JP2003213035A - Carbon black for black matrix and resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide carbon black preferable to form a black matrix excellent in shading performance and a resin composition for forming the black matrix. <P>SOLUTION: Carbon black particles are prepared by wet oxidation of carbon black having ≥50 m<SP>2</SP>/g nitrogen-absorbing specific surface area and ≤140 cm<SP>3</SP>/100 g DBP absorption to have ≥0.1 atom ratio of total oxygen atoms over total carbon atoms detected by X ray photoelectron spectroscopy. The carbon black for the black matrix is prepared by bonding a straight chain, branched or cyclic compound having ether bonds and an alcoholic hydroxy group on the terminal or in the side chain through esterification to carboxylic groups on the surface of the carbon black particles. The resin composition comprises 2-20 wt.% carbon black, 60-96 wt.% solvent and 2-20 wt.% resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black matrix pigment having a high light-shielding property and a high degree of blackness and having a low conductivity, which is a smooth surface, as a pigment for a black matrix used in a color filter for a liquid crystal display device, a plasma display or the like. The present invention relates to a carbon black suitable for forming a matrix and a resin composition for forming a black matrix using the carbon black.

[0002]

2. Description of the Related Art A liquid crystal display controls the transmission of incident light by sandwiching a crystalline material that becomes liquid crystal between transparent electrodes and applying a voltage between the electrodes to change the molecular arrangement of the liquid crystal.
It is used to display images and characters by combining a reflector and a polarizing plate and consumes less power. Therefore, it is widely used as a display device for mobile phones, watches, cameras, and various electric devices.

A color liquid crystal display in which this liquid crystal display is colorized is one in which red, blue, and green color filters are attached to each pixel to create the three primary colors of light, and the brightness of each pixel is controlled to express a color change. Is. That is,
The color filter creates pixels of three primary colors of red, blue, and green on a transparent substrate, controls the amount of light that passes through each pixel, and performs color display by coloring by adding the three primary colors. A blocking layer (black matrix) for blocking light between each pixel is formed in order to prevent deterioration of contrast and color purity.
The black matrix is a liquid crystal driving electrode or TFT provided on the substrate facing the color filter.
It also has a function of shielding a transistor such as a (thin film transistor) from light.

Therefore, in the black matrix,
Naturally, it is required to have excellent light-shielding properties, but in addition, it is required to have a smooth surface, a thin layer, and low conductivity. That is, when the surface smoothness is poor and the layer thickness is large, unevenness occurs when forming the color patterns of the three primary colors, and when the conductivity is high, the semiconductor element may malfunction due to the applied voltage. is there.

As the black matrix, a black matrix made of a metal thin film of Cr, Ni, Al or the like by a photolithography method, a black matrix made of a black organic resin film in which a black pigment is dispersed, is used.
Has been used. Among them, the black matrix formed by the metal thin film has high light-shielding rate and optical density and excellent resolution, but has high conductivity and high light reflectance, so that reflection due to reflected light is likely to occur and display quality is improved. There is a drawback that is damaged.

On the other hand, the black matrix composed of the black organic resin film has few problems as described above, and in particular,
Since carbon black has excellent blackness as a black pigment, it is suitable as a black pigment for a black matrix. Therefore, a method of applying a photopolymerizable resin composition in which carbon black is dispersed to a transparent substrate to form a black matrix, a method of printing an ink containing carbon black on a transparent substrate to form a black matrix, etc. have been developed. ing. The following techniques, for example, have been developed and proposed as the ones that regulate the characteristics of the carbon black for the black matrix or the carbon black of the black matrix using the carbon black.

In an ink containing at least carbon black in a resin, the carbon black has an oil absorption of 40 to 130 ml per 100 g of carbon black and has a volatilization loss of 3% by weight when heated at 950 ° C. for 7 minutes. The above is 10 with respect to 100 parts by weight of the resin.
In the liquid crystal color filter light-shielding layer ink (Japanese Patent Laid-Open No. 8-262223), a resin black matrix in which a light-shielding agent is dispersed in a resin, As below (A)
A resin black matrix comprising carbon black satisfying at least one of (D).
However, (A) PH value is 6.5 or less, (B) surface carboxyl group concentration [COOH] is 0.001 <[COOH] in terms of molar ratio per total carbon atom, (C) surface hydroxyl group concentration. [OH] is a molar ratio per total carbon atom of 0.00
1 <[OH], (D) surface sulfo group concentration [SO
₃ H] is 0.001 <in molar ratio per total carbon atom
[SO ₃ H], (JP-A-9-15403).

