Method for producing dispersion composition

Abstract

The present invention improves the life of a sealing mechanism in a dispersing treatment of a feed-material composition comprising a dispersion medium and a dispersed phase, thereby improving the efficiency of the production of a dispersion composition. Provided is a method for producing a dispersion composition using a dispersing device comprising: a dispersing mechanism which pressurizes and disperses a feed-material composition; a supply mechanism which is equipped with a plunger part and supplies the feed-material composition to the dispersing mechanism; and a sealing mechanism which seals the plunger part with a liquid medium for sealing. The feed-material composition comprises a dispersed phase and a dispersion medium, and the liquid medium for sealing at least includes the same dispersed phase as that of the feed-material composition and the same dispersion medium as that of the feed-material composition.

Description

Method for producing dispersion composition

[0001] The present invention relates to a method for producing a dispersion composition.

[0002] Methods for dispersing dispersoids in a dispersion medium include agitators, ball mill dispersers, bead mill dispersers, ultrasonic dispersers, single-screw kneaders, multi-screw kneaders, roll mill dispersers, and high-pressure homogenizers. Bead mill dispersers are widely used from the perspective of dispersion efficiency. While bead mills have the advantage of applying impact to the dispersoids to finely disperse them, the impact can damage the dispersoids, resulting in a deterioration of their original properties. High-pressure homogenizers can homogeneously disperse a treatment liquid by ejecting the treatment liquid from a nozzle or by passing the treatment liquid through a homogenization valve. Because the treatment liquid is supplied at high pressure to improve dispersion efficiency, the dispersoids can be finely dispersed by shear forces and collisions between the treatment liquids themselves and by collisions with the walls of the homogenization valve.

[0003] Valve-type high-pressure homogenizers are suitable for mass production because they can increase the flow rate of the processing liquid and do not require nozzles, which can cause clogging, and are used as homogenizers for aqueous systems such as dairy products and beverages. Dairy products and the like are aqueous with little solid content, so they have the advantage of having little effect on the components of the dispersion device, and for example, the packing of the high-pressure pump deteriorates slowly, allowing for longer replacement intervals.

[0004] In recent years, high-pressure homogenizers have also been used as dispersion devices for various dispersion compositions, such as inks. Various dispersoids and liquid media are used in inks and other compositions. Raw material compositions containing solids tend to attack the packings of high-pressure pumps, and deterioration of the packing can shorten the replacement intervals for the packings and reduce work efficiency. Furthermore, deterioration of the packing can also lead to the problem of increased leakage of the raw material composition from the high-pressure pump.

[0005] Patent Document 1 proposes a method in which a crude dispersion containing carbon nanotubes and a solvent is stored in a tank and then sent to a disperser using a high-pressure pump for dispersion processing, in which the high-temperature carbon nanotube dispersion discharged from the disperser is cooled to prevent the generation of bubbles in the dispersion, and the back pressure of the dispersion is reduced in multiple stages to prevent the generation of bubbles in the dispersion when atmospheric pressure is released, thereby improving the dispersibility of the carbon nanotubes.

[0006] International Publication No. 2015 / 015758 Japanese Patent Application Laid-Open No. 2018-511018

[0007] In conventional technologies such as those disclosed in Patent Document 1, a plunger is used in a high-pressure pump to supply a raw material composition to a dispersion mechanism at high pressure. Because the plunger is installed inside a cylinder, conventional technologies have placed a gland packing in the gap between the plunger and the cylinder. However, as mentioned above, gland packing deteriorates with repeated use and requires replacement, and the possibility of liquid leakage due to gland packing deterioration cannot be completely eliminated. In particular, when the raw material composition contains a dispersoid and a dispersion medium, solid content tends to cause gland packing deterioration. Therefore, there is a growing demand for new technologies that can solve the problem of gland packing deterioration in raw material compositions containing solid content. The sealing device disclosed in Patent Document 2 does not use a gland packing, but there was no prior knowledge that it could be used in a method for producing a dispersion composition containing solid content.

[0008] An object of the present invention is to improve the life of a sealing mechanism in the dispersion treatment of a raw material composition containing a dispersion medium and a dispersoid, and to improve the productivity of the dispersion composition.

[0009] The inventors of the present invention conducted extensive research aimed at solving the above-mentioned problems and discovered that by using a sealing liquid medium as a sealing mechanism for the plunger, it is possible to seal the plunger without using a gland packing as a sealing mechanism for the plunger. This fundamentally solves the problem of gland packing deterioration, extends the life of the sealing mechanism for the plunger, and enables long-term operation. Furthermore, by including in the sealing liquid medium at least the same dispersoid and dispersion medium as those in the raw material composition, deterioration in the quality of the dispersion composition can be suppressed.

[0010] That is, the present invention includes the following embodiments. The embodiments of the present invention are not limited to the following: <1> A method for producing a dispersion composition using a dispersing device including a dispersion mechanism that pressurizes and disperses a raw material composition, a supply mechanism that has a plunger portion and supplies the raw material composition to the dispersion mechanism, and a sealing mechanism that seals the plunger portion using a sealing liquid medium, wherein the raw material composition includes a dispersoid and a dispersion medium, and the sealing liquid medium includes at least the same dispersoid as in the raw material composition and the same dispersion medium as in the raw material composition.

[0011] <2> The method for producing a dispersion composition according to <1>, wherein the sealing liquid medium is pressurized using an independent pump and supplied to the sealing mechanism. <3> The method for producing a dispersion composition according to <1> or <2>, wherein the sealing liquid medium has a particle diameter D50 of 5 μm or less at a cumulative 50% volumetric percentage of a particle size distribution measured by dynamic light scattering. <4> The method for producing a dispersion composition according to any one of <1> to <3>, wherein the sealing liquid medium has a viscosity at 25°C of 10,000 mPa s or less.

[0012] According to one embodiment of the present invention, the life of a sealing mechanism can be improved in the dispersion treatment of a raw material composition containing a dispersion medium and a dispersoid, and the productivity of the dispersion composition can be improved.

[0013] It is a schematic diagram showing an example of a dispersing device. It is a cross-sectional view showing a high-pressure pump and a sealing mechanism of an example of a dispersing device. It is a cross-sectional view showing a homogenization valve of a dispersing part of an example of a dispersing device.

[0014] The method for producing a dispersion composition according to an embodiment of the present invention will be described in detail below. The present invention is not limited to the following embodiment, and the present invention also includes embodiments that are implemented within the scope of the present invention.

[0015] <Dispersion Device> A method for producing a dispersion composition containing a dispersoid and a dispersion medium using a dispersion device will be described below. The dispersion composition may further contain a dispersant. The dispersion composition can be produced using a dispersion device equipped with a dispersion mechanism that pressurizes and disperses the raw material composition, a supply mechanism that has a plunger unit and supplies the raw material composition to the dispersion mechanism, and a sealing mechanism that seals the plunger unit using a sealing liquid medium. The raw material composition is a composition that contains a mixture of the raw materials of the dispersion composition. The raw material composition may be a composition in a mixed state, or a composition in a coarsely dispersed state after mixing.

[0016] An example of such a dispersion device is a high-pressure homogenizer. A high-pressure homogenizer supplies a raw material composition at high pressure from a high-pressure pump to a dispersion section by reciprocating a plunger, and the raw material composition can be dispersed in the dispersion section. In one example of the dispersion section, the raw material composition is sprayed at high pressure from a minute nozzle at the tip, and dispersoids can be dispersed in the dispersion medium by collisions and shear forces between the raw material compositions. In another example of the dispersion section, the raw material composition is supplied at high pressure to a homogenizing valve, and the raw material composition is collided with the wall surface of the homogenizing valve to apply an impact, thereby dispersing the dispersoids in the dispersion medium. A method of performing dispersion treatment using a homogenizing valve can increase the flow rate of the raw material composition, avoid problems such as nozzle clogging, and is suitable for mass production.

