Method for producing dispersion, method for producing ceramic sintered body

Abstract

The present invention provides a method for manufacturing a dispersion by mixing a plurality of solid particles, water, and a liquid other than water. Further, it is a method for manufacturing a sintered body by forming and sintering the dispersion. When manufacturing the dispersion, the solid particles and the liquid are selected and used in such a way that the Hansen spheres (S11, S13) of at least two solid particles overlap with the Hansen sphere (S21) of at least one liquid. Further, the solid particles are selected and used in such a way that the Hansen solubility parameter distance Ra between the used solid particles and water is the largest among all the solid particles used in the manufacture of the dispersion, or at least two solid particles are selected and used from a group of solid particle candidates having a Hansen solubility parameter distance Ra from water of 28 MPa<supgt;1 / 2< / supgt; or more.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2020-034361 filed on February 28, 2020, the contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a method for producing a dispersion in which solid particles are dispersed in water and a method for producing a ceramic sintered body. Background Art

[0003] In the manufacturing process of products containing ceramic sintered bodies, solid particles that will become ceramic raw materials are dispersed in a liquid to produce a dispersion such as a slurry, a paste, or a clay. The dispersion is formed and sintered to produce a ceramic sintered body. From the viewpoint of preventing cracks caused by temperature differences during sintering in a ceramic sintered body with a large mass or volume, water is used as the liquid instead of an organic solvent.

[0004] When using water, there is a problem of dispersibility. The dispersibility of the dispersion composed of solid particles, liquid dispersants and water selected based on existing ideas and theories is unstable. That is, the tendency of dispersibility is different due to the combination of raw materials. In addition, even if the type of raw materials is fixed, if the manufacturer, batch, etc. change, the tendency of dispersibility sometimes changes. If the dispersibility changes, even if sintering is carried out under the same sintering conditions, cracks and other inappropriate situations may occur in the ceramic sintered body. The dispersibility can be temporarily improved by extending the mixing time during the manufacture of the dispersion, and sometimes a highly dispersed state can be obtained, but the highly dispersed state tends to be damaged over time. In order to improve the dispersibility, as disclosed in Patent Document 1, it is advocated to adopt the Hansen Solubility Parameter (i.e., HSP) theory.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Patent No. 4782282 Summary of the invention

[0008] Generally speaking, the research in the HSP theory is about the optimal selection of a solvent other than water for one raw material, or the optimal selection of a combination of multiple solvents. If multiple solid raw materials and water are used as a premise, the combination of solid particles and liquid dispersants is unlimited according to the purpose and use. In other words, in the case of mixing water and multiple solid particles, the index for improving dispersibility has not been technically established. Therefore, the actual situation depends on the operator's consideration, tips, or trial and error in the experiment to determine the combination.

[0009] An object of the present disclosure is to provide a method for producing a dispersion having good dispersibility and a method for producing a ceramic sintered body using the dispersion.

[0010] The first aspect of the present disclosure relates to a method for producing a dispersion, which is a method for producing a dispersion by mixing a plurality of solid particles, water, and a liquid other than water, wherein:

[0011] The solid particles and the liquid are selected for manufacturing the dispersion in such a manner that the Hansen spheres of at least two of the solid particles overlap with the Hansen spheres of at least one of the liquids, and the Hansen solubility parameter distance Ra between one of the solid particles overlapping with the Hansen sphere of the liquid and water is the largest among all the solid particles used in the manufacture of the dispersion.

[0012] A second aspect of the present disclosure relates to a method for producing a dispersion, which is a method for producing a dispersion by mixing a plurality of solid particles, water, and a liquid other than water, wherein:

[0013] The Hansen solubility parameter distance from water is Ra 28MPa. 1 / 2 At least two solid particles are selected from the solid particle candidate group, and the Hansen spheres of the solid particles overlap with the Hansen spheres of at least one liquid from the liquid candidate group, and the solid particles and the liquid are selected to produce the dispersion.

[0014] A third aspect of the present disclosure relates to a method for producing a ceramic sintered body, wherein:

[0015] The solid particles are ceramic raw materials, and the dispersion obtained by the above-mentioned production method is molded and sintered.

[0016] In the manufacturing method of the dispersion of the first and second schemes, a combination suitable for high dispersion is selected as solid particles and liquid. Therefore, according to the above-mentioned manufacturing method, a dispersion having good dispersibility can be manufactured despite containing water. As a result, for example, the deviation of the density of the dispersion can be reduced.

[0017] In the method for producing a ceramic sintered body according to the third aspect, since the dispersion is formed, the density variation of the formed body can be reduced, thereby preventing the ceramic sintered body from having problems such as cracks.

[0018] As described above, according to the above aspect, it is possible to provide a method for producing a dispersion having good dispersibility and a method for producing a ceramic sintered body using the dispersion.

[0019] In addition, the symbols in parentheses described in the claims indicate the correspondence relationship with the specific means described in the embodiments described later, and do not limit the technical scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above-mentioned purpose and other purposes, features and advantages of the present disclosure will become more apparent through the following detailed description with reference to the accompanying drawings. The accompanying drawings are:

[0021] Figure 1 This is an explanatory diagram showing a Hansen sphere of solid particles.

[0022] Figure 2 This is a schematic diagram showing the configuration of a contact angle measurement device based on the penetration rate method.

[0023] Figure 3 A three-dimensional diagram of a honeycomb structure.

[0024] Figure 4 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 1 on a plane of Figure 4 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 1 on a plane of Figure 4 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 1 on a plane.

[0025] Figure 5 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 2 on a plane of Figure 5 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 2 on a plane of Figure 5 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 2 on a plane.

[0026] Figure 6 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 3 on a plane of Figure 6 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 3 on a plane of Figure 6 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 3 on a plane.

[0027] Figure 7 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 4 on a plane of Figure 7 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 4 on a plane of Figure 7 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 4 on a plane.