Further, in a black matrix containing carbon black as a black pigment, the average particle size of the carbon black is 40 to 300 nm, and a black matrix for a color filter (JP-A-9-15419), In a black matrix containing carbon black as a black pigment, the carbon black contains CO and C in the volatile matter at 950 ° C.
A black matrix for a color filter, characterized in that the total oxygen amount calculated from O ₂ is 7 mg or more per 100 m ² of surface area of carbon black (JP-A-9-2265).
No. 3), average particle size 50-200 nm, DBP oil absorption 1
Color filter resist for black matrix, characterized by containing carbon black in the range of 0 to 40 ml / 100 g (JP-A-9-80220), average primary particle diameter 35 to 150 nm, aggregate diameter 60 to 300 nm, Carbon black for forming a black resist pattern, characterized in that carbon black having a dibutyl phthalate oil absorption of 30 to 90 ml / 100 g is coated with a resin (JP-A-11-80).
No. 583), etc. have also been proposed.

Further, carbon black for an insulating black matrix obtained by coating a carbon black having a total oxygen content of 15 mg / g or more and a total oxygen content / specific surface area of 0.10 mg / m ² or more (Japanese Patent Application Laid-Open No. Hei 10 (1999) -96). 9-95625), at least one of the surface carboxyl group concentration [COOH], the surface hydroxyl group concentration [OH], and the surface sulfonic acid group concentration [SO ₃ H] is 0 in terms of molar ratio per total carbon atom. .0
A resin black matrix comprising a resin containing a carbon black larger than 05 as a light-shielding agent and having a specific resistance of 7 × 10 ⁴ Ω · cm or more (Japanese Patent Laid-Open No. 9-265006). ) Etc. have been proposed.

Generally, the black matrix has a high degree of blackness and a light-shielding property, has a high light-shielding rate even when the film thickness of the light-shielding layer is thin, the surface of the light-shielding layer is smooth, and the conductivity of the light-shielding layer is small. , Etc. are needed.

Therefore, the present inventor has conducted research on the improvement of various performances required for these black matrices from a different viewpoint, and has a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or more and a DBP absorption amount of 140 cm. ^The value of the atomic ratio of total oxygen atoms per total carbon atom (oxygen bond energy strength / carbon bond energy strength) measured by X-ray photoelectron spectroscopy was 0. 1
Carbon black pigment for a black matrix obtained by reacting a vinyl monomer with a functional group on the surface of carbon black subjected to the above-mentioned oxidation as a backbone to chemically bond the vinyl polymer by cationic polymerization (Japanese Patent Application No. 2000-257473).
No.) and a functional group on the surface of the oxidized carbon black is converted to an azo group to form a backbone, and a vinyl polymer produced by radical graft polymerization of a monomer containing a vinyl group is chemically bonded to the backbone. Developed and proposed carbon black for matrix (Japanese Patent Application No. 2001-227404).

The black matrix using these carbon blacks as a light-shielding agent has excellent performance as a whole, but it was recognized that the film strength of the black matrix is slightly insufficient and there is a need for improvement. . Therefore,
The present inventor converts a carboxyl group on the surface of an oxidized carbon black into a potassium salt (COOK group) to form a backbone, and onto the backbone, a polyester produced by anionic ring-opening alternating copolymerization of an epoxide and a cyclic acid anhydride is grafted. A combined carbon black pigment for black matrix (Japanese Patent Application No. 2001-258986) was developed.

[0013]

By using this carbon black pigment for a black matrix, it becomes possible to improve the film strength of the formed black matrix. However, it has been recognized that the resin composition and the ink composition produced using this carbon black pigment have a problem that the viscosity increases. When the viscosity increases, for example, when a resin composition is applied to a transparent substrate by a slot coater or a roll coater and spin-coated, it is difficult to apply the resin composition uniformly, so that the film thickness of the formed black matrix becomes non-uniform and the light-shielding performance is increased. There is a problem that

The present inventor has conducted diligent research in order to solve this problem, and has a carboxyl group formed on the surface of carbon black particles by an oxidation treatment, and an ether bond and an alcoholic hydroxyl group at the terminal or side chain. It was confirmed that a resin composition or an ink composition suitable for forming a black matrix can be obtained by reacting a chain, branched or cyclic compound to form an ester bond.

