JP7587935B2 - Compound, dye composition, colorant and coloring method for anodized aluminum, and method for producing said compound - Google Patents

Description

The present invention relates to a compound, a dye composition, and a colorant for anodized aluminum. It also relates to a method for coloring anodized aluminum using the compound and the dye composition, and a method for producing the compound.

Conventionally, a method for coloring the surface of aluminum (including its oxides or alloys) has been used in which an electric current is passed through the aluminum as the anode in an electrolyte containing water and a suitable acid (anodic oxidation), forming a porous aluminum oxide film (anodized film) on the surface, and then coloring the surface with an organic dye as a colorant (Patent Documents 1 to 4).

In order to meet the recent demand for a wide variety of colored aluminum products, a dyeing method that can handle dyes of various colors (Patent Document 4) has been developed.

Japanese Patent Application Publication No. 9-302256 Japanese Unexamined Patent Publication No. 60-235867 Special Publication No. 2002-522617 Special Publication No. 2013-506053

For example, dyes for anodized aluminum coatings that are yellow to orange with a reddish tint are popular as gold colors, but conventional dyes do not have sufficient light resistance, and there is a demand for a single dye that does not require color mixing and has good light resistance.

Chromium-containing dyes for anodized aluminum coatings (Patent Documents 1 to 3, etc.) have excellent light and heat resistance and have been widely used, but in recent years, from an environmental perspective, there has been a demand for dyes with a variety of hues that do not contain heavy metals such as chromium.

The problem that the present invention aims to solve is to provide a compound capable of forming an anodized film that is excellent in light resistance and heat resistance and does not contain heavy metals such as chromium on the surface of aluminum, aluminum oxide, or aluminum alloy, a dye composition containing the compound, a colorant for anodized aluminum comprising the dye composition, a coloring method, and a method for producing the compound.

In order to solve the above problems, the inventors have thoroughly investigated pigments (dyes) for anodizing aluminum, and have found that by using a compound (azo dye) having a specific structure as a coloring agent for anodized aluminum, a coating having excellent light resistance and heat resistance can be formed on anodized aluminum. That is, the present invention is, for example, composed of the following:

［式（１）中、Ａは置換基を有していてよいアルキル基、置換基を有していてよいシクロアルキル基、又は下記式（Ｉａ）で表される基を表し、

Ｒ^１は―ＣＯＯ^－または―ＣＯＯＨを表し、
Ｒ^２～Ｒ^１１はそれぞれ独立に、―Ｈ、―ＯＨ、―ＣＯＯ^－、―ＣＯＯＨ、―ＮＯ_２、―ＮＯ、―ＣＮ、―ＳＯ_３ ^－、―ＳＯ_３Ｈ、―ＳＨ、
置換基を有していてもよい炭素原子数０～２０のアミノ基、
置換基を有していてもよい炭素原子数０～２０のスルホニル基、
置換基を有していてもよい炭素原子数１～２０の直鎖状もしくは分岐状のアルキル基、
置換基を有していてもよい炭素原子数３～２０のシクロアルキル基、
置換基を有していてもよい炭素原子数１～２０の直鎖状もしくは分岐状のアルコキシ基、
置換基を有していてもよい炭素原子数３～２０のシクロアルコキシ基、
置換基を有していてもよい炭素原子数２～２０の直鎖状もしくは分岐状のアルケニル基、
置換基を有していてもよい炭素原子数１～２０のアシル基、
置換基を有していてもよい炭素原子数６～３０の芳香族炭化水素基、または
置換基を有していてもよい環形成原子数５～３０の複素環基を表し、
Ｒ^２～Ｒ^５、Ｒ^７～Ｒ^１１は、隣り合う基同士で互いに結合して環を形成していてもよく、
Ｘは非発色カチオンを表し、ｋは１～６の整数を表す。］ [1] A compound represented by the following general formula (I):

In formula (1), A represents an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a group represented by the following formula (Ia):

R ¹ represents ^-COO- or -COOH;
R ² to R ¹¹ each independently represent —H, —OH, —COO ⁻ , —COOH, —NO ₂ , —NO, —CN, —SO ₃ ⁻ , —SO ₃ H, —SH,
an amino group having 0 to 20 carbon atoms which may have a substituent;
a sulfonyl group having 0 to 20 carbon atoms which may have a substituent;
a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent;
a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent;
a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent;
a cycloalkoxy group having 3 to 20 carbon atoms which may have a substituent;
a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent;
an acyl group having 1 to 20 carbon atoms which may have a substituent;
represents an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 30 ring atoms which may have a substituent,
adjacent groups of R ² to R ⁵ and R ⁷ to R ¹¹ may be bonded to each other to form a ring;
X represents a non-color-forming cation, and k represents an integer of 1 to 6.

[2] The compound described in [1], represented by the following general formula (1):

[In formula (1), R ¹ to R ¹¹ , X and k are as defined above.]

[3] The compound according to [1] or [2], wherein, in the general formula (I), R ⁴ and R ⁵ are each independently —H, —COO ⁻ , —COOH, —NO ₂ , —SO ₃ ⁻ , —SO ₃ H, or a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent.

[4] The compound according to any one of [1] to [3], wherein, in the general formula (I), R ⁶ is -COO ^- , -COOH, an amino group having 0 to 10 carbon atoms which may have a substituent, or a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent.

[5] The compound according to any one of [1] to [4], wherein in the general formula (1), R ⁷ to R ¹¹ are each independently -H, -NO ₂ , -SO ₃ ^- , -SO ₃ H, or -SO ₂ NH ₂ .

[6] A dye composition containing the compound described in any one of [1] to [5].

[7] A colorant for anodized aluminum containing the dye composition described in [6].

[8] A method for coloring anodized aluminum or anodized aluminum alloy, comprising using a dye composition containing 0.02 to 10 mass % of a compound according to any one of [1] to [5].

[9] A method for producing the compound according to any one of [1] to [5], wherein the compound represented by the general formula (I) is obtained by a diazo coupling reaction between a diazotized product obtained by diazotizing a compound represented by the following general formula (II) and a compound represented by the following general formula (III) and/or a salt thereof.

