JP3680862B2 - Benzimidazolone compounds - Google Patents

Description

  The present invention relates to a benzimidazolone compound that can be used as a purple pigment.

  Conventionally, a dioxazine pigment (CI Pigment Violet 23) is known as a typical purple pigment. This dioxazine-based pigment has a bright purple hue, but has a problem of poor solvent resistance (see, for example, Non-Patent Document 1). Furthermore, when used as a purple pigment in paints, the paints have a high thixotropy and poor storage stability.

H. Gaertner, J .; Oil & Color Chemists Assoc. 46, 13 (1963)

  The object of the present invention is to have a bright purple hue and can be used as a violet pigment having excellent solvent resistance. Further, when used as a violet pigment in a paint, the thixotropy is low and the storage stability is improved. Another object of the present invention is to provide a benzimidazolone compound capable of obtaining an excellent paint.

  As a result of intensive studies to solve the above problems, the present inventors have found that a benzimidazolone compound in which a benzimidazolone skeleton is introduced into an anthraquinone skeleton becomes a violet pigment having a bright purple hue. It was also found that the compound is excellent in solvent resistance, and further, when used as a purple pigment in a paint, the paint has low thixotropic properties and excellent storage stability.

  That is, the present invention provides a benzimidazolone compound represented by the following general formula (1).

（式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立して水素原子、炭素原子数１〜５のアルキル基、又は炭素原子数１〜５のアルコキシ基を表す。）

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.)

  Since the benzimidazolone compound of the present invention has a bright purple hue, it can be used as a purple pigment. Further, the compound has excellent solvent resistance, and when used as a violet pigment in a paint, the paint has low thixotropic properties and excellent storage stability.

Synthesis examples of the benzimidazolone compound represented by the general formula (1) of the present invention are described below.
(Synthesis method 1)
In the general formula (1), a benzimidazolone compound in which R ¹ and R ⁴ are the same group and R ² and R ³ are the same group can be obtained, for example, by the following method. That is, 1 equivalent of a compound represented by the following formula (2) (hereinafter referred to as “compound (2)”), 1 equivalent of a compound represented by the following general formula (3) (hereinafter referred to as “compound (3)”. ) And 1 equivalent of a compound represented by the following general formula (4) (hereinafter referred to as “compound (4)”) are converted into 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, N , N-dimethylformamide, N-methyl-2-pyrrolidone and the like in an aprotic polar solvent at a temperature of 150 to 200 ° C. for 8 to 25 hours. At this time, in order to remove hydrochloric acid generated during the reaction, sodium acetate, calcium acetate, potassium acetate or the like may be present in the reaction solution. Thereafter, the obtained reaction solution is cooled to room temperature, and the target compound can be obtained by filtering, washing, drying and pulverizing the precipitated crystals by a usual method.

（式中、Ｒ^１及びＲ^２はそれぞれ独立して水素原子、炭素原子数１〜５のアルキル基、又は炭素原子数１〜５のアルコキシ基を表す。）

(In the formula, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.)

（式中、Ｒ^３及びＲ^４はそれぞれ独立して水素原子、炭素原子数１〜５のアルキル基、又は炭素原子数１〜５のアルコキシ基を表す。）

(In the formula, R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.)

(Synthesis method 2)
In the compound represented by the general formula (1), R ¹ and R ⁴ are different groups or R ² and R ³ are different groups. It can be obtained by a two-step reaction under certain conditions. That is, first, 1 equivalent of the compound (2) and 1 equivalent of the compound (3) are reacted as the first stage reaction, and then the reaction product obtained in the first stage is reacted as the second stage reaction. 1 equivalent of compound (4) is reacted. The obtained reaction liquid is cooled to room temperature, and the target compound can be obtained by filtering, washing, drying and pulverizing the precipitated crystals by a usual method.

Among the compounds represented by the general formula (1), a compound represented by the following formula (5) in which R ¹ , R ² , R ³ and R ⁴ are all hydrogen atoms (hereinafter referred to as “compound (5)”) .) Is particularly preferable because vivid purple crystals are obtained.

  The purple crystal of the obtained compound (5) has a Bragg angle 2θ of 14.5 ± 0.2 °, 19.7 ± 0.2 °, 22 ° in an X-ray diffraction spectrum using Cu—Kα characteristic X-rays. It is a crystal having diffraction peaks at 2 ± 0.2 ° and 27.7 ± 0.2 °.

  Since the crystal of the compound (5) obtained by the above production method has a purple hue, it can be used as it is as a pigment, or it can be used in combination with other colorants to produce a colored composition. it can. In addition, for the purpose of enhancing coloring power, weather resistance, and transparency, the size of pigment crystals can be adjusted by post-treatment.

