JPS6256189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of treating azo pigments with certain amines or derivatives thereof.

The production of pigment granules by stirring together an aqueous dispersion of a pigment and a water-insoluble organic carrier dissolved in a water-immiscible organic solvent is known. However, in this known process, the final product contains some solvent and it is necessary to remove the organic solvent from the product by distillation. The inventors have found a method in which the product is obtained directly in the absence of solvent.

It is known to treat certain azo pigments with organic solvents, such as aromatic amines, without the addition of carriers, in order to improve their properties; such treatments are described, for example, in British Patent No. 1406797. No., no.
1455653 and 1456331, and U.S. Pat.
It is described in the specification of No. 3671281. However, the organic solvent is usually removed by washing or steam distillation.

The present invention provides a method for treating azo pigments, in which mono-azo pigments or bis-azo pigments based on coupling components of arylamides and pyrazolones are treated in the absence of water with optionally substituted aminobenzenes or carbon atoms containing 6 to 12 carbon atoms. A linear, branched or substituted alkyl amine or cycloalkyl amine is contacted at a temperature above the melting point of the amine, and the pigment and amine composition is then heated to a pH such that the amine is completely dissolved in water. and isolating the amine-free pigment.

Amine-free pigments are isolated by conventional techniques such as filtration and washing.

The amine is liquid at temperatures below 100°C, insoluble in water at a certain pH value, but soluble in water below a certain pH value.

The amine may be an optionally substituted aminobenzene, preferably aniline or an N-mono- or N,N-di-alkylaniline, each carrying a C1 -C8 alkyl radical.
Examples of amines that can be used include aniline, N-
Methylaniline, N-ethylaniline, N-propylaniline, N-butylaniline, N,N-dimethylaniline, N,N-diethylaniline,
N,N-dipropylaniline, N-cyclohexylaniline, N-cyclohexyl-N-hydroxyethylaniline, N-octylaniline, N-
Methyl-o-toluidine, N-ethyl-p-toluidine, N-butyl-m-toluidine, N,N-
Examples include diethyl-m-toluidine and methyl anthranilate, with N,N-diethylaniline being preferred. On the one hand, amines are
In particular C6 -C12 straight-chain or branched alkyls, although they can also be aliphatic amines, such as C6 -C12 straight-chain or branched or substituted alkyl amines or cycloalkylamines. Amines such as n-hexylamine, n-octylamine, di-isobutylamine, or Primene 81R (synthetic aliphatic amines with branched chains of 12 carbon atoms, such as Rohm and Haas)
[manufactured by Haas] is preferably 2-ethylhexylamine.

Azo pigments which can be treated particularly advantageously in the process of the invention are monoazo and diazo pigments based on arylamide and pyrazolone coupling components, such as those having the following basic structure:

(i) A-N=N-B, a monoazo pigment based on a monoamine and a monocoupling component; (ii) B-N=N-C-N=N-B, based on a diamine and a monocoupling component Bisazo pigment; (iii) A-N=N-D-N=NA, a bisazo pigment based on a monoamine and a biscoupling component.

Examples of monoamines representing residue A in the structures shown in (i) and (iii) are: 2-nitroaniline; 4-nitroaniline; 2
-nitro-4-methylaniline; 2-nitro-4
-chloroaniline; 2-nitro-4-methoxyaniline; 2-nitro-4-ethoxyaniline; 2
-Methyl-4-nitroaniline; 2-chloro-4
-nitroaniline; 2-methoxy-4-nitroaniline; 2-ethoxy-4-nitroaniline;
2,5-dichloroaniline; 2,4-dichloroaniline; 2,4,5-trichloroaniline; 2-
Methyl-4-chloroaniline; 2,4-dinitroaniline and functionalized derivatives such as 2-carboxyaniline, 3-carboxy-6-chloroaniline.

Examples of diamines representing residue C in the structure shown in (ii) are listed below.

3,3'-dichlorobenzidine;2,2'-dichlorobenzidine;2,2',5,5'-tetrachlorobenzidine;3,3'-dimethoxybenzidine; 2,
2'-dichloro-5,5'-dimethoxybenzidine and 3,3'-dimethylbenzidine.

Examples of monofunctional coupling components representing residue B in the structures shown in (i) and (ii) are acetoacetyl and 2-hydroxy-3-naphthoyl derivatives of aniline; 2-chloroaniline; 2-methoxyaniline ;2-ethoxyaniline;2-methylaniline;4-methylaniline;4-methoxyaniline;4-ethoxyaniline;2,4-dimethylaniline;2-methoxy-4-chloroaniline;
2,4-dimethoxyaniline; 2,4-dimethoxy-5-chloroaniline; 2,5-dimethoxy-
4-chloroaniline; 5-aminobenzimidazolone; 4-methyl-7-aminoquinolone; or 1
- pyrazolone derivatives such as phenyl-3-methylpyrazol-5-one; 1-tolyl-3-methylpyrazol-5-one; and 1-phenyl-3-
Ethoxycarboxylated pyrazol-5-ones, or heterocycles such as barbituric acid or 2-hydroxynaphthalenes.