[In formulas (II) and (III), A and R ¹ to R ¹¹ are as defined above.]

[10] A method for producing a compound represented by the general formula (1), wherein the compound represented by the general formula (1) is obtained by a diazo coupling reaction between a diazotized product obtained by diazotizing a compound represented by the following general formula (2) and a compound represented by the following general formula (3) and/or a salt thereof.

[In formulas (2) and (3), R ¹ to R ¹¹ are as defined above.]

The present invention provides a compound capable of forming an anodized film that is excellent in light resistance and heat resistance and does not contain heavy metals such as chromium on the surface of aluminum, aluminum oxide, or aluminum alloy, a dye composition containing the compound, a colorant for anodized aluminum comprising the dye composition, a coloring method, and a method for producing the compound.

The embodiment of the present invention will be described in detail below. The present invention is not limited to the following embodiment, and can be practiced in various modifications within the scope of the gist. The compound represented by the general formula (I) and the compound represented by the general formula (1) will be specifically described below, but the present invention is not limited thereto. The part in the square brackets [ ] in the compound represented by the general formula (I) and the compound represented by the general formula (1) is an anion, and forms a complex with the non-color-forming cation represented by X in the general formula (1). In the general formulas (I) and (1), the anion part may be one type of structure, or may be multiple types of structures different from each other, and is preferably one type of structure. In other words, the multiple R ¹ to R ¹¹ may be the same or different. X may be one type or a mixture of multiple Xs, and is preferably one type. When k is an integer of 2 to 6, the multiple Xs may be the same or different.

The compound according to this embodiment is a compound represented by the above-mentioned general formula (I). A represents an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a group represented by the following formula (Ia):

The alkyl group represented by A, which may have a substituent, may be, for example, a "straight-chain or branched alkyl group having 1 to 20 carbon atoms, which may have a substituent," as described below. A specific example of the alkyl group represented by A, which may have a substituent, is, for example, a methyl group. The cycloalkyl group represented by A, which may have a substituent, may be, for example, a "cycloalkyl group having 3 to 20 carbon atoms, which may have a substituent," as described below. A specific example of the cycloalkyl group represented by A, which may have a substituent, is, for example, a cyclohexyl group.

The compound represented by general formula (I) may be a compound represented by the above general formula (1) in which A is a group represented by formula (Ia). In this case, it becomes easier to form an anodized coating that is a single color with a yellow to orange reddish yellow color.

Examples of the "amino group having 0 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ include an unsubstituted amino group (-NH ₂ ), a monosubstituted amino group, and a disubstituted amino group. The number of carbon atoms in the monosubstituted amino group or disubstituted amino group is, for example, 1 to 20, may be 1 to 10, or may be 2 to 6. The amino group having 0 to 20 carbon atoms which may have a substituent may be a group to which an aromatic hydrocarbon group having 6 to 20 carbon atoms (for example, an aromatic hydrocarbon group described later), an acyl group having 1 to 20 carbon atoms, or a heterocyclic group having 5 to 20 ring atoms is bonded via -NH- or -N<. Examples of the monosubstituted amino group include an ethylamino group, an acetylamino group, a phenylamino group, and a benzoylamino group. Examples of the disubstituted amino group include a dimethylamino group, a diethylamino group, a diphenylamino group, and an acetylphenylamino group.

The "sulfonyl group which may have a substituent having 0 to 20 carbon atoms" represented by R ² to R ¹¹ means a sulfonyl group having a substituent R ¹⁰⁰ represented by -SO ₂ -R ¹⁰⁰ (or -S(=O) ₂ -R ¹⁰⁰ ). However, R ¹⁰⁰ is other than -OH and O ^- . R ¹⁰⁰ may be a group containing a carbon atom or a group not containing a carbon atom. When R ¹⁰⁰ is a group containing carbon, the number of carbon atoms of R ¹⁰⁰ is 1 to 20, optionally 1 to 10, or optionally 1 to 7. Examples of the sulfonyl group which may have a substituent having 0 to 20 carbon atoms include a sulfonamide group (-S(=O) ₂ -NH ₂ ), a mesyl group, and a tosyl group.

The number of carbon atoms in the "linear or branched alkyl group" in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ is 1 to 20, or may be 1 to 10, or may be 1 to 6, or may be 1 to 4. Specific examples of the "linear or branched alkyl group having 1 to 20 carbon atoms" in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" represented by ^{R 2} to R ¹¹ include linear alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, and n-decyl group; and branched alkyl groups such as isopropyl group, isobutyl group, s-butyl group, t-butyl group, isooctyl group, and t-octyl group.

Specific examples of the "cycloalkyl group having 3 to 20 carbon atoms" in the "cycloalkyl group having 3 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group.

Specific examples of the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms" in the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ include straight-chain alkoxy groups such as methoxy, ethoxy, propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, and n-decyloxy; and branched alkoxy groups such as isopropoxy, isobutoxy, s-butoxy, t-butoxy, isooctyloxy, and t-octyloxy.

Specific examples of the "cycloalkoxy group having 3 to 20 carbon atoms" in the "cycloalkoxy group having 3 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ include a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

Specific examples of the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ include a vinyl group, an allyl group, an isopropenyl group, a 2-butenyl group, a 1-hexenyl group, or a straight-chain or branched group in which a plurality of these alkenyl groups are bonded.

