Patent Publication Number: US-4370431-A

Title: Process for coloring fibre forming polyamides in the melt with azo pigments

Description:
The present invention relates to a process for colouring fibre forming polyamides in the melt with azo pigments of the formula ##STR2## wherein A is the radical of a diazo or tetraazo component, R 1 , R 2  and R 3  are hydrogen atoms, alkyl, cycloalkyl, phenalkyl or aryl radicals, and n is 1 or 2. 
     The radical A can be derived from any diazo components, for example of the benzene or naphthalene series. These can contain the customary substituents of azo pigments, in particular sulfo or carboxyl groups, and halogen atoms such as fluorine, chlorine or bromine; carbamoyl, sulfamoyl or cyano groups; alkyl, alkoxy or alkylmercapto groups containing 1 to 6 carbon atoms; phenoxy or phenylmercapto groups which are unsubstituted or substituted by halogen atoms or methyl or methoxy groups; naphthoxy groups, phenalkyl groups or acyl groups such as alkanoyl groups containing 2 to 6 carbon atoms; acylamino groups such as alkanoylamino groups containing 2 to 6 carbon atoms, e.g. acetylamino, chloroacetylamino, propionylamino or benzoylamino groups; alkylsulfamoyl groups containing 1 to 6 carbon atoms, alkylcarbamoyl groups containing 2 to 6 carbon atoms; phenylsulfonyl, phenylsulfamoyl or phenylcarbamoyl groups which are unsubstituted or substituted by chlorine atoms or methyl or methoxy groups; and phenylazo groups. 
     Suitable radicals of heterocyclic diazo components are, in particular, 5- or 6-membered nitrogen-containing heterocyclic rings of aromatic character, e.g. of the pyrrole, pyrazole, thiazole, oxdiazole, thiodiazole, triazole, tetrazole or pyridine series. Polynuclear condensed heterocyclic rings are also suitable, which rings preferably contain a fused benzene ring. Examples are the unsubstituted or substituted benzthiazole, benztriazole, indole, indazole, quinoline, phthalimide and phthalic anhydride rings. These mono- or polynuclear heterocyclic diazo radicals can also contain the customary substituents of azo pigments of the kind specified above. 
     A phthalimide radical A is preferably a radical of the formula ##STR3## wherein R 6  is a hydrogen atom, a C 1  -C 4  alkyl group or a phenyl radical which is unsubstituted or substituted by chlorine atoms or methyl or methoxy groups. 
     The radical A can also be the radical of a tetraazo component, i.e. it can be derived from a diamine, from a diaminodiphenyl or from a diaminodiphenyl derivative, the benzene rings of which are linked through a bridge member. Bridge members can be bivalent atoms such as O or S, or bivalent groups, e.g. an amino group which is unsubstituted or substituted by C 1-C   6  alkyl groups, or straight-chain or branched alkylene radicals preferably containing 1 to 6 carbon atoms, e.g. the methylene, 1,2-alkylene or 2,2-propylene group, cycloalkyl groups such as the 1,1-cyclohexyl group, and the radicals --CO--, --SO-- or --SO 2  --, --CH═CH--, --N═N--, --SO 2  O--, --SO 2  --NR--, --SO 2  NHSO 2  --, --RNCO-- or --RN--CO--NR--, wherein R is a hydrogen atom or a C 1  -C 6  alkyl group. 
     R 1 , R 2  and R 3  as alkyl radicals in formula (1) are preferably alkyl radicals of 1 to 6 carbon atoms which can be substituted, e.g. by hydroxyl groups, C 1  -C 4  alkoxy groups, cyano or phenyl groups. Examples of cycloalkyl radicals are cyclohexyl radicals. R 1 , R 2  or R 3  as aryl radicals are preferably phenyl radicals which can contain chlorine atoms, methyl, ethoxy or sulfo groups. 
     The pigments of the formula (1) preferably contain 1 or 2 carboxyl or sulfo groups in the molecule. 