Examples of bis-coupling components representing residue D in the structure shown in (iii) include the following diamines, bis-acetoacetyl derivatives and bis-2-hydroxy-
There are 3-naphthoyl derivatives: 1,3-diaminobenzene, 1,3-diamino-4-chlorobenzene, 1,4-diaminobenzene; 1,4-diamino-2-methyl-5-chlorobenzene; 1,4-diamino -2,5-dichlorobenzene; 3,3'-dimethylbenzidine and 3,
3'dimethoxy-benzidine.

The azo pigment may be in the form of a dry powder, presscake or aqueous slurry when initially contacted with the aniline compound.

When the pigment is added in the form of a dry powder, it is generally added at a concentration that produces an easily stirrable dispersion, or a thick dough that is usually mixed/sheared by high horsepower mixing equipment such as a Z-blade mixer. Add to the amine at the resulting concentration.

If the pigment is added in the form of a press cake, a similar fluid or mixer for high viscosity materials is utilized.

In this method, water is removed from the system by distillation, for example at temperatures of 100°C or higher.

Whether the pigment is added in the form of a dry powder or presscake, after contact with the amine is complete,
The mixture is contacted with a large amount of water at a pH suitable to solubilize all the amines, primarily as acid salts; the pigment is then isolated free of amines, e.g. by filtration and washing; washing may be necessary. If an acid is added to the wash water, complete removal of the amines should be achieved, so that the pigment is usually salt-free and neutral at the end of the wash; if drying is required, a standard Do it with technology.

Contact time varies from seconds to days, depending on the pigment, amine, temperature and desired changes.
For example, longer contact, higher temperatures and the use of aromatic amines produce the most changes. The main feature of this method is that, by appropriate addition of water of appropriate PH, active organic amines can be removed and the contact time can be tightly controlled, thus the transformation can be terminated at the desired point. It is.

The amount of amine used will depend to some extent on the method employed, for example whether the pigment is added in powdered or presscake form and whether the composition is made into a fluid or a highly viscous body. The amount of amine is conveniently 2% or more, preferably 15% or more, based on the weight of the pigment, and the upper limit is determined depending on process and cost considerations; Pigment properties change more.

The temperature at which the treatment is carried out is over a wide range, from 0°C
Although it may be as low as possible, it is preferably 50°C or higher. When using a press cake, remove the water and raise the temperature to near the boiling point of the amine compound at normal pressure; however, if the temperature exceeds the boiling point of the amine derivative, it is necessary to raise the pressure to above normal pressure; When used, if contact is made at a temperature above the boiling point of the amine compound, the pressure must be above normal pressure.

The acid used to remove amine compounds is
Any acid that forms a water-soluble salt with the above-mentioned amines may be used. Suitable acids are C1 -C4 fatty acid carboxylic acids, organic sulfonic acids or mineral acids. Preferred acids are hydrochloric acid, sulfuric acid or acetic acid. The amount of acid required to dissolve the amine depends on factors such as the initial pH, salt content of the water, temperature and concentration; generally a pH of 5 or less is required for dissolution;
A pH of 3.5 or less is preferred for complete removal of amine.

The amine compound becomes insoluble by raising the pH of the filtrate to 7 or above, for example to 10 or above by adding an alkali, and can be separated from the water and recovered and reused, for example by decantation. The amine compound may be further purified by steam distillation if necessary.

The method of the present invention provides an easy method for adjusting pigment properties and a simple method for solvent separation and pigment regeneration. Amine compounds isolated as salts in the filtrate can be easily recovered by adding alkali to the filtrate. This method improves properties such as gloss, rheology, especially opacity and fastness to weather and light. The properties of fastness and opacity are particularly desirable for brightly colored dot coatings where weather resistance is particularly required.

The following examples illustrate the invention in more detail. Parts and percentages are expressed by weight.

Example 1 100 parts of diethylaniline was added to a 25% aqueous press cake of CI (color index) pigment yellow 17.
Add to 100 parts with stirring. The temperature is raised to 120° C. by immersing the container in an oil bath, the pigment is transferred into diethylaniline to form a thick paste, and the water is separated. Hold at 120° C. for 3 hours; water present in the mixture is completely removed by evaporation. The paste is cooled to 80° C. and sufficient water and hydrochloric acid are added with stirring to form a 5% by weight aqueous pigment slurry with a pH of 1. The diethylaniline is extracted back into water as the soluble hydrochloride salt and the pigment is isolated as a powder, washed and dried.

