NO148045B - ELECTROSTATIC SHELTER METER. - Google Patents

Description

Concentrated, stable solution of a

basic dye, and method

for its production.

The present invention relates to concentrated, stable solutions of carboxylic acid salts of basic dyes.

Basic dyes of the di- and triarylmethane series, as well as basic azo and azomethine or methine dyes are used in the paper, textile and leather industry in large quantities in the form of aqueous solutions. For the production of these solutions, finely ground dyes are mostly used. However, this form of application has significant disadvantages. Thus, for example, dissolution difficulties occur when the finely ground dry powder, as a result of improper storage due to the influence of moisture or heat, is partially or completely baked together into lumps or tubers. Likewise, the weighing, refilling or filling of the powdery, water-soluble extremely intensely colored dyes is associated with an unpleasant dust development. When the faryéat agents are dissolved and when the solutions are stirred, strong foaming often occurs, which leads to overfoaming of the solutions and thus to contamination and losses.

In order to avoid the dusting of the finely ground dyes and the foaming during the preparation of the solutions, the addition of specific substances has been proposed. Likewise, numerous wetting agents are recommended which will favor a rapid and complete dissolution of the dye powder. With all these additions, however, it is always about excipients that reduce the aforementioned disadvantages, but cannot completely remove them. The disadvantages of finely ground basic dyes in the application technique can be avoided by using highly concentrated stock solutions supplied by the dye manufacturer. However, very highly concentrated, aqueous solutions could not yet be produced. The commonly used salts of basic dyes, which are in many cases the hydrochlorides, dissolve in water or other suitable liquids, above all at room temperature only in relatively low concentrations. The solutions obtained in this way have no practical significance due to the large proportion of solvent and the associated high transport and packaging costs and due to the risk of freezing or drying out.

The present invention relates to a concentrated, stable solution containing at least 20% by weight of a basic dye, and the solution is characterized in that it contains a salt of the basic dye with a water-soluble carboxylic acid, which may be present in excess, and an anhydrous or aqueous liquid, water-unlimited miscible solvent, which can be a polyhydric alcohol, an ether or ester thereof, a polyether, an amide, a lactone, a nitrile, dimethylsulfoxide, tetrahydrofuran and/or dioxane.

The invention also relates to a method for producing said solution, and the method is characterized by dissolving a color base in a mixture of a water-soluble carboxylic acid and a solvent as described above.

As mentioned, the solutions may contain an excess of the water-soluble carboxylic acids, preferably however no more than the stoichiometric excess, based on dye. (This amount is sufficient to prevent the hydrolysis of the carboxylic acid salts.) Furthermore, the solutions can contain water, preferably in a ratio of solvent to water of 10:1, especially 1:1.

The solutions advantageously contain the dyes in an amount of 20 to 80 percent by weight. In many cases it is also possible to prepare solutions with up to 90%, however preferred for technical reasons, especially for solutions of di- and triaryl-methane dyes, 50 to 80% by weight. The solution according to the invention of cyanine-based substances preferably contains from 30 to 50% by weight of dyes.

The term basic dyes refers to such dye salts, whose coloring component is a colored cation. Examples include dyes from the di- and triarylmethane, pyronine, rhodamine, acridine, safranine, oxazine, quinoline dye and thiazole dye series, as well as basic azo dyes, azomethine and polymethine or azapolymethine dyes. Of these, for the preparation of the solution according to the invention, di- and triarylmethane dyes and diazapolymethine dyes come into particular consideration, of which the former are preferable.

By basic di- and triarylmethane dyes is meant e.g. sulfonic acid group-free, salt-forming dyes from the di- and triarylmethane series.

As examples of solutions containing dyes according to the invention, the following basic dyes can be mentioned which, in the form of their carboxylic acid salts, serve to produce the solution according to the invention:

Water-soluble carboxylic acids are e.g. monocarboxylic acids or dicarboxylic acids, the latter preferably with more than 2 C atoms, especially aliphatic mono- and dicarboxylic acids. Low molecular weight liquid carboxylic acids are preferably used, e.g. with less than 7 carbon atoms, however, solid carboxylic acids can also be used for salt formation provided they are water-soluble. Likewise, water-soluble hydroxycarboxylic acids are suitable. For example, formic acid, acetic acid, propionic acid, maleic acid and lactic acid can be mentioned as water-soluble carboxylic acids.

As water-soluble, at normal temperature liquid polyhydric alcohols and their ethers and esters, 2- and 3-hydric alcohols and their low molecular weight ethers or esters are preferably considered, for example ethylene glycol, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, triethylene glycol and dipropylene glycol, further ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 1,2-propylene glycol, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monopropyl ether, ethylene glycol monoacetate, methyl glycol acetate and 1,4-butanediol.