     Particularly interesting pigments are those of the formula (1), wherein A is a phenyl or naphthyl radical, in particular one of the formula ##STR4## wherein X is a hydrogen or halogen atom, an alkyl or alkoxy group, each of 1 to 6 carbon atoms, an alkoxycarbonyl group of 2 to 6 carbon atoms, a nitro, cyano or trifluoro methyl group, a sulfo or carboxyl group, or an alkanoylamino group of 2 to 6 carbon atoms, a phenoxy, phenylcarbamoyl, phenoxycarbonyl, phenylsulfonyl or phenoxysulfonyl group, each of which can be substituted by chlorine atoms or methyl or methoxy groups, or a group of the formula 
     
         --SO.sub.2 NR.sub.4 R.sub.5 
    
     wherein R 4  is a hydrogen atom, an alkyl group of 1 to 6 carbon atoms, a phenyl group which is unsubstituted or substituted by chlorine atoms or methyl groups, R 5  is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, Y is a hydrogen or halogen atom, or a methyl, carboxyl or sulfo group, and Z is a hydrogen or halogen atom or a methyl group. 
     Preferred pigments are those of the formula ##STR5## wherein X, Y and Z are as defined above. 
     Further preferred pigments are those of the formula ##STR6## wherein X 1  is a carboxyl or sulfo group, Y 1  is a hydrogen atom or a methyl or carboxyl group, and also the novel pigments of the formula ##STR7## wherein X, Y and Z are as defined above, one of R 1  &#39;, R 2  &#39; and R 3  &#39; is a sulfophenyl group which is unsubstituted or substituted by chlorine atoms or methyl or methoxy groups, and the others are hydrogen atoms, alkyl groups of 1 to 6 carbon atoms or phenyl groups which are unsubstituted or substituted by chlorine atoms or methyl or methoxy groups. 
     Particularly interesting pigments of the disazo series are those of the formula ##STR8## wherein R 1 , R 2  and R 3  are as defined above, Q is a direct bond or a bridge member, V is a hydrogen or chlorine atom or a methyl or methoxy group. 
     Some of the pigments of this invention are known [German Offenlegungsschrift No. 1 719 080 and Chem. Pharma Bull. 7, pp. 1-6 (1959)] and can be obtained by the methods described therein by coupling a diazotised monoamine or a tetraazotised diamine with one or two moles of a triaminopyrimidine of the formula ##STR9## by conventional methods, in acid, neutral or alkaline medium, optionally in the presence of a water-soluble solvent such as ethanol or dioxane. 
     If 1-aminobenzene-2-sulfonamides or -carboxamides are used as diazo components, then the diazotisation results in the formation of benztriazinones, which have to be cleaved with alkalies before the coupling in alkaline medium. 
