JPH1036751A - Method for producing pigment ink composition and pigment ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a pigment ink composition comprising at least a pigment, a solvent, and a pigment dispersant suitable for a writing implement ink and a pigment ink composition obtained by the method. SOLUTION: A solution comprising at least a pigment, a solvent, and a pigment dispersant is caused to collide at least once by two nozzles 20, 20 at the same pressure and acceleration force, and then merged. Is a method for producing a pigment ink composition in which a pigment obtained by pulverizing, dispersing, and dispersing fine particles into fine particles is used, wherein the liquid flow paths 21 and 21 from the nozzles 20 and 20 to the merger reduce energy loss. A method for producing a pigment ink composition, wherein the liquid flow path is curved so that the solution hardly collides with the flow path wall surface. A pigment ink composition which has been micronized using the above method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a pigment ink composition comprising at least a pigment, a solvent and a pigment dispersant, and a pigment ink composition obtained by the method.

[0002]

2. Description of the Related Art Hitherto, fine particles of pigments have generally been formed using a bead mill, a sand mill, a ball mill, a roll mill or the like. These bead mills, sand mills,
Ball mills and the like use a stirring medium inside to make them into fine particles. However, repeated use requires maintenance such as replacement. In the case of using another color pigment with the same machine, the stirring medium must be exchanged, and a dedicated pigment is required for each color. In particular, in the case of a roll mill, stirring media is not required,
The viscosity of the solution to be micronized must be high, and since the operation is performed in an open state, the solvent used for the solution must satisfy conditions such as that a fast drying solvent cannot be used.

[0003] Therefore, ultrahigh-pressure dispersing machines such as a microfluidizer (manufactured by Microfluidics) and a nanomizer (manufactured by Nanomizer) have been proposed as machines capable of forming fine particles in a sealed state without requiring a stirring medium. A method for preparing a pigment using such an ultra-high pressure disperser is known (Japanese Patent Publication No. 8-30158, Japanese Patent Application Laid-Open No. 8-48898).

However, the ultrahigh-pressure dispersers disclosed in these publications also have a mechanism in which the high-pressure, high-acceleration solution is caused to collide with the diamond wall and then collide with each other. There is a problem that the diamond wall is seriously damaged and regular replacement and maintenance are required. In addition, there is a problem that energy efficiency at the time of collision between solutions decreases due to energy loss at the time of collision with a wall surface. Furthermore, these ultra-high pressure dispersers have a considerably narrowed liquid flow path in order to bring the liquid under a high pressure, and the minimum flow path diameter is as small as φ0.15 mm or less. Is limited to a small amount.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art when using an ultrahigh-pressure disperser such as the microfluidizer or the nanomizer, and is intended to solve the problem. It is an object of the present invention to provide a method for producing a pigment ink composition which is extremely low, has a high processing ability, and has fine pigment particles and good dispersibility, and a pigment ink composition obtained by the method.

[0006]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems of the prior art, the present inventors have found that the use of a dispersing device having a specific structure under specific conditions allows the production of the pigment ink composition of the above object. The method and the pigment ink composition obtained by the method were successfully obtained, and the present invention was completed.

That is, the present invention resides in the following. In the method for producing a pigment ink composition of the present invention, a solution comprising at least a pigment, a solvent, and a pigment dispersant is caused to collide at least once at the same pressurizing acceleration force from two nozzle portions and then merged. A method for producing a pigment ink composition in which the pigment obtained by pulverizing and dispersing the pigment into fine particles by the impact force of the pigment is finely divided, wherein the liquid flow path from the nozzle to the junction reduces energy loss. In addition, the liquid flow path is curved so that the solution hardly collides with the flow path wall surface. Manufacturing method of the minimum flow passage area of the curved allowed liquid flow path from the nozzle portion to merging, the pigment ink composition described above is 0.03 mm ² 1.0 mm ^2. A pigment ink composition in which the pigment is made into fine particles using the method described in or above. The pigment ink composition as described above, wherein the solvent is water.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 are drawings showing an example of a dispersing apparatus used in an embodiment of the present invention. FIG. 1 is a schematic basic flow diagram of the dispersing apparatus, and FIG. 2 is a schematic cross section showing a completely opposing collision mechanism. FIG. 3 is a schematic perspective view of FIG.

In FIG. 1, reference numeral 10 denotes a raw material tank filled with a solution (hereinafter, referred to as "raw material solution") comprising at least a pigment, a solvent, and a pigment dispersant. The raw material solution is supplied from the raw material tank 10 to the liquid flow path 11, the branch liquid flow paths 12,
And is introduced into the dispersion unit 13. The raw solution is pressurized in the middle of the branch liquid flow paths 12, 12 by hydraulic pressure increasing type pressurizing pumps 15, 15 controlled by a hydraulic pressure generation / control unit 14. 16, 16,... Are check valves, and 17, 17 are air release valves.