[0028] Figure 8 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 1 on a plane of Figure 8 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 1 on a plane of Figure 8 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the Hansen spheres of the liquid in Example 1 on a plane.

[0029] Fig. 9 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 2 on a plane of Fig. 9 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 2 on a plane of Fig. 9 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 2 on a plane.

[0030] Fig.10(a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 3 on a plane of Fig.10 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 3 on a plane of Fig.10 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 3 on a plane.

[0031] Fig.11 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 4 on a plane of Fig.11 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 4 on a plane of Fig.11 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 4 on a plane.

[0032] Fig.12 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 5 on a plane of Fig.12 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 5 on a plane of Fig.12 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 5 on a plane.

[0033] Fig.13 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 6 on a plane of Fig.13 (b) is the dipole force δ p and hydrogen bond force δ hAn explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 6 on a plane of Fig.13 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 6 on a plane.

[0034] Fig.14 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 7 on a plane of Fig.14 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 7 on a plane of Fig.14 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Example 7 on a plane.

[0035] Fig.15 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 8 on a plane of Fig.15 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 8 on a plane of Fig.15 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Example 8 on a plane.

[0036] Fig.16 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 9 on a plane of Fig.16 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 9 on a plane of Fig.16 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 9 on a plane.

[0037] Fig.17 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 10 on a plane of Fig.17 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 10 on a plane of Fig.17 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Example 10 on a plane.

[0038] Fig.18 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 11 on a plane of Fig.18 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 11 on a plane of Fig.18 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 11 on a plane.

[0039] Fig.19 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 5 on a plane of Fig.19 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 5 on a plane of Fig.19 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 5 on a plane.

[0040] Fig. 20 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 6 on a plane of Fig. 20(b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 6 on a plane of Fig. 20 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 6 on a plane.

[0041] Fig.21 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 7 on a plane of Fig.21 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 7 on a plane of Fig.21 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 7 on a plane.

[0042] Fig. 22 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 8 on a plane of Fig. 22 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Comparative Example 8 on a plane of Fig. 22 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of solid particles and liquid Hansen spheres in Comparative Example 8 on a plane.

[0043] Fig.23 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 12 on a plane of Fig.23 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 12 on a plane of Fig.23 (c) is the London dispersion force δ d and hydrogen bond force δ hAn explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 12 on a plane.

[0044] Fig.24 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 13 on a plane of Fig.24 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 13 on a plane of Fig.24 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 13 on a plane.

[0045] Fig.25 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 14 on a plane of Fig.25 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 14 on a plane of Fig.25 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 14 on a plane.

[0046] Fig.26 (a) is the London dispersion force δ d and the dipole force δ p An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 15 on a plane of Fig.26 (b) is the dipole force δ p and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 15 on a plane of Fig.26 (c) is the London dispersion force δ d and hydrogen bond force δ h An explanatory diagram showing the overlap of the solid particles and the liquid Hansen spheres in Example 15 on a plane. DETAILED DESCRIPTION

[0047] (Implementation Method 1)

[0048] Embodiments of the method for producing a dispersion are described. The dispersion can be produced by mixing solid particles, water and a liquid. The liquid is a liquid other than water. When producing the dispersion, two or more solid particles and one or more liquids can be used. The solid particles are specifically powders, for example, composed of inorganic substances. The liquid is composed of, for example, liquid organic matter, also referred to as a dispersant, a lubricant, an adhesive, etc. Such a liquid is appropriately referred to as a "non-aqueous liquid" hereinafter.

[0049] As solid particles and non-aqueous liquids used in the manufacture of dispersions, substances in which Hansen spheres of at least two solid particles overlap with Hansen spheres of at least one non-aqueous liquid are selected. For example, when Hansen spheres of two solid particles overlap with each other, and at least one of these Hansen spheres overlaps with Hansen spheres of a non-aqueous liquid, it means that the Hansen spheres overlap with each other. In addition, when Hansen spheres of one of the two solid particles overlap with Hansen spheres of a non-aqueous liquid, and any one of these Hansen spheres overlaps with Hansen spheres of the other, it also means that the Hansen spheres overlap with each other. In addition, when three Hansen spheres of two solid particles and non-aqueous liquids overlap with each other, it also means that the Hansen spheres overlap with each other. That is to say, when there are two or more overlaps on three Hansen spheres, it means that Hansen spheres of at least two solid particles overlap with Hansen spheres of at least one non-aqueous liquid. Furthermore, as long as the Hansen spheres are in at least point contact with each other, it means that the Hansen spheres overlap with each other. Even if the Hansen spheres share a portion of each other's volume, or one Hansen sphere contains another Hansen sphere, it means that the Hansen spheres overlap.

[0050] In addition, at least one of the solid particles overlapping the Hansen spheres of the non-aqueous liquid is selected to have the largest Hansen solubility parameter distance Ra among all the solid particles used in the preparation of the dispersion, and is used to prepare the dispersion. The Hansen solubility parameter distance Ra is the distance between the Hansen solubility parameter of water and the Hansen solubility parameter of the solid particle. In the following description, the Hansen solubility parameter is preferably expressed as "HSP".

[0051] Therefore, in the production of the dispersion, solid particles and non-aqueous liquids satisfying the following conditions A and B can be used in combination.

[0052] Condition A: From the solid particle candidate group and the non-aqueous liquid candidate group, determine a combination of solid particles and non-aqueous liquids in which at least two types of Hansen spheres of solid particles and at least one type of Hansen spheres of non-aqueous liquid overlap with each other.

[0053] Condition B: The HSP distance Ra between one of the solid particles satisfying Condition A and water is the largest among all the solid particles used in the production of the dispersion.