  In the case of growing pigment crystals into larger crystals, for example, a method of heat-treating compound (5) in an organic solvent, water, or a mixed solvent thereof at normal pressure or under pressure can be used. Examples of the organic solvent include aromatic solvents such as benzene, xylene, and toluene; pyridine solvents such as pyridine, picoline, and quinoline; ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone; methanol, butanol, isobutanol, and the like. Examples include alcohol solvents; ether solvents such as ethylene glycol monomethyl ether and monoethyl ether; and aprotic polar solvents such as dimethyl sulfoxide, N-methyl-2-pyrrolidone and N, N-dimethylformamide. Moreover, these organic solvents may be used independently or may combine 2 or more types.

  Further, when the pigment crystal is made finer, for example, a method of grinding with a grinding device such as a kneader, a ball mill, or an attritor can be used. At this time, the grinding treatment can be performed in the presence of a grinding medium such as sodium chloride or a liquid grinding aid such as diethylene glycol, if necessary.

  Hereinafter, the present invention will be described with reference to examples. Unless otherwise specified, “parts” and “%” are based on mass.

(Example 1)
4-Aminobenzimidazolone (44.7 parts), 1,5-dichloroanthraquinone (33 parts) and sodium acetate (21.5 parts) are added to 1,3-dimethyl-2-imidazolidinone (500 parts) at 175 ° C. for 25 hours. Stir. After cooling to room temperature, the precipitate was filtered, washed with 200 parts of 1,3-dimethyl-2-imidazolidinone and 600 parts of acetone, dried under reduced pressure at 110 ° C. for 8 hours, and 32.6 parts of purple crystals ( Yield 54%) was obtained.

  When the obtained purple crystals were subjected to infrared spectroscopic analysis and FD-MS analysis, the following results were obtained.

<Infrared spectroscopic analysis>
3400 cm ^-1: aromatic amines N-H stretching vibration 3200 cm ^-1: imidazolone the N-H stretching vibration 1700cm ^-1: C = O stretching vibration of aromatic ketone

<FD-MS>
As a result of mass spectrometry, a molecular ion peak (M +) having a molecular weight of 502 was detected.

  From the above analysis results, it was confirmed that the obtained purple crystals were the compound (5) having the structural formula represented by the formula (5).

Further, the obtained purple crystal was subjected to powder X-ray diffraction analysis by Cu-Kα ray irradiation under the following conditions using an X-ray diffractometer “RINT Ultimate +” manufactured by Rigaku Corporation.
Power consumption: 40kV, 30mA
Sampling angle: 0.020 °
Divergence / scattering slit: (1/2)
Light emitting slit: 0.3mm
Scanning speed: 2 ° / min

  FIG. 1 shows the X-ray diffraction spectrum. The purple crystal of compound (5) has a Bragg angle 2θ of 14.5 ± 0.2 °, 19.7 ± 0.2 °, 22.2 ± 0 in an X-ray diffraction spectrum using Cu—Kα characteristic X-rays. It had diffraction peaks at 2 ° and 27.7 ± 0.2 °.

<Preparation of paint for evaluation>
Alkyd resin for baking paint (Dainippon Ink Chemical Co., Ltd. product name “Beccosol J-524-IM-60”) 70% and melamine resin (Dainippon Ink Chemical Co., Ltd. product name “Super Becamine” G-821-60 ") 30 parts of a mixed resin with 66% was dissolved in 12 parts of a mixed solvent of xylene: n-butanol = 7: 3 to obtain a resin composition.

  A mixture of 78 parts of the resin composition and 2 parts of the compound (5) obtained above was kneaded for 2 hours using a paint conditioner (manufactured by Toyo Seiki Co., Ltd., using 3.0 mmφ glass beads) to give a pigment. A dispersion was obtained. To 12 parts of this pigment dispersion, 18 parts of a resin solution mixed with the mixed resin: the mixed solvent = 4: 3 was added and diluted to prepare an evaluation paint.

<Preparation of coating film for evaluation>
The coating material for evaluation obtained above was applied onto art paper using an applicator and then baked at 130 ° C. for 30 minutes to obtain a coating film. The obtained coating film was glossy purple.

<Color measurement of coating film for evaluation>
The coating film for evaluation obtained above was measured using a color difference meter (“SZ-Σ90” manufactured by Nippon Denshoku Industries Co., Ltd., using a C / 2 light source), and chromaticity (L ^* , a ^* , b ^* ) was determined.

<Solvent resistance test>
0.5 part of the compound (5) was placed in 10 ml of ethanol, toluene or ethyl acetate, subjected to ultrasonic dispersion for 30 minutes, and then filtered through a syringe filter having a pore diameter of 0.45 μm. The presence or absence of coloration of the resulting filtrate was determined solvent resistance to the solvent.

