JPH11130972A - Organic pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an org. pigment which is excellent not only in tinting strength and clarity but also in resistnaces to light, solvents, acids, alkalis, heat, etc., by synthesizing a novel epindolidione pigment which is a fused polycyclic pigment represented by a specified formula. SOLUTION: This pigment is represented by the formula (wherein R1 to R8 are each H, alkyl, aralkyl, or aryl provided they are not simultaneously H) provided each of the benzene rings has at least one substituent. Pref., R1 and R5 are each 1-4C alkyl. When the pigment has a symmetric chemical structure, it can be produced by a process comprising four steps; the esterification of dihydroxyfumaric acid, the condensation by dehydration with a substd. aniline, and two steps of condensation by cyclization. The pigment in the form of a synthetic product as it is can be used, though it may be made suitable for application by subjecting it to the step of controlling particle size and the step of surface treating with rosin, a resin, a surfactant, a dispersant, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel epindridione pigment.

[0002]

2. Description of the Related Art Among organic pigments, a group of pigments called condensed polycyclic pigments are also called high-grade pigments because of their excellent heat resistance, light resistance, solvent resistance, and other various resistances. Pigments have been developed. Under these circumstances, anthraquinone, a representative pigment developed relatively early,
Perylene, perinone and the like are known. Subsequently, dioxazine, quinacridone, isoindolinone, etc. were developed,
In recent years, quinophthalones, methine pigments, and the like have been developed.

[0003] Among these pigments, isoindolinone and quinophthalone have been developed especially as yellow or orange pigments.
As reported in Chem. Soc., 1941 , 625, there was a first report in 1941. Then BP833,548 or Paint Tec
hnol.Official Digest, 37 , 1071, etc.
It was used as a pigment in the 0's. Especially because it is excellent in weather resistance, solvent resistance and heat resistance,
It is widely used for coloring resins, fibers, paints, etc. Furthermore, in recent years, there has been a great demand as an alternative to heavy metal-based inorganic pigments. Quinophthalone is a bright yellow compound synthesized by the condensation of quinaldine with phthalic anhydride. Studies have been conducted on this compound as a pigment, particularly for improving light resistance and solvent resistance. For example, it has been used as a pigment since the 1970s, as shown in JP-B-47-3476.

Other known condensed polycyclic pigments include pigments such as fluorbin and epindridione. Fluorubin is a compound synthesized for the first time in 1903 as shown in Ber., 36 , 4048. As a pigment, for example, it has excellent light resistance and solvent resistance as shown in JP-B-38-17831. I have. Also, as reported in Ann. Chem., 518 , 245, quinacridone synthesized for the first time in 1935 is a new red pigment in 1958 as seen in USP 2,884,484 and USP 2,884,485. As printing ink,
It has become widely used in the paint industry. This led to a search for compounds with a structure similar to quinacridone. Epindridione was one of the compounds studied at that time. Epindridione is a structure lacking a central benzene ring in the chemical structure of quinacridone, which corresponds to a structural isomer of indigo. This compound was first synthesized as a 2,8-dimethyl substituent as reported in J. Chem. Soc., 1934 , 1508, and as seen in Helv. Chim. Acta, 31 , 716. 194
The mother skeleton was first synthesized in eight years. A patent as a pigment is described in US Pat. No. 3,334,102, in which dimethoxy, diethoxy-substituted and di-, tri-, and tetra-halogen-substituted pigments are described as pigments having excellent light fastness and coloring power.

In general, the properties required for pigments include:
Color properties such as tinting strength, clarity, hue, light resistance, heat resistance, acid resistance, alkali resistance, solvent resistance, durability such as migration resistance, and suitability for use such as dispersibility and fluidity are exemplified. Of these required properties, the color properties and durability are properties that directly affect the quality of the pigment and are particularly important. Also, when a pigment is used as a plastic colorant, in most cases, the pigment goes through a molten state at a temperature of 200 ° C. or higher, and at this time, the hue is formed by the interaction of the pigment with a metal salt used as a pigment dispersant. May show changes. Therefore, the pigment is also required to have heat resistance from such a viewpoint. Regarding the above-mentioned high-condensed polycyclic pigments, pigments satisfying all of the above-mentioned required characteristics are very limited at present, and the emergence of new pigments having more excellent properties has been increasing. Expected.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide, among the required characteristics of a pigment, a color characteristic which particularly affects the quality, particularly excellent coloring power and sharpness, and a light resistance, a solvent resistance, and the like. It is an object of the present invention to provide a novel epidridione pigment which is excellent in durability such as acid resistance and alkali resistance and has excellent heat resistance as a plastic colorant which does not cause a hue change upon heating.