     Representative examples of diazo components are: 
     1-amino-2-, -3- or -4-chlorobenzene 
     1-amino-2,3-, -2,4-, -3,4- or -2,5-dichlorobenzene 
     1-amino-3-chloro-4-methylbenzene 
     1-amino-2- or -4-methylbenzene 
     1-amino-2- or -4-methoxybenzene 
     1-aminobenzene-2,3- or -4-sulfonic acid 
     1-aminobenzene-2,5-disulfonic acid 
     1-amino-2-chlorobenzene-4-sulfonic acid 
     1-amino-4-chlorobenzene-3-sulfonic acid 
     1-amino-2,5-dichlorobenzene-4-sulfonic acid 
     1-aminobenzene-2-, -3- or -4-sulfophenyl ester 
     1-aminobenzene-2-, -3- or -4-sulfonamide 
     1-aminobenzene-2-, -3- or -4-sulfomethylamide 
     1-aminobenzene-2-, -3- or -4-sulfoethylamide 
     1-aminobenzene-2-, -3- or -4-sulfophenylamide 
     1-aminobenzene-2-, -3- or -4-carboxylic acid 
     1-aminobenzene-2,3- -2,4- or -3,4-dicarboxylic acid 
     1-amino-2-chloro-5-benzoic acid 
     1-aminobenzene-2-, -3- or -4-carboxylic acid methyl ester 
     1-aminobenzene-2-, -3- or -4-carboxylic acid ethyl ester 
     1-aminobenzene-2-, -3- or -4-carboxylic acid phenyl ester 
     1-aminobenzene-2-, -3- or -4-carboxamide 
     1-aminobenzene-2-, -3- or -4-carboxylic acid ethylamide 
     1-aminobenzene-2-, -3- or -4-carboxanilide 
     1-aminobenzene-2-, -3- or -4-carboxylic acid N-ethylanilide 
     1-aminobenzene-2-, -3- or -4-methylsulfonylbenzene 
     4-aminoazobenzene 
     4-aminoazobenzene-2&#39;-, -3&#39;- or -4&#39;-sulfonic acid 
     4-amino-3&#39;-chloroazobenzene 
     4-amino-2-methylazobenzene 
     4-amino-4&#39;-methylazobenzene 
     4-amino-2-methoxyazobenzene 
     2-amino-diphenyl ether 
     2-amino-4,4&#39;-dichloro-2&#39;-sulfo-diphenyl ether 
     2-aminobenzophenone 
     4-amino-4&#39;-methylbenzophenone 
     2-amino-4&#39;-methyl-diphenylsulfone 
     3-amino-4-chloro-diphenylsulfone 
     2-amino-3&#39;-sulfo-diphenylsulfone 
     1-aminobenzene-naphthalene-4-sulfonic acid 
     2-aminobenzene-naphthalene-4-sulfonic acid 
     2-aminobenzene-naphthalene-3,6-disulfonic acid 
     4-aminophthalic anhydride 
     3-aminophthalic anhydride 
     3- or 4-aminophthalimide 
     3-amino-phthalo-2&#39;-methyl-5&#39;-chlorophenylimide 
     3-amino-phthalo-2&#39;-methoxy-5&#39;-chlorophenylimide. 
     Representative examples of tetraazo components are: 
     3,3&#39;-dichlorobenzidine 
     3,3&#39;-dimethylbenzidine 
     3,3&#39;-dimethoxybenzidine 
     4,4&#39;-diaminostilbene 
     2,2&#39;-, 3,3&#39;- and 4,4&#39;-diaminodiphenylsulfone 
     3,3&#39;-diaminobenzophenone 
     4,4&#39;-diaminodiphenyl oxide 
     4,4&#39;-diaminodiphenylsulfide 
     4,4&#39;-diaminodiphenylmethane 
     2,2-bis-(4&#39;-aminophenyl)propane 
     4,4&#39;-diaminodiphenylamine 
     4,4&#39;-diaminodiphenylurea 
     4,4&#39;-diaminobenzanilide 
     4,4&#39;-diaminoazobenzene. 
     The coupling components are known compounds. They are obtained by known methods, e.g. by reacting trichloropyrimidine with ammonia or the corresponding amines, for example methylamine, ethylamine, propylamine, isopropylamine, N-butylamine, n-hexylamine, n-octylamine, cyclohexylamine, aniline, 2-, -3- or -4-chloroaniline, 2-, -3- or -4-methylaniline or anilino-2-, -3- or -4-sulfonic acid. The three chlorine atoms of the trichloropyrimidine can be replaced either by identical or different amines of the kind specified above. 
     Suitable fibre forming polyamides for the process of this invention are the linear polyamides which can be obtained e.g. from ε-caprolactam (&#34;Perlon&#34;, nylon 6), ω-aminoundecanoic acid (&#34;Rilsan&#34;), hexamethylenediamine and adipic acid (nylon 66) or from analogous starting materials. Further suitable polyamides are copolyamides e.g. obtained from ε-caprolactam and hexamethylenediamine and adipic acid. 