The "acyl group having 1 to 20 carbon atoms which may have a substituent" represented by R ² to R ¹¹ is a group represented by -(C=O)-R ^101. The number of carbon atoms in the acyl group is the total number of carbon atoms in the acyl group and the substituent R ^101. The substituent R ¹⁰¹ may be a group containing carbon atoms, or may be a group not containing carbon atoms. When the substituent R ¹⁰¹ is a group containing carbon atoms, the number of carbon atoms in the substituent R ¹⁰¹ may be, for example, 1 to 20, or may be 1 to 10. The acyl group having 1 to 20 carbon atoms which may have a substituent may be a group having a total of 1 to 20 carbon atoms to which an aromatic hydrocarbon group described below is bonded via the acyl group, or a group having a total of 1 to 20 carbon atoms to which a heterocyclic group having 5 to 20 ring atoms described below is bonded via the acyl group. Examples of the substituent _R ¹⁰¹ include -H, _-CH3 , _-CH2CH2CH3 , -CH= _CH2 , and _-C6H5 (phenyl group). Specific examples of the "acyl group having 1 to ₂₀ carbon _atoms " in the "acyl group having 1 to 20 carbon atoms which may have a substituent" include a formyl group, an acetyl group, a propionyl group, an acryloyl group, and a benzoyl group.

Specific examples of the "aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent" represented by R ² to R ¹¹ include a phenyl group, a benzoyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a triphenylenyl group, an indenyl group, a fluorenyl group, etc. Here, the "aromatic hydrocarbon group" in the present invention represents an aromatic hydrocarbon group and a condensed polycyclic aromatic group, and among these, a phenyl group or a naphthyl group is preferred.

Specific examples of the "heterocyclic group having 5 to 30 ring atoms which may have a substituent" represented by R ² to R ¹¹ include a piperazinyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an indolyl group, a benzimidazolyl group, a carbazonyl group, a carbolinyl group, an acridinyl group, a phenanthrolinyl group, a hydantoin group, a furanyl group, a benzofuranyl group, a dibenzofuranyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, and a benzothiazolyl group.

Represented by R ² to R ¹¹ ;
"A substituted amino group having 0 to 20 carbon atoms,"
"A substituted sulfonyl group having 0 to 20 carbon atoms",
"A linear or branched alkyl group having 1 to 20 carbon atoms and having a substituent,"
"A cycloalkyl group having 3 to 20 carbon atoms and having a substituent,"
"A linear or branched alkoxy group having 1 to 20 carbon atoms and having a substituent",
"A cycloalkoxy group having 3 to 20 carbon atoms and having a substituent",
"A substituted linear or branched alkenyl group having 2 to 20 carbon atoms",
"A substituted acyl group having 1 to 20 carbon atoms,"
Examples of the "substituent" in the "substituted aromatic hydrocarbon group having 6 to 30 carbon atoms" or the "substituted heterocyclic group having 5 to 30 ring atoms" include:
Specifically, the following groups are included: a hydroxyl group (-OH), -COO ^- , a carboxyl group (-COOH), a nitro group (-NO ₂ ), a nitroso group (-NO), a cyano group (-CN), -SO ₃ ^- , a sulfonic acid group (-SO ₃ H), a thiol group (-SH),
An unsubstituted amino group; a monosubstituted amino group having a group of 0 to 20 carbon atoms bonded via —NH—; a disubstituted amino group having a group of 0 to 20 carbon atoms bonded via —N<;
a group having a sulfonamide (-S(=O) ₂ -NH ₂ ) group, a mesyl group, a tosyl group or _the like;
linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, pentyl, n-hexyl, isohexyl, heptyl, n-octyl, t-octyl, isooctyl, nonyl, and decyl groups;
cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group;
linear or branched alkoxy groups, such as a methoxy group, an ethoxy group, a propoxy group, a t-butoxy group, an n-pentyloxy group, or an n-hexyloxy group;
cycloalkoxy groups such as a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, and a cyclohexyloxy group;
a vinyl group, a 1-propenyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a 1-pentenyl group, a 1-hexenyl group, an isopropenyl group, an isobutenyl group, or a linear or branched alkenyl group in which a plurality of these alkenyl groups are bonded;
acyl groups such as a formyl group, an acetyl group, a propionyl group, an acryloyl group (acrylyl group), and a benzoyl group;
Aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group, a triphenylenyl group, an indenyl group, or a fluorenyl group;
heterocyclic groups such as a pyridyl group, a pyrimidinyl group, a triazinyl group, a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a pyrazinyl group, a pyridazinyl group, a piperidinyl group, a piperazinyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an indolyl group, a benzimidazolyl group, a carbazonyl group, a carbolinyl group, an acridinyl group, a phenanthrolinyl group, a phenanthridinyl group, a hydantoin group, a furanyl group, a benzofuranyl group, a dibenzofuranyl group, a pyranyl group, a coumarinyl group, an isobenzofuranyl group, a xanthenyl group, an oxanthrenyl group, a pyranonyl group, a thienyl group, a thiopyranyl group, a benzothienyl group, a dibenzothienyl group, a thioxanthenyl group, an oxazolyl group, a benzoxazolyl group, a morpholinyl group, a thiazolyl group, and a benzothiazolyl group;
Examples include cyclic olefin groups such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a (1,3- or 1,4-)cyclohexadienyl group, and a 1,5-cyclooctadienyl group.
These "substituents" may be contained only one or more, and when more than one is contained, they may be the same or different. In addition, these "substituents" may have the above-mentioned substituents. When the "substituent" contains a carbon atom, the carbon atom is counted in the above "0 to 20 carbon atoms", "1 to 20 carbon atoms", "2 to 20 carbon atoms", "3 to 20 carbon atoms" and "6 to 30 carbon atoms". Similarly, when the "substituent" contains a ring-forming atom, the ring-forming atom is counted in the "5 to 30 ring-forming atoms". Furthermore, these substituents may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom or a sulfur atom to form a ring.

R ¹ is ^-COO- or -COOH. R ² is preferably -H, -COO- ^, -COOH, -NO ₂ , -SO ₃ ^- , -SO ₃ H, or a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent. R ³ is preferably -H, -NO ₂ , or an amino group having 0 to 10 carbon atoms which may have a substituent, and more preferably -H. R ⁴ and R ⁵ are each independently preferably -H, -COO- ^, -COOH, -NO ₂ , -SO ₃ ^- , -SO ₃ H, or a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent, and more preferably R ⁴ is -COO- ^, -COOH, -NO ₂ , -SO ₃ ^- , -SO ₃ H, or -SO ₂ NH ₂ .