[0054] The solid particle candidate group and the non-aqueous liquid candidate group can be determined according to the dispersion to be produced. For example, when the dispersion is used for a ceramic sintered body, the solid particle candidate group can be determined in such a way that, after sintering, the raw materials of the solid particles react chemically with each other to obtain a ceramic sintered body of the desired material. The solid particle candidate group can contain solid particles of different manufacturers, batches, and collection locations. The non-aqueous liquid candidate group can contain, for example, liquid solvents, dispersants, lubricants, adhesives, etc. that can be used to disperse solid particles.

[0055] The material of the solid particles is not particularly limited, for example, it can be determined according to the purpose of use of the dispersion. Solid particles include, for example, ceramic raw materials. For example, when the dispersion is used to manufacture a honeycomb structure for an exhaust gas purification filter and a sealing portion for sealing its end face, as solid particles, silicon dioxide, aluminum hydroxide, talc, kaolin, alumina, pore-forming materials, etc. can be listed. When the dispersion is used to manufacture a honeycomb structure for a monolithic carrier used by carrying an exhaust gas purification catalyst, as solid particles, kaolin, aluminum hydroxide, silicon dioxide, alumina, talc, pore-forming materials, etc. can be listed. When the dispersion is used to manufacture a honeycomb structure having a catalyst function (specifically, a co-catalyst function of a precious metal catalyst), as solid particles, cerium dioxide, zirconium oxide, a cerium dioxide zirconium oxide solid solution, aluminum oxide, etc. can be listed. In addition, the dispersion can also be used for the manufacture of diaphragms, electrodes, solid electrolyte bodies of sensors, insulators, etc. of solid batteries. In this case, as solid particles, solid electrolytes, aluminum oxide, etc. can be listed. As the non-aqueous liquid, active solvents such as amphoteric solvents, acidic solvents, and alkaline solvents, and inactive solvents can be used.

[0056] The properties and viscosity of the dispersion are not particularly limited. The dispersion is a concept that includes a mixture of water, a non-aqueous liquid other than water, and solid particles, such as slurry, paste, and clay. In the dispersion, for example, solid particles and a non-aqueous liquid other than water are dispersoids, and water is a dispersion medium.

[0057] When preparing a dispersion, the Hansen sphere of solid particles and non-aqueous liquid, and the Hansen solubility parameter distance Ra between water and solid particles are determined. The Hansen sphere and HSP distance Ra are described below.

[0058] First, the HSP theory is explained. Generally speaking, in this theory, the surface energy of the solute, solvent, and gas is numerically expressed and classified into three terms. The three energies are the London dispersion force δ d , dipole force δ p , hydrogen bond force δ h The unit of each energy is MPa 1 / 2 That is, the HSP value is calculated by dividing the London dispersion force δ d, dipole force δ p , hydrogen bond force δ h The coordinate axes are expressed as coordinates in a three-dimensional space called Hansen space.

[0059] Based on the HSP theory, for example, a study is conducted to investigate the solubility of solute A and solvent B. If the HSP value of solute A is (δ dA , δ pA , δ hA ), the HSP value of solvent B is (δ dB , δ pB , δ hB ), then the distance between these HSP values ​​(i.e., HSP distance Ra1) can be expressed by the following formula I.

[0060] Ra1={4·(δ dA -δ dB ) 2 +(δ pA -δ pB ) 2 +(δ hA -δ hB ) 2} 1 / 2 Formula I

[0061] The smaller the HSP distance Ra1 is, the easier it is for the solute to dissolve in the solvent. In the case of an insoluble solute, the solvent becomes the dispersion medium, the solute becomes the dispersoid, and the dispersoid is easily dispersed in the dispersion medium. In the case of a dispersion medium and a dispersoid, a high dispersion state can be obtained when Ra1≤5, and an ultra-high dispersion state can be obtained when Ra1≤2.

[0062] Compared with the above-mentioned HSP theory, the present disclosure focuses on the overlap of Hansen spheres and the HSP distance Ra between solid particles and water. That is, in a mixture of at least two solid particles, a non-aqueous liquid and water, the dispersibility is evaluated based on the overlap of Hansen spheres and the HSP distance Ra, thereby obtaining a highly dispersed dispersion. The HSP distance Ra can be calculated based on Formula I by using the HSP value of water as the HSP value of solvent B. Furthermore, the HSP value of water is δ d :15.5、δ p :16.0、δ h :42.3.

[0063] The determination of the HSP value of the solid particles, the Hansen spheres of the non-aqueous liquids can be performed by classifying the reagents of at least 14 pure solvents whose HSP values ​​are known into good solvents and poor solvents.

[0064] The Hansen sphere and HSP value can be obtained, for example, by using analysis software. As the analysis software, the software HSPiP version 5.2.05 developed by Dr. Hansen can be used. Details about HSPiP are described in https: / / www.hansen-solubility.com. First, a score is added to the classification result of the solvent reagent, and then the score is input into the analysis software. Specifically, the good solvent can be set to a score of 1 and the poor solvent can be set to a score of 0. Thus, the London dispersion force δ can be set to 0 on the analysis software. d 、Dipole force δ p , hydrogen bond force δ h The Hansen sphere is depicted in the three-dimensional Hansen space with coordinate axes. Figure 1 The Hansen sphere S1 of a solid particle is shown in FIG. Figure 1 Similarly, the Hansen sphere S2 of the non-aqueous liquid can also be depicted in the Hansen space. The HSP value can be determined as the center (specifically, the center coordinates) of the Hansen sphere. Furthermore, if the above-mentioned analysis software and version are not available, the Hansen sphere and HSP value can be obtained by other available software and other versions using the same measurement principle and calculation using the same measurement principle.

[0065] The classification of good solvent and poor solvent can be determined based on a threshold value of a certain measurement value. In the case of using the above-mentioned analysis software, the threshold value can be determined by confirming the fitting value. The closer the fitting value is to 1, the more correct the Hansen sphere is depicted. Therefore, the threshold value can be determined in a manner such that the fitting value is 1 or a maximum value lower than 1. Furthermore, although there is an empirical judgment based on previous experiments, when the fitting value is lower than 0.8, there is a concern that sufficient measurement accuracy cannot be obtained, so it is preferably determined by reselecting a solvent reagent.