[0017] The pressure of the raw material composition when supplied to the dispersion section is preferably 10 to 150 MPa. When the dispersion section is of a nozzle type, the pressure of the raw material composition when supplied to the dispersion section is preferably in the normal range of 60 to 150 MPa. When the dispersing machine is of a valve type, the pressure of the raw material composition when supplied to the dispersing machine is preferably in the normal range of 10 to 150 MPa.

[0018] 1 shows a schematic diagram of an example of a dispersing device. The dispersing device 100 includes a high-pressure pump 20, which is a form of a supply mechanism, a dispersing section 30, which is a form of a dispersing mechanism, and a sealing mechanism 40. The high-pressure pump 20 includes a plunger 10. The raw material composition tank 50 is a container that contains the raw material composition to be supplied to the high-pressure pump 20.

[0019] The high-pressure pump 20 includes a supply port 22 through which the raw material composition is supplied from the raw material composition tank 50, and a discharge port 23 through which the raw material composition is discharged to the dispersion section 30. The high-pressure pump 20 includes a cylinder 21 that supports the plunger 10 so that the plunger 10 can reciprocate in the axial direction. The cylinder 21 is provided with a sealing mechanism 40 to prevent the raw material composition and pressure from leaking from the high-pressure pump 20 to the outside.

[0020] One end of the plunger 10 is inserted into the high-pressure pump 20, and the other end extends outside the high-pressure pump 20 and is supported by a cylinder 21. The sliding surfaces between the plunger 10 and the cylinder 21 are preferably slidably sealed to prevent leakage of the raw material composition from the high-pressure pump 20, and it is also preferable that pressure loss due to air escaping from the high-pressure pump 20 to the outside is not generated. The plunger 10 reciprocates in the axial direction, changing the volume of the pressure chamber of the high-pressure pump 20. When the plunger 10 is withdrawn from the high-pressure pump 20 and the volume of the pressure chamber increases, the raw material composition is sucked in through the supply port 22 of the high-pressure pump 20, and when the plunger 10 is pushed out into the high-pressure pump 20 and the volume of the pressure chamber decreases, the raw material composition is discharged through the discharge port 23 of the high-pressure pump 20. The supply port 22 and the discharge port 23 of the high-pressure pump 20 may each be provided with a valve to prevent backflow of the raw material composition.

[0021] The raw material composition discharged from the high-pressure pump 20 is supplied to the dispersion section 30 at high pressure. The dispersion section 30 may be of either a nozzle type or a valve type. Because it is possible to supply a large amount of raw material composition at high pressure to the dispersion section 30 using a plunger 10, the dispersion section 30 is preferably of a valve type, and more specifically, a homogenizing valve is preferred. After the dispersion treatment, a dispersion composition in which dispersoids are dispersed in a dispersion medium is obtained. Although not shown, the dispersion treated dispersion composition can be recovered in a dispersion composition tank from the outlet of the dispersion section 30 via piping.

[0022] The sealing mechanism 40 includes a sealing liquid medium supply pipe 41, a sealing liquid medium discharge pipe 42, and a storage section 43 that supplies the sealing liquid medium to the sealing liquid medium supply pipe 41 and recovers the sealing liquid medium from the sealing liquid medium discharge pipe 42.

[0023] The sealing liquid medium supplied from the sealing mechanism 40 into the cylinder 21 fills the gap G between the outer circumferential surface of the plunger 10 and the inner circumferential surface of the cylinder 21, thereby sealing the gap G. To improve the sealing performance, it is preferable that the gap G be tightly filled with the raw material composition and / or the sealing liquid medium.

[0024] The gap G is preferably formed over the entire circumference of the outer circumferential surface of the plunger 10. Since the plunger 10 and the cylinder 21 do not come into direct contact with each other, the pressure load can be reduced. Furthermore, since the outer circumferential surface of the plunger 10 is supported over the entire circumference by the pressurized liquid medium, the axial fluctuation of the reciprocating movement of the plunger 10 can be reduced. From this perspective, the liquid medium in contact with the outer circumferential surface of the plunger 10 may be a sealing liquid medium or a raw material composition indirectly pressurized by the sealing liquid medium.

[0025] The raw material composition supplied to the pump chamber 24 and the sealing liquid medium supplied to the gap G come into contact at their interface. In this case, the boundary B between the raw material composition and the sealing liquid medium may form an interface without mixing with each other, or may mix with each other and show a concentration gradient. Preferably, the boundary B is formed in the gap G between the outer circumferential surface of the plunger 10 and the inner circumferential surface of the cylinder 21. The supply pressures of the sealing liquid medium and the raw material composition may be adjusted so that the boundary B is not formed on the pump chamber 24 side of the tip of the plunger 10 within the range of the reciprocating movement of the plunger 10 in the axial direction of the plunger 10.

[0026] According to one embodiment, even if the sealing liquid medium is mixed into the raw material composition, the solid content concentration and the like in the resulting dispersion composition do not fluctuate significantly. However, it is preferable to prevent a large amount of the sealing liquid medium from being discharged into the pump chamber 24.

[0027] In the illustrated example, the sealing liquid medium is supplied from and collected in the storage section 43. The sealing liquid medium collected in the storage section 43 may be reused and recycled. In another example, the sealing liquid medium discharged from the sealing liquid medium discharge pipe 42 may be discarded.

[0028] In the illustrated example, the sealing liquid medium discharge pipe 42 is disposed on the pump chamber 24 side in the axial direction of the plunger 10, and the sealing liquid medium supply pipe 41 is disposed on the opposite side. In this example, the composition of the sealing liquid medium is maintained in the region opposite the pump chamber 24 in the axial direction of the plunger 10. As the sealing liquid medium and the raw material composition mix, the composition of the sealing liquid medium may change as the plunger 10 moves toward the pump chamber 24. By discharging the sealing liquid medium when the concentration gradient of the sealing liquid medium reaches a certain concentration, an increase in the amount of the sealing liquid medium mixed into the raw material composition can be suppressed. The supply and discharge positions of the sealing liquid medium to and from the cylinder 21 are not limited to the illustrated example and can be changed. For example, in addition to these changes, the allowable range of the amount of the sealing liquid medium mixed into the pump chamber 24, the compositional identity between the raw material composition and the sealing liquid medium, etc. may be adjusted.

[0029] In the illustrated example, an outer sleeve 25 is provided at the end of plunger 10 on the outer side of the device in the axial direction, covering the opening of cylinder 21. Since the sealing mechanism 40 ensures sealing of the raw material composition within cylinder 21, the opening of cylinder 21 may be open, but providing outer sleeve 25 can further suppress liquid leakage.

[0030] The sealing liquid medium may be pressurized using an independent pump and supplied to the sealing mechanism. For example, although not shown, a pump may be provided in the sealing liquid medium supply pipe 41 so that a high-pressure sealing liquid medium can be supplied into the cylinder 21. Pressurization by this pump applies shear force to the sealing liquid medium, making it possible to maintain good dispersibility of the dispersoids in the sealing liquid medium. Furthermore, when the sealing liquid medium is mixed with the raw material composition, the possibility of causing aggregation of the dispersoids can be further reduced.

[0031] A specific example of a dispersion device will be described using Figures 2 and 3. Components common to Figure 1 are assigned the same reference numerals, and parts not particularly described are as described in Figure 1 above. In Figure 2, a check valve 22a and a check valve 23a are provided at the supply port 22 and the discharge port 23 of the high-pressure pump 20, respectively. A sealing mechanism 40 tightly fills a chamber 44 on the inner circumferential surface of the cylinder 21 with a sealing liquid medium. A plunger 10 is provided within the cylinder 21. The outer end of the high-pressure pump 20 in the axial direction of the plunger 10 is provided with a mechanism for transmitting reciprocating movement via a rod 81 by a crankshaft 82, allowing the plunger 10 to reciprocate in the axial direction.