[0007]

Means for Solving the Problems The present inventors have intensively studied pigments in order to solve the above-mentioned problems. As a result, they have found that an epindrizione pigment represented by the following general formula (1) solves the problems in color characteristics and durability, and has completed the present invention. That is, the present invention relates to an epidindrione pigment represented by the following general formula (1). General formula (1)

[0008]

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(Wherein, R _{1 to} R ₈ each independently represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group, and the alkyl group, the aralkyl group or the aryl group may be substituted with a halogen atom. , R _{1 to} R ₈ are not hydrogen atoms.) The present invention also relates to the above organic pigment wherein R ₁ and R ₅ are alkyl groups. The present invention also relates to the above organic pigment, wherein R _{2 to} R ₄ and R _{6 to} R ₈ are all hydrogen atoms. The present invention also relates to the above organic pigment wherein R ₁ and R ₅ are a methyl group.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Usually, epindridione has a property that it is extremely insoluble in an organic solvent. This property is due to a strong intermolecular bond caused by a hydrogen bond between the oxygen of the carbonyl group in the molecular structure and the hydrogen atom of the imide group in the other molecular structure. More prominent observations are reported in J. Org. Chem., 33 , 4004 (1968). In the case of indigo, it is known that a spectrum in a solid state transits to a longer wavelength region due to intermolecular hydrogen bonding as compared with a spectrum in a solution. Since the observation results in the case of epidridione are similar to those in the case of indigo, it is inferred that similar intermolecular hydrogen bonds exist.

A feature of the chemical structure of the epindridione pigment of the present invention is that the benzene ring constituting the molecule has at least one alkyl group, aralkyl group or aryl group. The alkyl group has 1 to 4 carbon atoms.
Are preferred, and any of a linear or branched structure may be used. An aralkyl group is a benzene ring,
Refers to an alkyl group substituted with an aromatic ring such as a naphthalene ring. Further, the aryl group is a benzene ring, a naphthalene ring,
An aromatic ring such as an anthracene ring or a phenanthrene ring. In the present invention, the alkyl group, aralkyl group or aryl group as the substituent causes a change in the intermolecular interaction, and as a result, a pigment having properties balanced with respect to color characteristics and various resistances can be obtained.

When the pigment is used as a plastic colorant such as polypropylene, a pigment having the above substituents at R ₁ and R ₅ is particularly suitable. Usually, when a pigment is used as a plastic colorant, it is necessary to heat a mixture of the plastic, the pigment and the metal stearate as a dispersant to a temperature of 200 ° C. or more, and at this time, the metal salt and the pigment May change the hue of the coloring matter. It is considered that such a phenomenon is caused by the formation of a certain metal complex due to the interaction between the metal ion generated from the molten metal salt and the nitrogen atom in the pigment structure. Here, when a pigment having a substituent at R ₁ and R ₅ is used, the interaction between the two is hindered by steric hindrance, so that the formation of a metal complex does not occur, and as a result, the hue of the colorant does not change. It is considered something.

[0013] The method for producing the epipindridione pigment of the present invention differs depending on whether the chemical structure of the pigment is symmetric or asymmetric. In the case of a symmetrical chemical structure, it can be produced through a four-step process of esterifying dihydroxyfumaric acid, dehydration-condensation with a substituted aniline, and then a two-stage condensed cyclization process. In the case of an asymmetric chemical structure, it can be manufactured by the following method. First, glycine having a structure in which a nitrogen atom is substituted with an alkylphenyl group is esterified, and an oxalacetic acid diester substituted with a halogenated phenylamino group is synthesized by reacting the ester with oxalic acid diester. Next, this diester is reacted with a substituted aniline to synthesize a mixture of maleic diester and fumaric diester in which adjacent carbon atoms are substituted with different alkylphenylamino groups. From this diester mixture, an epindridione pigment having a structure in which substituents are asymmetrically substituted can be produced through a two-stage condensed cyclization step in the same manner as in the case of epindridione having a symmetric structure.