[0066] The classification of good solvents and poor solvents for determining the Hansen sphere and HSP values ​​of solid particles can be based on (1) confirmation of the precipitation state by visual inspection, (2) measurement of the particle size by the Stokes method, (3) measurement of the particle size by a concentrated particle size analyzer, and (4) measurement of the contact angle by an infiltration rate method. If (1) classification by visual inspection is not possible, (2) measurement of the particle size by the Stokes method is selected. If (2) measurement of the particle size by the Stokes method is not possible, (3) measurement of the particle size by a concentrated particle size analyzer is selected. If (3) measurement of the particle size by a concentrated particle size analyzer is not possible, (4) measurement of the contact angle by the infiltration rate method is selected. The specific method is shown below. In addition, the classification and measurement are carried out at room temperature (temperature 20 to 25°C).

[0067] (1) Visual method

[0068] The precipitation in the solvent reagent is visually confirmed. The specific sequence is, for example, as follows (1-1) to (1-3).

[0069] (1-1) Prepare at least 14 solvent reagents having known HSP values.

[0070] (1-2) 0.05 g of the solid particles to be measured were placed in 20 ml of each solvent reagent, and the mixture was shaken 30 times to disperse the solid particles in the solvent reagent, and then allowed to stand.

[0071] (1-3) Visually confirm the precipitation state of solid particles in the solvent reagent after standing for 15 minutes. If precipitation is observed, it is determined to be a poor solvent, and if no precipitation is observed, it is determined to be a good solvent. The above operation is performed for at least 14 solvent reagents.

[0072] (2) Stokes method

[0073] The particle size of solid particles is measured by the Stokes method, and the good solvent and the poor solvent can be classified based on the particle size. The smaller the particle size, the better the solvent. The specific order is, for example, as follows (2-1) to (2-5).

[0074] (2-1) Prepare at least 14 solvent reagents having known HSP values.

[0075] (2-2) 2 g of the solid particles to be measured are placed in a 25 mL measuring cylinder. Next, a solvent reagent is placed up to the 20 mL line of the measuring cylinder, and the measuring cylinder is shaken 30 times and then allowed to stand. Furthermore, after standing, if the solid particles in the solvent reagent are visually precipitated quickly, it is not necessary to perform the particle size measurement described later, and it can be determined that the solvent is poorly dispersible.

[0076] (2-3) The height of the interface between the clear layer and the accumulation layer is measured three times after 5 minutes, 10 minutes, 15 minutes, 20 minutes, and 25 minutes have passed since the standing, and the average value is calculated. Thus, the average value of the interface height after each elapsed time can be obtained. The sedimentation velocity ν (unit: cm / s) is calculated from the average value of the interface height and the elapsed time.

[0077] (2-4) The particle size D is calculated by Stokes equation represented by the following formula II: p (Unit: cm). In formula II, η: viscosity coefficient of the reagent (unit: cm·s), ν: sedimentation velocity (unit: cm / s), ρ p : Density of particles (unit: g / cm 3 ), ρ0: Density of the reagent (unit: g / cm 3 ), g: gravitational acceleration. Particle density ρ pThe gravitational acceleration g is 980 cm / s 2 . Particle size D was determined for at least 14 solvent reagents. p Determination of particle size D p is the average particle size.

[0078] (2-5) Based on particle size D p The threshold value is used to classify the solvent reagent into a good solvent and a poor solvent. The method for determining the threshold value is as described above. p It is easier to classify the solvents and reagents if you arrange them in order from small to large.

[0079] [Formula 1]

[0080]

[0081] (3) Concentrated particle size analyzer

[0082] The particle size of the solid particles (specifically, the average particle size) is measured using a concentrated particle size analyzer, and the good solvent and the poor solvent can be classified based on the particle size. For example, a concentrated particle size analyzer "FPAR-100" manufactured by Otsuka Electronics Co., Ltd. is used in the measurement. The smaller the particle size, the better the solvent. The specific order is, for example, as follows (3-1) to (3-4).

[0083] (3-1) Prepare at least 14 solvent reagents having known HSP values.

[0084] (3-2) Using the solid particles to be measured and the solvent reagent, a particle concentration of 5.0×10 -4 g / cc dispersion.

[0085] (3-3) The dispersion is placed in a concentrated particle size analyzer to measure the particle size. The particle size is measured for at least 14 solvent reagents.

[0086] (3-4) Based on the threshold value of particle size, the solvent reagents are classified into good solvents and poor solvents. The method for determining the threshold value is as described above. Furthermore, for example, if the solvent reagents are arranged in order from small to large particle size, the classification is easy.

[0087] (4) Infiltration rate method

[0088] The contact angle between solid particles and each solvent reagent is measured by the penetration rate method, and the solvent can be classified into good solvent and poor solvent based on the contact angle. Figure 2 The measurement device 5 shown in FIG. Figure 2As shown, the measuring device 5 can be composed of a lifting device 51, an iron column 52, an electronic balance 53, and a recording device 54. The lifting device 51 has a lifting platform 511, and a beaker 55 containing a solvent reagent is placed on the lifting platform 511. The iron column 52 and the electronic balance 53 are connected, and the weight in the iron column 52 can be measured by the electronic balance. The lower surface of the iron column 52 is composed of filter paper 521, and the iron column 52 is filled with a powder 50 of solid particles as a measurement object. The iron column 52 is suspended on the beaker 55. The recording device 54 is, for example, a computer, and records the measurement results of the electronic balance 53. The measurement and classification of the contact angle using the measuring device 5 are specifically performed in the following order (4-1) to (4-4), for example.

[0089] (4-1) Prepare at least 14 solvent reagents having known HSP values.