[0032] The sealing mechanism 40 includes a sealing liquid medium supply pipe 41, a sealing liquid medium discharge pipe 42, and a pump 45 capable of supplying the sealing liquid medium at high pressure to the sealing liquid medium supply pipe 41. Although not shown, a tank may be provided to store the sealing liquid medium to be supplied to the pump 45. Although not shown, a mechanism may be provided to recover the sealing liquid medium discharged from the sealing liquid medium discharge pipe 42 into this tank and recirculate it.

[0033] In FIG. 2 , the sealing mechanism 40 includes a chamber 44 that holds a sealing liquid medium on the inner circumferential surface of the cylinder 21. A gap G is formed between the inner circumferential surface of the cylinder 21 and the outer circumferential surface of the plunger 10. A raw material composition is supplied from the pump chamber 24 to fill this gap G. Pressure is released between the gap G and the chamber 44 via a through-opening 44 a. Regarding the pressure environment, the raw material composition in the gap G is at a positive pressure relative to the sealing liquid medium in the chamber 44. This prevents the sealing liquid medium from flowing from the gap G into the dispersion section. Furthermore, the raw material composition in the gap G is tightly filled onto the outer circumferential surface of the plunger 10 by the pressure from the sealing liquid medium in the chamber 44, thereby improving sealing performance.

[0034] When the sealing liquid medium is supplied into the chamber 44 by the pump 45, the external pressure inside the chamber 44 can be adjusted by adjusting the output of the pump 45. Furthermore, the internal pressure of the raw material composition can be adjusted by adjusting the output of the plunger 10. Although not limited to the example shown in the figure, when the external pressure is 50 to 5000 bar, the internal pressure is preferably 80 to 8000 bar, and more preferably when the external pressure is 300 to 1000 bar, the internal pressure is 400 to 1500 bar.

[0035] The chamber 44 is preferably formed around the entire circumference of the cylinder 21 in the circumferential direction. The chamber 44 may be provided at one or more locations in the axial direction of the cylinder 21. In the example shown, two chambers 44 are arranged at two locations in the axial direction of the cylinder 21, with a partition therebetween. This allows for more uniform sealing in the gap G within the axial movement range of the plunger 10. Furthermore, in the example shown, the contact area between the raw material composition and the sealing liquid medium can be reduced, thereby further suppressing mixing of the two liquid media and further reducing fluctuations in the solid content of the resulting dispersion composition.

[0036] The chambers 44 at the multiple locations may be connected to one another, and the sealing liquid medium may be supplied to and discharged from the chambers 44 using a pair of sealing liquid medium supply pipes 41 and sealing liquid medium discharge pipes 42. Alternatively, the chambers 44 at the multiple locations may be isolated from one another, and each chamber may be provided with a pair of sealing liquid medium supply pipes 41 and sealing liquid medium discharge pipes 42.

[0037] In another example, the chambers 44 may be arranged over a wide range of the axial movement of the plunger 10, with each chamber 44 having one or more through openings in the axial direction of the plunger 10.

[0038] A plurality of through openings 44a may be provided so as to be separated from one another in the circumferential direction of the chamber 44. In another example, the through openings 44a may be provided so as to communicate with each other over the entire circumferential direction of the chamber 44.

[0039] Fig. 3 is a cross-sectional view schematically showing the homogenizing valve of the dispersion section 30. In Fig. 3, the homogenizing valve of the dispersion section 30 includes a valve seat 31, an impact ring 32, and a homogenizing valve 33. The raw material composition supplied from the high-pressure pump 20 is supplied to the homogenizing valve at high pressure in the direction of the arrow in the figure, where it is subjected to a fine dispersion treatment, and then discharged from a discharge port (not shown).

[0040] Examples of dispersing devices that can be used include valve-type high-pressure homogenizers such as the "HC3 Series" manufactured by Sanmaru Machinery Co., Ltd., the "HV-H Series" manufactured by Izumi Food Machinery, and the "R-Model" manufactured by SPX Flow. Other examples of dispersing devices include nozzle-type high-pressure homogenizers. Examples of nozzle-type high-pressure homogenizers that can be used include, but are not limited to, the "Genus PY" manufactured by Genus Corporation, the "Starburst" manufactured by Sugino Machine Co., Ltd., and the "Nanomizer" manufactured by Nanomizer. Nozzle-type high-pressure homogenizers include, but are not limited to, a pump and one or more nozzles, and various nozzle shapes are available for dispersion processing. Examples include, but are not limited to, types that collide raw materials with each other at high pressure, types that collide high-pressure raw materials with ceramic balls or pass them through slits and process them using the resulting shear force, and types that utilize cavitation caused by a jet of high-pressure raw materials. In these commercially available dispersing devices, the sealing mechanism between the plunger and cylinder can be modified to the sealing mechanism described above.

[0041] <Raw Material Composition> The raw material composition supplied to the dispersion device is not particularly limited as long as it contains a dispersoid and a dispersion medium. The raw material composition may further contain a dispersant to achieve dispersion stability of the dispersoid. The raw material composition may also contain optional components such as a resin emulsion, a surfactant, a binder resin, a wetting agent, a wetting penetrating agent, and a leveling agent, as necessary.

[0042] The dispersoid may be inorganic particles, organic particles, inorganic-organic composite particles, or a combination thereof. Particles that are dispersible in a dispersion medium are preferred, and those that are insoluble in a dispersion medium are preferred. Examples of inorganic particles include carbon materials, ceramics, and metals. Examples of carbon materials include carbon black, carbon nanotubes, fullerenes, graphene, multilayer graphene, and graphite. Examples of carbon black include acetylene black, furnace black, hollow carbon black, and Ketjen black. These carbon materials may be neutral, acidic, or basic, and may be subjected to oxidation or graphitization treatment. Examples of ceramics include metal oxides, carbonates, nitrides, phosphates, and carbides, such as calcium oxide, calcium carbonate, magnesium oxide, magnesium carbonate, magnesium phosphate, aluminum oxide, aluminum nitride, aluminum phosphate, boron nitride, silicon oxide, silicon nitride, silicon carbide, zirconium oxide, titanium oxide, and kaolin clay. Examples of metals include zinc, lead, titanium, cadmium, iron, copper, cobalt, and the like, and alloys thereof.

[0043] As the organic particles, resin particles are preferred, and examples thereof include polystyrene, polyurethane, polyester, polyamide, vinyl polymers, acrylic polymers, composite polymers thereof, cellulose, pulp fibers, and the like.

[0044] As the dispersoid, an organic pigment or an inorganic pigment may be used. Examples of organic pigments include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, dictopyrrolopyrrole-based, and isoindoline-based pigments. More specific examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, cromophtal yellow, cromophtal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, diketopyrrolopyrrole red, aniline black, and daylight fluorescent pigments. Further, examples of organic pigments include, among the colorants listed in the Color Index International (C.I.), organic compounds or organometallic complexes such as C.I. Pigment Black, C.I. Pigment Blue, C.I. Pigment Green, C.I. Pigment Red, C.I. Pigment Violet, C.I. Pigment Yellow, C.I. Pigment Orange, and C.I. Pigment Brown.

[0045] Examples of inorganic pigments include white pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, and silica; and non-white pigments such as aluminum powder, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, aluminum hydroxide, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, titanium oxide, and zinc oxide.

[0046] The dispersoid may be surface-treated. The dispersoid may be used alone or in combination of two or more. The content of the dispersoid in the raw material composition is not particularly limited, and may be appropriately adjusted depending on the materials of the dispersoid and the dispersion medium within a range in which the dispersoid can be dispersed in the dispersion medium after dispersion treatment.

[0047] As the dispersion medium, a dispersion medium capable of dispersing the dispersoid may be used depending on the type of dispersoid. The dispersion medium may be a non-aqueous dispersion medium or an aqueous dispersion medium. The dispersion medium may contain either an organic solvent or water. The dispersion medium may contain at least one of a water-insoluble organic solvent and a water-soluble organic solvent. When water and an organic solvent are combined, from the viewpoint of compatibility, the dispersion medium is preferably a combination of a water-soluble organic solvent and water. Alternatively, the dispersion medium may consist of only water.