The pigment obtained by the above-mentioned production process can be used as a pigment as it is for the epindridione pigment of the present invention, but it is further subjected to a post-processing step, for example, salt milling, dry milling, solvent milling, acid pasting or solvent heat treatment. And the like, and a surface treatment step using a rosin, a resin, a surfactant, a dispersant, or the like, thereby giving desired application suitability. Epindridione pigments of the present invention are excellent in color properties, especially in coloring power and sharpness, and are also excellent in various resistances such as light resistance, solvent resistance, acid resistance, alkali resistance, heat resistance, and printing inks. It can be widely used as a colorant in paints, plastics, rubber, leather, textile printing and the like. In particular, high heat resistance and light resistance are required as a colorant for plastics, but the pigment of the present invention is suitable.

[0015]

The present invention will be described in more detail with reference to examples.
In addition, the part in an Example represents a weight part. Example 1 44.4 parts of dihydroxyfumaric acid are dissolved in 190 parts of methanol, and 60 parts of anhydrous magnesium sulfate are added to this solution. The suspension is cooled to 0-5 ° C. and hydrogen chloride is bubbled in at this temperature for 4.5 hours with stirring. Next, the suspension is allowed to stand at room temperature for 3 days, and the precipitated crystals are filtered. The obtained crystals are washed with a small amount of methanol, suspended in 600 parts of cold water, and then quickly filtered. Further, the crystals were washed with cold water until the washing liquid became neutral, and dried at 70 ° C. to obtain 45.3 parts of an ester having the following structure.

[0016]

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Next, after suspending 44.0 parts of the above ester in 158 parts of methanol, 59.3 parts of p-toluidine and 3 parts of concentrated hydrochloric acid are added to the suspension, and the mixture is refluxed for 6 hours. . During the heating, the reaction solution once becomes a solution, and then pale yellow crystals precipitate. After the reaction solution was cooled to 5 to 10 ° C., the precipitated crystals were filtered and dried at 70 ° C. to obtain 76.3 parts of a compound having the following structure.

[0018]

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A suspension prepared by adding 70.8 parts of the above compound to 708 parts of Dowtherm A (a mixture of biphenyl and diphenyl ether) is heated to 120 to 130 ° C. to form a solution. To 3
Add over 0 minutes. Thereafter, reflux heating is performed for 15 minutes while removing a mixed solution of Dowtherm A and generated methanol, and the mixture is cooled to room temperature. The precipitated crystals are washed with petroleum ether and dried at 70 ° C. to give Compound 5 having the following structure:
6.8 parts were obtained.

[0020]

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54.7 parts of the above compound are added to 547 parts of polyphosphoric acid with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C, it is heated at 145 to 150 ° C for 2 hours, and then cooled to 40 to 50 ° C. Then 121
6 parts of methanol are added slowly while maintaining 40-50 ° C. After the addition is completed, the mixture is heated under reflux for 90 minutes and filtered. Rinse with water until the washing liquid becomes neutral, and dry to obtain pigment 4 represented by compound No. 1 in Table 1.
8.1 parts were obtained. Using the pigment obtained by the above method, a resistance test as described below was performed. (Resistance test) Light resistance 0.5 part of pigment and 2 parts of varnish for printing ink are kneaded by repeating 100 rotations four times using a Hoover-Muller. Printing was performed on white paper using the ink thus prepared. For this printing paper, Suga Test Machine UV Long Life Fade Meter FAL-3C
For 192 hours, and the color difference between the colorimetric value of the printing paper at this time and the colorimetric value before light irradiation was used as an index of light fastness.
2. Shake 0.1 part of acid-, alkali-, and solvent-resistant pigment and 20 parts of the test liquid shown below at room temperature for 2 hours, filter, and measure the maximum absorbance in the wavelength region of 330 to 800 nanometers. I do.