[0090] (4-2) A solvent reagent is placed in a beaker 55. A powder 50 of solid particles to be measured is filled in an iron column 52.

[0091] (4-3) The lifting device 51 is operated to immerse the lower surface side of the iron column 52 in the solvent reagent in the beaker 55. As a result, the solvent reagent is impregnated into the powder 50 of solid particles in the iron column 52. After the immersion, the impregnation weight is measured by the electronic balance 53 every 1 second, and the measurement result is recorded by the recording device 54. The impregnation weight is the weight of the solvent reagent impregnated into the filling powder (specifically, the powder 50) in the iron column 52.

[0092] (4-4) The contact angle θ (unit: °) is calculated by the Washburn equation represented by the following formula III. In formula III, l: liquid penetration height (unit: m), t: penetration time (unit: s), r: capillary radius of the filling powder (unit: m), γ: surface tension of the liquid (unit: mN / m), η: viscosity of the liquid (unit: mPa·s). The contact angle θ is measured for at least 14 solvent reagents. Furthermore, the volume of the liquid that has penetrated into the column can be calculated from the density of the liquid (specifically, the solvent reagent) and the penetration weight, and the penetration height l can be calculated from the volume and the cross-sectional area of ​​the container. The contact angle θ is measured for at least 14 solvent reagents.

[0093] l 2 / t=r·γcosθ / 2η Formula III

[0094] (4-5) Based on the threshold of the contact angle, the solvent is classified into a good solvent and a poor solvent. The smaller the contact angle, the faster the penetration of the solvent reagent into the powder. The faster the penetration, the better the solvent. On the other hand, the larger the contact angle, the slower the penetration of the solvent reagent into the powder. The slower the penetration, the poorer the solvent. The threshold is determined as described above. Furthermore, for example, if the solvent reagents are arranged in order of the contact angle θ from small to large, it is easy to classify.

[0095] The classification of good solvents and poor solvents for determining the Hansen sphere of the non-aqueous liquid can be performed, for example, by visually confirming the solubility of the non-aqueous liquid and the solvent reagent. Specifically, at least 14 solvent reagents with known HSP values ​​are prepared. 1 ml of the non-aqueous liquid to be measured is placed in a spiral tube, and 1 mL of the solvent reagent is also placed. After shaking the spiral tube 20 times, the state inside the tube is visually confirmed. In the case where the non-aqueous liquid is dissolved in the solvent reagent, the solvent reagent is judged to be a good solvent. In the case where the non-aqueous liquid is not completely dissolved in the solvent reagent and a part is separated, or the non-aqueous liquid is completely insoluble in the solvent reagent and the two are completely separated, the solvent reagent is judged to be a poor solvent. The judgment is performed under room temperature (temperature 20-25°C). The above operation is performed on at least 14 solvent reagents.

[0096] As a solvent reagent used in the measurement of solid particles and non-aqueous liquid Hansen spheres, for example, δ d is 14 to 21, and δ p is 0 to 20, and δ h The number of pure solvents is 0 to 22. The more solvent reagents there are, the more accurately the HSP value and Hansen sphere can be measured, but as long as there are 14 to 20, they can be calculated with sufficiently high accuracy. Even if the number is increased, the measurement result remains roughly unchanged, and at least 14 solvent reagents are sufficient. Table 1 shows solvent reagents with known HSP values ​​and their HSP values. By using at least 14 solvent reagents from the list shown in Table 1, the Hansen sphere and HSP value can be determined.

[0097] Table 1

[0098]

[0099] The method for selecting the solvent reagent used in the measurement is not limited, but it is preferred to avoid the value of each surface energy of the solvent reagent (i.e., δ d , δ p , δ h ) rather than combinations of reagents that are close to each other, we choose combinations that are dispersed over a wide range.

[0100] Specifically, among the solvent reagents shown in Table 1, for example, all the solvent reagents belonging to the first group are used, and the solvent reagents can be selected from the second group and the third group according to the solid particles and non-aqueous liquids as the measurement objects. Regarding the non-aqueous liquids and the solid particles that can be measured by visual observation, the solvent reagents belonging to the first group and the solvent reagents belonging to the second group can be used in combination. In this case, when the fitting value is poor, it is preferred to further use the solvent reagent of the third group in a manner that the fitting value is close to 1. In addition, according to the measurement method, there are solvent reagents that cannot determine good solvents and poor solvents. Therefore, the solvent reagents can be selected from the second group and the third group in comparison with the measurement method.

[0101] The above results in the Hansen sphere of solid particles and non-aqueous liquids. In addition, the HSP value of solid particles can be obtained from the Hansen sphere. From the result, the HSP distance Ra between the solid particles and water can be calculated.

[0102] like Figure 1 As shown, Hansen sphere S1 is represented in three-dimensional space. When preparing the dispersion, solid particles and non-aqueous liquid are selectively used in such a way that at least two solid particles overlap with Hansen spheres of one non-aqueous liquid. A specific example of the overlapping of Hansen spheres is shown by an experimental example.

[0103] In the manufacturing method of this embodiment, a dispersion is manufactured by mixing a plurality of solid particles (specifically, powder), water, and a liquid other than water. Furthermore, the solid particles and liquid used in the manufacture of the dispersion are determined based on the overlap of the Hansen spheres and the HSP distance Ra from water. Thus, a combination suitable for high dispersion can be selected as solid particles and non-aqueous liquids. As a result, a dispersion with good dispersibility can be manufactured despite containing water. Therefore, the deviation of the density of the dispersion can be reduced. In addition, the time-dependent change of the viscosity of the dispersion can also be reduced.

[0104] Hereinafter, the solid particles overlapping with the Hansen spheres of the non-aqueous liquid are appropriately referred to as "liquid-affinity solid particles". It is preferred to select solid particles for the manufacture of the dispersion in such a manner that the proportion of one of the liquid-affinity solid particles is the largest among all the solid particles used in the manufacture of the dispersion. In this case, a dispersion with better dispersibility can be manufactured. This is because the solid particles used in the largest amount have good affinity with the liquid. Furthermore, the proportion is a mass ratio.

