DE2452537A1 - MONOAZOPIGMENTS AND METHOD FOR THEIR PRODUCTION - Google Patents

Description

Monoazo pigments and processes for their preparation

The subject of patent application P 23 ^ 7 532.3 are monoazo pigments of formula I.

CH, CO

N = N-CH-CONH.

(D

in whichR represents a hydrogen or chlorine atom and method for the production of these pigments. Azo pigments with excellent light and weather fastness are obtained using the process mentioned.

In pursuing the idea of the invention, it has now been found that the new azo pigments of the formula II

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-Z-

co

, N = N-CH-CONH

»0 (II)

in which X is a hydrogen or chlorine atom, and Y and R are a hydrogen atom or a methyl group, where two each where X, Y and R are hydrogen atoms, have similar good properties exhibit.

These compounds are made by adding 2,5-dichloroaniline diazotized in a known manner and with a compound of the formula

CH ₃ -CO-CH ₂ -CO-NH

X Y

in which X, Y and R have the abovementioned meanings, coupling and the still moist pigment was it in the form of the accumulated aqueous suspension or in the form of a moist press cake, either in water between 80 and 150 ⁰ C or in a water-soluble or: water organic solvent is heated to temperatures between 80 and 180 C or heated, the dried untreated pigment with a water-soluble or water-insoluble organic solvent to temperatures between 80 and 18O ⁰ C. The pigments can be prepared in such a way that the solution of the diazo compound is combined with the azo component present in a weakly acidic medium in the form of a fine dispersion or that the alkaline solution of the azo component is added to the initially introduced, for example by adding sodium acetate, to the pH value 5 to 6, the solution of the diazo component can flow. Another possibility for carrying out the coupling consists in allowing the solutions of the diazo and azo components to flow together to form a buffer mixture, preferably a sodium acetate-acetic acid mixture.

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In all of these modes of operation, the presence of cationic, anionic or nonionic surface-active compound may be advantageous. .

To produce the optimal pigment shape in terms of grain softness, Color strength, hiding power and processability in paints and plastics is then the above-mentioned thermal aftertreatment necessary.

This aftertreatment can be carried out in such a way that the aqueous pigment suspension obtained from the manufacture of the pigments is removed or the resulting moist press cake either in water at temperatures between 80 and 150 C, that is, if appropriate, below Pressure, or in an organic solvent at temperatures between 80 and 180 ° C, optionally under pressure, treated. That Organic solvents used here can be water-soluble or water-insoluble. For example, alkanols with preferably 1 to 6 carbon atoms, lower carboxylic acid, such as formic acid, acetic acid or propionic acid, carboxylic acid alkyl esters, such as preferably lower alkyl acetic or propionate or methyl or ethyl benzoate, aromatic hydrocarbons, such as benzene, toluene, xylene or cumene, chlorinated aromatic hydrocarbons such as chlorobenzene, o-dichlorobenzene or Bromobenzene, or dipolar aprotic solvents such as dimethylformamide, phosphoric acid tris (dimethylamide), dimethyl sulfoxide, N-methylpyrrolidone, tetramethylene sulfone or tetramethylurea, can be applied.

The aftertreatment can, however, also be carried out in such a way that the above-mentioned organic solvents either alone or as a mixture with one another on the dried, untreated pigment at temperatures Let it take effect between 80 and 180 ° C.

The thermal aftertreatment of the "pigments in an organic solvent is compared to the purely aqueous aftertreatment preferred embodiment.

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The azo pigments according to the invention are yellow powders which are contained in the. common solvents are completely insoluble. You stand out good color strength, impeccable overcoating and migration fastness and especially characterized by excellent light and weather fastness. Particularly high requirements with regard to the latter Fastness properties are set on pigments that are used in so-called "metal effect paints. These are synthetic resin paints, for example acrylic melamine resin lacquers, which contain aluminum powder of various particle sizes in the weight ratio of pigment to aluminum powder from 9: 1 to 1: 1 can be added.

The pigments according to the invention prove to be particularly useful in these Metal-effect stains are significantly superior to comparable azo pigments in terms of their fastness to light and weather.

The new azo pigments can be used for a wide variety of pigment applications, for example for the production of printing inks, for the preparation of lacquer paints and emulsion paints or for coloring rubber, plastics or natural or synthetic resins. The pigments are also suitable for pigment printing on the substrate, in particular a textile fiber _s and on other sheetlike structures, such as paper, they can also be used for other purposes, for example, or esters for the dyeing of rayon viscose, or cellulose ethers, such as .Polyolefinen , Polyamides ^ polyurethanes, polyglycol terephthalates or polyacrylonitrile can be used in the spinning pulp or for dyeing paper.