     The pigments are blended with the polyamide by known methods in solid or liquid form or as a solution, and the resultant mix is subjected to an intermediate drying, if desired. 
     It is preferred to dust the polyamides to be coloured in the form of powders, granules or chips with the dry pigment powder, i.e. to blend them mechanically such that the surface of these particles is coated with a layer of pigment. The pigment is conveniently in finely divided form. 
     Instead of using the pure pigments, it can sometimes be advantageous to use preparations which contain a carrier in addition to the pigment, preferably a calcium or magnesium salt of a higher fatty acid, for example of stearic or behenic acid. 
     The polyamide particles containing the pigment or pigment preparation are fused and the melt is then spun by known methods or otherwise shaped to sheets or other moulded articles, e.g. to injection moulded articles. 
     The pigment or pigment preparation can also be incorporated in solid or liquid form in the fused polyamide, which is then spun or shaped. 
     The articles obtained are uniformly coloured and have excellent fastness to light, wet processing, rubbing and thermofixation. 
     The pigments are uniformly and finely dispersed in the coloured material. Although their solubility in organic solvents such as chlorinated hydrocarbons, lower ketones, esters and alcohols is not high, they are often present in the polyamide in dissolved form. 
     The coloured articles conveniently contain 0.01 to 3% of colorant. 
     It is surprising that the azo pigments to be used in the practice of this invention withstand the high temperatures and the reducing conditions of the melt process without substantial decomposition and that the textile properties of the fibres are not greatly impaired. 
     Compared with the arylazopyrazolonesulfonic acids known from GDR patent specification No. 107 065, the azo compounds containing sulfo groups of this invention have a better thermostability and can therefore be used in a substantially broader temperature range and over longer spinning times. 
     Azo compounds of the present invention which contain carboxyl groups are superior in rub fastness (bleeding) to the azopyridine compounds which do not contain acid groups described in German Offenlegungsschrift No. 2 409 754. 
    
    
     The invention is illustrated by the following Examples, in which parts and percentages are by weight, unless otherwise indicated. 
     EXAMPLE 1 
     5 g of the azo pigment of formula (1) or of an isomer of the formula ##STR10## are dissolved in 1000 ml of warm water, then 500 g of polycaprolactam granules are added and the solution is heated, with constant stirring or agitating, to the boil. After 1/2 hour to 1 hour 5 ml of acetic acid or 5-10 g of ammonium acetate are added and boiling is continued until the bulk of the pigment is exhausted onto the polyamide. The granules are then collected by filtration, washed thoroughly with water and dried. Melt spinning yields a fibre material coloured in a strong, level yellow shade of very good fastness to water, washing, shampooing, solvents, rubbing, thermofixation, peroxide bleaching and light. 
     EXAMPLE 2 
     99 g of polyamide obtained from ε-caprolactam (polyamide 6) in the form of chips are dusted dry with 1 g of the azo pigment of the formula ##STR11## The treated chips are spun at 270°-280° C. in an extruder, to give a fibre material coloured in a level yellow shade of excellent fastness to light, wet processing and thermofixation. 
     EXAMPLE 3 
     60 g of the azo pigment of the formula ##STR12## and 60 g of magnesium stearate are processed at 150°-160° C. in a laboratory kneader. After a homogeneous mixture has been obtained, the cooled, brittle product is ground, to give a preparation containing 50% of colorant. 
     98 g of polyamide 6 in granular form are dusted dry with 2 g of the colorant preparation. The treated granules are spun at 270°-280° C. in an extruder, to give a fibre material coloured in a strong yellow shade of very good performance properties. 
     EXAMPLES 4-56 
     Fibres which are also coloured in very fast, level yellow to orange shades are obtained by the melt coloration of polyamide 6 in accordance with Examples 1 to 3, using one of the monoazo pigments listed in Table 1 or one of the disazo pigments listed in Table 2. 