The present invention has been completed based on the above findings, and an object thereof is as a black pigment for forming a black matrix, which has a high degree of light-shielding property and blackness, low conductivity, smoothness, It is an object of the present invention to provide a carbon black and a resin composition suitable for forming a black matrix having excellent insulation properties and film strength.

[0016]

[Means for Solving the Problems] That is, the carbon black for a black matrix according to the present invention has a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or more and a DBP absorption amount of 140 cm ³ /
Carbon black of 100 g or less is wet-oxidized to have an atomic ratio (intensity of oxygen bond energy / intensity of carbon bond energy) of total oxygen atoms to total carbon atoms of 0.1 or more measured by X-ray photoelectron spectroscopy. The carbon black particles formed by the oxidation treatment have ether groups and linear, branched or cyclic compounds having an alcoholic hydroxyl group at the terminal or side chain bonded to the carboxyl groups on the surface by esterification reaction. Is a structural feature.

The resin composition for forming a black matrix according to the present invention contains the above carbon black in an amount of 2 to
20 wt%, solvent 60-96 wt%, resin 2-20 wt%
The compositional feature is that the composition is mixed in the amount ratio of.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the carbon blacks of the present invention is a nitrogen adsorption specific surface area ^{_{(N 2 SA) 50m 2 /}} g or more, the following properties DBP absorption 140cm ^3/100 g is applied. When the nitrogen adsorption specific surface area (N ₂ SA) is less than 50 m ² / g, the average particle size of carbon black in the dispersion becomes large when dispersed in a solvent, and the blackness of the formed black matrix and light shielding This is because the force is reduced and the light-shielding layer becomes thicker. However, those having 300 m ² / g or less are preferably used. Moreover, the DBP absorption amount using the following carbon black 140cm ^3/100 g, when exceeding 140cm ^3/100 g, because the smoothness of the light-shielding layer viscosity when mixed with a solvent such as a resin is increased is impaired is there. Incidentally, preferably DBP absorption include: 110 cm ^3/100 g is used.

The black matrix for carbon black of the present invention, the nitrogen adsorption specific surface area ^{_{(N 2 SA) 50m 2 /}} g or more, as a target of carbon black having the following properties DBP absorption 140cm ^3/100 g, wet oxidation A functional group is generated on the surface of carbon black particles by treatment, and a linear, branched, or cyclic compound having a carboxyl group among the generated functional groups, an ether bond, and an alcoholic hydroxyl group at the terminal or side chain is esterified. It is formed by binding by a chemical reaction.

In the wet oxidation treatment of carbon black, a peroxo diacid salt such as peroxo disulfate, peroxo diborate, peroxo dicarbonate or peroxo diphosphate or a peroxo acid is preferably used as an oxidizing agent. As the peroxo diacid salt, alkali metal salts and ammonium salts are preferable. The wet oxidation treatment is performed by putting carbon black in these oxidant aqueous solutions and stirring and mixing.

The degree of oxidation treatment is controlled by appropriately setting the concentration of the oxidant aqueous solution, the amount of carbon black added, the reaction temperature, the reaction time, etc. Specifically, the total amount measured by X-ray photoelectron spectroscopy. The wet oxidation treatment is performed so that the value of the atomic ratio of oxygen atoms to total carbon atoms (oxygen bond energy strength / carbon bond energy strength) becomes 0.1 or more.

That is, the value of the atomic ratio of total oxygen atoms to total carbon atoms (intensity of oxygen bond energy / intensity of carbon bond energy) measured by X-ray photoelectron spectroscopy such as XPS or ESCA is the surface of carbon black particles. When the value is less than 0.1, the amount of carboxyl groups is small. The esterification reaction with the branched or cyclic compound does not proceed uniformly, and the dispersibility in a solvent is reduced when preparing a resin composition for forming a black matrix, which causes a reduction in the light-shielding performance of the black matrix. It will be. It should be noted that this value should be 0.
Since it is difficult to efficiently perform the oxidation treatment of 1 or more, the wet oxidation treatment is applied.