[0048] The organic solvent may be either a non-polar solvent or a polar solvent, and a combination of these may be used within the range of miscibility. Examples of non-polar solvents include aliphatic hydrocarbon solvents such as hexane, cyclohexane, and paraffin, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and other petroleum-based hydrocarbon solvents. Examples of polar solvents include ester-based solvents, ether-based solvents, alcohol-based solvents, ketone-based solvents, amide-based solvents, heterocyclic solvents, sulfoxide-based solvents, sulfone-based solvents, and carbonate-based solvents.

[0049] More specifically, examples of the organic solvent include amides (N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methylcaprolactam, etc.), heterocyclics (cyclohexylpyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, etc.), sulfoxides (dimethyl sulfoxide, etc.), sulfones (hexamethylphosphorotriamide, sulfolane, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), carbonates (diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, fluoroethylene carbonate, propylene carbonate, ethylene carbonate), tetrahydrofuran, acetonitrile, etc.

[0050] Examples of the organic solvent include formic acid, acetic acid, methanol, ethanol, propanol, methyl acetate, ethyl acetate, and diethyl ether. Examples of the organic solvent include ethyl lactate, benzyl alcohol, 1,2,3-trichloropropane, 1,3-butanediol, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl-1,3-propanediol, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl-1,3-butanediol, and 3-methoxy-3-methyl-1-butane. alcohol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, n-butyl alcohol, n-butylbenzene, n-propyl acetate, o-xylene, o-chlorotoluene, o-diethylbenzene, o-dichlorobenzene, p-chlorotoluene, p-diethylbenzene, sec-butylbenzene, tert-butylbenzene, isobutyl alcohol, isophorone, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotertiary butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimethyl ether,Examples of the dispersion medium include dipropylene glycol methyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, triacetin, tripropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methylcyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, and dibasic acid esters. The dispersion medium may be used alone or in combination of two or more.

[0051] The raw material composition may further contain a dispersant. The dispersant may be either a resin-type dispersant or a surfactant, but a suitable type of dispersant can be used in a suitable amount depending on the properties required for dispersing the dispersoid.

[0052] Examples of resin-type dispersants that can be used include (meth)acrylic polymers, polymers derived from ethylenically unsaturated hydrocarbons, cellulose derivatives, and copolymers thereof. Examples of polymers derived from ethylenically unsaturated hydrocarbons include polyvinyl alcohol resins, polyvinylpyrrolidone resins, polyacrylonitrile resins, and nitrile rubbers. Examples of polyvinyl alcohol resins include polyvinyl alcohol, modified polyvinyl alcohols having functional groups other than hydroxyl groups (e.g., acetyl groups, sulfo groups, carboxy groups, carbonyl groups, and amino groups), polyvinyl alcohols modified with various salts, other anion- or cation-modified polyvinyl alcohols, and polyvinyl acetals (polyvinyl acetoacetal, polyvinyl butyral, etc.) modified with aldehydes (acetoacetal-modified, butyral-modified, etc.). The polyacrylonitrile resin may be a polyacrylonitrile homopolymer, a polyacrylonitrile copolymer, or a modified product thereof. Preferred examples include polyacrylonitrile resins having at least one selected from the group consisting of active hydrogen groups such as hydroxyl groups, carboxy groups, primary amino groups, secondary amino groups, and mercapto groups, basic groups, and alkyl groups derived from (meth)acrylic acid alkyl esters or α-olefins. For example, the acrylonitrile copolymer described in JP 2020-163362 A can be used. Nitrile rubbers include acrylonitrile butadiene rubber and hydrogenated acrylonitrile butadiene rubber. Cellulose derivatives include cellulose acetate, cellulose acetate butyrate, cellulose butyrate, cyanoethyl cellulose, ethylhydroxyethyl cellulose, nitrocellulose, methylcellulose, ethylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, and copolymers thereof.In addition, dispersants described in International Publication No. 2008 / 108360, JP 2018-192379 A, ​​JP 2019-087304 A, Japanese Patent No. 6524479 A, ​​and JP 2009-026744 A may be used, but are not limited to these. Particularly preferred are methyl cellulose, ethyl cellulose, polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, polyacrylonitrile homopolymers, polyacrylonitrile copolymers, and hydrogenated acrylonitrile butadiene rubber. Polymers in which other substituents have been introduced into a portion of these polymers, modified polymers, etc. may also be used. The surfactant may be any of anionic surfactants, cationic surfactants, zwitterionic surfactants, and nonionic surfactants. The dispersant is preferably used in an amount of 5 to 300 parts by weight, more preferably 10 to 200 parts by weight, and even more preferably 15 to 100 parts by weight per 100 parts by weight of the dispersoid.

[0053] The content of the dispersoid relative to the total amount of the raw material composition varies depending on the specific gravity of the dispersoid, but is preferably 0.1 to 80 mass%, more preferably 0.5 to 60 mass%, and even more preferably 0.7 to 50 mass%. The solid content of the raw material composition is preferably 0.5 to 80 mass%, more preferably 0.7 to 60 mass%, and even more preferably 1 to 50 mass%.

[0054] <Sealing liquid medium> The sealing liquid medium contains at least the same dispersoid as the raw material composition and the same dispersion medium as the raw material composition. For example, the sealing liquid medium may contain at least the same dispersoid of a simple substance or compound as the raw material composition and the same dispersion medium as the raw material composition. By using such a sealing liquid medium, it becomes possible to adjust the solid content of the resulting dispersion composition to a desired range in a dispersion device with an improved sealing mechanism life.

[0055] The sealing liquid medium contains at least the same dispersoid as that of the raw material composition. That is, it is sufficient that at least one dispersoid is the same between the sealing liquid medium and the raw material composition. When two or more dispersoids are contained in either the sealing liquid medium or the raw material composition, it is sufficient that any one dispersoid is the same between the sealing liquid medium and the raw material composition. Preferably, the sealing liquid medium and the raw material composition each contain one dispersoid, and these dispersoids are the same as each other. When the sealing liquid medium and the raw material composition each contain two or more dispersoids, it is preferable that these two or more dispersoids are the same as each other.

[0056] The sealing liquid medium contains at least the same dispersion medium as that of the raw material composition. That is, it is sufficient that at least one dispersion medium is the same between the sealing liquid medium and the raw material composition. When two or more dispersion media are contained in either the sealing liquid medium or the raw material composition, it is sufficient that any one dispersion medium is the same between the sealing liquid medium and the raw material composition. Preferably, the sealing liquid medium and the raw material composition each contain one dispersion medium, and these dispersion media are the same as each other. When the sealing liquid medium and the raw material composition each contain two or more dispersion media, it is preferable that these two or more dispersion media are the same as each other.

[0057] For example, it is sufficient that at least one dispersoid and at least one dispersion medium are the same between the sealing liquid medium and the raw material composition. Preferably, the sealing liquid medium and the raw material composition each contain one dispersoid and one dispersion medium, which are the same between the sealing liquid medium and the raw material composition. Also, it is preferable that the sealing liquid medium and the raw material composition each contain two or more dispersoids and two or more dispersion mediums, which are the same between the sealing liquid medium and the raw material composition.

[0058] From the above viewpoint, the sealing liquid medium may contain a single dispersoid or two or more dispersoids. The type of dispersoid in the sealing liquid medium is not particularly limited, and one or more dispersoids may be selected from those described for the raw material composition. In this case, the dispersoids in the sealing liquid medium are selected so that at least one dispersoid is the same as the dispersoid in the raw material composition.