Examples of amides, which also include cyclic amides, lactones and nitriles that are suitable for the preparation of solutions according to the invention, include: formamide, dimethylformamide, N-methylpyrrolidone, butyrolactone and acetonitrile.

Water-soluble polyesters are polymerization products of alkylene oxides, whose end groups may be etherified or esterified, as polyethylene condensation products with molecular weights of e.g. 191 or 281.

Of the solvents mentioned, ethylene glycol, diethylene glycol monoethyl ether, dipropylene glycol, propylene glycol, formamide and dimethylformamide are preferred.

The solvents can either be unmixed or in mixtures with each other or used with water.

Water-soluble polyethers are the polymerization products of alkylene oxides, whose end group can be etherified or esterified, as polyethylene condensation products with molecular weights of e.g. 191 or 281.

The solutions are prepared by dissolving the salts of the basic dyes with water-soluble carboxylic acid in the aforementioned water-soluble solvents at normal or elevated temperature. Advantageously, however, the possibly still water-moist carbinol base is dissolved, e.g. basic di- or triarylmethane dyes, in a mixture of a water-soluble carboxylic acid which is used in a stoichiometric amount or in a multiple, e.g. 1.5 to 2-fold excess, and a solvent of the aforementioned kind. The dye base can also first be stirred with the carboxylic acid and then the solvent added.

If desired, small quantities are also added to the solutions obtained in this way, e.g. 0.1 to 3% of an antifoam agent.

When preparing the solutions, one starts from pure or already tinted dyes or, after the preparation of the solutions, these are mixed with each other or tinted.

The solution according to the invention contains the dyes in very high concentrations, e.g. from 20 to 80, in some cases up to 90%, preferably 50 to 80

weight percent, and despite their high dye content, they have the character of real solutions. Although the solution according to the invention is supersaturated, they also remain liquid at temperatures far below freezing and the dissolved dyes do not crystallize out. There is also no drop in concentration when the solution is left to stand for a long time.

The solutions according to the invention are miscible in any ratio with water or, if desired, also with suitable organic solvents. The solutions diluted with water react less acidly than aqueous solutions of the same content of the usually used hydrochlorides of the basic dyes. The nature of the highly concentrated solutions obtainable in the manner indicated enables an exact volumetric dosing of the dyes.

In addition to the production of color solutions for paper or textile fibers

the highly concentrated dye solutions are also suitable for other purposes, e.g. for the production of non-drying ink or ink for self-registering indicating instruments. In this case, it is only necessary to dilute the stock solution by adding e.g. ethylene glycol to the desired final color strength. This process for the production of ink is significantly simpler than that described in British patent document No. 865 965. Moreover, practically any desired color tone of the ink can be set in this way, while the poor solubility of most color salts with inorganic acids in ethylene glycol does not allow this.

Furthermore, the solutions can be used for the production of printing ink or printing ink for stamp pads and for typewriter ink ribbons.

In the literature site Venkataraman "The Chemistry of Synthetic Dyes", volume II, New York 1952, page 866, it is described how to transfer a kype dye over the sulfuric acid ester of the leuco form into finely divided form. The Swedish patent document 68 977 describes a method for the production of highly soluble leucoforms from kype-coloured substances.

In both cases, basic dyes are not involved.

US patent 2 983 651 describes the dissolution of a basic dye which exists as hydrochloride in 2-butoxyethanol. From this patent, however, it cannot be deduced how stable highly concentrated solutions could be produced. Nor does the statement in US patent 3,070,418, that stable methyl violet hydrochloride solutions are obtained when resorcin is added to the solution, give any indication that the solutions could be prepared according to the present invention.

German patent document 1 045 222 describes the preparation of dilute aqueous solutions of basic phthalcyanine dyes. British patent document 865 965 describes dilute solutions of basic dyes in ethylene glycol, and British patent document 844 405 describes the preparation of kype dye pigments in finely divided form. None of these literature sources are close to the preparation of the solutions according to the invention.

The same applies to the indications that can be derived from the book L. Diseren's "Die neuesten Fortschritte in der Anwendung der Farbstoffe" (1949), volume II, pages 132 - 134, because of the general enumeration of solvents for basic dyes in their commercial form , it cannot be inferred that the solution according to the invention can be highly concentrated and stable. The same applies to the literature site L. Diseren's "Chemical Technology of Dyeing and Printing", volume II, 1951, pages 92 - 93, 89 - 99 and 106 - 108.