The test liquid is as follows. Acid resistance: hydrochloric acid consisting of 2 parts of hydrogen chloride and 98 parts of water Alkali resistance: solution of 2 parts of sodium hydroxide dissolved in 98 parts of water Solvent resistance: ethanol, xylene, ethyl acetate, methyl ethyl ketone

Example 2 44.0 parts of the methyl ester of dihydroxyfumaric acid described in Example 1 were suspended in 158 parts of methanol, and 89.2 of 1-aminobenzotrifluoride was added to the suspension.
And 3 parts of concentrated hydrochloric acid, and the mixture is heated under reflux for 6 hours. During the heating, the reaction solution once becomes a solution, and then pale yellow crystals precipitate. After the reaction solution was cooled to 5 to 10 ° C., the precipitated crystals were filtered and dried at 70 ° C. to obtain 101.6 parts of a compound having the following structure.

[0024]

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92.4 parts of the above compound was added to Dowtherm A924
The suspension added in the solution was heated to 120 to 130 ° C. to form a solution, and the solution was heated under reflux to Dowtherm A37.
Add to 0 parts over 30 minutes. Thereafter, reflux heating is performed for 15 minutes while removing a mixed solution of Dowtherm A and generated methanol, and the mixture is cooled to room temperature. The precipitated crystals were washed with petroleum ether and dried at 70 ° C. to obtain 82.3 parts of a compound having the following structure.

[0026]

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77.4 parts of the above compound are added to 774 parts of polyphosphoric acid with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C, it is heated at 145 to 150 ° C for 2 hours, and then cooled to 40 to 50 ° C. Then 1720
Parts of methanol are added slowly while maintaining 40 to 50 ° C. After the addition is completed, reflux heating is performed for 90 minutes,
Filter. Wash with water until the washing liquid becomes neutral, and dry to obtain 69.5 of the pigment represented by compound No. 2 in Table 1.
Got a part. The same resistance test as in Example 1 was performed using this pigment.

Example 3 14.3 parts of sodium ethoxide are added with stirring to 78.9 parts of ethanol. After complete dissolution of sodium ethoxide, diethyl oxalate 2 was added at room temperature.
9.2 parts and 38.6 parts of ethyl ester of N- (4-methylphenyl) glycine are added and at 25 ° C.
Stir for hours. Next, ethanol was distilled off under reduced pressure, and water 15 was removed.
0 parts and 15 parts of acetic acid are added and stirred vigorously. Furthermore,
After adding 104 parts of toluene and stirring a little, the mixture is allowed to stand at room temperature, and the reaction solution is separated into an oil layer and an aqueous layer. The aqueous layer is separated, extracted twice with 35 parts of toluene, the extract is mixed with the oil layer and filtered. The filtrate was washed with 120 parts of water, and toluene was removed by distillation under reduced pressure to obtain 53.3 parts of a compound having the following structure.

[0029]

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52.7 parts of the above compound, 19.7 parts of m-toluidine and 1.8 parts of concentrated hydrochloric acid are heated under reflux in 101 parts of ethanol for 3 hours. Next, after removing 61 parts of ethanol by distillation under reduced pressure, the precipitated crystal was filtered, and 1 part of ethanol was removed.
After washing with 6 parts of ethanol and drying at 70 ° C., a mixture 4 comprising compounds of the two structures shown below:
4.4 parts were obtained.

[0031]

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[0032]

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The above compound (42.9 parts) was added to Dowtherm A429.
The suspension added in the mixture was heated to 120 to 130 ° C. to form a solution, and this solution was heated under reflux to Dowtherm A19.
Add to 0 parts over 30 minutes. Thereafter, reflux heating is performed for 15 minutes while removing a mixed solution of Dowtherm A and generated methanol, and the mixture is cooled to room temperature. The precipitated crystals were washed with petroleum ether and dried at 70 ° C. to obtain 34,8 parts of a compound having the following structure.

[0034]

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32.6 parts of the above compound are added to 326 parts of polyphosphoric acid with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C, it is heated at 145 to 150 ° C for 2 hours, and then cooled to 40 to 50 ° C. Next, 723 parts of methanol are gradually added while maintaining 40 to 50 ° C. After the addition is completed, the mixture is heated under reflux for 90 minutes and filtered. The resultant was washed with water until the washing liquid became neutral, and dried to obtain 28.6 parts of a pigment represented by Compound No. 3 in Table 1. The same resistance test as in Example 1 was performed using this pigment.