In German patent specification 1 227 585 and in German Laid-Open Specification 1 8o8 017 describes comparable azo pigments; surprisingly, those according to the invention are Pigments are still considerably superior to these pigments in terms of light and weather fastness.

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example 1

.5.

32.4 g of 2,5-dichloroaniline are stirred in 160 ml of 15% hydrochloric acid over a period of time. A volume of 500 ml and ⁰ ° C. is set with ice and water. Then 40 ml of 5 N sodium nitrite solution are quickly added, the inlet pipe dipping below the surface. 56 g of 6-chloroacetolone (6-chloro-5-acetoacetylamino-benzimidazol-2-one) are dissolved in 400 ml of water and 36 ml of 33% sodium hydroxide solution. One puts 100 ml of water, 80 ml of 4N sodium acetate solution, 24 ml of glacial acetic acid and 40 ml of a 10 # solution of an oxethylated oleyl alcohol (with an average of 30 ethylene oxide units) and allows the above diazonium salt solution and the solution of the coupling component within at -10 C at the same time Run in for 1 hour.

The mixture is stirred for 15 P4 minutes, checked for complete coupling, heated to 95 ° C. and this temperature is maintained for 30 minutes. The greenish yellow pigment is then filtered off with suction while hot, washed with water and dried. The aftertreatment of the crude pigment in 300 ml of glacial acetic acid at 115 ° C. gives a grain-soft pigment after 30 minutes.
Yield: 44.1 g

Example 2

16.2 g of 2,5-dichloroaniline are stirred overnight in a mixture of 40 ml of 31% hydrochloric acid and 40 ml of water. It is then cooled to 0 ° C. and 20 ml of 5N sodium nitrile solution are quickly poured in (below the surface). The mixture is subsequently stirred at 0 to 5 ° C. for one hour. After adding a little sulfamic acid, the diazo solution is freed from excess nitrite and clarified with activated charcoal. In a second vessel, 26 g of S-acetoacetylamino-γ-methylbenzimidazol-2-one are dissolved in a mixture of 300 ml of water and 21.8 ml of 33% sodium hydroxide solution. This solution is also clarified over activated charcoal and, at the same time as the diazonium salt solution prepared above, is allowed to run over a mixture of 40 ml of 4N sodium acetate solution, 6 ml of glacial acetic acid and 200 ml of water within 40 minutes with rapid stirring. The clutch is finished very quickly. It is heated to 90 ^° C. and this temperature is maintained for 30 minutes

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upright. It is then filtered off with suction, washed and dried. Yield hO g

The crude pigment is heated to 110 ° C. for about 30 minutes with 600 ml of pyridine and, after cooling to 70 ° C., is filtered off with suction, with methanol and water washed and dried.

Example 3

16.2 g of 2,5-dichloroaniline are mixed in 80 ml of 15% hydrochloric acid overnight. It is then ^{cooled to 0} ° C. with ice and diazotized with 20 ml of 5N sodium nitrite solution, which is introduced very quickly under the surface of the solution.

26 g of l-N-methyl-5-acetylamino-benzimidazol-2-one are in 200 ml Stirred water and dissolved with 20 ml 33% sodium hydroxide solution.

At 10 ° C, the above diazonium salt solution and the solution of the coupling component run under simultaneously within ^ 5 minutes rapid stirring to a solution of 400 ml of water, 50 ml of 5N Sodium acetate solution and 12 ml glacial acetic acid.

When the feed has ended, the mixture is heated to 95 ° C. and at for 30 minutes kept this temperature. The yellow pigment is then filtered off with suction, washed with water and dried.

The crude pigment is then treated with glacial acetic acid at 100 ° C. for 30 minutes, filtered off with suction, washed with methanol and water and dried.

Yield 37 _} 2 g.

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Claims (3)

Claims 1. Compounds of the formula Cl CO
I. N = N-CH-CONH C = O Y R in which X is a hydrogen or chlorine atom and Y and R are hydrogen atom or a methyl group, two of the radicals X, Y and R being hydrogen atoms. 2. Process for the preparation of the compounds according to claim 1, characterized in that 2,5-dichloroaniline is diazotized with a compound of the formula CH ₃ -CO-CH ₂ -CO-NH "C = O in which X ₉ Y and R have the meaning given in claim 1, and the still moist pigment is heated either in water to temperatures of 80 to 150 C or in a water-soluble or water-insoluble organic solvent to temperatures of 80 to 100 C or the dried , untreated pigment in a water-soluble or water-insoluble organic solvent heated to 80 to 180 ° C. 3. · Use of compounds according to claim 1 as pigments for dyeing or printing plastics, natural or synthetic Resins, rubber, paper, viscose silk, cellulose esters or. ethers, polyolefins, polyurethanes, polyacrylonitrile or Polyglycol terephthalates, as well as for the production of printing inks, lacquer paints or emulsion paints. 609820/1081