Nor do the German patent documents 95 828 and 101 273 provide any evidence for the preparation of the solution according to the invention, because neither highly concentrated solutions nor solutions of carboxylic acid salts of basic dyes are described.

Finally, US patent 3,019,143 relates to a method for coloring anodized aluminum with dye solutions, under which the basic dyes generally mentioned are triarylmethane, thiazine and oxazine. Nor does this patent document indicate any reference to the production of highly concentrated, stable solutions.

From the following examples, where parts mean parts by weight, the production of the aforementioned dye solutions will be apparent. The indication CI. No. relates to Color Index, 2nd Edition, Volume 3.

Example 1.

To a mixture of 60 parts of glacial acetic acid and 20 parts of diethylene glycol monobutyl ether, 100 parts of the carbinol base of methyl violet (CI. No. 42 535) are added with stirring and the mixture is heated for approximately half an hour to an hour at 50 to 70°C. A viscous, even in the cold (e.g. -13°C) pourable solution of the acetic acid salt of methyl violet is thereby formed, of which 125 parts have the same shade and color strength as 100 parts of the usually solid form used hydrochloric acid salt (CI. No. 42 535) of methyl violet.

Example 2.

200 parts of the carbinol base of methyl violet (CI. No. 42 535) are introduced with stirring into a mixture of 120 parts of formic acid and 40 parts of monobutyl ether of diethylene glycol. A highly concentrated solution of the methyl violet formate is thereby formed which also remains low-viscous at -5°C 125 parts have the same color strength as 100 parts solid methyl violet hydrochloride.

Example 3.

200 parts of methyl violet base (CI. No. 42 535) are introduced into a mixture of 120 parts of propionic acid and 40 parts of diethylene glycol monobutyl ether at 70°C and a permanently highly concentrated solution of the methyl violet propionate is obtained, of which 125 parts have the same color strength as 100 parts of the ordinary solid methyl violet hydrochloride. Example 4.

200 parts of methyl violet base (CI. No. 42 535) are stirred in at approx. 50°C in a mixture of 104 parts diethylene glycol monobutyl ether and 76 parts maleic acid and heated for 2 to 3 hours at 70°C. A highly concentrated permanent solution of methyl violet maleate is formed, of which 140 parts exhibit the color strength of 100 parts methyl violet.

Example 5.

400 parts of freshly precipitated methyl violet base are introduced into a mixture of 80 parts of glacial acetic acid and 80 parts of triethylene glycol monopropyl ether and stirred for one hour at 70°C and a liquid is formed which does not solidify even at low temperatures and which does not change after standing for a long time.. 145 parts has the same color strength as 100 parts of methyl violet in the commercial form.

Example 6.

It is prepared from an aqueous solution of 200 parts Victoria blue R (CI. No.

44 040) in a known manner using diluted caustic soda as the color base.

The filtered moist color base is stirred with 87.5 parts of glacial acetic acid for 2 to 3

hours at approx. 60°C. Then 250 parts of water are distilled off at normal or reduced air pressure. 75 parts of dipropylene glycol are added to the distillation residue. Optionally, small amounts (0.2 to 2%) of a foam prevention agent are also added.

You get approx. 450 parts of a still at -4°C free-flowing product which contains no undissolved constituents and which is completely miscible with water and whose dye content corresponds to 200 parts Victoria Blue R. The solubility of Victoria Blue R in water at room temperature varies to less than 0, 01%.

Example 7.

1614 parts of moist Victoria blue base B (CI. No. 44 045) are stirred with 125 parts of glacial acetic acid for 4 hours at 80°C. 920 parts of water are then distilled and 155 parts of dipropylene glycol are added to the residue. You get 970 parts of a thin liquid dye solution which has the same dye content as 510 parts of a highly concentrated powder brand that is available in the market.

Example 8.

The dye base is prepared in a known manner from a mixture of 250 parts of ethyl violet (CI. No. 42 600) and 65 parts of crystal violet (CI. No. 42 555). The dye base is then added to the moist press cake with 150 parts of dipropylene glycol and 84 parts of glacial acetic acid at 50 to 120°C You get 569 parts of a thin-flowing, up to -14°C liquid dye solution which has the same dye content as 325 parts of a highly concentrated powder brand that is on the market.

Example 9.

The aqueous solution of 100 parts "Safranin T" (CI. No. 50 240) is added

at 75 to 80°C with 100 parts of 10% caustic soda. The precipitated color base is suctioned off immediately after cooling and is then reacted under heating with a mixture of 55 parts propionic acid, 40 parts glacial acetic acid and 60 parts ethylene glycol.

You get 255 parts of a concentrated red dye solution whose color strength corresponds to that of the starting material.