     
                       TABLE 1                                                     
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Ex-                                                                       
am-  Monoazo pigments from      Shade on                                  
ple  diazo component  coupling component                                  
                                    PA 6                                  
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4    1-aminobenzene-2-sulfonic                                            
                      2,4,6-triaminopyrim-                                
                                    greenish                              
     acid             idine         yellow                                
5    1-aminobenzene-4-sulfonic                                            
                      2,4,6-triaminopyrim-                                
                                    greenish                              
     acid             idine         yellow                                
6    1-amino-4-chlorobenzene-                                             
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     2-sulfonic acid  idine                                               
7    1-amino-2-chlorobenzene-                                             
                      2,4,6-triaminopyrim-                                
                                    greenish                              
     5-sulfonic acid  idine         yellow                                
8    1-amino-2-chlorobenzene-                                             
                      2,4,6-triaminopyrim-                                
                                    greenish                              
     4-sulfonic acid  idine         yellow                                
9    1-amino-3-chloro-6-meth-                                             
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     ylbenzene-4-sulfonic                                                 
                      idine                                               
     acid                                                                 
10   1-amino-2,5-dichloroben-                                             
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     zene-4-sulfonic acid                                                 
                      idine                                               
11   1-amino-benzene-2,4-di-                                              
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     sulfonic acid    idine                                               
12   3-aminophthalic acid                                                 
                      2,4,6-triaminopyrim-                                
                                    reddish                               
                      idine         yellow                                
13   4-aminophthalic acid                                                 
                      2,4,6-triaminopyrim-                                
                                    reddish                               
                      idine         yellow                                
14   1-amino-4-sulfobenzene-                                              
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     2-carboxylic acid                                                    
                      idine                                               
15   2-amino-3&#39;-sulfodiphen-                                              
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     ylsulfone        idine                                               
16   1-aminobenzene-2-sul-                                                
                      2,4,6-triaminopyrim-                                
                                    yellow                                
     fonic acid-N-- ethyl-N--                                             
                      idine                                               
     4&#39;-sulfophenylamide                                                  
17   1-amino-2,5-dichloro-                                                
                      2,4,6-triethylamino-                                
                                    reddish                               
     benzene-4-sulfonic                                                   
                      pyrimidine    yellow                                
     acid                                                                 
18   1-amino-2,5-dichloro-                                                
                      2,4,6-tri-n-butyl-                                  
                                    reddish                               
     benzene-4-sulfonic                                                   
                      aminopyrimidine                                     
                                    yellow                                
     acid                                                                 
19   1-amino-2,5-dichloro-                                                
                      2,4,6-tri-phenyl-                                   
                                    orange                                
     benzene-4-sulfonic                                                   
                      aminopyrimidine                                     
     acid                                                                 
20   1-aminobenzene-2-sul-                                                
                      2,4,6-triethylamino-                                
                                    yellow                                
     fonic acid N--ethyl-N--                                              
                      pyrimidine                                          
     4&#39;-sulfophenylamide                                                  
21   1-aminobenzene-2-sul-                                                
                      2,4,6-tri-β-hydroxy-                           
                                    yellow                                
     fonic acid N--ethyl-N                                                
                       ethylaminopyrimi-                                  
     4&#39;-sulfophenylamide                                                  
                      dine                                                
22   2,3-dichloroanilide                                                  
                      mixture of 2,4-di-                                  
                      amino-6-(3&#39;-sulfo-                                  
                      phenylamino)-                                       
                      pyrimidine and 2,6-                                 
                      diamino-4-(3&#39;-sulfo-                                
                      phenylamino)-                                       
                      pyrimidine                                          
23   3,4-dichloroaniline                                                  
                      mixture of 2,4-di-                                  
                                    yellow                                
                      amino-6-(3&#39;-sulfo-                                  
                      phenylamino)-                                       
                      pyrimidine and 2,6-                                 
                      diamino-4-(3&#39;-sulfo-                                
                      phenylamino)-                                       
                      pyrimidine                                          
24   3-trifluoromethylaniline                                             
                      mixture of 2,4-di-                                  
