DE1112232B - Process for the production of disazo pigments - Google Patents

Description

Process for Making Disazo Pigments The invention relates to a process for the production of disazo pigments, which are used for coloring rubber, Dyes and synthetic polymeric fabrics and for dyeing viscose silk in the mass are suitable.

In British patent specification 1730 from 1911, disazo dyes are described which are particularly suitable for the production of colored pigment colors (lakes) and which are produced by adding tetrazotised 3,3'-dichlorobenzidine with 2 molar parts of a 1-aryl-3- methyl-5-pyrazolones is coupled. The only 1-aryl-3-methyl-5-pyrazolone disclosed in the patent is 1-phenyl-3-methyl-5-pyrazolone.

Furthermore, some disazo pigments are common known; namely Patent USA.-are 1995 902 a disazo pigment of the above general formula wherein both X = OCHS, both mean Y = C H3, in the USA. Patent 2,031,426 a disazo pigment of the above general formula wherein both X = Cl, both mean Y = CH ", and in US Pat. No. 2,254,395 a disazo pigment of the above general formula, in which both X = phenyl, both mean Y = H, are described.

The disazo pigments according to the invention correspond to the formula where R is an alkyl radical with not more than 3 carbon atoms, a phenyl radical or a p-chlorophenyl radical and B is - Cl, - O CH3, - C, HS or - COOR ', where R' is an alkyl radical with not more than 3 carbon atoms.

Alkyl radicals R and R 'are e.g. B. methyl, ethyl and isopropyl.

A particular embodiment of the invention is a process for the preparation of the disazo pigments in which 2 molar parts of a pyrazolone of the formula with 1 molar part of a tetrazotized benzidine which is substituted in the 3 and Y positions by substituents B, where R and B have the meanings given.

The process is carried out by adding the solution of the tetrazotized, substituted benzidine mixed with an alkaline solution of the pyrazolone, the The mixture is stirred until the coupling is complete and the pigment which has precipitated out Filter isolate, wash and, if necessary, dry.

If appropriate, mixtures of pyrazolones of the specified Formula or mixtures of tetrazotized benzidines can be used.

The pyrazolones of the above formula that are used in the invention Methods used can be prepared by making an aniline, the is substituted in the p-position by a radical of the formula R0, in which R is the specified Has meaning diazotized with a reducing agent, e.g. B. treated sodium sulfite, the hydrazine formed is condensed with ethyl acetoacetate, the resulting Condensed hydrazine with ethyl acetoacetate and the hydrazone obtained with Sodium Hydroxide Treated.

As examples of suitable pyrazolones in the invention Methods that can be used include: 1- (p-methoxyphenyl) -3-methyl-5-pyrazolone, 1- (p-ethoxyphenyl) -3-methyl-5-pyrazolone, 1- (p-phenoxyphenyl) -3-methyl-5-pyrazolone, 1- (p- (4'-Chlorophenoxy) -phenyl) -3-methyl-5-pyrazolone, as examples of substituted Benzidines that can be used in the present process are 3,3'-dimethoxybenzidine, 3,3'-dicarbomethoxybenzidine and 3,3'-dichlorobenzidine are mentioned.

The pigments according to the invention are either individually or in mixtures in the form of dry powder suitable for coloring rubber, with strong luminous Shades of color are obtained that are not even during processing of the rubber are impaired, have excellent lightfastness and do not migrate. on the other hand the pigments can also be used for coloring synthetic polymeric materials, e.g. B. Use polyvinyl chloride, polyethylene, or cellulose acetate, with bright red orange until red shades are obtained that are excellent light and heat fast. The dry powders can also be used for color preparations as they are extremely lightfast in alkyd or other colored base masses, in fact themselves when they are used in amounts such that pale tints are obtained.

The pigments produced according to the invention can also be used in the form of pastes that are used for the production of emulsion paints, for stirring in in color base or lithographic varnish or for pigmenting viscose in the mass can be used. Pastes suitable for such purposes can be z. B. produce by filtering and washing the obtained after coupling Pigment with water and a dispersant such as disodium dinaphthylmethane di-f-sulfonate married. A dispersant can also be used advantageously in one or both of the Implementation reaching solutions can be used during the manufacture of the pigment. The shades obtained that are obtained when the paste in emulsion paints or viscose is incorporated are excellent lightfast.

If necessary, you can also use the red-orange to red shades of the pigments according to the invention to brown shades by changing the Pigments according to the process described in British patent specification 642 204 Soot incorporated.