Example 10.

The aqueous solution of 100 parts of thioflavin (CI. No. 49 005) is added while stirring at approx. 70°C 100 parts 10% caustic soda. The orange-coloured precipitate is suctioned off and washed neutrally with water.

The moist color base is reacted with 50 parts dipropylene glycol and 40 parts glacial acetic acid, while heating.

You get 255 parts of a concentrated dye solution whose color strength corresponds to that of 91 parts of the starting material.

Example 11.”

100 parts of dry auramine base (CI. No. 41 000 B) are added at room temperature

a mixture of 60 parts dipropylene glycol, 20 parts methyl glycol and 80 parts glacial acetic acid. When stirred, the color base dissolves with a yellow color.

You get 260 parts of a stable auramine solution whose color strength does not noticeably decrease even after a longer period of delay. 142 parts of the solution has the same color strength as 100 parts of commercial "Auramin O."

Example 12.

520 parts of an 80% aqueous paste of freshly precipitated dye base of the basic azo dye "Vesuvin" (CI. No. 21,000) are dissolved at temperatures below 50°C in a mixture of 180 parts of glacial acetic acid and 100 parts of the monobutyl ether of diethylene glycol .

You get a highly concentrated permanent solution of the basic azo dye with a dye content of approx. 67%.

Example 13.

The still moist aqueous paste (approx. 90% dry matter content) of the dye base obtainable by precipitation of the aqueous solution of 603 parts "Chrysoidin B" (CI. No. 11 270) with ammonia solution is dissolved in a to approx. 40 to 50°C heated mixture of 400 parts of the monobutyl ether of diethylene glycol and 300 parts of 80% lactic acid.

This thin-flowing, very stable solution under vacuum contains approx. 45% of the basic azo dye.

Example 14.

In a mixture of 660 parts of glacial acetic acid and 340 parts of diethylene glycol, the dye base obtained by alkaline precipitation of the dye of the formula known from German patent document no. 1 038 522, page 2 is dissolved at room temperature slowly with stirring

from a solution of 200 parts of this dye in 40,000 parts of water.

The resulting solution is very stable and can be used for dyeing polyacrylic

Example 15.

280 parts of methyl violet carbinol base (CI. No. 42 535) in freshly precipitated moist form (with a solids content of approx. 70 to 71%) are stirred at room temperature into a mixture of 80 parts of glacial acetic acid and 100 parts of formamide.

After a short period of time, a homogeneous solution is formed from which no solid substances are separated even after a long period of delay. The solution is frost-resistant up to -15°C 145 parts of this solution has the same color strength and shade as 100 parts of the commercial dye methyl violet. Example 16.

In a mixture of 100 parts of N-methylpyrrolidone and 160 parts of 50% aqueous acetic acid, 200 parts of methyl violet base (CI. No. 42 535) are introduced at room temperature with stirring. The resolution obtained is very stable and even at longer,

time storage at -15°C occurs where no deposition or change in concentration occurs. 150 parts correspond to 100 parts methyl violet in solid form.

Example 17.

If you proceed as indicated in example 15, but replace the 100 parts of formamide with 100 parts of butyrolacetone, you get a very stable solution of the methyl violet acetate of the same color strength as the solution obtained according to example 15. It is frost resistant down to at least -15°C

Example 18.

To a mixture of 25 parts of succinic acid, 150 parts of acetonitrile and 100 parts of water, slowly add 200 parts of rhodamine B base (CI. No. 45 170) at 50 to 60°C with stirring. The highly concentrated solution formed is very stable and even at low temperatures (e.g. -15°C) does not separate any solid matter and remains homogeneous. 200 parts of the same color strength as 100 parts of the commercial rhodamine B extra in solid form.

Example 19.

The base obtainable from 25 parts "Chrysoidin B" (CI. No. 11 270) by precipitation of the aqueous solution with caustic soda in a known manner is introduced in still moist form into a mixture of 10 parts glacial acetic acid and 15 parts acetonitrile at 60°C Man obtains a stable solution of the basic azo dye. 200 parts of this solution corresponds to 100 parts of the commercially available dye.

Example 20.

20 parts of Victoria blue base B (CI.No.44 045) are stirred at 60°C in a mixture of 10 parts of formamide and 16 parts of 50% acetic acid. You get a permanent solution of the dye, of which 160 parts correspond to 100 parts of the usual dye. Example 21.