R ⁶ is preferably —COO ⁻ , —COOH, an amino group having 0 to 10 carbon atoms which may have a substituent, or a linear or branched alkyl group having 1 to 10 carbon atoms which may have a substituent.

It is preferred that R ⁷ to R ¹¹ each independently represent -H, -NO ₂ , -SO ₃ ^- , -SO ₃ H, or -SO ₂ NH ₂ , and it is more preferred that at least one of R ⁷ to R ¹¹ is -SO ₃ ^- or -SO ₃ H.

R ² to R ⁵ and R ⁷ to R ¹¹ each represent a substituent as described above, but adjacent groups may be bonded to each other by a single bond, or a bond via an oxygen atom (—O—) or a bond via a sulfur atom (—S—) to form a ring. For example, adjacent groups R ² to R ⁵ may be bonded to each other to form a benzene ring, and R ⁴ and R ⁵ may be bonded to each other to form a benzene ring.

"X" is a non-coloring cation. A non-coloring cation is a cation that does not have a chromophore (e.g., a nitro group, an azo group, or a carbonyl group). Specific examples of non-coloring cations include alkali metal ions such as hydrogen ion (H ⁺ ), lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), and potassium ion (K ⁺ ); and cations containing nitrogen atoms such as ammonium ion (NH ₄ ⁺ ) and substituted ammonium ion (amino ion). Specific examples of cations containing nitrogen atoms include ammonium ions represented by R ¹² R ¹³ R ¹⁴ R ¹⁵ N ⁺ , where R ¹² to R ¹⁵ each independently represent -H, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent, and may be bonded to each other to form a ring. In the formula, the details of the "substituent", the "linear or branched alkyl group having 1 to 20 carbon atoms" and the "aromatic hydrocarbon group having 6 to 20 carbon atoms" in R ¹² to R ¹⁵ are the same as those of R ² to R ¹¹ in the general formula (1). Of these cations, X is more preferably an alkali metal ion, and particularly preferably K ⁺ or Na ⁺ .

k represents the number of non-color-forming cations "X" and is an integer from 1 to 6, preferably an integer from 1 to 4.

The compounds represented by the above general formula include all possible stereoisomers. Specific examples of the compounds of the present invention represented by the above general formula are shown below, but the present invention is not limited to these. In the example compounds, the anion moiety in square brackets [ ] indicates its total charge, and some hydrogen atoms are omitted in the structural formula.

The compound represented by general formula (I) can be obtained, for example, by a method including a step of diazo coupling reaction between a diazotized product obtained by diazotizing a compound represented by the following general formula (II) and a compound represented by the following general formula (II) and/or a salt thereof (coupling step). That is, the compound represented by general formula (I1) may be obtained by a diazo coupling reaction between a diazotized product obtained by diazotizing a compound represented by the following general formula (II) and a compound represented by the following general formula (III) and/or a salt thereof.

The method for producing a compound represented by general formula (I) may further include, for example, a step of diazotizing a compound represented by general formula (II) prior to the coupling step.

An example of a method for producing the compound of the present invention represented by the general formula (1) is shown below, but is not limited to this method. Specifically, first, an aromatic amine derivative having an appropriate substituent represented by the general formula (2) below is reacted with a basic aqueous solution prepared using sodium nitrite or the like in an aqueous acid solution such as hydrochloric acid or sulfuric acid at an appropriate temperature to obtain a compound represented by the general formula (2a) below and/or a salt thereof (diazo component).

[In formula (2), R ¹ to R ⁵ are as defined above.]

[In formula (2a), R ¹ to R ⁵ are as defined above.]

On the other hand, a salt (coupler component) of the compound represented by the following general formula (3) can be obtained by dissolving the compound represented by the following general formula (3) in an aqueous solution of sodium hydroxide or the like and reacting it. The compound represented by the general formula (3) can also be used as the coupler component as it is.

[In the formula, R ⁶ to R ¹¹ are as defined above.]

Next, the diazo component and the coupler component are reacted (diazo coupling reaction) to obtain a compound represented by the following general formula (1a) and/or a salt thereof as an azo compound (azo dye). The method for producing the compound represented by the general formula (1) according to this embodiment includes a step of obtaining the compound represented by the general formula (1a) obtained as described above.

[In the formula, R ¹ to R ¹¹ are as defined above.]

The compound represented by general formula (I) can be purified by known methods such as purification by column chromatography; adsorption purification using silica gel, activated carbon, activated clay, etc.; and recrystallization or crystallization using a solvent. In addition, identification and evaluation of the physical properties of the compound can be performed using ultraviolet-visible absorption spectroscopy (UV-Vis), thermogravimetry-differential thermal analysis (TG-DTA), gas chromatography analysis (GC), thin layer chromatography analysis (TLC), gas chromatography-mass spectrometry (GC/MS), nuclear magnetic resonance analysis (NMR) analysis, etc.

The compound represented by the general formula (I) (compound (I)) can be used as a component of a dye composition. Compound (I) can be used alone to color aluminum or aluminum oxide, fibers, etc. That is, compound (I) can be used suitably as a dye compound for coloring aluminum, aluminum oxide, fibers, etc., using one type of monochromatic dye alone. Compound (I) may be used in combination with two or more types to obtain a variety of colors by mixing colors. The dye composition may be mixed with other components for optimal dyeing (coloring using a dye). Specific examples include liquids (solvents) such as water, alcohol, and solvents; additives such as surfactants; and the like. Water is preferred as the solvent. Compound (I) may be used as a component of a dye composition in combination with other dyes. The other dyes are compounds, pigments, dyes, etc. other than compound (I), and specifically include ruthenium complexes, coumarin dyes, cyanine dyes, merocyanine dyes, rhodacyanine dyes, phthalocyanine dyes, porphyrin dyes, xanthene dyes, etc. When compound (I) is used in combination with other components, the amount of the other components relative to compound (I) is preferably 10 to 200% by mass, more preferably 20 to 100% by mass. Aluminum oxide is a composition containing mainly aluminum and oxygen, in which aluminum is oxidized, and the composition ratio may be arbitrary. It contains aluminum oxide, and the crystal system may be single crystal, polycrystalline, or amorphous, or a mixture of these.