The raw material solution introduced into the dispersion section 13 is branched into branch liquid flow paths 18, 18, and introduced into the respective nozzle sections 20, 20. In the present embodiment, as shown in FIGS. 2 and 3, each of the nozzles 20 is accelerated at least once toward the center of the pulverizing unit 30 with the same pressurizing and accelerating force so as to be opposed to each other. It is to join.
Liquid flow path 2 from each of the nozzles 20 and 20 to the junction
In order to reduce energy loss, the liquid channels 1 and 21 are formed by curving the liquid flow path so that the solution hardly collides with the flow path wall surface.

As shown in FIGS. 2 and 3, the liquid flow paths 21 and 21 from the respective nozzle portions 20 and 20 to the junction are
Since the material solution is curved and formed with an aspherical curve, the raw material solution is unlikely to collide with the liquid flow path wall surface and the energy loss is extremely reduced, so the wear resistance of the flow path is extremely high, and until the collision. Since the raw material solution has a laminar flow without generating a turbulent flow or a vortex, a reliable collision effect can be obtained. In the case of performing two or more complete opposition collisions (two passes) in the pulverizing section 30, the pulverized / particulated raw material solution is controlled by controlling the three-way valve 31 as shown in FIG. By returning to 10, the completely opposing collision is repeatedly performed.

The area of the outlets 22, 22, which are the minimum flow paths of the curved liquid flow paths 21, 21 from the respective nozzle portions 20, 20 to the junction, is preferably 0.03 mm ^{2 to} 1.0 mm ² . it is preferable is 0.05 mm ² to 0.8 mm ^2.
If the minimum flow path area is less than 0.03 mm ² , if the substance to be dispersed / crushed is not less than 0.1 mm, smooth liquid transfer will not be performed, and therefore, preliminary dispersion as pretreatment is required. In many cases, preliminary dispersion is also required when particles having a size of about 0.15 mm or more are mixed. On the other hand, if the minimum flow path area exceeds 1.0 mm ² , turbulence is likely to occur in the liquid supply in the flow path, and the energy of the opposing collision is lost, which is not preferable. In the conventional ultra-high pressure disperser, the raw material solution collides with the wall surface and then collides.Moreover, the liquid flow path is narrowed considerably to keep the liquid under high pressure, and the minimum flow path diameter is φ0.1
Although it was as small as 5 mm or less, in the present invention, the liquid flow paths 21 and 21 from the respective nozzle portions 20 and 20 to the junction are formed.
As described above, since the raw material solution is formed with an aspherical curve, the raw material solution hardly collides with the liquid flow path wall surface, the energy loss is extremely small, and the raw material solution generates a turbulent flow or a vortex until completely opposed collision. Because it has a laminar flow
A sufficient flow rate can be obtained. Therefore, the minimum flow path area can be set to 0.2 mm ² or more (up to 1.0 mm ² ) as compared with the conventional ultra-high pressure dispersers such as microfluidizers and nanomizers. ) And the productivity will be excellent.

Further, the pressure from the respective nozzle portions 20 and 20, 200~4000kgf / cm is preferably ^2, impact pressure caused by the pressurization 200 kgf / cm ²
It is preferable that it is the above. The above pressure is 200
If it is less than kgf / cm ² , sufficient dispersing and pulverizing ability cannot be obtained, and if it exceeds 4000 kgf / cm ^2, it is difficult to secure a flow path system capable of withstanding the pressure, which is not preferable.

The dispersing device that can be used in the present invention may be any device having a curved liquid flow path from the nozzle to the junction (completely opposed collision) so that the solution hardly collides with the flow path wall surface. For example, an ultimateizer (manufactured by Sugino Machine Co., Ltd.) is used.

The amount of the pigment in the raw material solution used in the present invention is as follows:
It is used in a weight ratio of 1 to 20%, preferably 2 to 10%. If the amount of the pigment is less than 1% by weight, the concentration is low and the number of collisions between the particles is reduced, so that the efficiency is reduced. Do not collide with each other, but the ratio of particles that once collide and lose energy is increased, and therefore the efficiency of dispersion and pulverization is reduced, which is not preferable. As a pigment, for example,
C. I. Pigment Black 7, C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 2, C.I. I. Pigment Yellow 3, C.I. I. Pigment Red 5,
C. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment Blue 3 and the like, but are not limited thereto.