[0059] By including the same dispersoid in the raw material composition and the sealing liquid medium, it is possible to further reduce fluctuations in the solid content concentration in the dispersion composition after the dispersion treatment, and further reduce fluctuations in the component uniformity of the solid content. From this perspective, for example, the raw material composition and the sealing liquid medium may each include dispersoids having the same chemical composition, or may each include dispersoids that are the same simple substance or compound. For example, the raw material composition and the sealing liquid medium may each include the same simple substance or compound selected from inorganic particles, organic particles, inorganic-organic composite particles, etc. Examples of inorganic particles include carbon materials and titanium oxide, and examples of organic particles include phthalocyanine blue and isoindolinone pigments.

[0060] When the raw material composition and the sealing liquid medium are mixed in the sealing mechanism, the dispersoids are identical, which reduces variations in dispersibility of the dispersoids in the mixture of the raw material composition and the sealing liquid medium. From this perspective, for example, the raw material composition and the sealing liquid medium may each contain dispersoids having the same particle shape. In the present disclosure, the particle shape being identical may mean that at least one of the physical properties, such as particle appearance observation, average particle size, particle size distribution, and specific surface area, is within a predetermined range. For example, under the same measurement conditions, the particle diameter D50 at the cumulative 50% volumetric percentage of the particle size distribution of the sealing liquid medium measured by dynamic light scattering may be within ±20% of the particle diameter D50 at the cumulative 50% volumetric percentage of the particle size distribution of the raw material composition measured by dynamic light scattering.

[0061] Furthermore, the raw material composition and the sealing liquid medium may each contain a dispersoid that is the same allotrope. For example, allotropes of carbon materials include graphite, fullerenes, carbon nanotubes, and graphene. These examples of carbon materials can be treated as the same dispersoid material, but it is preferable that the raw material composition and the sealing liquid medium each contain the same allotrope, for example, carbon nanotubes, as the dispersoid. This can further reduce fluctuations in the solid content concentration in the dispersion composition after the dispersion treatment, and can further reduce fluctuations in the component uniformity of the solid content.

[0062] When carbon nanotubes are used as the dispersoid, either single-walled carbon nanotubes or multi-walled carbon nanotubes may be used. When carbon nanotubes are used, regardless of the type, such as single-walled carbon nanotubes or multi-walled carbon nanotubes, at least one of them may be contained as a dispersoid in the raw material composition and the sealing liquid medium, respectively. From the viewpoint of maintaining the uniformity of the solid content in the dispersion composition and suppressing the generation of aggregates during dispersion treatment, it is preferable that the raw material composition and the sealing liquid medium each contain single-walled carbon nanotubes or multi-walled carbon nanotubes as a dispersoid.

[0063] From the above perspective, the sealing liquid medium may contain a single-component dispersion medium or may contain two or more dispersion media. The type of dispersion medium in the sealing liquid medium is not particularly limited, and one or more dispersion media may be selected from those described for the raw material composition. In this case, the dispersion medium in the sealing liquid medium is selected so that at least one is the same as the dispersion medium in the raw material composition. For example, the raw material composition and the sealing liquid medium may each contain a dispersion medium having the same chemical composition, or may each contain a dispersion medium that is the same compound. For example, the raw material composition and the sealing liquid medium may each contain the same compound, such as N-methyl-2-pyrrolidone, water, or propylene glycol monomethyl acetate.

[0064] The content of the dispersoid relative to the total amount of the sealing liquid medium varies depending on the specific gravity of the dispersoid, but is preferably 0.1 to 80 mass%, more preferably 0.5 to 60 mass%, and even more preferably 0.7 to 50 mass%. The sealing liquid medium preferably has a solids content of 0.5 to 80 mass%, more preferably 0.7 to 60 mass%, and even more preferably 1 to 50 mass%.

[0065] Furthermore, in the sealing liquid medium, the content of the dispersoid in the raw material composition varies within a range of 80 to 120% by mass relative to the total amount of the sealing liquid medium, thereby enabling the solid content to be more appropriately maintained in the resulting dispersion composition. Furthermore, in the sealing liquid medium, the content of the dispersoid in the sealing liquid medium varies within a range of 80 to 120% by mass relative to the total amount of the raw material composition, thereby enabling the solid content to be more appropriately maintained in the resulting dispersion composition.

[0066] The sealing liquid medium may further contain a dispersant to achieve dispersion stability of the dispersoid. Both resin-type dispersants and surfactants can be used as dispersants, but a suitable type of dispersant can be used in a suitable amount depending on the properties required for dispersing the dispersoid. As the dispersant, at least one type can be selected from the dispersants listed for the raw material composition above. The raw material composition and the sealing liquid medium preferably contain the same dispersant. This can further suppress a decrease in dispersibility of the dispersoid when the raw material composition and the sealing liquid medium come into contact or mix in a sealing mechanism. Furthermore, by varying the mass ratio of the dispersant to the dispersoid in the sealing liquid medium within a range of 80 to 120% by mass relative to that of the raw material composition, the mass ratio of the dispersant to the dispersoid can be maintained in the resulting dispersion composition, further suppressing a decrease in dispersibility.

[0067] The sealing liquid medium may contain optional components such as a resin emulsion, a surfactant, a binder resin, a wetting agent, a wetting penetrating agent, and a leveling agent, as necessary. It is preferable that the raw material composition and the sealing liquid medium each contain the same optional components. This can further suppress a decrease in the dispersibility of the dispersoid when the raw material composition and the sealing liquid medium come into contact with or are mixed in a sealing mechanism.

[0068] The sealing liquid medium preferably has a particle diameter D50 of 5 μm or less at a cumulative 50% volumetric percentage of the particle size distribution measured by dynamic light scattering. Hereinafter, this particle diameter D50 will also be referred to simply as D50. If the sealing liquid medium has an excessively large D50, friction with the inner surface of the cylinder 21 or the outer surface of the plunger 10 in the sealing mechanism may occur, potentially promoting deterioration of these components. Furthermore, if coarse particles are present in the sealing mechanism while the sealing liquid medium is held within the chamber 44, clogging in the gaps between components cannot be eliminated, potentially promoting component deterioration. From this perspective, the D50 of the sealing liquid medium may be 5 μm or less, 3 μm or less, 1 μm or less, or 0.5 μm or less. From the perspective of suppressing aggregation of fine particles, the D50 of the sealing liquid medium may be 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more. For example, the D50 of the sealing liquid medium may be 0.1 to 5 μm, 0.1 to 3 μm, 0.1 to 1 μm, or 0.1 to 0.5 μm. From the viewpoint of further suppressing deterioration of the sealing mechanism members, the D50 of the sealing liquid medium is more preferably 0 to 5 μm, 0.1 to 3 μm, or 0.1 to 2 μm.

[0069] Furthermore, when the sealing liquid medium contains carbon nanotubes, it is preferable that the D50 of the sealing liquid medium satisfy the above-mentioned numerical range. Although carbon nanotubes are a relatively hard dispersoid, when the D50 satisfies the above-mentioned numerical range, deterioration of the sealing mechanism components can be more reliably suppressed.

[0070] In the present disclosure, unless otherwise specified, the particle size distribution of dispersoids in a dispersion medium is measured using a dynamic light scattering method. More specifically, it can be measured according to the method described in the Examples.

[0071] The viscosity of the sealing liquid medium at 25°C is preferably 20,000 mPa·s or less. If the viscosity of the sealing liquid medium is too high, the frictional force between the cylinder 21 and the plunger 10 in the sealing mechanism increases, which increases the driving load and may promote component deterioration. Furthermore, if a high-viscosity sealing liquid medium is held in the chamber 44 in the sealing mechanism, clogging cannot be eliminated in the gaps between the components, which may promote component deterioration. From this perspective, the viscosity of the sealing liquid medium may be 20,000 mPa·s or less, 15,000 mPa·s or less, 10,000 mPa·s or less, 8,000 mPa·s or less, or 5,000 mPa·s or less. While the lower limit of the viscosity is not particularly limited, from the perspective of ensuring the fluidity of the sealing liquid medium, the viscosity of the sealing liquid medium may be 1 mPa·s or more, 10 mPa·s or more, 30 mPa·s or more, or 100 mPa·s or more. For example, the viscosity of the sealing liquid medium may be 10 to 20,000 mPa s, 10 to 15,000 mPa s, 30 to 10,000 mPa s, 30 to 8,000 mPa s, or 100 to 5,000 mPa s. From the viewpoint of suppressing deterioration of the members of the sealing mechanism, the viscosity of the sealing liquid medium is more preferably 10 to 10,000 mPa s, 10 to 8,000 mPa s, or 10 to 5,000 mPa s.

