JPS5962670A - Preparation of highly concentrated solution of cationic dye - Google Patents

Abstract

PURPOSE:To prepare a dye solution having high concentration and excellent stability, easily, by reacting a polybasic acid (its salt or ester) with a cationic dye hardly soluble in water and containing a zinc compound in the form of a double salt, under specific pH condition, and removing the zinc compound. CONSTITUTION:A cationic dye (e.g. the dye of formula I , II, etc.) containing a zinc compound in the form of a double salt, is made to react with a polybasic acid, polybasic acid salt, or its alkyl ester in water and/or a water-soluble organic solvent (e.g. ethylene glycol) under acidic condition of 2.0-4.5pH, and the zinc compound is removed from the cationic dye to obtain a highly concentrated solution of the dye. The amount of the polybasic acid, etc. is preferably 0.5- 1.0mol per 1mol of the dye.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a 1y-
Do 1. More specifically, it is a method for producing a highly concentrated solution of a cationic dye from a cationic dye that is difficult to dissolve in water and is in the form of a double salt of a zinc compound.

Hitherto, these cationic dyes have been commercially available and put to practical use in the form of solid powders or crystals, and in some cases, in the form of fine powder products mixed with appropriate solid diluents and auxiliaries. However, these solid products are generally not sufficiently soluble in water, especially in the double salt form of zinc compounds! The cationic dye possessed by μ is sparingly soluble and requires a large amount of water to dissolve, and further requires troublesome operations such as heating and addition.

Regarding a method for producing a highly concentrated solution of such a cationic dye with poor solubility, for example, Japanese Patent Publication No. 39-4879 discloses that after the cationic dye is treated in an alkaline aqueous solution and converted into a dye base, A technique for forming a counter ion for a monobasic organic acid such as acetic acid has been disclosed.

However, in this method of converting dyes to bases, pH
In the case of cationic dyes lacking in stability, the cationic dyes decompose when made alkaline, resulting in a decrease in color density, shift in hue, etc.

The present inventors investigated a method for producing a highly concentrated solution free of these drawbacks for highly soluble cationic dyes in the form of double salts of zinc compounds. We have found that a highly concentrated solution of a cationic dye can be obtained very easily by using the method. That is, the present invention provides the following methods: in water and/or water-soluble organic solvent,
Under acidic conditions of pH 2.0 to 4.5, a cationic dye containing a double salt of a zinc compound is reacted with a polybasic acid, a polybasic acid salt, or an ester thereof to remove the zinc compound from the cationic dye. This is a method for producing a highly concentrated solution of a cationic dye.

Cationic dyes suitable for producing the highly concentrated solutions of the present invention include triphenylmethane dyes, methine thread dyes,
Polymethine dyes, polyazamethine dyes, azine dyes, oxazine dyes, thiazine dyes, azo yarn dyes,
It is a cationic dye, such as a triazene dye, which has at least one quaternary ammonium group in its molecule and has a zinc compound as a counter ion.

Furthermore, the polybasic acid, polybasic acid salt, or ester thereof used in the present invention is one that strongly binds to the zinc compound, which is the counter ion of the cationic dye, and forms a salt that is insoluble in water and other solvents. Any type of dye may be used as long as it does not adversely affect the dye itself, but oxalic acid, sodium oxalate, birophosphoric acid, or alkyl esters thereof are particularly preferred.

The solvent used in the present invention is water and/or a water-soluble organic solvent. Examples of water-soluble organic solvents include solvents having a boiling point of 80°C or higher, preferably 100°C or higher, such as acetic acid, isopropanol, etc. tools, butanol, glycerin,
Ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,4 butanediol, polyoxyethylene glycol and their methyl-, ethyl-, propyl-1 or butyl-
Examples include (mono)ether, ethylene glycol monoacetate, thiodiethylene glycol, bisoxyethyl sulfone, dimethyl sulfoxide, tetrahydrofuran, and dioxane.

However, among these, particularly useful in practice are ethylene glycol, diethylene or dipropylene glycol and their lower alkyl ether compounds, especially dimethyl or bisoxyethyl. These solvents are used as they are or mixed with water to form a homogeneous solution and then mixed with each other.

Further, examples of the base used for adjusting the pH to 2.0 to 4.5 in the present invention include caustic soda, soda carbonate, sodium bicarbonate, sodium oxalate, sodium acetate, ammonium acetate, and organic amines. The highly concentrated solution of cationic dye of the present invention can be produced as follows.

First, a cationic dye in the form of a double salt of a zinc compound is added to water and/or the above water-soluble organic solvent, and then a polybasic acid, a polybasic acid salt, or an alkyl ester thereof is added, and if necessary, It can be produced by stirring while heating and then distributing the separated and precipitated dissolvable zinc compound from house to house. The polyhydrochloric acid, polybasic acid salt, or alkyl ester thereof used in the present invention has a 0.0.
The molar ratio is from 4 to 6.5, preferably from 0.5 to 1.0.