The brown pigments obtained in this way are also used for coloring rubber, Dyes and synthetic polymeric substances and for pigmenting viscose Suitable in bulk, since the brown shades obtained are also excellent are lightfast.

A preferred class of disazo pigments are those made by Coupling 1 molar part of tetrazotized 3,3'-dichlorobenzidine with 2 molar parts one of the pyrazolones defined above can be obtained. If you put them in rubber, Incorporating paints and synthetic polymeric fabrics, these disazo pigments are by far more lightfast than the disazo pigments, which tetrazotized by coupling 1 molar part 3,3'-dichlorobenzidine was obtained with 2 molar parts of 1-phenyl-3-methyl-5-pyrazolone will. If you change the tint of this preferred class of pigments to a brown tint modified by incorporating carbon black into them as mentioned above are those pigments obtained particularly suitable for pigmenting viscose in bulk, because of the brown tints compared to chemical treatments that normally occur are used in the processing of the viscose threads, very resistant, excellent lightfastness and also very resistant to dry cleaning are.

A second preferred class of disazo pigments according to the invention are those obtained by coupling of one molar part tetrazotized 3,3'-dimethoxybenzidine with 2 molar parts of one of the pyrazolones defined above can be obtained. The pigments in this class are used for pigmenting viscose in bulk and for Pigmentation of rubber is particularly valuable and results in bright red shades, which are excellent lightfast.

The disazo pigments according to the invention are the above-mentioned known disazo pigments respect far superior in light fastness, as is particularly evident when comparing the from-USA. patents 1995 902 and 2031426 known disazo pigments, wherein Y each represents = C Ha, with the novel disazo the same formula, Y = 0 C H3, gives. The same also applies to a comparison of the known disazo pigment of US Pat. No. 2254395, in which X = H, with the disazo pigment according to the invention of the same formula, in which Y = OCHS.

The invention is explained in more detail in the following examples. Parts are parts by weight.

Example 1 351 parts of 3,3'-dichlorobenzidine sulfate become a solution of 400 parts of sulfuric acid in 4000 parts of water were added. The amine is more common Way tetrazotized, and the obtained solution of the tetrazotized benzidine is clarified, by stirring them with decolorizing charcoal and filtering. The solution is at 5 ° C stirred and a solution of 468 parts of 1- (p-methoxyphenyl) -3-methyl-5-pyrazolonund 96 parts of 1- (p-methoxyphenyl) -3-methyl-5-pyrazolone and 96 parts of caustic soda in 8000 Parts of water are added. The pigment suspension thus obtained is stirred for 1 hour, to complete the coupling. The suspension is then heated to 95.degree heated, filtered and the paste obtained washed with cold water. The paste is dried at 50 ° C and then ground to a fine powder.

The dry pigment obtained in this way can be used without further treatment incorporate in rubber, polyvinyl chloride, cellulose acetate and polyethylene to to get strong red shades that are excellent lightfast and opposite are resistant to the processing conditions. If you work them into color masses, yellowish-red shades are obtained, which are compared with even pale shades Light, heat and solvents are very resistant. Example 2 In place of the 468 parts of 1- (p-methoxyphenyl) -3-methyl-5-pyrazolone used in Example 1 501 parts of 1- (p-ethoxyphenyl) -3-methyl-5-pyrazolone are used. That The dry pigment obtained gives yellower shades than the pigment of the example Example 1 3 820 parts of carbon black are dispersed by mixing them with water, caustic soda and disodium dinaphthylmethanedi-ß-sulfonate milled, and the suspension thus obtained is added to a filtered tetrazone sulfate solution, which consists of 351 parts of 3,3'-dichlorobenzidine has been prepared. The suspension is stirred and an aqueous solution of 53 Share disodium dinaphthyl methanedi-ß-sulfonate and then a solution of 468 Parts of 1- (p-methoxyphenyl) -3-methyl-5-pyrazolone, 400 parts of crystallized sodium acetate and 96 parts of caustic soda in 6000 parts of water were added. The brown pigment suspension obtained is stirred for 1 hour to complete the reaction, heated to 90 ° C, filtered and washed with cold water. The pigment paste is made with 500 parts of disodium dinaphthyl methanedi-ß-sulfonate and 1500 parts of water are mixed and the mixture milled, with a permanent flowable paste is obtained. The preparation can be used without further ado, to pigment viscose before spinning it. It leads to deep brown tints of high color strength, opposite to light and commonly used to treat The chemicals used in viscose threads are extremely resistant. The pigmented one Yarn is also opposite to the solvents used in dry cleaning real.