[0072] Furthermore, when the sealing liquid medium contains carbon nanotubes, the viscosity of the sealing liquid medium preferably satisfies the above-mentioned range. Carbon nanotubes are a dispersoid that has a relatively high viscosity, but when the viscosity satisfies the above-mentioned range, deterioration of the sealing mechanism components can be more reliably suppressed.

[0073] In the present disclosure, unless otherwise specified, the viscosity of a composition containing a dispersoid and a dispersion medium is the viscosity measured at 25° C. using a Brookfield viscometer at 60 rpm. More specifically, it can be measured according to the method described in the examples.

[0074] The sealing mechanism life can be determined by operating a dispersion device for 100 hours using a combination of a raw material composition and a sealing liquid medium described in the Examples below, and measuring the amount of raw material composition leaking from the sealing mechanism and the amount of raw material composition supplied, as expressed by the following formula, to calculate the leakage rate (%): Leakage rate (%) = (leakage amount (L) / amount of raw material composition supplied (L)) x 100

[0075] In the above formula, the leakage amount of the raw material composition from the sealing mechanism is the amount of the raw material composition that leaked from the sealing mechanism during 100 hours of operation, and the supply amount of the raw material composition is the total amount discharged from the dispersing device during 100 hours of operation.

[0076] From the viewpoint of the production efficiency of the dispersion composition using the dispersing device, it is preferable that the sealing mechanism of the dispersing device be replaced less frequently. When the dispersing device is sealed using a sealing liquid medium, there is no need to replace the gland packing periodically, and the leakage rate can be controlled by pressure, thereby improving production efficiency.

[0077] The leakage rate represented by the above formula is preferably 0.2% or less, more preferably 0.1% or less. If the leakage rate is 0.21% or more, the amount of raw material composition leaking from the sealing mechanism increases as the operating time increases, and the yield of the dispersion composition tends to decrease. If the sealing performance of the dispersion device can be further ensured by controlling the sealing pressure of the sealing liquid medium, the particle diameter D50 at 50% cumulative volume of the particle size distribution measured by dynamic light scattering, the viscosity, etc., it is expected that the leakage rate represented by the above formula will approach 0%.

[0078] <Raw Material Composition Containing Carbon Nanotubes> The dispersing device according to one embodiment is capable of dispersing particles by high-pressure treatment without subjecting them to mechanical shock, making it suitable for applications requiring dispersion while maintaining particle shape. Furthermore, it is suitable for applications requiring defibration of aggregates, such as fibrous particles, to enhance dispersibility. For example, it can be suitably used in a method for producing a carbon nanotube dispersion. Hereinafter, carbon nanotubes are also referred to as CNTs. The dispersion medium in the raw material composition containing carbon nanotubes can be any of the above-described dispersion media. In the raw material composition containing carbon nanotubes, the dispersion medium may be either a non-aqueous dispersion medium or an aqueous dispersion medium. However, it preferably contains an aprotic solvent, a non-polar solvent, or a combination thereof, more preferably an aprotic solvent, and even more preferably an aprotic polar solvent. The aprotic polar solvent can better prevent aggregation of carbon nanotubes and also exhibits excellent solubility for resin-type dispersants suitable for dispersing carbon nanotubes. Among these, it is preferable to contain an amide solvent, and specifically, it is more preferable to contain at least one selected from the group consisting of N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and 1-n-octyl-2-pyrrolidone.

[0079] It is preferable that carbon nanotubes used in the raw material composition have the following properties before dispersion. CNTs have a cylindrical shape with planar graphite rolled up, and examples thereof include single-walled CNTs and multi-walled CNTs, and these may be mixed. Single-walled CNTs have a structure with one layer of graphite rolled up. Multi-walled CNTs have a structure with two or more layers of graphite rolled up. Furthermore, the sidewalls of CNTs do not have to have a graphite structure. Furthermore, for example, CNTs with sidewalls having an amorphous structure are also considered CNTs in the present disclosure.

[0080] The shape of the CNTs is not limited. Examples of such shapes include needle-like, cylindrical tubular, fishbone-like (fishbone or cup stacked), trump-like (platelet), and coil-like. Of these, needle-like or cylindrical tubular shapes are preferred. The CNTs may have a single shape or a combination of two or more shapes.

[0081] Examples of the form of CNT include graphite whiskers, filamentous carbon, graphite fibers, ultrafine carbon tubes, carbon tubes, carbon fibrils, carbon microtubes, and carbon nanofibers. The carbon nanotubes may have a single form or a combination of two or more of these forms.

[0082] The average outer diameter of the CNTs is preferably 1 nm or more, more preferably 4 nm or more. It is also preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less. The average outer diameter of the CNTs can be calculated by first observing and photographing the CNTs using a transmission electron microscope, randomly selecting 300 CNTs from the photograph, measuring the outer diameter of each, and averaging the measurements.

[0083] The average fiber length of the CNTs is preferably 0.5 μm or more, more preferably 0.8 μm or more, and even more preferably 1.0 μm or more. It is also preferably 1000 μm or less, more preferably 100 μm or less, and even more preferably 10 μm or less. The average fiber length of the CNTs can be calculated by first observing and photographing the CNTs using a scanning electron microscope, randomly selecting 300 CNTs from the photograph, measuring the fiber length of each, and averaging the measured values.

[0084] The aspect ratio is the value obtained by dividing the fiber length of a CNT by its outer diameter. A typical aspect ratio can be calculated using the average fiber length and the average outer diameter. A conductive material with a higher aspect ratio can provide higher conductivity when formed into an electrode. The aspect ratio of a CNT is preferably 30 or more, more preferably 50 or more, and even more preferably 80 or more. It is also preferably 1,000,000 or less, more preferably 100,000 or less, and even more preferably 10,000 or less.

[0085] The specific surface area of ​​CNT is 100m ２ / g or more, and２ / g or more is more preferable, and 200m ２ / g or more is more preferable. ２ / g or less, and ２ The specific surface area of ​​the CNT is calculated by the BET method using nitrogen adsorption measurement.

[0086] The carbon nanotubes may be surface-treated carbon nanotubes, carbon nanotube derivatives to which functional groups such as carboxyl groups have been added, or carbon nanotubes encapsulating organic compounds, metal atoms, or substances such as fullerenes.

[0087] The raw material composition containing carbon nanotubes may contain a dispersant, and the above-mentioned dispersants can be used as the dispersant. To further enhance the dispersion stability of carbon nanotubes in the dispersion medium, it is preferable to use a resin-type dispersant. Particularly preferred are methyl cellulose, ethyl cellulose, polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, polyacrylonitrile homopolymer, polyacrylonitrile copolymer, and hydrogenated acrylonitrile butadiene rubber. The raw material composition containing carbon nanotubes may further contain optional components such as the above-mentioned binder resin.

[0088] The content of carbon nanotubes is preferably 0.1 to 20 mass%, more preferably 0.5 to 15 mass%, and even more preferably 0.7 to 10 mass%, relative to the total amount of the raw material composition. The content of the dispersant is preferably 5.0 to 300 mass parts per 100 mass parts of carbon nanotubes. The raw material composition containing carbon nanotubes has a solids content of preferably 0.5 to 50 mass%, more preferably 0.7 to 30 mass%, and even more preferably 1 to 20 mass%.