[0105] In addition, if the solid particle with the largest HSP distance Ra with water among all the solid particles used in the manufacture of the dispersion is used as the first solid particle, it is preferred to select the first solid particle as the solid particle with the largest HSP distance Ra among the solid particle candidate group that can be used in the manufacture of the dispersion. In this case, a dispersion with better dispersibility can also be manufactured. This is because the first solid particle with the lowest affinity with water in the solid particle candidate group has good affinity with the liquid.

[0106] Either the selection of solid particles with the largest HSP distance Ra or the selection of a combination of solid particles and liquids whose Hansen spheres overlap with each other can be performed first. In other words, the order of selection can also be interchanged. For example, the HSP value of the solid particle candidate group is calculated, and the solid particle candidate group is arranged in descending order of the HSP distance Ra from water. Next, solid particles and liquids can be selected in such a way that the solid particles with a large HSP distance Ra from water overlap with the Hansen spheres of the liquid, for use in manufacturing a dispersion. On the other hand, the combinations of solid particles and liquids can be investigated first from the overlap of Hansen spheres, and a combination containing solid particles with a large HSP distance Ra from water can be selected from these combinations.

[0107] Preferably, a solid particle other than the first solid particle among the liquid affinity solid particles, that is, a second solid particle, is selected from the solid particle candidate group as the solid particle with the second largest HSP distance Ra for manufacturing a dispersion. In this case, a dispersion with better dispersibility can also be manufactured. This is because the first solid particle and the second solid particle, which have the lowest affinity with water in the solid particle candidate group, have good affinity with the liquid.

[0108] Preferably, the solid particles other than the first solid particles in the liquid affinity solid particles are selected as the second solid particles whose proportion is the first or second largest solid particles in all solid particles used in the dispersion making. In this case, a dispersion with better dispersibility can also be manufactured. This is because the second solid particles with many usage amounts have good affinity with the liquid. Moreover, the proportion is a mass ratio.

[0109] As described above, according to the present embodiment, a method for producing a dispersion having good dispersibility can be provided.

[0110] (Implementation Method 2)

[0111] Other embodiments of the method for producing a dispersion are described. In addition, in the symbols used in Embodiment 2 and thereafter, the same symbols as those used in the previous embodiments represent the same constituent elements as those in the previous embodiments unless otherwise specified.

[0112] The dispersion produced by this embodiment can be produced by mixing solid particles, water, and a non-aqueous liquid in the same manner as in Embodiment 1. The solid particles and the non-aqueous liquid used in the production of the dispersion are selected as follows.

[0113] The distance from HSP to water is Ra 28MPa 1 / 2 At least two solid particles are selected from the above solid particle candidate group. Then, solid particles and liquids are selected in such a way that the Hansen spheres of these solid particles overlap with the Hansen spheres of at least one non-aqueous liquid in the non-aqueous liquid candidate group. The HSP distance Ra between the solid particles and water is as shown in Implementation Example 1, and the distance can be calculated by measuring each HSP value.

[0114] The distance from HSP to water is Ra 28MPa 1 / 2 The reason for selecting solid particles from the above solid particle candidate group is as follows. 1 / 2 When the HSP distance Ra with water is less than 28 MPa, the dispersion is not significantly deteriorated, so a good dispersion can be obtained by the mechanical energy generated by kneading or stirring. 1 / 2 When the solid particles form aggregates in water, it is highly likely that the aggregates will be dispersed by the mechanical energy. 1 / 2 Solid particles are selected from the above solid particle candidate group.

[0115] By using the solid particles and the liquid selected as described above, a dispersion with good dispersibility can be produced.

[0116] Preferably, solid particles are selected in a maximum mode among all solid particles used in the manufacture of dispersion with at least one proportion of solid particles selected from the solid particle candidate group, for the manufacture of dispersion. In this case, a dispersion with better dispersibility can be manufactured. This is because the solid particles with the maximum usage amount have good affinity with liquid. Moreover, the proportion is a mass ratio. In addition, it is possible to implement in the same manner as embodiment 1, and the same effect is achieved.

[0117] (Implementation 3)

[0118] An embodiment of manufacturing a honeycomb structure 2 using a dispersion as a ceramic sintered body 1 is described. Figure 3 As shown, the honeycomb structure 2 has, for example, a cylindrical outer skin 21 and partition walls 23 that divide the inner part of the outer skin 21 into a plurality of cells 22. The partition walls 23 are arranged in a lattice shape. The cells 22 extend along the axial direction X of the outer skin 21. The axial direction X of the outer skin 21 is also the axial direction X of the honeycomb structure 2.

[0119] The honeycomb structure 2 has a monolithic substrate for carrying an exhaust gas purification catalyst such as a precious metal catalyst, and an exhaust gas purification filter for collecting particulate matter in the exhaust gas by forming a sealing portion. The sealing portion is omitted in the figure, but the sealing portion is formed on both ends 28 and 29 of the honeycomb structure 2 in the axial direction X. In each unit 22, the first end 28 or the second end 29 is sealed by the sealing portion, and the sealing portion and the opening portion not sealed by the sealing portion are arranged in a checkered pattern on the first end 28 or the second end 29. Hereinafter, the honeycomb structure for the monolithic substrate is referred to as the "first honeycomb structure", and the honeycomb structure for the exhaust gas purification filter is referred to as the "second honeycomb structure".

[0120] The first honeycomb structure and the second honeycomb structure both have Figure 3 The honeycomb structure shown is composed of cordierite, SiC, aluminum titanate, etc. For example, even if the cordierite is the same, different raw materials are used because the required performances such as heat resistance, strength, and porosity are different in the first honeycomb structure and the second honeycomb structure.