Example 4 82 parts of carbon black are dispersed by mixing them with water and sodium hydroxide in the presence of 2 parts of disodium dinaphthyl methanedi-ß-sulfonate ground, the suspension thus obtained is a filtered tetrazonium sulfate solution added, which has been prepared from 351 parts of 3,3'-dichlorobenzidine. The suspension is stirred and a solution of 468 parts of 1- (p-methoxyphenyl) -3-methyl-5-pyrazolone, 400 parts of crystallized sodium acetate and 96 parts of sodium hydroxide in 6000 Parts of water are added. The pigment suspension obtained is stirred for 1 hour to complete the clutch. The suspension is then heated to 95 ° C, filtered and washed with cold water. The paste is dried at 90 ° C and then grind to a fine powder. The dry pigment obtained can be used without further treatment in rubber, polyvinylchloride, polyethylene or paint bases incorporate, with dark brown shades obtained, which are excellent are resistant.

If you replace the 82 parts of carbon black in the previous example have been used, 20 parts of carbon black is used, becomes a. get dry pigment, which results in light brown, also extremely resistant shades. example 5 Instead of the 351 parts used in Example 3, 3,3'-dichlorobenzidine sulfate is used 244 parts of 3,3'-dimethoxybenzidine were used. The pigment obtained gives dark reddish brown Shades of color if you work it into viscose. Example 6 244 parts of 3,3'-dimethoxybenzidine are added to a solution of 500 parts of sulfuric acid in 4000 parts of water. The amine is tetrazotized in the usual way and the tetrazonium solution obtained clarified by stirring them with decolorizing charcoal and filtering. The solution will be stirred at 5 ° C and with a solution of 50 parts of disodium dinaphthylmethanedi-ß-sulfonate in 150 parts of water and then with a solution of 480 parts of 1- (p-methoxyphenyl) -3-methyl-5-pyrazolone, 800 parts of crystallized sodium acetate and 100 parts of sodium hydroxide in 8,000 Parts of water are added. The suspension is then heated to 90 ° C. and filtered and the paste obtained is washed with water.

The pigment paste thus obtained is in the presence of 240 parts of disodium dinaphthylmethane di-ß-sulfonate and grind 720 parts of water to form a persistent flowable paste will. If you work them in viscose, a bright red color is obtained, which has excellent fastness properties.

Example 7 Instead of the 244 parts of 3,3'-dimethoxybenzidine, which are im Example 6 used will be 351 parts 3,3'-dichlorobenzidine sulfate used. The pigment paste obtained is obtained when it is incorporated into viscose and the latter spun, a steady red hue, more yellowish than the shade obtained with the pigment paste of Example 6. The pigmented yarn is against light, washing and the solvents used in dry cleaning excellent resistance.

Example 8 Instead of the 244 parts of 3,3'-dimethoxybenzidine used in Example 6 a mixture of 333.5 parts of 3,3'-dichlorobenzidine sulfate and 12.2 parts of 3,3'-dimethoxybenzidine used. If you work them into viscose, you get the pigment paste thus obtained a red shade that also has excellent fastness properties.

The following table lists the hues of other pigments obtained by coupling 1 molar part of a tetrazotized 3,3'-disubstituted benzidine with 2 molar parts of a pyrazolone. wherein R is an alkyl radical with not more than 3 carbon atoms, a phenyl radical or a p-chlorophenyl radical and B is -C1, -OCHS, - C, H, or - COOR ', where R' 35 is an alkyl radical with not more than 3 carbon atoms means, characterized in that 2 molar parts of a pyrazolone of the formula When the application was announced, a coloring table with an explanation was displayed. Color Substituted pyrazolone tint Benzidine des Pigments 3,3'-dichlorobenzidine 1- (p-isopropoxy red phenyl) -3-methyl- 5-pyrazolone 3,3'-dichlorobenzidine 1- (p-chlorophenoxy red phenyl) -3-methyl-orange 5-pyrazolone 3,3'-dicarbo- 1- (p-methoxy- red- methoxybenzidine phenyl) -3-methyl-orange 5-pyrazolone All pigments listed in the table above are extremely lightfast in their color base.

Claims (2)

PATENT CLAIMS: 1. Process for the production of disazo pigments of the formula with 1 molar part of a tetrazotized benzidine, which is in 3- and 3'-position is substituted by substituents B, where R and B are those given above Have meaning. 2. The method according to claim 1, characterized in that the coupling in the presence of carbon black which has been dispersed in one or both of the aqueous solutions which are used in carrying out the coupling, can proceed, so as to produce brown pigments. References considered: British Patent No. 1730 (1911); U.S. Patent Nos. 1995 902, 2 031426. 2254395.