[0089] <Sealing liquid medium containing carbon nanotubes> When a raw material composition containing carbon nanotubes is used, the sealing liquid medium preferably contains carbon nanotubes as a dispersoid. Details of CNTs are as described above. Preferably, when a raw material composition containing carbon nanotubes is used, the sealing liquid medium contains carbon nanotubes as a dispersoid and an aprotic solvent, a nonpolar solvent, or a combination thereof as a dispersion medium.

[0090] The content of carbon nanotubes relative to the total amount of the sealing liquid medium is preferably 0.1 to 80 mass%, more preferably 0.5 to 60 mass%, and even more preferably 0.7 to 50 mass%. The content of the dispersant is preferably 5.0 to 300 mass parts per 100 mass parts of carbon nanotubes. The solid content of the sealing liquid medium is preferably 0.5 to 80 mass%, more preferably 0.7 to 60 mass%, and even more preferably 1 to 50 mass%.

[0091] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples as long as it does not depart from the gist of the invention. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass".

[0092] (Raw material composition) The formulation of the raw material composition is as shown in Table 1. The components were mixed according to the formulation shown in the table to obtain a raw material composition. Details of the components shown in the table are as follows: Multi-walled CNT: "K-Nanos 100P" (trade name), manufactured by Kumho Petrochemical. Single-walled CNT: "TNSR" (trade name), manufactured by Timesnano. Copper phthalocyanine: "FASTOGEN EP-210" (trade name), manufactured by DIC. Zetpol 2000L (trade name): manufactured by Nippon Zeon Co., Ltd. APP-84 (trade name): carboxymethyl cellulose, manufactured by Nippon Paper Industries Co., Ltd., "Sunrose A APP-84" (trade name), weight average molecular weight 17,600. BYK-P104 (trade name): manufactured by BYK Corporation. PGMAc shown in the table is propylene glycol monomethyl acetate. The binder resin solutions shown in the table are the same as those prepared using a CuPc dispersion liquid as a sealing liquid medium, which will be described later.

[0093] (Sealing Liquid Medium) The formulation of the sealing liquid medium will be explained below. In the formulation below, the same components as those in the sealing liquid medium described above are used.

[0094] Formulation of CNT dispersion (1): Multi-walled CNT: 3% by mass, N-methyl-2-pyrrolidone: 96% by mass, Dispersant "Zetpol 2000L" (trade name): 1% by mass, Dispersion time: 20 hours

[0095] Formulation of CNT dispersion (2): Multi-walled CNT: 3% by mass, N-methyl-2-pyrrolidone: 96% by mass, Dispersant "Zetpol 2000L" (trade name): 1% by mass, Dispersion time: 5 hours

[0096] Formulation of CNT dispersion (3): Multi-walled CNT: 6% by mass, N-methyl-2-pyrrolidone: 93% by mass, Dispersant "Zetpol 2000L" (trade name): 1% by mass, Dispersion time: 20 hours

[0097] Formulation of CNT dispersion (4): Single-walled CNT: 1 mass % N-methyl-2-pyrrolidone: 98 mass % Dispersant "Zetpol 2000L" (trade name): 2 mass % Dispersion time: 20 hours

[0098] Formulation of CNT dispersion (5): Multi-walled CNT: 2% by mass, Ion-exchanged water: 97% by mass, Dispersant "APP-84 (trade name)": 1% by mass, Dispersion time: 20 hours

[0099] Formulation of CuPc dispersion: Copper phthalocyanine (manufactured by DIC under the trade name "FASTOGEN EP-210"): 10% by mass, Resin-type dispersant solution: 7.5% by mass, Binder resin solution: 35% by mass, PGMAc: 47.5% by mass, Dispersion time: 20 hours

[0100] The method for producing the CNT dispersion liquid of the sealing liquid medium is as follows. The components were mixed according to the above recipe, and a CNT dispersion liquid was obtained using the following dispersing device. The dispersing device used was a valve-type high-pressure homogenizer "HC3-5" (trade name) manufactured by Sanmaru Machinery Co., Ltd. The dispersing conditions were as follows. <Dispersing conditions> Treatment pressure: 100 MPa Type of homogenizing part: flat valve Flow rate of raw material composition: 2000 L / H

[0101] The CuPc dispersion liquid of the sealing liquid medium was produced as follows: The components were mixed according to the above recipe, and a CuPc dispersion liquid was obtained using a dispersing device in the same procedure as for the CNT dispersion liquid of the sealing liquid medium.

[0102] (Resin-type dispersant solution) The method for producing the resin-type dispersant solution in the CuPc dispersion formulation is as follows: PGMAc was added to BYK-P104 (manufactured by BYK Japan: non-volatile content 50%) to adjust the non-volatile content to 40%, thereby obtaining a resin-type dispersant solution.

[0103] (Binder Resin Solution) The method for producing the binder resin solution from the CuPc dispersion formulation is as follows. 70.0 parts of cyclohexanone were charged into a separable four-neck flask equipped with a thermometer, a condenser, a nitrogen gas inlet tube, and a stirrer. The temperature was raised to 80°C, and the atmosphere inside the reaction vessel was replaced with nitrogen. A mixture of 13.3 parts of n-butyl methacrylate, 4.6 parts of 2-hydroxyethyl methacrylate, 4.3 parts of methacrylic acid, 7.4 parts of paracumylphenol ethylene oxide-modified acrylate ("Aronix M110" manufactured by Toagosei Co., Ltd.), and 0.4 parts of 2,2'-azobisisobutyronyltyl was added dropwise over 2 hours from the dropping tube. After completion of the dropwise addition, the reaction was continued for a further 3 hours, yielding a solution of acrylic resin with a weight average molecular weight (Mw) of 26,000. After cooling to room temperature, approximately 2 g of the resin solution was sampled and dried by heating at 180°C for 20 minutes, and the non-volatile content was measured. Propylene glycol monoethyl ether acetate (PGMAc) was added to the resin solution synthesized above so that the non-volatile content was 20 mass % to obtain a binder resin solution.

[0104] (Dispersion Treatment) For the dispersion treatment of the raw material composition, a dispersion device equipped with a supply mechanism equivalent to the high-pressure pump 20 shown in Figure 2 and a dispersion mechanism using a homogenizing valve was used. In this dispersion device, the raw material composition is supplied from the supply mechanism to a plunger, and the raw material composition is supplied from the plunger to the dispersion mechanism. In the plunger, the outer peripheral surface of the plunger is sealed with a sealing liquid medium. Dispersion treatment was carried out using the raw material composition and the sealing liquid medium in the combination shown in Table 1. The dispersion conditions were as follows. <Dispersion Conditions> Treatment pressure: 100 MPa Type of homogenizing part: flat valve Flow rate of raw material composition: 2000 L / H

[0105] In Comparative Example 1, N-methyl-2-pyrrolidone was used as the sealing liquid medium, except for this, the same conditions as in Example 1 were used.

[0106] In Comparative Example 2, a gland packing was used for the sealing mechanism. Specifically, a valve-type high-pressure homogenizer "HC3-5" (product name) manufactured by Sanmaru Machinery Co., Ltd. was used as the dispersion device. The dispersion conditions were as follows. Other than this, the same conditions as in Example 1 were used. <Dispersion conditions> Treatment pressure: 100 MPa Type of homogenization section: flat valve Flow rate of raw material composition: 2000 L / H

[0107] Each evaluation is explained below. The evaluation results are shown in Table 1.

[0108] The D50 of the sealing liquid medium was measured using the same procedure as the particle size distribution of the dispersion composition after the dispersion treatment described below. The viscosity of the sealing liquid medium was measured after leaving the carbon nanotube dispersion in a thermostatic chamber at 25°C for at least one hour, using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd., "BL") at a rotor rotation speed of 60 rpm. The types of rotors used in the measurements were No. 1 for viscosity values ​​less than 100 mPa·s, No. 2 for viscosity values ​​between 100 and 500 mPa·s, No. 3 for viscosity values ​​between 500 and 2,000 mPa·s, and No. 4 for viscosity values ​​between 2,000 and 10,000 mPa·s.

