) was obtained for the dye represented by the formula (I).

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of a β-type crystal which is stable to heat. FIG. 2 is an X-ray diffraction diagram of a thermally unstable α-type crystal (amorphous). 1 and 2, the horizontal axis indicates the diffraction angle 2θ, and the vertical axis indicates the diffraction intensity.

Claims (2)

(57) [Claims] In a powder X-ray diffraction method using Cu-Kα radiation, a peak having a diffraction angle (2θ) [°] of 25.8 and a diffraction angle (2
θ) [°] A crystal modification of the dye represented by formula (I) characterized by an X-ray diffraction pattern having somewhat strong peaks at 4.2, 12.9, 13.5, and 14.2. 2. A heat treatment of a dye having a structure represented by the formula (I) of claim 1 and having a crystal modification which is unstable to heat at a temperature of 40 ° C. or more in water. A method for producing a crystal modification according to claim 1 characterized by the following features: