JP3235483B2 - Method for producing surface-treated carbon black - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing surface-treated carbon black.

[0002]

2. Description of the Related Art Pigments are generally insoluble in solvents such as organic solvents and water. Therefore, when used in coloring image forming materials such as inks, paints, plastic colorants, liquid developers, etc., organic solvents may be used depending on the application. Often dispersed in water or water. In particular, recently, there is a strong demand for water-based treatment due to environmental problems and the effect on the human body, and the stability of aqueous dispersion is required.
Conventionally, in order to disperse carbon black in water, the surface of the carbon black is modified with a surfactant, a dispersant, or a dispersing resin to form an aqueous ink or an aqueous coating. However, most carbon blacks are lipophilic and maintain a dispersed state with an aqueous vehicle.Therefore, it is necessary to select a dispersant or surfactant for each carbon black, change the dispersion conditions, or require pre-dispersion. However, there is a problem that dispersion is not easy. In the case of an ink jet pigment type ink, the dispersed ink aggregates at the nozzle portion and is difficult to re-disperse. In a coating material, there are problems such as sedimentation of pigment particles due to aggregation.

[0003] Therefore, various attempts have been made to improve the dispersion stability, one of which is to improve the hydrophilicity of carbon black by oxidation treatment. Traditionally,
As an oxidation treatment method of carbon black, an ozone treatment method or a plasma treatment method has been devised as gas phase oxidation, and a treatment method using nitric acid, hydrogen peroxide solution, or sodium perchlorate has been devised as liquid phase oxidation. Compared with general oxidation treatment conditions, liquid phase oxidation is more effective than gas phase oxidation, and in liquid phase oxidation, nitric acid increases surface acidity and improves hydrophilicity compared to hydrogen peroxide solution. It has been known. However, in the liquid phase oxidation, especially in the nitric acid treatment, the problem of mutagenicity has been pointed out for the carbon black treated.
Further, the gas phase oxidation has a feature that it is easy because there is no washing and filtration steps, but there is a problem that the hydrophilicity is not sufficient because the acidity is low.

On the other hand, a method of treating a pigment surface using fluorine gas has been devised (Kagaku, Vol. 46, No. 9, 199).
1). In this method, it is described that the carbon particle surface is hydrophilicized by ionizing the carbon particle surface with fluorine gas to obtain carbon having excellent dispersibility. However, ionization of the carbon particle surface has a problem in performance stability during storage in a powder state, and has a drawback that it is unstable with respect to pH and temperature changes in a dispersion system.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a carbon black which is excellent in initial dispersibility and long-term dispersibility in water and an organic solvent, and which hardly causes aggregation of carbon black particles. It is intended to provide a method for hydrophilizing the surface of carbon black for improving the property.

[0006]

That is, according to the present invention, the following method for producing surface-treated carbon black is provided. (1) Carbon black is dispersed in a sulfonation reaction solvent, and sulfuric acid, fuming sulfuric acid, sulfur trioxide, chlorosulfuric acid, fluorosulfuric acid, amidosulfuric acid, or sulfur trioxide and tertiary amine are dispersed on the surface of carbon black particles. A method for producing a surface-treated carbon black, in which a sulfonic acid group is introduced by at least one sulfonating agent selected from complexes of the following: (2) The surface according to (1), wherein sulfonic acid groups are introduced into the carbon black particle surface with a sulfonating agent while finely dispersing the aggregated particles of carbon black in a sulfonation reaction solvent using a pulverizer or a disperser. Method for producing treated carbon black. (3) The method for producing a surface-treated carbon black according to (2), wherein the fine dispersion by the pulverizer or the disperser is due to a shear stress or an impact force by a medium. (4) The method for producing a surface-treated carbon black according to any one of (1) to (3), wherein the sulfonating agent is a sulfonated pyridine salt or amidosulfuric acid. (5) The method for producing a surface-treated carbon black according to any one of (1) to (4), wherein the sulfonation reaction solvent is a basic solvent that forms a complex with sulfur trioxide. (6) The method for producing a surface-treated carbon black according to (5), wherein the sulfonation reaction solvent is at least one of N, N-dimethylformamide, dioxane, pyridine, triethylamine, trimethylamine, nitromethane, and acetonitrile. (7) The method for producing a surface-treated carbon black according to any one of (1) to (4), wherein the sulfonation reaction solvent is sulfolane or N-methyl-2-pyrrolidone.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the carbon black used in the method for producing a surface-treated carbon black of the present invention, any of furnace black, acetylene black and channel black can be used without any particular limitation. In addition, carbon black subjected to ordinary ozone treatment, plasma treatment, and liquid phase oxidation treatment can also be used. The particle size of the carbon black particles to be used is the same as the particle size range of the carbon black usually used for inks and coatings, but is preferably 50 to 0.01 μm, and particularly preferably 1 to 0.01 μm.
0 to 0.01 μm.