                                    greenish                              
                      amino-6-(3&#39;-sulfo-                                  
                                    yellow                                
                      phenylamino)-                                       
                      pyrimidine and 2,6-                                 
                      diamino-4-(3&#39;-sulfo-                                
                      phenylamino)-                                       
                      pyrimidine                                          
25   3-sulfomoylaniline                                                   
                      mixture of 2,4-di-                                  
                                    greenish                              
                      amino-5-(3&#39;-sulfo-                                  
                                    yellow                                
                      phenylamino)-                                       
                      pyrimidine and 2,6-                                 
                      diamino-4-(3&#39;-sulfo-                                
                      phenylamino)-                                       
                      pyrimidine                                          
26   2-cyanoaniline   mixture of 2,4-di-                                  
                                    yellow                                
                      amino-5-(3&#39;-sulfo-                                  
                      phenylamino)-                                       
                      pyrimidine and 2,6-                                 
                      diamino-4-(3&#39;-sulfo-                                
                      phenylamino)-                                       
                      pyrimidine                                          
27   4-chloroaniline  mixture of 2,4-dicyc-                               
                                    yellow                                
                      lohexylamino-6-(3&#39;-                                 
                      sulfophenylamino)-                                  
                      pyrimidine and 2,6-                                 
                      dicyclohexylamino-                                  
                      4-(3&#39;-sulfophenyl-                                  
                      amino)-pyrimidine                                   
28   4-chloraniline   2-cyclohexylamino-                                  
                                    reddish                               
                      4,6-di-(3&#39;-sulfo-                                   
                                    yellow                                
                      phenylamino)pyri-                                   
                      midine                                              
29   1-amino-4-chlorobenzene-                                             
                      mixture of 2,4-di-                                  
                                    reddish                               
     4-sulfonic acid  ethylamino-6(4&#39; -                                   
                                    yellow                                
                      chlorophenyl-                                       
                      amino)-pyrimidine                                   
                      and the 2,6,4-isomer                                
30   2,5-dichloroaniline                                                  
                      mixture of 2,4-di-                                  
                                    yellow                                
                      amino-6-(3&#39;-methyl-                                 
                      4&#39;-sulfophenyl-                                     
                      amino)-pyrimidine                                   
                      and the 2,6,4-isomer                                
31   2,5-dichloroaniline                                                  
                      mixture of 2,4-di-                                  
                                    yellow                                
                      amino-6-(2&#39;-meth-                                   
                      oxy-5&#39;-sulfophenyl-                                 
                      amino)-pyrimidine                                   
                      and the 2,6,4-isomer                                
32   3-amino-4-methylbenzoic                                              
                      2,4,6-triaminopyr-                                  
                                    greenish                              
     acid             imidine       yellow                                
33   3-aminobenzoic acid                                                  
                      2,4,6-triaminopyr-                                  
                                    yellow                                
                      imidine                                             
34   1-amino-3-chloro-4-                                                  
                      2,4,6-triaminopyr-                                  
                                    yellow                                
     methyl-6-benzene-                                                    
                      imidine                                             
     sulfonic acid                                                        
35   1-amino-4-methyl-6-                                                  
                      2,4,6-triaminopyr-                                  
                                    greenish                              
     benzenesulfonic acid                                                 
                      imidine       yellow                                
36   1-aminobenzene-2,5-                                                  
                      2,4,6-triaminopyr-                                  
                                    greenish                              
     disulfonic acid  imidine       yellow                                
37   3-aminophthalic an-                                                  
                      2,4,6-triaminopyr-                                  
                                    yellow                                
     hydride          imidine                                             
38   4-aminophthalic acid 2&#39;-                                             
                      2,4,6-triaminopyr-                                  
                                    reddish                               
     methoxy-5&#39;-chlorophenyl-                                             
                      imidine       yellow                                
     imide                                                                
39   4-aminophthalic acid 4&#39;-                                             
                      2,4,6-triaminopyr-                                  
                                    reddish                               
     chlorophenylimide                                                    
                      imidine       yellow                                
40   3-aminophthalic acid 2&#39;-                                             
                      2,4,6-triaminopyr-                                  
                                    yellow                                
     methyl-5&#39;-chlorophenyl-                                              
                      imidine                                             
     imide                                                                