[0121] When the first honeycomb structure is made of cordierite, the raw material can be selected from kaolin, aluminum hydroxide, silicon dioxide, alumina, talc, pore-forming materials, etc. In addition, when the second honeycomb structure is made of cordierite, the raw material can be selected from silicon dioxide such as porous silica, aluminum hydroxide, talc, pore-forming materials, etc. On the other hand, in order to improve the dispersibility by improving the wettability of the raw material with water, a lubricating oil or a dispersant can be used as the non-aqueous liquid.

[0122] The manufacturing method of the honeycomb structure is as follows. First, solid particles of a raw material selected from a candidate group, a non-aqueous liquid selected from a candidate group and water are mixed and kneaded to prepare a green clay. The green clay is a dispersion. Next, the green clay is extruded into a honeycomb shape to obtain a formed body. After the formed body is dried, the honeycomb structure can be obtained by sintering.

[0123] As in Embodiments 1 and 2, by selecting solid particles and non-aqueous liquid to modulate the green clay, a green clay with good dispersibility can be obtained. Thus, after sintering, it is possible to prevent inappropriate situations such as cracks and distortion of the unit. By adopting the dispersion of Embodiments 1 and 2, even when the ceramic sintered body 1 has a thin-walled portion, such as the partition wall 23 of the honeycomb structure 2, it is possible to prevent the occurrence of shape abnormalities in the thin-walled portion after forming or sintering. In addition, since a dispersion in a highly dispersed state can be obtained even if the amount of the non-aqueous liquid is reduced, the deviation of the non-aqueous liquid component in the green clay is reduced. As a result, the stress during sintering can be suppressed, and it is possible to further prevent inappropriate situations from occurring in the sintered body.

[0124] (Experimental Example 1)

[0125] This example is an example of selecting solid particles and non-aqueous liquid used in the manufacture of a honeycomb structure made of cordierite from the candidate group. Specifically, solid particles and non-aqueous liquid used in the manufacture of a first honeycomb structure for a monolithic substrate are selected.

[0126] In this example, in the manufacture of the first honeycomb structure, aluminum hydroxide, aluminum oxide, silicon dioxide, and talc are used as solid particles of the raw materials. Then, these raw materials, water, and a liquid dispersant are mixed to produce a dispersion, and the dispersion is formed, dried, and sintered to produce a honeycomb structure. First, the HSP values ​​of the solid particles and non-aqueous liquid used in the raw materials of the honeycomb structure are measured by the method shown in Embodiment 1.

[0127] Tables 2 to 4 show the measurement objects of the HSP values ​​and the solvent reagents used in the measurement. The rounded symbols in the tables indicate that the reagents were used, and the blanks indicate that the reagents were not used. Tables 2 to 4 also show the measurement objects and solvent reagents used as the raw materials for the second honeycomb structure for manufacturing the exhaust gas purification filter described in Experimental Example 2. In addition, the measurement objects with letters in the tables indicate that the manufacturers, production places, product names (product numbers), etc. are different.

[0128] Table 2

[0129]

[0130] Table 3

[0131]

[0132] Table 4

[0133]

[0134] Table 5 shows the measurement results of the HSP value of solid particles and the HSP distance Ra from water, and Table 6 shows the measurement results of the HSP value of non-aqueous liquids. In addition, Tables 7 to 22 show the classification results of solvent reagents used in the measurement of the HSP values ​​of solid particles and non-aqueous liquids as the measurement objects. A score of 1 indicates a good solvent, and a score of 0 indicates a poor solvent. Furthermore, the "-" in Tables 7, 8, 10 to 14 means that the judgment was made by visual inspection. The illustration of the three-dimensional Hansen sphere of each measurement object is omitted, but the corresponding Figure 1 Same Hansen sphere.

[0135]

[0136] Table 6

[0137]

[0138] *: Unilube is a registered trademark

[0139]

[0140] Table 8 Aluminum hydroxide D

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149] Table 16 Canola Oil

[0150]

[0151]

[0152] Table 18 Dispersant B

[0153]

[0154] Table 19 Dispersant C

[0155]

[0156]

[0157]

[0158]

[0159] As shown in Tables 5 to 22, the method shown in Embodiment 1 can be used to classify the solid particles and non-aqueous liquid solvent reagents that are the measurement objects. The Hansen sphere and HSP value can be measured from the results. In addition, the HSP distance Ra of the solid particles to water can be calculated. The Hansen sphere is usually expressed in terms of London dispersion force δ, δ, and δ. d , dipole force δ p and hydrogen bond force δ h In the three-dimensional space called Hansen space as the coordinate axis, but in this experimental example 1, Figures 4 to 18As shown in FIG. 1 , in order to clearly indicate the overlap of the Hansen spheres, the Hansen spheres are represented in three two-dimensional coordinates. Figure 19 to Figure 26 Same here.

[0160] Figures 4 to 18 (a) in the figure can be said to be the London dispersion force δ d 、Dipole force δ p and hydrogen bond force δ h The Hansen sphere projection represented by the three-dimensional coordinates of the axis is based on the London dispersion force δ d and dipole force δ p is a graph of the two-dimensional coordinates of the axes. In other words, Figures 4 to 18 (a) shows the London dispersion force δ d and dipole force δ p is the shape of the Hansen sphere on the two-dimensional coordinates of the axis. Figures 4 to 18 (b) in the figure can be said to be the projection of the Hansen sphere represented by three-dimensional coordinates onto the dipole force δ p and hydrogen bond force δ h is a graph of the two-dimensional coordinates of the axes. In other words, Figures 4 to 18 (b) shows the dipole force δ p and hydrogen bond force δ h is the shape of the Hansen sphere on the two-dimensional coordinates of the axis. Figures 4 to 18 (c) in the figure can be said to be the projection of the Hansen sphere represented by three-dimensional coordinates onto the London dispersion force δ d and hydrogen bond force δ h is a graph of the two-dimensional coordinates of the axes. In other words, Figures 4 to 18 (c) shows the London dispersion force δ d and hydrogen bond force δ h is the shape of the Hansen sphere on the two-dimensional coordinates of the axis. Figure 19 to Figure 26 Same here.