The dye composition described above can be used as a colorant for anodized aluminum. The dye composition described above can also be used as a colorant for anodized aluminum alloys. That is, as one embodiment of the present invention, the use (application) of a compound represented by general formula (I) or a dye composition containing the compound for coloring anodized aluminum or anodized aluminum alloys is provided. Also, as one embodiment of the present invention, the use of a compound represented by general formula (I) or a dye composition containing the compound for producing a colorant for anodized aluminum or anodized aluminum alloys is provided.

When compound (I) is used as a colorant for anodized aluminum or anodized aluminum alloy, the concentration of compound (I) in the dye composition containing compound (I) in the coloring (dyeing) method is preferably 0.02 to 10 mass %, and more preferably 0.05 to 3 mass %, based on the total mass of the dye composition. The lower the concentration of the compound, the lighter the coloring can be, and the higher the concentration, the medium to darker the coloring can be.

Here, anodized aluminum refers to aluminum that has been electrolytically treated in an electrolyte such as an acidic aqueous solution, and has been treated to form an oxide layer with fine pores on the surface. A colorant for anodized aluminum refers to an agent that can color (dye) this aluminum surface with fine pores by adsorbing compound (I) into the pores. Usually, a sealing treatment is carried out to close the pores after coloring in order to improve the durability and light resistance of the colored aluminum surface.

Here, anodized aluminum alloy refers to an alloy in which the surface of an aluminum alloy has been anodized. The aluminum alloy in anodized aluminum alloy refers to an alloy containing aluminum as the main component, and refers to an alloy with metals such as copper, manganese, silicon, magnesium, zinc, and nickel. There are no particular limitations on the composition ratio of aluminum to other metals.

The aluminum in anodized aluminum can be aluminum, aluminum oxide, or a metal or metal compound containing aluminum, such as an aluminum alloy with another metal.

The method of coloring aluminum using the above-mentioned coloring agent can be a method known as anodizing. For example, the method described in Japanese Industrial Standards (JIS H 8601: 1999 "Anodized Films of Aluminum and Aluminum Alloys") and Patent Document 1 can be used. The method of coloring aluminum is not particularly limited, but an example is shown below.

First, the aluminum plate is degreased with an aqueous acid solution such as sulfuric acid, oxalic acid, chromic acid, or sulfonic acid, and washed with water. Next, the degreased aluminum plate is used as the anode and electrolyzed with an aqueous acid solution as the electrolyte to form an anodized film (anodized film) having many pores on the aluminum anode surface (anodized treatment), and washed with water. Then, after performing surface conditioning, washing with water, etc. as appropriate, the plate is immersed in an aqueous colorant solution for anodized aluminum containing a dye composition containing the compound of the present invention, and the dye is adsorbed into the pores (dyeing, electrolytic coloring), and the pores on the surface are sealed with aluminum oxide hydrate or the like to form a sealing material, thereby coloring the plate.
When two or more kinds of the dye composition of the present invention are used in combination, or when the dye composition of the present invention is used in combination with other dyes, a mixed solution of all the dyes to be used may be prepared and the anodized aluminum may be immersed in the mixed solution, or each dye solution may be prepared separately and the anodized aluminum may be immersed in each solution in turn.

The electrolysis conditions during coloring in the present invention may be DC electrolysis or AC electrolysis, with DC electrolysis being preferred. The current density is preferably 0.1 to 10 A/ ^dm2 , more preferably 0.5 to 3 A/ ^dm2 . The current application time is preferably 10 seconds to 60 minutes. The thickness of the anodized film is preferably 2 to 20 μm. With regard to these anodizing conditions, the longer the current application time and the thicker the anodized film, the darker the coloring will be, and therefore, by adjusting these conditions, it is possible to adjust the color from light to medium to dark.

The processing temperature for each of the above steps is preferably an appropriate temperature. The temperature for anodizing is preferably 0 to 80°C. The temperature for dyeing is preferably 10 to 70°C. The other processing temperatures are preferably 10 to 80°C.

The dye composition in this embodiment can be used in the same way for anodized oxides using metals other than aluminum. For example, it can be applied to nonmetals such as conductive plastics, as long as the anodized pores can adsorb the dye, such as magnesium, zinc, titanium, and zirconium.

The colorant for anodized aluminum of this embodiment can be evaluated by measuring the properties of a sample obtained by coloring aluminum, such as hue, light resistance, heat resistance, etc. The hue can be evaluated by visually observing the color tone and/or uniformity, or it may be measured as density (K/Sd), color tone (L ^* , a ^* , b ^* ) and color difference (ΔE ^* ) using a color difference meter.

The colors that can be expressed using the colorant for anodized aluminum of this embodiment can be yellow to red colors, and more preferably yellow to orange colors. Colors of different shades, such as yellow, orange, red, pink, brown, and light colors of these (light yellow, light orange, pink, etc.) or dark colors (dark yellow, dark orange, etc.), can be expressed. The colorant for anodized aluminum of this embodiment can also express mixed colors (intermediate colors such as yellow-red, yellowish orange, brown, and bronze) by using the above-mentioned compounds in combination with other pigments.

The light fastness test of the aluminum colored with the coloring agent for anodized aluminum of this embodiment may be performed by irradiating the sample with light for a certain period of time using a tester that simulates sunlight including ultraviolet light, and measuring the change in the hue of the colored aluminum before and after the test. Specifically, the color fastness may be evaluated by measuring the color tone in the CIE L ^* a ^* _b ^* color system using a color ^difference meter or the like, and then judging the color fastness by visually observing the hue of the colored aluminum using a gray scale according to ^the method defined in the Japanese Industrial Standards (JIS L 0804 "Gray scale for discoloration").