In the present invention, the zinc compound in the cationic dye reacts with polyhydrochloric acid, polybasic acid salt, or alkyl ester thereof in an acidic state with a pH of 2.0 to 4.5! It is thought that an excellent high-density solution can be obtained because a resolvable zinc salt is formed and released from the cationic dye Ni1.

The highly concentrated solution obtained in the present invention can be prepared using only a water-free solvent by the 2'1 reaction, but usually has a concentration of several percent to 90%.
Contains a certain amount of water. Depending on the purpose, this solution composition may further contain organic or inorganic weak acids or bases, antifoaming agents, punitive agents, penetrants, oil hydrotropes, and other known auxiliary agents. . Furthermore, depending on the purpose and case, dyes other than cationic dyes, such as anionic acid dyes, direct dyes, various metal-containing dyes, fluorescent dyes, or disperse dyes dispersed or solubilized by an appropriate method,
It may also contain vat dyes, pigments, etc.

Of the high aqueous solutions according to the present invention, what is practically important for nails is a stable concentrated solution that can be mixed with water in any proportion, and whose dye concentration is the same as that of commercially available solid compound cationic dyes. It usually reaches 25-300% compared to This highly concentrated solution is a concentrated solution containing 5 to 60% pure dye.

Furthermore, the highly concentrated solution of cationic dye obtained by the present invention has exactly the same performance as a powder product with the same structure, and can be used for polyacrylonitrile fibers, acid-modified polyester fibers,
etc. are dyed by known dip dyeing and printing methods to give vivid and durable dyed products.

Next, the present invention will be explained with reference to examples, but the present invention is not limited to the following examples. In the text, unless otherwise specified, parts or percentages refer to parts by weight or weight percentages.

Example 1 32 parts of a yellow cationic dye represented by the following 1-part formula was added to a solvent consisting of 60 parts of water, 20 parts of glacial acetic acid, and 20 parts of ethylene glycol, kept at a temperature of 80°C, and stirred. Add 5.4 parts of powder, then add 40 parts as a pH adjuster.
% caustic powder was added to adjust the pH of the system to 3.7. After this state was maintained for 2 hours, the solution was allowed to cool down to hot water, and the zinc oxalate precipitated in the system was filtered out to obtain about 135 parts of a uniform solution with a 7-day concentration. No precipitation of dye was observed in this highly concentrated solution even when it was stored at a temperature of -5 to 5°C for about 6 months.

When polyacrylonitrile fibers were dyed using the stored high-concentration solution in a conventional manner, they had exactly the same hue as the commercially available powder product. For comparison, the same solvent as above was prepared except that oxalic acid was not used, and when the above cationic dye was added and dissolved, saturation was reached at 5.0 parts.

Example 2 55.5 parts of a red cationic dye represented by the following structural formula was added to a solvent consisting of 50 parts of water, 1720 parts of diethylene glycol, 20 parts of glacial acetic acid, and 10 parts of dioxane, and the mixture was heated at a temperature of 70 to 80°C.
℃, add 6.2 parts of oxalic acid monomethyl ester while stirring, and then I) I-I FJ! 4.6 parts of monomethylamine was added as a J adjustment agent, and the pI in the system was
( was set to 4.0. After maintaining this state for 2 hours, it was allowed to cool to room temperature, and the zinc oxalate precipitated in the system was filtered off to obtain about 132 parts of a uniform high concentration solution. No dye precipitation was observed in the highly concentrated solution even after storage for approximately 69' months at a temperature of -5 to 5°C.For comparison, the same solvent as above was used except that oxalic acid monomethyl ester was not used. When the above cationic dye was dissolved, saturation was reached at 6.9 parts.

Example! 1-7 Cationic dye shown below, Cl13 U01□2□. 2 (Cation Dye Person) (Cation Dye B) Crystal゛ (Blue 1/2ZnCt2 (Cation Dye C) (Cation Dye D) Cll3 """ctOl,,2y,nct2 (Cation Dye E) and, Using the solvent composition and polybasic acid, salt or alkyl ester thereof listed in the table on the next page, the same treatment as in Example 1 was carried out to obtain a highly concentrated solution of each cationic dye.

The concentrations of these solutions are also listed in the table on the next page.

As is clear from the above results, the dye solution obtained in the present invention had a high degree of strength and its stability was also very good.

Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] In water and/or water-soluble organic solvent, pH 2.0-4.
The method is characterized in that a cationic dye containing a zinc compound in the form of a double salt is reacted with a polybasic acid, a polybasic octa salt, or an ester thereof under acidic conditions according to No. 5 to remove the zinc compound from the cationic dye. Method for producing highly concentrated solutions of cationic dyes.