The amount of the pigment dispersant in the raw material solution used in the present invention is 0.1 to 0.8 by weight, preferably 0.1 to 0.5, relative to 1 pigment. Yes, two or more types may be mixed. If the amount of the pigment dispersant is less than 0.1 with respect to the weight of the pigment 1, sufficient dispersion cannot be obtained. If the amount of the pigment dispersant exceeds 0.8 with respect to the weight of the pigment 1, the viscosity increases. Cause and not preferred. Examples of the pigment dispersant include, for example, acrylic resin, styrene resin, styrene acrylic resin, styrene maleic resin, polyamide resin, vinyl resin, and the like. It is not limited.

The amount of the solvent in the raw material solution used in the present invention is
It is used in the range of 40 to 95% by weight, and one or two or more kinds are used as a mixture. Examples of the solvent include water (purified water), ethyl acetate, ethyl alcohol, glycerin, and the like. Preferably, water (purified water) is used because it does not adversely affect the seal packing in the liquid flow path such as swelling. Is used. When two or more solvents are mixed, they may be added after being dispersed by the dispersion method of the present invention.

In the present invention, a pH adjuster, a preservative, a rust preventive, an extender, a viscosity adjuster, a dispersant, and the like may be further added as necessary. Further, these may be stirred and mixed by a despa or the like after being dispersed by the method of the present invention.

The pigment ink composition obtained by the present invention, which comprises at least a pigment, a solvent and a pigment dispersant, is obtained as a dispersion without using a stirring medium, and the pigment has an average particle size of 0.1. It can be adjusted to 2 μm or less, for example, which is suitable as an ink for writing implements.

[0020]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

EXAMPLE 1 Carbon black was stirred while stirring a solution composed of 74.5 parts of purified water, 10 parts of ethylene glycol, 5 parts of ammonium styrene acrylate, 0.4 part of triethanolamine and 0.1 part of benzotriazole. 10 parts of MCF-88 [manufactured by Mitsubishi Kasei Corporation] was added, and the mixture was stirred for 30 minutes. The solution thus obtained was subjected to three passes at a pressure of 1500 kgf / cm ² using an Ultimateizer (manufactured by Sugino Machine Co., Ltd.).

Next, the solution from which coarse particles have been removed by filtration is taken in a glass bottle and stored in a high-temperature bath at 50 ° C., and even after 3 months, sedimentation and gelation are observed. And a good dispersion was obtained. In addition, the solution is supplied to a commercially available writing implement container PX.
21 (manufactured by Mitsubishi Pencil Co., Ltd.), and good writing lines were obtained.

Example 2 Phthalocyanine blue was stirred while stirring a solution consisting of 79.5 parts of purified water, 5 parts of glycerin, 10 parts of styrene maleic acid resin ammonium salt, 0.4 part of triethanolamine and 0.1 part of benzotriazole. Chromoline Blu
10 parts of e4965 [Dainippon Seika Co., Ltd.] was added, and the mixture was stirred for 30 minutes after the addition. The solution thus obtained was subjected to 1500 using an Ultimateizer (manufactured by Sugino Machine Co., Ltd.).
Three passes were performed at a pressure of kgf / cm ² .

Next, the solution from which coarse particles were removed by filtration was taken out in a glass bottle and stored in a high-temperature bath at 50 ° C., and even after three months, sedimentation and gelation were observed. And a good dispersion was obtained. In addition, the solution is supplied to a commercially available writing implement container PX.
21 (manufactured by Mitsubishi Pencil Co., Ltd.), and good writing lines were obtained.

[0025]

According to the present invention, there is provided a method for producing a pigment ink composition having a remarkably high processing capacity and excellent productivity. The obtained dispersibility becomes good.

[Brief description of the drawings]

FIG. 1 is a schematic basic flow diagram of a dispersion apparatus showing an example of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a completely opposing collision mechanism according to the present invention.

FIG. 3 is a schematic perspective view of FIG.

[Explanation of symbols]

 Reference Signs List 10 Raw material tank 18, 18 Branch liquid flow path 20, 20 Nozzle section 21, 21 Liquid flow path 22, 22, Outflow port

Claims (4)

[Claims] 1. A solution comprising at least a pigment, a solvent and a pigment dispersant is caused to collide at least once by two nozzles at the same pressure and acceleration force and then merged, and the pigment is pulverized by the collision force at that time. A method for producing a pigment ink composition in which a pigment obtained by dispersing and dispersing into fine particles is formed into fine particles, wherein the liquid flow path from the nozzle portion to the merger reduces the energy loss, A method for producing a pigment ink composition, characterized in that a liquid flow path is curved so as to be less likely to collide with a pigment ink composition. 2. A minimum flow area of the curved allowed liquid flow path leading to the merging from the nozzle unit The production method of claim 1 pigment ink composition according is 0.03 mm ² 1.0 mm ^2. 3. A pigment ink composition obtained by using the method according to claim 1 or 2 to make pigment fine particles. 4. The pigment ink composition according to claim 3, wherein the solvent is water.