The heat resistance test of aluminum colored using the colorant for anodized aluminum of this embodiment can be performed by heating the aluminum for an appropriate fixed period of time, such as 30 minutes to 50 hours, in an incubator or hot air dryer at a temperature range of 50 to 300°C, and evaluating the change in hue before and after the test in the same manner as the light resistance test.

Colored aluminum produced using the colorant for anodized aluminum of this embodiment can be used in a wide variety of aluminum sheet materials and products that use aluminum exteriors.

The present invention will be described in detail below with reference to examples, but is not limited to the following examples. The compounds obtained in the synthesis examples were identified by ¹ H-NMR and ¹³ C-NMR analysis (Nuclear Magnetic Resonance Spectrometer, Model: JNM-ECZ400S/L1, manufactured by JEOL Ltd.), and the measurement results are shown in the synthesis examples below.

Synthesis Example 1 Synthesis of Compound (1-1) (Preparation of Diazo Component) 8.0 g of 4-nitroanthranilic acid, 32 mL of water, and 6.0 g of 35% hydrochloric acid were placed in a reaction vessel, and 8.0 g of a 40% by mass aqueous solution of sodium nitrite was added dropwise while stirring the reaction solution at 10° C. or less, and the reaction was carried out for 2 hours to obtain a diazo component solution.

(Preparation of Coupler Component) 11.4 g of 3-methyl-1-(4-sulfophenyl)-2- pyrazolin -5-one (p-SMP), 40 mL of water, 10.3 g of 24% aqueous sodium hydroxide solution, and 2.4 g of sodium carbonate were placed in a reaction vessel and stirred at 10° C. or lower for 30 minutes to obtain a coupler component solution.

(Diazo coupling reaction) The diazo component solution was added to the stirred coupler component solution, and the solution was stirred overnight at room temperature to carry out the diazo coupling reaction. The completion of the reaction was confirmed by thin layer chromatography (TLC). The purity of the product was confirmed by high performance liquid chromatography (HPLC) based on the retention time peak position and area observed for typical azo dyes.
After the reaction, sulfuric acid was added to make the mixture acidic, and the precipitated solid was collected by filtration and dried under reduced pressure to obtain the compound represented by formula (1-1) as a solid powder (20.3 g, yield 94.0%).

¹ H-NMR (400 MHz, DMSO-d ₆ ): δ (ppm) = 1.87 (s, 1H), 2.23 (s, 3H), 7.64 (dd, 2H), 7.87 (dd , 2H), 7.91 (d, 1H), 8.17 (d, 1H), 8.50 (d, 1H).
^13C -NMR (100MHz, DMSO-d ₆ ): δ (ppm) = 12.27, 21.41, 109.34, 117.29, 117.79, 126.84, 130.57, 133.66, 138.64, 145.40, 146.06, 149.47, 150.56, 156.06, 167.24.

Synthesis Example 2 Synthesis of Compound (1-6) (Preparation of Diazo Component) 8.0 g of 2-aminoterephthalic acid, 32 mL of water, and 6.0 g of 35% hydrochloric acid were placed in a reaction vessel, and 8.0 g of a 40% by mass aqueous solution of sodium nitrite was added dropwise while stirring the reaction liquid at 10° C. or less, and the reaction was carried out for 2 hours to obtain a diazo component liquid.

(Preparation of Coupler Component) 13.8 g of 3-carboxy-1-(4-sulfophenyl)-2- pyrazolin -5-one, 40 mL of water, 10.3 g of 24% aqueous sodium hydroxide solution, and 2.4 g of sodium carbonate were placed in a reaction vessel and stirred at 10° C. or lower for 30 minutes to obtain a coupler component solution.

(Diazo coupling reaction) The diazo component solution was added to the stirred coupler component solution, and the solution was stirred overnight at room temperature to carry out the diazo coupling reaction. The completion of the reaction was confirmed by thin layer chromatography (TLC). The purity of the product was confirmed by high performance liquid chromatography (HPLC) based on the retention time peak position and area observed for typical azo dyes.
After the reaction, sulfuric acid was added to make the mixture acidic, and the precipitated solid was collected by filtration and dried under reduced pressure to obtain the compound represented by the formula (1-6) as a solid powder (17.3 g, yield 82.4%).

Synthesis Example 3 Synthesis of Compound (1-10) (Preparation of Diazo Component) 8.0 g of 2-aminoterephthalic acid, 32 mL of water, and 6.0 g of 35% hydrochloric acid were placed in a reaction vessel, and 8.0 g of a 40% by mass aqueous solution of sodium nitrite was added dropwise while stirring the reaction liquid at 10° C. or less, and the reaction was carried out for 2 hours to obtain a diazo component liquid.

(Preparation of coupler component) 7.9 g of 3-amino-1-phenyl-2-pyrazolin-5-one, 50 mL of water, 10.3 g of 24% aqueous sodium hydroxide solution, and 2.4 g of sodium carbonate were placed in a reaction vessel and stirred at 10°C or less for 30 minutes to obtain a coupler component solution.

(Diazo coupling reaction) The diazo component solution was added to the stirred coupler component solution, and the solution was stirred overnight at room temperature to carry out the diazo coupling reaction. The completion of the reaction was confirmed by thin layer chromatography (TLC). The purity of the product was confirmed by high performance liquid chromatography (HPLC) based on the retention time peak position and area observed for typical azo dyes.
After the reaction, sulfuric acid was added to make the mixture acidic, and the precipitated solid was collected by filtration and dried under reduced pressure to obtain the compound represented by the formula (1-10) as a solid powder (15.1 g, yield 93.2%).

Synthesis Example 4 Synthesis of Compound (1-36) (Preparation of Diazo Component) 8.0 g of 2-aminoterephthalic acid, 32 mL of water, and 6.0 g of 35% hydrochloric acid were placed in a reaction vessel, and 8.0 g of a 40% by mass aqueous solution of sodium nitrite was added dropwise while stirring the reaction liquid at 10° C. or less, and the reaction was carried out for 2 hours to obtain a diazo component liquid.