The carbon black for the black matrix of the present invention is a linear chain having a carboxyl group thus formed on the surface of the carbon black particles by the wet oxidation treatment, an ether bond, and an alcoholic hydroxyl group at the terminal or side chain, A branched or cyclic compound is bound by an esterification reaction.

The esterification reaction is carried out by placing the above-mentioned wet-oxidized carbon black in a container, in which a linear, branched or cyclic carbon bond having an ether bond and an alcoholic hydroxyl group at the terminal or side chain is contained. The compound and the condensing agent are added, and the mixture is stirred and mixed at a predetermined temperature for a predetermined time to react, whereby the esterification reaction proceeds according to the reaction formulas shown in the following formulas (1) to (5). Then, the unreacted solution is recovered by an evaporator and then vacuum dried to obtain the carbon black for a black matrix of the present invention. In addition,
In the formulas (1) to (5), R ₁ is hydrogen, a methyl group, an ethyl group, an aromatic hydrocarbon, etc., and R ₂ is a divalent hydrocarbon group having 1 to 4 carbon atoms (for example, a methylene group, an ethylene group, Propylene group, butylene group, etc.), and n is 1 to 5.

[0025]

[Chemical 1]

[0026]

[Chemical 2]

[0027]

[Chemical 3]

[0028]

[Chemical 4]

[0029]

[Chemical 5]

The linear compound having an ether bond and an alcoholic hydroxyl group at the terminal or side chain is, for example, 2-methoxyethanol, 2-ethoxyethanol, 2-
(Methoxymethoxy) ethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2-phenoxyethanol, 2- (benzyloxy) ethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether and the like, and the branched compound is 1-methoxy. -2-Propanol, 1-Ethoxy-2-propanol, cyclic compounds such as furfuryl alcohol, tetrahydo Dorofurfuryl alcohol,
Are exemplified.

As the condensing agent, for example, hydrogen chloride,
Concentrated sulfuric acid, inorganic acids such as boron fluoride, N, N-dicyclohexylcarbodiimide, N, N-diisopropylcarbodiimide, 1-isopropyl-3- (3-dimethylaminopropyl) carbodiimide perchlorate, 1-ethyl-3- (3-Dimethylaminopropyl) carbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N- (3-dimethylaminopropyl) -N-ethylcarbodiimide hydrochloride, met-P-toluenesulfonic acid There are carbodiimides such as -1-cyclohexyl-3- (2-morpholinoethyl) carbodiimide, thionyl chloride / N-methyl-2-pyropidone, thionyl chloride / N, N-dimethylformamide, and thionyl chloride / pyridine. In addition, a desiccant such as anhydrous magnesium sulfate or molecular sieve 5A is placed in a Soxhlet extractor or an azeotropic distillation method using a Dean-Stark water separator without using a condensing agent, and the solvent is subjected to dry distillation for condensation. You may use the method of.

The resin composition for the black matrix of the present invention has a composition in which the carbon black is mixed in an amount of 2 to 20 wt%, the solvent is 60 to 96 wt%, and the resin is mixed in an amount ratio of 2 to 20 wt%.

Examples of the solvent include methyl cellosolve,
Ethyl cellosolve, butyl cellosolve, diethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, benzene, chloroform, dichloromethane, ethyl acetate, methyl lactate, ethyl lactate, methanol, ethanol, propanol, butanol, Tetrahydrofuran, N-methyl-2-pyrrolidone, N, N'-dimethylformamide, N, N'-dimethylacetamide, N, N'-dimethylsulfoxide, etc. Various solvents can be used, unless otherwise provided.

As the resin, for example, phenol resin, melamine resin, xylene resin, diallyl phthalate resin, glyptal resin, epoxy resin, alkylbenzene resin, polyimide resin, acrylic resin, methacrylic acid resin, polyvinyl alcohol, polyester resin, etc. Various resins are used as long as they do not affect the fluidity and the dispersibility of carbon black.

In the resin composition for a black matrix of the present invention, 2 to 20 wt% of carbon black and 6 of solvent are used.
The amount ratio of 0 to 96 wt% and resin to 2 to 20 wt% is set so that when the carbon black is less than 2 wt%, the light-shielding property of the formed black matrix becomes low, while on the other hand, 20 wt%
This is because the thickness of the black matrix becomes thicker if it exceeds. Further, if the amount of the solvent is less than 60% by weight, the fluidity is remarkably reduced, so that it becomes difficult to form a black matrix having a uniform thickness, and if it exceeds 96% by weight, the light shielding property is remarkably reduced. Also, if the resin content is less than 2 wt%, the film strength of the black matrix will be reduced,
If it exceeds, the viscosity of the resin composition increases and it becomes difficult to control the film thickness.

Hereinafter, examples of the present invention will be specifically described in comparison with comparative examples.

[Preparation of Carbon Black Samples] Examples 1 to 3 and Comparative Examples 4 to 6 Using carbon black having different nitrogen adsorption specific surface area (N ₂ SA) and DBP absorption amount, 100 g of carbon black was added at a concentration of 1.0 mol. It was added to 3dm ³ of an aqueous solution of sodium peroxodisulfate of / dm ³ and a wet oxidation treatment was performed at a temperature of 60 ° C. for 10 hours while stirring at a rotation speed of 0.12 s ⁻¹ . After that, an ultrafiltration membrane (AHP-1010, manufactured by Asahi Kasei, molecular weight cutoff 5
0000), the excess salt remaining in the oxidation reaction solution was purified and separated, and further concentrated and purified. Then, the purified solution is heated to 110 ° C.
After vacuum drying for 16 hours at 85 ° C., 85 g of carbon black sample was obtained which was crushed by a mixer and subjected to oxidation treatment.

In a separable flask (volume 2000 cm ³ ),
20 g of the above oxidized carbon black sample and 400 cm ^{3 of} dipropylene glycol monomethyl ether were put, and the mixture was stirred and mixed for 60 minutes at 300 rpm in a nitrogen atmosphere using an ultrasonic cleaner. Then, in this dispersion, N, N
A solution prepared by dissolving 2.9 g of'-dicyclohexylcarbodiimide in 40 cm ^{3 of} dipropylene glycol monomethyl ether was added, and the mixture was reacted at a temperature of 60 ° C. for 12 hours.

After the reaction, unreacted dipropylene glycol monomethyl ether was recovered by using an evaporator and then placed in a vacuum dryer and dried at 110 ° C. for 16 hours to completely remove dipropylene glycol monomethyl ether. In this way, a carbon black sample for a black matrix was prepared in which dipropylene glycol monomethyl ether was ester-bonded to the carboxyl groups on the surface of the carbon black particles by an esterification reaction.

Example 4 A carbon black sample was prepared in the same manner as in Example 2, except that 2-methoxyethanol was used instead of dipropylene glycol monomethyl ether in Example 2.

Comparative Examples 1 to 3 Using the same carbon black as that used in Examples 1 to 3, the same oxidation treatment as in Examples 1 to 3 was performed to obtain carbon black samples.

Comparative Examples 7 to 9 Using the same carbon black as that used in Examples 1 to 3, 150 g of carbon black was placed in an ozonizer to produce an ozone generator (Japan Ozone Co., Ltd.).
A carbon black sample was prepared in the same manner as in Examples 1 to 3 except that the production voltage was 200 V and the ozone generation rate was 5 mg / s, and the gas phase oxidation treatment with ozone was performed for 5 hours. .

Comparative Example 10 In a separable flask (volume: 2000 cm ³ ), the same carbon black as in Example 2 was oxidized by the same method as in Example 2, 20 g of carbon black, 400 cm ^{3 of} hexamethylphosphoric triamide, 20 g of cresol. In a nitrogen atmosphere at an rpm of 300 rpm using an ultrasonic cleaner.
Stir and mix for 0 minutes. Then, in this dispersion, N, N ′
A solution of 2.9 g of dicyclohexylcarbodiimide dissolved in 40 cm ³ of hexamethylphosphoric triamide was added, and a carbon black sample for a black matrix in which cresol was ester-bonded was prepared in the same manner as in Example 2.

With respect to the carbon black sample for black matrix thus produced, the carbon black sample at the stage of oxidation treatment before the esterification reaction was analyzed by S-Probe ESCA Model 2803 (Surface Science Instrument Instrument).
(manufactured by nts) was used to measure the intensity of oxygen binding energy and the intensity of carbon binding energy, and the atomic ratio of all oxygen atoms to all carbon atoms was determined. For the measurement, wide-scan measurement (qualitative analysis) was performed on the surface of the sample in a visible state, and high-resolution measurement (state analysis) of the detected element was performed. The binding energy was standardized by setting C-C and C-H to 284.6 eV. The obtained results are shown in Table 1.