<Measurement of decomposition temperature>
The compound (5) was subjected to thermal analysis under the following conditions using a differential thermal analyzer (“TG8101D” manufactured by Rigaku Corporation), and the decomposition temperature was measured.
Measurement temperature range: 30-800 ° C
Temperature rising rate: 10 ° C / min Flowing gas: Nitrogen Flowing gas flow rate: 200ml / min Measuring container: Platinum pan

<Thixotropic test>
About the coating material for evaluation immediately after preparation obtained above, the steady flow viscosity measurement was performed on condition of the following using the viscoelasticity measuring apparatus ("RheoStress RS150" by HAAKE). A value (TI value: thixotropic index) obtained by dividing the viscosity at a shear rate of 5 s ⁻¹ obtained by the measurement by the viscosity at 50 s ⁻¹ was calculated.
Cone plate size: 60mm
Cone plate angle: 2 °
Pre-shear: Shear rate 10 s ⁻¹ , 60 seconds Standing time before measurement: 60 seconds Measurement shear rate range: ^{1 to} 100 s ⁻¹

<Storage stability test (average particle size)>
The volume average particle diameter of the paint for evaluation immediately after preparation obtained above and the paint that was allowed to stand for 4 days after preparation was measured using a particle size distribution analyzer ("Microtrac UPA150" manufactured by Nikkiso Co., Ltd.). did. Using the volume average particle diameter obtained by the measurement, the change rate of the average particle diameter was calculated by the following formula.

<Storage stability test (viscosity)>
Viscosity measurement was performed in the same manner as the thixotropy test described above for the paint that was allowed to stand for 1 week after the preparation of the evaluation paint. The viscosity of the viscosity and 50s ^-1 at a shear rate of 5s ^-1 obtained by the measurement, was calculated change rate at each viscosity by the following equation.

(Comparative Example 1)
The above evaluation was performed in the same manner using a dioxazine pigment (product name “Fastogen Super Violet RVS” manufactured by Dainippon Ink and Chemicals, Inc .; CI Pigment Violet 23) instead of the compound (5). It was.

  The evaluation results in Example 1 and Comparative Example 1 are shown in Table 1.

  From the evaluation results in Table 1, the following could be confirmed.

(Solvent resistance)
The benzimidazolone compound of the present invention was insoluble in toluene and ethyl acetate, whereas the dioxazine pigment was slightly dissolved in toluene and ethyl acetate. Therefore, it was confirmed that the benzimidazolone compound of the present invention was superior in solvent resistance as compared with the dioxazine pigment.

(Decomposition temperature)
The benzimidazolone compound of the present invention showed a high decomposition temperature of 504 ° C., and was confirmed to be stable even at high temperatures.

(Thixotropic)
The paint using the benzimidazolone compound of the present invention had a TI value of 1.10 and exhibited Newtonian viscosity. In contrast, the paint using the dioxazine pigment had a TI value of 1.71 and a non-Newtonian viscosity. Therefore, it was confirmed that the paint using the benzimidazolone compound of the present invention has an excellent characteristic that the viscosity does not change under any conditions.

(Storage stability)
The paint using the benzimidazolone compound of the present invention has little change with time in the average particle size of the benzimidazolone compound contained in the paint and little change with time in the viscosity of the paint. On the other hand, in the paint using the dioxazine pigment, the average particle diameter of the dioxazine pigment contained in the paint increased with time, and the viscosity of the paint also increased greatly with time. Therefore, it was confirmed that the paint using the benzimidazolone compound of the present invention was superior in storage stability as compared with the paint using the dioxazine pigment.

  The benzimidazolone compound of the present invention can be used as a purple pigment and has excellent solvent resistance. In addition, when used as a violet pigment in paints, a paint with low thixotropy and excellent storage stability can be obtained, so it can be used in a wide range of applications such as printing inks, paints, colored plastics, toners, inkjet inks, and color filters. Can be used.

2 is an X-ray diffraction spectrum using Cu-Kα characteristic X-ray of the compound (5) of the present invention obtained in Example 1. FIG.

Claims (3)

A benzimidazolone compound represented by the following general formula (1).

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.) The benzimidazolone compound according to claim ¹ , wherein, in the general formula (1), R ¹ , R ² , R ³ and R ⁴ are all hydrogen atoms. The Bragg angle 2θ in the X-ray diffraction spectrum using Cu-Kα characteristic X-ray is 14.5 ± 0.2 °, 19.7 ± 0.2 °, 22.2 ± 0.2 °, and 27.7 ±. The benzimidazolone compound according to claim 2, which has a diffraction peak at 0.2 °.

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