(Preparation of Coupler Component) 5.1 g of 1,3-dimethyl-5- pyrazolone , 50 mL of water, 10.3 g of 24% aqueous sodium hydroxide solution, and 2.4 g of sodium carbonate were placed in a reaction vessel and stirred at 10° C. or lower for 30 minutes to obtain a coupler component solution.

(Diazo coupling reaction) The diazo component solution was added to the stirred coupler component solution, and the solution was stirred overnight at room temperature to carry out the diazo coupling reaction. The completion of the reaction was confirmed by thin layer chromatography (TLC). The purity of the product was confirmed by high performance liquid chromatography (HPLC) based on the retention time peak position and area observed for typical azo dyes.
The reaction proceeded quantitatively, and the mixture was acidified with sulfuric acid, and the precipitated solid was collected by filtration. The solid was dried to obtain a compound represented by the following formula (1-36) as a solid powder.

<Evaluation of color and light fastness>
[Example 1]
Colored aluminum was produced by anodizing an aluminum substrate in the following manner: In the anodizing and dyeing steps, two types of dyeing conditions were set, in which the treatment time and the dye compound concentration were changed.
(Degreasing) A degreasing solution was prepared by mixing 150 mL of a degreasing agent (TOP ADD-100, manufactured by Okuno Chemical Industries Co., Ltd.), 70 mL of 98% sulfuric acid, and 1000 mL of water in a container. An aluminum substrate for dyeing cut to an appropriate size was immersed in the solution and subjected to a degreasing treatment at 60° C. for 3 minutes, and then washed with water.
Anodization was performed at a temperature of 20±1° C., a current density of 1.0 A/dm2, and a current application time of 1.0 A/ ^dm2 for anodization to obtain an anodized film having the following thickness. After oxidation, the substrate was washed with water.
Anodizing condition (1): Electric current for 25 minutes Anodizing film thickness: 7 μm
Anodizing condition (2): Electric current for 40 minutes Anodizing film thickness: 11 μm
Anodizing condition (3): Electric current for 54 minutes Anodizing film thickness: 15 μm
(Surface Conditioning) A surface conditioner (TAC Somar 121, manufactured by Okuno Chemical Industries Co., Ltd.) and water were used to prepare a surface conditioner solution with a concentration of 50 mL/L, and the aluminum substrate was immersed in the solution for 1 minute at 45° C. After immersion, the aluminum substrate was washed with water.
(Dyeing) Using the compound (1-1) obtained in Synthesis Example 1 as the dye, dyeing aqueous solutions containing the dyes in the following concentrations were prepared as the dye compositions of the present invention, and the substrates were immersed for the following dyeing times and dyed at a temperature (make-up bath temperature) of 55° C. After dyeing, the aluminum substrate was washed with water.
Dyeing condition (1): Dye concentration 2.0% by mass Dyeing time: 30 seconds Dyeing condition (2): Dye concentration 1.0% by mass Dyeing time: 5 minutes (sealing) A 40 mL/L sealing solution was prepared using a sealer (Topseal H-298, manufactured by Okuno Chemical Industries Co., Ltd.) and water, and sealing treatment was performed for 15 minutes at about 90° C. After sealing treatment, it was dried with hot air.

(Evaluation of Hue) The hue of the colored aluminum plate colored with the dye of compound (1-1) was evaluated visually and with a colorimeter (apparatus name: Konica Minolta spectrophotometer, model: CM-3700A) according to the CIE L ^* a ^* b ^* color system. The results of the evaluated hue are shown in Table 1.

(Lightfastness Test) A colored aluminum plate colored with the dye of compound (1-1) was subjected to a lightfastness test by the following method. Using a xenon fade meter/ATLAS Ci3000+Xenon Weather Ometer (manufactured by Atlas), the colored aluminum plate was irradiated for 50, 100 and 200 hours under the conditions of irradiance: 300-400 nm, 60 W/m ² , temperature in test chamber: 38° C., humidity: 50%, black panel (BP) temperature: 63° C., and the hue and color difference ΔE ^* before and after light irradiation were measured by a color difference meter. In addition, the lightfastness was judged by visual judgment of color fastness by gray scale series (JIS L 0804 "gray scale for discoloration"). The grade is highest at grade 5 and lowest at grade 1, and the higher the grade, the darker the color (the smaller the color difference ΔE ^* ) and the more the hue before irradiation is maintained. In the evaluation method of the present invention, the grade judgment results are divided into three stages and evaluated according to the following judgment criteria, and the results are summarized in Table 1.
Grayscale criterion: Correspondence between the grade and the evaluation in the present invention Grade 5 to Grade 4: A (particularly good light resistance)
Grade 3: B (normal level of light resistance)
Grade 2 or lower: C (low light resistance)
As a result, it was found that the dye of compound (1-1) had particularly good light resistance under any of the above-mentioned anodizing conditions, dyeing conditions, and irradiation times.

[Examples 2 to 4]
Instead of the dye of compound (1-1) evaluated in Example 1, colored aluminum was produced under the anodizing condition (1) and the dyeing condition (1) for compounds (1-6), (1-10), and (1-36), in the same manner as in Example 1. The hue, color difference ΔE ^*, and visual light fastness were evaluated, and the results are shown in Table 1.

[Comparative Example 1 to Comparative Example 2]
Instead of the dye of compound (1-1) evaluated in Example 1, the following dye not belonging to the present invention was used:
(D-1) Acid Yellow 23,
(D-2) TAC Yellow RHM (201) (manufactured by Hodogaya Chemical Co., Ltd., a mixture of a known yellow-based alumite dye, a Cr-containing dye, and a plurality of dyes) was used to prepare colored aluminum under the dyeing conditions of the anodizing conditions (1) and the dyeing conditions (1) in the same manner as in Example 1, and the results of evaluating the hue, color difference ΔE ^*, and light fastness by visual observation are summarized in Table 1.