Example 4 After suspending 44.0 parts of the methyl ester of dihydroxyfumaric acid described in Example 1 in 158 parts of methanol, 58.9 parts of o-toluidine and 3 parts of concentrated hydrochloric acid were added to the suspension. And heating at reflux for 6 hours. During the heating, the reaction solution once becomes a solution, and then pale yellow crystals precipitate. After the reaction solution was cooled to 10 ° C., the precipitated crystals were filtered and dried at 70 ° C. to obtain 61.1 parts of a compound having the following structure.

[0037]

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The above compound (56.7 parts) was added to Dowtherm A340.
The suspension added in this part is heated and heated, and reflux heating is performed for 15 minutes while removing a mixed liquid of Dowtherm A and formed methanol, followed by cooling to room temperature. Next, 340 parts of petroleum ether is added, and the precipitated crystals are filtered and washed with petroleum ether. The obtained crystals were dried at 70 ° C. to obtain 34.6 parts of a compound having the following structure.

[0039]

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To 322 parts of polyphosphoric acid, 32.2 parts of the above compound are added with stirring. The mixture is added for 15 hours in one hour.
After heating to 0 ° C, it is heated at 145 to 150 ° C for 2 hours, and then cooled to 40 to 50 ° C. Then 644 parts of methanol are slowly added while maintaining 40-50 ° C. After the addition is completed, the mixture is heated under reflux for 90 minutes and filtered. The resultant was washed with water until the washing liquid became neutral, and dried to obtain 28.4 parts of a pigment represented by Compound No. 4 in Table 1. The same resistance test as in Example 1 was performed using this pigment. (Plastic coloring test) 100 parts of polypropylene, 0.1 part of pigment and 0.1 part of metal soap (equivalent mixture of calcium stearate and zinc stearate) were mixed, and the mixture was extruded at 200 ° C to 300 ° C using an extruder. To produce a plate-like colored material in which the pigment was uniformly dispersed in polypropylene, and the state of coloring with the pigment was observed.

Examples 5 to 14 and Comparative Examples 1 to 3 Examples of the epindridione pigment of the present invention carried out in accordance with Example 1 are shown in Table 1 below. Table 2 shows the results of the resistance test of the pigments shown in Table 1, and Table 3 shows the results of the resistance test of three types of epindridione pigments having the following structures as comparative examples of the resistance test.

[0042]

[Table 1]

[0043]

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[0044]

[Table 2]

[0045]

[Table 3]

The symbols A, B, C and D in the solvent resistance columns of Tables 2 and 3 represent ethanol, xylene, ethyl acetate and methyl ethyl ketone used as test liquids, respectively. Since the numerical values in Tables 2 and 3 indicate the color difference, the value closer to 0 is better with less discoloration.

Examples 15-18, Comparative Examples 4-7 Further, Table 4 shows the results of plastic coloring tests of the Epindridione pigment of the present invention and the following three kinds of Epindridione pigments. The test results in Table 4 are for the case where polypropylene was used as the plastic, and the temperatures in the table indicate the heating temperatures as already described in Example 4. Before heating, all the test pieces were yellow.

[0048]

[Table 4]

As is evident from Tables 2 and 3, the Epindridione pigments of the present invention exhibited the same or higher resistance to the three pigments listed as Comparative Examples. The pigment in each example was superior to the pigment of the comparative example in coloring power and sharpness. Also, from Table 4, the pigment of the present invention does not cause a hue change even in a plastic coloring test, and has very excellent properties as a plastic colorant.

[0050]

The epidindridione pigment of the present invention has excellent color characteristics, especially excellent coloring power and sharpness, and has light resistance,
It shows excellent properties such as solvent resistance, acid resistance, alkali resistance and heat resistance, and can be used as a colorant in a wide range of applications.

Claims (4)

[Claims] An organic pigment represented by the following general formula (1). General formula (1) (Wherein, R _{1 to} R ₈ may be each independently substituted with a hydrogen atom, an alkyl group optionally substituted with a halogen atom, an aralkyl group optionally substituted with a halogen atom, or a halogen atom. Represents an aryl group, except that all of R _{1 to} R ₈ are hydrogen atoms.) 2. The method according to claim 1, wherein R ₁ and R ₅ are alkyl groups.
The organic pigment of the above. 3. The organic pigment according to claim 2, wherein R _{2 to} R ₄ and R _{6 to} R ₈ are all hydrogen atoms. 4. The organic pigment according to claim 2, wherein R ₁ and R ₅ are a methyl group.