[0045]

[Table 1] Table Note: * 1 A; dipropylene glycol monomethyl ether B; 2-methoxyethanol C; cresol

[Preparation of Resin Composition] A carbon black sample (16 g), cyclohexanone (64 g) and methacrylic acid resin (20 g) were lightly mixed, and then the carbon black was finely dispersed by a homogenizer to prepare a resin composition for forming a black matrix. The viscosity, surface tension, and particle size of carbon black particle aggregates in this resin composition were measured by the following methods, and the results are shown in Table 2.

Viscosity: The viscosity at a temperature of 25 ° C. was measured using a rotary vibration type viscometer (VM-100A-L manufactured by Yamaichi Denki Co., Ltd.).

Surface tension: Surface tension at a temperature of 25 ° C. was measured using a surface tension measuring device manufactured by Kyowa Interface Science Co., Ltd.

Particle size: Heterodyne laser Doppler system particle size distribution measuring device (Microtrac UPA model 93
40). For the measurement, the value of 50% cumulative frequency was determined as the average particle size and the value of 99% cumulative frequency was determined as the maximum particle size from the cumulative frequency distribution curve of the particle size distribution of carbon black particle aggregates in the resin composition. Cyclohexanone was used as a solvent for viscosity adjustment during measurement.

[0050]

[Table 2]

[Formation of Black Matrix] The prepared resin composition was applied onto a transparent glass plate washed with trichloroethylene at a rotation speed of 0.06 s ⁻¹ by using a spin coater, and kept at room temperature for 30 minutes, then 120 ~ 250 ° C
On a hot plate for 120 seconds. Then 5
The coating film was irradiated with energy of 100 mJ / cm ² through a photomask on which a black matrix pattern was drawn using a 00 W ultra-high pressure mercury lamp. After that, sodium carbonate 0.05%, Emulgen A-60 (made by Kao) 0.4%
Flow rate of 8.33 cm ³ / s using the developing solution (25 ℃)
The shower cleaning was performed for 60 seconds at a discharge pressure of 0.098 MPa. After washing with water, post-baking was performed on a hot plate having a surface temperature of 250 ° C. to form a black matrix.

The black matrix thus formed was measured and evaluated by the following methods, and the results are shown in Table 3.

Optical density (OD value): Measured using a Macbeth densitometer (RD-927, manufactured by Kolmogen Co.), and a film thickness of 1
The optical density per μm was determined.

Film thickness: The film cross section was observed with an SEM (electron microscope, S-2100B manufactured by Hitachi Ltd.) to measure the film thickness.

Surface roughness: The surface was observed with an SPM (scanning probe microscope, SPI-3100 manufactured by AFM Mode SII) to measure the surface roughness.

Volume resistivity: A coating film was formed in the same manner as the black matrix except that the glass plate was changed to a chromium vapor deposition substrate, and a circular electrode having an area of 0.28 cm ² (S) was silver on the cured coating film. It is formed by paste, and a constant voltage (100V) is applied between this electrode and the chromium vapor deposition surface, which is the counter electrode, using a constant voltage generator (PA36-2A regulated DC power supply manufactured by Kenwood) to form a film. The current (I) flowing through was measured with an ammeter (R644C digital multimeter manufactured by Advantest). Next, the thickness of the black film
(d) cm is measured, volume specific resistance R is calculated from the following equation,
The logarithmic value (log ₁₀ R) was calculated. R (Ω ・ cm) = (V ・ S) / (I ・ d)

Film hardness: Measured according to the method of JIS K5400 "Pencil scratch test".