(Heat resistance test)
[Examples 5 to 8]
For the dyes (1-1), (1-6), (1-10) and (1-36), heat resistance tests were carried out on aluminum plates colored in the same manner as in Examples 1 to 4 above, by the following method. The samples were heated under the following exposure conditions using a constant temperature dryer (manufactured by AS ONE Corporation, model: 87L EOP-450V).
Dryer temperature and heating time: 200°C-5 hours, or 250°C-3 hours. The heat resistance of the present invention was evaluated by measuring the color difference of the colored aluminum sample before and after heating with a color difference meter described below, and visually evaluating the color difference according to the following criteria. The results are shown in Table 2.
Equipment: Colorimeter (Konica Minolta spectrophotometer, model: CM-3700A)
Color difference calculation formula: ΔE ^* _ab (L ^* a ^* b ^* , CIE 1976)
and ΔE ^* ₀₀ (CIE DE2000)
Viewing angle: 10°
Heat resistance criteria:
A: Good heat resistance ΔE ^* ≦2.0
B: Normal level of heat resistance 2.0<ΔE ^* ≦5.0
C: Low heat resistance ΔE ^* >5.0

[Comparative Examples 4 to 5]
The heat resistance of samples similarly colored with the compounds (D-1) and (D-2) of Comparative Examples 1 and 2 was evaluated in the same manner as in Examples 5 to 8. The results are summarized in Table 2.

The results in Tables 1 and 2 show that by using an anodized aluminum colorant made of a dye composition containing the compound of the present invention, a yellow or reddish yellow film can be formed on the aluminum, and a film with high light and heat resistance can be formed. On the other hand, the comparative examples using the dyes did not have sufficient light and/or heat resistance.

Specifically, compounds (1-1), (1-6), and (1-10) as well as compound (1-36) were superior in light resistance and heat resistance compared to the compounds of the comparative examples. Compounds (1-1), (1-6), and (1-10) were capable of forming a monochromatic reddish yellow colored film. When Acid Yellow 3, a known dye compound, was used, it was difficult to form such a monochromatic reddish yellow colored film.

The dye composition containing the compound according to the present invention can provide a colorant for anodized aluminum that forms a colored film that is excellent in light resistance and heat resistance and does not contain heavy metals such as chromium. Furthermore, by using the colorant, an anodized aluminum film that is excellent in light resistance and heat resistance can be obtained. According to some aspects of the present invention, it is possible to obtain a colorant for anodized aluminum that forms a monochrome colored film in a yellow or orange color, particularly a reddish yellow color.

Claims (9)

A colorant for anodized aluminum, comprising a dye composition containing a compound represented by the following general formula (I):

In formula ( I ), A represents a group represented by the following formula (Ia):

R ¹ represents ^-COO- or -COOH;
^R4 represents _-NO2 ,
R ² , R ³ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ and R ¹¹ represent -H;
R6 represents -CH3 _; ^​
R ⁹ represents —SO ₃ ⁻ or —SO ₃ H;
X represents a non-color-forming cation, and k represents an integer of 1 to 6. A compound represented by the following general formula (I):

[In formula (I), A represents an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or a group represented by the following formula (Ia):

R ¹ represents ^-COO- or -COOH;
^R6 represents _-NH2 ,
R ² to R ⁵ and R ⁷ to R ¹¹ each independently represent —H, —OH, —COO ⁻ , —COOH, —NO ₂ , —NO, —CN, —SO ₃ ⁻ , —SO ₃ H, —SH,
an amino group having 0 to 20 carbon atoms which may have a substituent;
a sulfonyl group having 0 to 20 carbon atoms which may have a substituent;
a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent;
a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent;
a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent;
a cycloalkoxy group having 3 to 20 carbon atoms which may have a substituent,
a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent;
an acyl group having 1 to 20 carbon atoms which may have a substituent;
represents an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 30 ring atoms which may have a substituent,
adjacent groups of R ² to R ⁵ and R ⁷ to R ¹¹ may be bonded to each other to form a ring;
X represents a non-color-forming cation, and k represents an integer of 1 to 6. A colorant for anodized aluminum, comprising a dye composition containing a compound represented by the following general formula (I):

[In formula (I), A represents _—CH3 ;
R ¹ represents ^-COO- or -COOH;
R ² to R ⁵ each independently represent —H, —OH, —COO ⁻ , —COOH, —NO ₂ , —NO, —CN, —SO ₃ ⁻ , —SO ₃ H, —SH,
an amino group having 0 to 20 carbon atoms which may have a substituent;
a sulfonyl group having 0 to 20 carbon atoms which may have a substituent;
a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent;
a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent;
a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent;
a cycloalkoxy group having 3 to 20 carbon atoms which may have a substituent;
a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent;
an acyl group having 1 to 20 carbon atoms which may have a substituent;
represents an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 30 ring atoms which may have a substituent,
^R6 represents _-CH3 ;
Adjacent groups of R ² to R ⁵ may be bonded to each other to form a ring;
X represents a non-color-forming cation, and k represents an integer of 1 to 6. The compound according to claim 2 , wherein in said general formula (I), R ² to R ³ and R ⁵ are all -H. A dye composition comprising the compound according to claim 2 . A colorant for anodized aluminum containing the dye composition according to claim 5. A method for coloring anodized aluminum or anodized aluminum alloy, comprising using a dye composition containing 0.02 to 10% by mass of the compound according to claim 2 . A method for producing the compound according to claim 2 , comprising the steps of:
The compound represented by the general formula (I) is obtained by a diazo coupling reaction between a diazotized product obtained by diazotizing a compound represented by the following general formula (II) and a compound represented by the following general formula (III) and/or a salt thereof:

[In formulas (II) and (III), A and R ¹ to R ¹¹ are as defined above.] A colorant for anodized aluminum, comprising a dye composition containing a compound represented by the following formula (I):

In formula ( I ), A represents a group represented by the following formula (Ia):

R ¹ , R ⁴ and R ⁶ each represent ^-COO- or -COOH;
R ² , R ³ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ and R ¹¹ all represent —H;
R ⁹ represents —SO ₃ ⁻ or —SO ₃ H;
X represents a non-color-forming cation, and k represents an integer of 1 to 6.