[0109] (Sealing Mechanism Life) The sealing mechanism life was evaluated by the following procedure. That is, a dispersion device was used to operate for 100 hours using the combinations of raw material compositions and sealing liquid media shown in Table 1. The amount of raw material composition leaking from the sealing mechanism and the amount of raw material composition supplied per 100 hours of operation were measured, and the leakage rate (%) was calculated using the following formula: Leakage rate (%) = (leakage amount (L) / amount of raw material composition supplied (L)) × 100

[0110] In the above formula, the leakage amount is a value calculated using the following formula. When the sealing mechanism is a sealing liquid medium: (1) The liquid in the sealing liquid medium tank before the start of operation is A liters. (2) The liquid in the sealing liquid medium tank when the total operating time reaches 100 hours is B liters. Leakage amount (L) = B(L) - A(L)

[0111] When the sealing mechanism is a gland packing: When the sealing mechanism is a gland packing, the leakage rate was calculated from the amount of raw material composition leaking from the sealing mechanism of the gland packing portion, and the sealing mechanism life was evaluated. (1) When the gland packing is replaced, the coolant is also replaced. The amount of coolant at this time is set to X liters. (2) When the total operating time reaches 100 hours, the liquid in the coolant circulation tank is set to Y liters. Leakage amount (L) = Y(L) - X(L)

[0112] <Evaluation criteria> ◯: Leakage rate 0.1% or less △: Leakage rate over 0.1% but not exceeding 0.2% ×: Leakage rate 0.21% or more

[0113] (Solid content of dispersion composition) After the dispersion treatment, 1.5 g to 2.0 g of the dispersion composition was placed in an aluminum dish with a diameter of 7.5 cm and a height of 1 cm, and dried in an electric oven at 120°C ± 5°C for 1 hour. Thereafter, the mass of the solid content was measured, and the measured solid content was calculated. The difference between the measured solid content and the theoretical solid content was evaluated according to the following criteria. The theoretical solid content was calculated from the mass of the solid content of the raw materials of the raw material composition. <Evaluation criteria> ◯: (theoretical solid content) - (measured solid content) is 0.5% or less △: (theoretical solid content) - (measured solid content) is more than 0.5% and 1.0% or less ×: (theoretical solid content) - (measured solid content) is 1.1% or more

[0114] (Particle Size Distribution of Dispersion Composition) The particle size distribution of the dispersion composition after dispersion treatment was evaluated by dynamic light scattering using the following procedure. After leaving the dispersion composition in a thermostatic chamber at 25°C for at least one hour, the dispersion composition was thoroughly stirred and diluted, and then the 50% particle size (D50) of the dispersion composition was measured on a volume basis using a particle size distribution analyzer (Microtrac-Bell Corporation, Nanotrac UPA, model UPA-EX). The dilution concentration of the CNT dispersion was set so that the loading index value was 0.85 to 1.25. The refractive indexes and densities of the raw materials used in the measurement were as follows: refractive index of water: 1.333, refractive index of N-methyl-2-pyrrolidone: 1.47, refractive index of PGMAc: 1.402, density of multi-walled CNT and single-walled CNT: 1.80, density of copper phthalocyanine: 1.84

[0115] <Evaluation criteria> ◯: D50≦0.5 μm △: 0.5 μm<D50≦5 μm ×: D50>5 μm

[0116]

[0117]

[0118] The above table shows that the life of the sealing mechanism in each Example is improved compared to the sealing mechanism using a conventional gland packing. In this case, it can be seen that the solids concentration in the resulting dispersion composition is maintained by using the same at least one dispersion medium and at least one dispersoid between the raw material composition and the sealing liquid medium.

[0119] It is also clear that the life of the sealing mechanism tends to be improved by reducing the D50 of the sealing liquid medium. In this case, it is also clear that the D50 can be controlled in the resulting dispersion composition. It is also clear that the life of the sealing mechanism tends to be improved by reducing the viscosity of the sealing liquid medium.

[0120] Although the present invention has been described with reference to the above-mentioned several embodiments, the present invention is not limited to these several embodiments. Various modifications can be made to the configuration and details of the present invention within the scope of the present invention.

[0121] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-097975, filed on June 14, 2023, the entire disclosure of which is incorporated herein by reference.

[0122] DESCRIPTION OF SYMBOLS 10 Plunger, 20 High-pressure pump, 21 Cylinder, 22 Supply port portion, 22a Check valve, 23 Discharge port portion, 23a Check valve, 24 Pump chamber, 25 Outer sleeve, 30 Dispersion portion, 31 Valve seat, 32 Impact ring, 33 Homo valve, 40 Sealing mechanism, 41 Sealing liquid medium supply pipe, 42 Sealing liquid medium discharge pipe, 43 Storage portion, 44 Chamber, 44a Through opening, 45 Pump, 50 Raw material composition tank, 81 Rod, 82 Crankshaft

Claims

1. A method for producing a dispersed composition using a dispersion apparatus comprising: a dispersion mechanism for pressurizing and dispersing a raw material composition; a supply mechanism equipped with a plunger portion for supplying the raw material composition to the dispersion mechanism; and a sealing mechanism for sealing the plunger portion using a sealing liquid medium, wherein A method for producing a dispersion composition, wherein the raw material composition comprises a dispersed phase and a dispersion medium, and the sealing liquid medium comprises at least the same dispersed phase and the same dispersion medium as the raw material composition.

2. The method for producing the dispersion composition according to claim 1, wherein the sealing liquid medium is supplied to the sealing mechanism under pressure using an independent pump.

3. A method for producing a dispersion composition according to claim 1 or 2, wherein the sealing liquid medium has a particle diameter D50 of 50% of the volume-based cumulative particle size distribution measured by dynamic light scattering, which is 5 μm or less.

4. The method for producing the dispersion composition according to claim 1 or 2, wherein the sealing liquid medium has a viscosity of 10,000 mPa·s or less at 25°C.

5. A method for producing a dispersion composition according to claim 1 or 2, wherein the sealing liquid medium has a particle diameter D50 of 50% of the volume-based cumulative particle size distribution measured by dynamic light scattering, which is 5 μm or less, and the sealing liquid medium has a viscosity of 10,000 mPa·s or less at 25°C.

6. The method for producing a dispersion composition according to claim 1 or 2, wherein the plunger portion comprises a cylinder and a plunger, a void G is formed between the inner circumferential surface of the cylinder and the outer circumferential surface of the plunger, the raw material composition in the void G is under positive pressure with respect to the sealing liquid medium, the external pressure pressurizing the sealing liquid medium is 50 to 5000 bar, and the internal pressure pressurizing the raw material composition is 80 to 8000 bar.

7. A method for producing a dispersion composition according to claim 1 or 2, wherein the plunger portion comprises a cylinder and a plunger, a gap G is formed between the inner circumferential surface of the cylinder and the outer circumferential surface of the plunger, and the sealing mechanism includes supplying the sealing liquid medium into the cylinder to fill the gap G, discharging and recovering the sealing liquid medium from the gap G, and discarding or recirculating the recovered sealing liquid medium into the cylinder.

8. The plunger portion comprises a cylinder and a plunger, a gap G is formed between the inner circumferential surface of the cylinder and the outer circumferential surface of the plunger, a chamber for holding the sealing liquid medium is formed on the inner circumferential surface of the cylinder, the gap G and the chamber are released from pressure through a through hole, and the sealing mechanism includes supplying the sealing liquid medium to the chamber, discharging and recovering the sealing liquid medium from the chamber, and discarding or recirculating the recovered sealing liquid medium to the chamber, the method for producing a dispersion composition according to claim 1 or 2.