[0058]

[Table 3]

From Tables 1 to ³ , carbon black having a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or more and a DBP absorption amount of 140 cm 3/100 g or less was wet-oxidized with an aqueous sodium peroxodisulfate solution to obtain all carbon black. The atomic ratio of oxygen atoms / total carbon atoms is 0.
Examples 1 to 3 in which the carboxyl group produced by an oxidation treatment to 1 or more and the produced carboxyl group and dipropylene glycol monomethyl ether are subjected to an esterification reaction to form an ester bond, and 2-
The resin composition prepared from the carbon black of Example 4 which was esterified with methoxyethanol to form an ester bond had a low viscosity, and the carbon black aggregate particle size in the resin composition was also low. It is recognized that the formed black matrix is at a good level in terms of optical density, film thickness, surface roughness, volume resistivity, film hardness and the like.

On the other hand, Comparative Examples 1 to 3 are Examples 1 to 1.
The same carbon black as that of No. 3 was subjected to the same oxidation treatment, but the esterification reaction with dipropylene glycol monomethyl ether as in Examples 1 to 3 was not performed, so that the viscosity of the prepared resin composition was It is recognized that the surface tension is high and the carbon black particle aggregates are also large. Also, it can be seen that the formed black matrix is inferior in all of the optical density, the film thickness, the surface roughness, the volume specific resistance, the film hardness, etc., as compared with Examples 1 to 3.

The nitrogen adsorption specific surface area (N ₂ SA) and DB
In Comparative Examples 4 to 6 in which the carbon black property of P absorption amount deviates from the requirement specified in the present invention, the optical density of the black matrix formed is lower and the surface roughness is slightly larger than those in Examples 1 to 4. Is recognized.

Comparative Example 7 in which vapor-phase oxidation with ozone was carried out
No. 9 had an insufficient oxidation treatment, so the atomic ratio of total oxygen atoms / total carbon atoms was remarkably low as compared with Examples 1 to 4, the prepared resin composition had high viscosity, surface tension, and carbon black particle aggregates. Is also large. As a result, it is found that the formed black matrix is inferior in all of optical density, film thickness, surface roughness, volume resistivity and film hardness.

Comparative Example 10 is a case where the carbon black sample obtained by oxidizing the same carbon black as in Example 2 with the same method as in Example 2 was subjected to esterification reaction with cresol. The prepared resin composition has a high viscosity, a large surface tension and a large aggregate of carbon black particles, and the formed black matrix is inferior in all of optical density, film thickness, surface roughness, volume resistivity and film hardness. is there.

[0064]

As described above, the carbon black for a black matrix of the present invention has a nitrogen adsorption specific surface area (N ₂ SA)
And carbon black having a DBP absorption amount within a specific range by wet oxidation to oxidize the atomic ratio of all oxygen atoms to all carbon atoms to 0.1 or more, and to the carboxyl group on the surface of the generated carbon black particles, an ether bond, And a resin for a black matrix of the present invention in which this carbon black is dispersed, characterized by a structure in which a linear, branched or cyclic compound having an alcoholic hydroxyl group at the terminal or side chain is ester-bonded by an esterification reaction. The composition has a low viscosity. According to this resin composition, a black matrix exhibiting excellent light-shielding properties, surface smoothness, film strength, etc., high volume resistivity and excellent insulation properties, and a high light-shielding rate even when the film thickness is thin Can be formed.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H042 AA06 AA09 AA15 AA26                 2H048 BA11 BA45 BA47 BA48 BB28                       BB42                 4J002 BE021 BG041 CC031 CC101                       CC121 CC181 CD001 CF001                       CF181 CM041 DA036 FB086                       FD096 GP00                 4J037 AA02 CB04 CB07 CC15 CC16                       CC21 CC22 CC23 CC24 DD07                       DD20 DD23 EE02 EE19 EE43

Claims (2)

[Claims] 1. A nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or more,
The DBP absorption 140cm ^3/100 g or less of the carbon black is wet oxidation, the value of the atomic ratio of the total oxygen atom and the total carbon atoms measured by X-ray photoelectron spectroscopy (intensity of the intensity / carbon bond energy of the oxygen binding energy) Esterification reaction of a linear, branched or cyclic compound having an ether bond with the carboxyl group on the surface of carbon black particles produced by oxidation of 0.1 to 0.1 and an alcoholic hydroxyl group at the terminal or side chain A carbon black for a black matrix, which is characterized by being bonded by. 2. The carbon black according to claim 1 is contained in an amount of 2 to 20.
A resin composition for a black matrix, which has a composition in which an amount of wt%, a solvent of 60 to 96% by weight, and a resin of 2 to 20% by weight are mixed.