[0008] As the carbon black surface treatment method in the present invention, a sulfonation reaction that can be carried out by a usual organic reaction can be used if a solvent in which the dispersing solvent of the reaction system does not react with the sulfonating agent is selected. As the sulfonating agent, sulfuric acid, fuming sulfuric acid, sulfur trioxide, chlorosulfuric acid, fluorosulfuric acid, or amidosulfuric acid is used. In addition, when the reactivity of sulfur trioxide itself is too large to control the reaction, sulfonation can be carried out using a complex of sulfur trioxide and a tertiary amine (New Experimental Chemistry, Vol. 14, ,
1773, Maruzen). The type of solvent in the reaction, the reaction temperature, the reaction time, the type of sulfonating agent, etc. cannot be specified because the specific surface area, particle size, type and amount of surface functional groups of carbon black, and the reaction system differ for each reaction system. Examples of solvents that can be used include sulfolane, N-methyl-2-pyrrolidone, dimethylacetamide, quinoline, hexamethylphosphoric triamide,
Chloroform, dichloroethane, tetrachloroethane,
Examples include tetrachloroethylene, dichloromethane, nitromethane, nitrobenzene, liquid sulfur dioxide, carbon disulfide, and trichlorofluoromethane.

When a sulfur trioxide complex is used as a sulfonating agent, the reaction solvent forms a complex with sulfur trioxide, such as a basic solvent such as N, N-dimethylformamide, dioxane, pyridine, triethylamine and trimethylamine. Nitromethane and acetonitrile can be used alone or in combination with one or more other solvents described above as long as they are reactive such as forming a complex with a sulfonating agent. Specific reaction examples will be described with reference to Examples.

As the pulverizer or disperser used in the carbon black surface treatment method of the present invention, various known pulverizers or dispersers can be used. The following specific examples can be used as long as the aggregated particles of carbon black can be finely dispersed. Is not specified. As a specific example, a three-roll mill for finely dispersing carbon black particles by shear stress,
Roll mills, ball mills, attritors, sand mills, co-ball mills, basket mills, vibration mills, paint conditioners, etc. that finely disperse by the impact force of the collision of carbon black particles with media such as glass beads, zirconia beads, and agate balls. Dispersers, homogenizers, clear mixes, etc. that finely disperse by rotating blades that generate shear stress, cavitation, collision force, potential core, etc., collision force and shear stress between carbon black particles or between carbon black particles and vehicle or wall For example, a kneader, an extruder, a jet mill, or the like for finely dispersing with an ultrasonic wave, or an ultrasonic dispersing machine for finely dispersing with an ultrasonic wave can be applied. Since a sulfonating agent is used in the carbon black surface treatment method of the present invention, it is desirable that any pulverizer, disperser or, if necessary, the medium used is acid-resistant. In addition, since the three-roll mill and the two-roll mill are generally open-type, it is necessary to pay attention to changes in the reaction system due to the control of the reaction temperature or the volatilization of the solvent, the effects of ignition on the human body, etc. . Also, when using a closed type pulverizer or disperser, attention must be paid to fire, especially explosion due to static electricity and pressure control, since the inside of the system is filled with the vapor of the solvent.

The surface-treated carbon black obtained by the carbon black surface treatment method of the present invention reacts with a reactive functional group or an aromatic ring on the surface of the carbon black, and a sulfonic acid group is bonded to the surface of the carbon black particles. It is considered that carbon black improves the affinity with the vehicle and the solvent and shows excellent dispersion stability. Also,
By bonding the sulfonic acid group to the surface of the carbon black particles, the treated carbon black can be uniformly acidified, and has a reactivity or binding property with the sulfonic acid group at the site of the introduced sulfonic acid group. By introducing a compound newly, it is also possible to develop it into a surface treatment method such as grafting or encapsulation. Further, by adjusting the surface properties of the carbon black to some extent, the range of the pH value on the surface of the carbon black can be controlled, the structure of the dispersant and the vehicle can be unified, and the formulation at the time of ink preparation becomes easy. In addition, by performing a surface treatment reaction while finely dispersing the aggregated particles of carbon black with a pulverizer or a disperser, the reaction effect was conventionally given only to the surface of the aggregated particles, but on the surface of the finely dispersed particles The reaction effect can be given up to now, and the dispersibility in water and organic solvents has been improved.

The surface-treated carbon black obtained by the production method of the present invention is used for printing inks, paints, cosmetics, writing inks, toners, liquid developers, electrophotographic materials, recording materials such as ink jets, and colorants such as plastics. It can be used in a wide range of fields.

[0013]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. However, unless the scope of the present invention exceeds the gist thereof,
It is not limited to the embodiment. The evaluation of the obtained surface-treated carbon black was performed by the following method. Dispersion stability: After the prepared ink was allowed to stand at 50 ° C. for 2 months, the state of the precipitate in the ink was examined, and evaluated by △ x.は indicates no precipitate, △ indicates slight precipitate, and × indicates a large amount of precipitate. The particle size distribution of the pigment particles was measured with a laser particle size analyzer (LPA-3000 / 3100, manufactured by Otsuka Electronics Co., Ltd.), and the average particle size of the dispersed pigment particles was determined.

Embodiments 1, 3, 5, 7, 9, 11, 13,
15 Under the conditions shown in Table 1, carbon black is dispersed in a solvent and heated to a set temperature. Next, a sulfonating agent is added, and the mixture is reacted with stirring for a set time. After the reaction, the surface-treated carbon black is washed several times with an excess solvent, and then poured into water to obtain a surface-treated carbon black from the filtrate. Was.

Embodiments 2, 4, 6, 8, 10, 12, 1
4,16 Under the conditions shown in Table 1, carbon black is added to the solvent, mixed, and heated to the set temperature. Next, a sulfonating agent is added, and a reaction is performed while finely dispersing the pigment aggregated particles with a set pulverizer or a disperser for a set time and a set pulverizer or disperser. After washing, the mixture was poured into water to obtain a surface-treated carbon black from the filtrate.

Comparative Examples 1 to 8 Untreated carbon black was used as a comparative example.

[0017]

[Table 1] However, the three-roll mill (RMZ1 manufactured by Irie Shokai Co., Ltd.) Ball mill (V-2M type manufactured by Irie Shokai Co., Ltd.) Paint conditioner (5400-N2 manufactured by Red Devil Co., Ltd.) Homogenizer (CLEARMIX M TECHNIC Co., Ltd.)

Application Examples (Evaluation of dispersion stability) The acrylic emulsion was dissolved in water and propylene glycol according to the following formulation, and the surface-treated carbon black obtained in Examples 1 to 16 or Comparative Examples 1 to 8 was added thereto.
Untreated carbon black and zirconia beads
The mixture was mixed and dispersed with a paint conditioner for 3 hours to obtain an aqueous ink, and a dispersion stability test was performed. Table 1 shows the results. Surface-treated carbon black 8 parts by weight Water-soluble acrylic resin 20 parts by weight (John Krill J-61 manufactured by Johnson Polymer) 1.3 parts by weight of dimethylaminoethanol (reagent grade manufactured by Wako Pure Chemical Industries) Zirconia beads 0.5φ 25 parts by weight 45.7 parts by weight of purified water

[0019]

The surface-treated carbon black obtained by the production method of the present invention has excellent dispersion stability when mixed with a vehicle and a solvent to form an ink or paint, as compared with untreated carbon black. No aggregation or sedimentation of carbon black is observed even during long-term storage.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09C 1/00-3/12

Claims (7)

(57) [Claims] A carbon black is dispersed in a sulfonation reaction solvent, and sulfuric acid,
Fuming sulfuric acid, sulfur trioxide, chlorosulfuric acid, fluorosulfuric acid,
From a complex of misidosulfuric acid or sulfur trioxide with a tertiary amine
A method for producing a surface-treated carbon black in which a sulfonic acid group is introduced by at least one selected sulfonating agent. 2. A sulfonic acid group is introduced into the surface of carbon black particles by a sulfonating agent while finely dispersing aggregated particles of carbon black in a sulfonation reaction solvent with a pulverizer or a disperser. A method for producing surface-treated carbon black. 3. The method for producing surface-treated carbon black according to claim 2, wherein the fine dispersion by the pulverizer or the disperser is due to a shear stress or an impact force due to a medium. 4. The method for producing a surface-treated carbon black according to claim 1, wherein the sulfonating agent is a sulfonated pyridine salt or amidosulfuric acid . 5. The method for producing surface-treated carbon black according to claim 1, wherein the sulfonation reaction solvent is a basic solvent which forms a complex with sulfur trioxide. 6. A sulfonation reaction solvent, N, N- dimethylformamide, dioxane, pyridine, triethylamine, trimethylamine, nitromethane or Asetonito <br/> surface-treated carbon black of at least one of which is claimed in claim 5, wherein lil Production method. 7. The sulfonation reaction solvent is sulfolane or N
The method for producing a surface-treated carbon black according to any one of claims 1 to 4, which is -methyl-2-pyrrolidone.