41   5-aminoisophthalic acid                                              
                      2,4,6-triaminopyr-                                  
                                    greenish                              
                      imidine       yellow                                
42   3-aminophthalic acid                                                 
                      2,4,6-triphenyl-                                    
                                    orange                                
                      amino-pyrimidine                                    
43   aminoterephthalic acid                                               
                      2,4,6-triaminopyr-                                  
                                    greenish                              
                      imidine       yellow                                
44   3-aminophthalic acid                                                 
                      2,4,6-triisopropyl-                                 
                                    yellow                                
                      aminopyrimidine                                     
45   4-aminophthalophenyl-                                                
                      2,4,6-triaminopyr-                                  
                                    reddish                               
     imide            imidine       yellow                                
46   1-amino-3-methyl-4-                                                  
                      2,4,6-triaminopyr-                                  
                                    greenish                              
     chloro-6-benzenesul-                                                 
                      imidine                                             
     fonic acid                                                           
47   2-amino-4-sulfonic acid-                                             
                      2,4,6-triaminopyr-                                  
                                    greenish                              
     benzoic acid     imidine       yellow                                
48   1-amino-3-chloro-4-                                                  
                      2,4,6-tribenzyl-                                    
                                    greenish                              
     methyl-6-benzene-                                                    
                      amino-pyrimidine                                    
                                    yellow                                
     sulfonic acid                                                        
49   3-aminophthalic acid                                                 
                      2,4,6-trimethyl-                                    
                                    reddish                               
                      amino-pyrimidine                                    
                                    yellow                                
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                       TABLE 2                                                     
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Ex-   Disazo pigment from       Shade on                                  
ample tetraazo component                                                  
                     coupling component                                   
                                    PA 6                                  
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50    4,4&#39;-diaminodiphenyl-                                               
                     mixture of 2,4-di-                                   
                                    reddish                               
      sulfone        amino-6-(3&#39;-sulfo-                                   
                                    yellow                                
                     phenylamino)-pyr-                                    
                     imidine and the                                      
                     2,6,4-isomer                                         
51    3,3&#39;-diaminodiphenyl-                                               
                     mixture of 2,4-di-                                   
                                    greenish                              
      sulfone        amino-6-(3&#39;-sulfo-                                   
                                    yellow                                
                     phenylamino)-pyr-                                    
                     imidine and the                                      
                     2,6,4-isomer                                         
52    2,2&#39;-diamino-4,4&#39;-di-                                               
                     mixture of 2,4-di-                                   
                                    yellow                                
      chloro-diphenylsulfide                                              
                     amino-6-(3&#39;-sulfo-                                   
                     phenylamino)-pyr-                                    
                     imidine and the                                      
                     2,6,4-isomer                                         
53    4,4&#39;-diaminodiphenyl-                                               
                     mixture of 2,4-di-                                   
                                    yellow                                
      methane        amino-6-(3&#39;-sulfo-                                   
                     phenylamino)-pyr-                                    
                     imidine and the                                      
                     2,6,4-isomer                                         
54    4,4&#39;-diamino-2,2&#39;-di-                                               
                     mixture of 2,4-di-                                   
                                    yellow                                
      methyldiphenyl amino-6-(3&#39;-sulfo-                                   
                     phenylamino)-pyr-                                    
                     imidine and the                                      
                     2,6,4-isomer                                         
55    4,4&#39;-diaminodiphenyl-                                               
                     mixture of 2,4-di-                                   
                                    golden                                
      sulfone        ethylamino-6-(3&#39;-                                    
                                    yellow                                
                     sulfophenylamino)pyr-                                
                     imidine and the                                      
                     2,6,4-isomer                                         
56    2-amino-4-(4&#39;-amino-                                                
                     2,4,6-triaminopyr-                                   
                                    yellow                                
      phenylsulfonylamino)-                                               
                     imidine                                              
      benzenesulfonic acid                                                
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     EXAMPLE 57 
     The pigment of Example 12 is obtained as follows: 45 parts of the disodium salt of 3-aminophthalic acid (0.2 l mole) are dissolved in 200 parts of water, and then 90 parts by volume of 30% hydrochloric acid are added. Diazotisation is subsequently carried out at 0°-3° C. with 50 parts by volume of 4 N NaNO 2  solution, whereupon the diazonium salt precipitates after briefly going into solution. 