20 parts of dry methyl violet base (CI. No. 42 535) are rubbed into a paste with 16 parts of 50% acetic acid. This mixture is heated to 50 to 60°C and 10 parts of dimethylsulfoxide are added. In this way, a highly concentrated, stable dye solution is obtained. Example 22. 20 parts of methyl violet base (CI. No. 42 535) are introduced into a mixture of 16 parts of 50% acetic acid and 10 parts of tetrahydrofuran and the mixture is heated for some time under reflux. The solution, which can be diluted to any extent with water, remains stable even at low temperatures.

Example 23.

If you proceed as described in example 22, but instead of 10 parts of tetrahydrofuran you use 10 parts of dioxane, you likewise get a permanent, concentrated dye solution, of which approximately 150 to 160 parts correspond to 100 parts of commercial methyl violet.

Example 24.

From an aqueous solution of 20 parts of the red basic azo dye of

the formula:

precipitate the base and convert it at once with 15 parts of glacial acetic acid to acetate. After dilution with 10 parts of dimethylformamide, a concentrated solution stable up to -10°C is obtained.

Example 25.

20 parts of dry Victoria blue base (CI.No. 44 045) are dissolved at 60°C in a mixture of 10 parts of glacial acetic acid with 8 parts of water and diluted with 10 parts of dimethylformamide. 145 parts of this highly concentrated, homogenous solution in a wide temperature range has the same color strength as 100 parts of the powdered, commercially available dye. Example 26.

134 parts of "Auramin O" base (CI. No. 41 000 B) are measured in a ball mill for 4 hours with 225 parts of formamide. A mixture of 90 parts glacial acetic acid and 55 parts formamide is slowly added to the thin liquid mass. The mixture is then processed for approx. 8 hours in a ball mill. The brown liquid mass is freed by filtration for undissolved components.

You get 467 parts of a solution with a content of 32.3% auramine dye. The residue can be processed into Michler's ketone.

Instead of glacial acetic acid, you can also use 50 parts of formic acid and in this way get 432 parts of a solution with a dye content of 33.3%.

Example 27.

134 parts of "Auramin O" base (CI. No. 41 000 B) are dissolved in 630 parts of benzene under heating and the solution is filtered. A solution of 37 parts of propionic acid and 225 parts of formamide is allowed to flow into the filtrate at normal temperature during approx. 20 minutes, during which the temperature rises from 33 to 36°C. 20 minutes, they separate the two layers and free the formamide layer under reduced pressure of small amounts of benzene. In this way, you get 375 parts of a dark solution with a dye content of approx. 41% which can be easily diluted with water. Example 28.

134 parts of "Auramin O" base (CI. No. 41 000 B) are dissolved in 630 parts of benzene under heating. 30 parts of acrylic acid dissolved in approx. 40 parts benzene. The temperature then rises from 31 to 42°C. Even during the influx of the acrylic acid, the product formed separates in the form of yellow crystals. Stirring is continued for an hour, the product is filtered and washed with benzene.

100 parts of the moist product obtained in this way are dissolved in 100 parts of formamide at ordinary temperature. You get a wine-red auramine solution containing approx. 47% dye.

You can also add the acrylic acid dissolved in 225 parts of formamide to the benzene solution of the "Auramin O" base and get, after the layers have been separated, 357 parts of an auramine solution containing approx. 42% dye.

Claims (7)

1. Concentrated solution of a basic dye containing at least 20% by weight of the dye, characterized in that it contains a salt of the basic dye with a water-soluble carboxylic acid, which may be present in excess, and an anhydrous or aqueous liquid, with unlimited water miscible solvent, which may be a polyhydric alcohol, an ether or ester thereof, a polyether, an amide, a lactone, a nitrile, dimethylsulfoxide, tetrahydrofuran and/or dioxane. 2. Solution according to claim 1, characterized in that it contains from 20 to 80 percent by weight, and preferably from 50 to 80 percent by weight, of the basic dye. 3. Solution according to claim 1, characterized in that it contains as basic dye a salt of a dye from the diarylmethane, triarylmethane or diazapolymethane series with a monocarboxylic acid with 1-6 carbon atoms. 4. Solution according to claim 1, characterized in that the solvent contains up to 50% water by weight. 5. Solution according to claim 1, characterized in that it contains ethylene glycol, diethylene glycol monobutyl ether, dipropylene glycol, formamide and/or dimethylformamide as a solvent. 6. Solution according to claim 1, characterized in that it contains as a dye methyl violet (CI. No. 42 535), rhodamine B (CI. No. 45 170), Victoria blue B (CI. No. 44 045), vesuvin BA (CI. No. 21 000) or a dye of the formula: 7. Method for producing a solution according to claim 1, characterized in that a color base is dissolved in a mixture of a water-soluble carboxylic acid and a solvent as stated in claim 1.