The resulting pigment, when evaluated as an oil-based ink or decorative paint, yields a more opaque film than the same pigment treated as described above in the absence of diethylaniline.

Example 2 10 parts of CI pigment yellow 17 powder prepared by the conventional azo coupling method are added to 100 parts of diethylaniline and the temperature is raised to 120°C. The dispersion is maintained at the same temperature for 3 hours and the temperature is lowered to 80°C. This mixture is added to sufficient water and hydrogen chloride to obtain a 5% by weight pigment aqueous slurry at PH1. Diethylaniline is extracted into water as a water-soluble hydrochloride in the same manner as in Example 1, and the pigment slurry is isolated and dried in the same manner as in Example 1 to obtain a powder. When this powder is incorporated into industrial paints based on alkyd resins and melamine/formaldehyde, there is increased opacity, gloss, and weather resistance compared to paints using the original powder.

Example 3 The procedure of Example 2 is repeated except using CI pigment yellow 83 which has been treated as described in Example 15 of GB 986116. The resulting powder is tested in alkyd melamine/formaldehyde paints and shows improved gloss, coverage and weatherability over paints using the starting material.

Example 4 10 parts of CI Pigment Yellow 13 powder prepared by conventional azo coupling and isolation methods are stirred in 100 parts of 2-ethylhexylamine for 48 hours. The product is then added to hydrochloric acid and isolated as in Example 1. When the treated pigment is incorporated into a nitrocellulose packaging ink, there is improvement in gloss and rheology as compared to a similarly heat treated product without the presence of 2-ethyl-hexylamine.

Example 5 20 parts of CI Pigment Yellow 3 powder are stirred in 200 parts of N-cyclohexylaniline at 100°C. Heating is continued for 1 hour and the resulting mixture is added dropwise to a stirred solution of dilute hydrochloric acid in an amount sufficient to make the equilibrium mixture acidic to a pH of 2. The product is then isolated by filtration, washed to remove all traces of amine salts, and dried when incorporated into decorative paints.
A powder is obtained which provides improved opacity and weatherability compared to paints containing untreated starting pigments.

Example 6 The procedure of Example 5 is repeated except that the amine used is n-hexylamine.

The resulting product was found to have increased gloss, weatherability, and opacity compared to the original pigment in alkylmelamine/formaldehyde paints.

Example 7 10 parts of CI Pigment Yellow 74 powder are added to 50 parts of methyl anthranilate with stirring and heated to 150°C.

After 30 minutes at this temperature, the mixture is cooled to 80° C. and stirred in water. Dilute sulfuric acid is added to reach and maintain pH 3. The product is filtered, washed and dried. The resulting powder product provides improved gloss and opacity in industrial paints compared to those containing untreated pigments.

Claims (1)

[Scope of Claims] 1. A process for the treatment of azo pigments, which comprises contacting the pigment with an amine, optionally replacing mono-azo pigments or bis-azo pigments based on coupling components of arylamides and pyrazolones in the absence of water. amino-benzene or carbon number 6
to 12 linear, branched or substituted alkyl amines or cycloalkylamines at a temperature above the melting point of the amine, and then the composition of the pigment and amine is brought into contact with the amine until the amine is completely dissolved.
A method for treating an azo pigment, characterized by contacting it with water and an acid at a pH. 2. The amine is aniline, each alkyl group is N-mono-alkylaniline or N,N-di-alkylaniline having 1 to 8 carbon atoms, or a linear alkylamine having 6 to 12 carbon atoms or a straight-chain alkylamine having 6 to 12 carbon atoms. A method according to claim 1, wherein the branched alkyl amine is a branched alkylamine. 3 The amine is N,N-diethylaniline or 2-
The method of claim 1, wherein ethyl-hexylamine is used. 4. The method according to any one of claims 1 to 3, wherein the pigment is added as a dry powder. 5. A method according to any one of claims 1 to 3, wherein the pigment is in the form of a presscake and water is removed from the system by distillation. 6 Any one of claims 1 to 5, in which the amount of amine is 2% by weight or more of the pigment.
The method described in section. 7. The method according to any one of claims 1 to 6, wherein the acid is an aliphatic carboxylic acid having 1 to 4 carbon atoms, an organic sulfonic acid, or a mineral acid. 8. The method according to any one of claims 1 to 7, wherein the acid is hydrochloric acid, sulfuric acid, or acetic acid.