     25 parts (0.2 mole) of 2,4,6-triaminopyridine are first dissolved in 300 parts of water at 55° C. and then precipitated at room temperature. The above suspension of the diazonium salt is then added to the suspension of the coupling component over about 90 minutes at 15°-20° C. and pH 8-9 with the gradual addition of about 57 parts by volume of 30% aqueous sodium hydroxide. The coupling is complete after 2 hours. Then 72 parts of 30% hydrochloric acid are added and the suspension is adjusted to pH 1 and further stirred for 30 minutes at 80° C. The precipitated product is isolated by filtration in conventional manner and washed with water until neutral. The filter cake is then dried in vacuo at 80° C., affording 64 parts (95.5% of theory) of a yellow pigment powder of the formula ##STR13## which contains 1 mole of water of crystallisation. 
     Combustion analysis: Theory (with 1 mole of H 2  O) C 12  H 11  N 7  O 4 .H 2  O (mol. wt.: 335)--C %, 42.4; H %, 3.88; N %, 29.2. Found: C %, 42.5; H %, 3.7; N % 28.5. 
     EXAMPLE 58 
     Using the same amount of the disodium salt of 4-aminophthalic acid instead of the 3-aminophthalic acid derivative yields 63 parts of a yellow pigment of the formula ##STR14## which also contains 1 mole of water of crystallisation. 
     C 12  H 11  N 7  O.sub.β.H 2  O (mol. wt.: 335)-- Found: C %, 43.5; H %, 3.9; N %, 29.9. Theory: C %, 42.9; H %, 3.88; N %, 29.2%. 
     EXAMPLE 59 
     99 g of polyamide graunules obtained from ε-caprolactam (polyamide 6) are dusted dry with 1 g of the azo pigment of the formula ##STR15## The treated chips are spun at 270°-280° C. in an extruder, to give a fibre material coloured in a level yellow orange shade of excellent fastness to washing, shampooing, solvents, dry heat and rubbing. 
     EXAMPLE 60 
     Fibres coloured in very fast level shades are likewise obtained by the melt coloration of polyamide 6 as described in Examples 1 to 3 and 59, using an azo pigment listed in Table 3. 
     
                       TABLE 3                                                     
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Azo pigment obtained from   Shade on                                      
Example                                                                   
       diazo component                                                    
                   coupling component                                     
                                    PA 6                                  
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61     3-aminoindazole                                                    
                   mixture of 2,4-diamino-                                
                                    yellow                                
                   6-(3&#39;-sulfophenylamino)-                               
                   pyrimidine and the                                     
                   2,6,4-isomer                                           
62     6-aminoindazole                                                    
                   mixture of 2,4-diamino-                                
                                    yellow                                
                   6-(3&#39;-sulfophenylamino)-                               
                   pyrimidine and the                                     
                   2,6,4-isomer                                           
63     3,3&#39;-dichloro-                                                     
                   mixture of 2,4-diamino-                                
                                    red                                   
       benzidine   6-(3&#39;-sulfophenylamino)-                               
                   pyrimidine and the                                     
                   2,6,4-isomer, 2-equi-                                  
                   valents                                                
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