[0161] Furthermore, Figure 4 to Figure 26 The Hansen balls shown are the following solid particles and Hansen balls of non-aqueous liquids. Hansen balls S11 are Hansen balls of aluminum hydroxide A. Hansen balls S12 are Hansen balls of aluminum hydroxide D. Hansen balls S13 are Hansen balls of talc A. Hansen balls S14 are Hansen balls of talc B. Hansen balls S15 are Hansen balls of talc C. Hansen balls S16 are Hansen balls of talc D. Hansen balls S17 are Hansen balls of porous silica. Hansen balls S21 are Hansen balls of canola oil. Hansen balls S22 are Hansen balls of dispersant A. Hansen balls S23 are Hansen balls of dispersant B. Hansen balls S24 are Hansen balls of dispersant C.

[0162] As shown in Examples 1 to 12 and Comparative Examples 1 to 4 in Tables 23 and 24, solid particles and dispersants that are raw materials of the monolithic substrate were selected. The "○" in the selected column means that the solid particles and dispersants were selected, and the blank column means that they were not selected. The solid particles and dispersants were selected based on the above measurement results, the HSP distance Ra to water, Figures 4 to 18 The overlap of the Hansen spheres shown is performed. Figures 8 to 18 As shown, in Examples 1 to 12, two solid particle Hansen spheres S1 and one non-aqueous liquid Hansen sphere S2 are selected so as to overlap each other. Figures 4 to 7 As shown, in the solid particles and non-aqueous liquids used in Comparative Examples 1 to 4, there is a combination in which the Hansen spheres S1 and S2 do not overlap. Figures 4 to 18 As mentioned above, the Hansen sphere is represented by a two-dimensional circle, so the overlap of the Hansen spheres is represented by the overlap of the circles. Figure 19 to Figure 26 Same here.

[0163] Table 23, Table 24, Figures 4 to 18 The two solid particles of the combination shown, one non-aqueous liquid, and further kaolin, silica, alumina and water are mixed to prepare a first honeycomb structure for the molded clay. Among the solid particles used in the manufacture of the dispersion (specifically, the molded clay for the monolithic type) of this example, the raw material with the largest amount (mass ratio) is talc, and the second largest raw material is aluminum hydroxide. In addition, as shown in Tables 23 and 24, in the solid particle candidate group, the raw material with the largest HSP distance from water is talc A, and the second largest raw material is talc D. Furthermore, the "○" in the column of overlapping Hansen spheres in Tables 23, 24, and Table 25 described later means that any one of the Hansen spheres S1 of the two solid particles overlaps with the Hansen spheres S2 of the non-aqueous liquid, and the "×" means that one of the Hansen spheres S1 of the two solid particles does not overlap with the Hansen spheres S2 of the non-aqueous liquid.

[0164] Next, in order to investigate the dispersibility of the green clay of Examples 1, 2, Comparative Examples 1, 2, the deviation of the green clay density was measured. Specifically, the green clay after kneading and before forming was taken out, and the green clay was dug out at random from 8 positions to obtain a test sample. The test sample was placed in a measuring fixture with a diameter of 25 mm and a length of 20 mm, and the test sample was compressed under the conditions of a pressurization speed of 1 mm / min and a pressure of 1 kN. Then, the height and weight of the test sample taken out from the measuring fixture were measured, and the density was calculated from the results. Next, the difference between the measured value of the actual green clay density and the theoretical green clay density that can be calculated in advance based on the raw material combination was calculated. When the measured value is small compared to the theoretical green clay density and the difference is large, it means that the wettability of the test sample is poor. In this case, there is air on the surface of the particles, for example, there is a concern that cracks may occur due to sintering. On the other hand, if the theoretical green clay density and the measured value are the same value, it means that the dispersibility is good. The results are shown in Table 23.

[0165]

[0166]

[0167] As shown in Table 23 and Table 24, in the comparative examples, the average values ​​of the measured clay density results are all about 10% lower than the theoretical clay density. In addition, although not shown in the table, the deviation caused by the location of the clay sample is large, and the measured value of the clay density is 17% lower than the theoretical value. In contrast, in the examples, the deviation from the theoretical value is less than 5% on average, and there is no particularly low place, and the deviation is small.

[0168] Furthermore, the honeycomb structure was manufactured by using the clay of the examples and comparative examples and performing molding, drying and sintering in the same manner as in Embodiment 3. As a result, the defective rate during sintering in the examples was less than half of that in the comparative examples, assuming that the heating rate conditions were not changed.

[0169] (Experimental Example 2)

[0170] In this example, the solid particles and non-aqueous liquid used in the manufacture of a honeycomb structure composed of cordierite are selected. Specifically, the solid particles and non-aqueous liquid used in the manufacture of a second honeycomb structure for an exhaust gas purification filter are selected. The second honeycomb structure has the same structure as the first honeycomb structure. The exhaust gas purification filter is formed by forming a sealing portion that alternately seals the units of the second honeycomb structure at both ends of the axial direction.

[0171] In the manufacture of the second honeycomb structure for the exhaust gas purification filter, porous silica, aluminum hydroxide, and talc are used in a manner to achieve a desired cordierite composition. Then, these raw materials, water, and a liquid dispersant are mixed to produce a dispersion, and the dispersion is formed, dried, and sintered to produce a honeycomb structure.

[0172] Based on the HSP value of each measurement object measured in Experimental Example 1, the HSP distance Ra from water, and the Hansen sphere, the raw materials for the exhaust gas purification filter were selected. Table 24, Figure 19 to Figure 26 The results are shown in Table 25. Figure 19 to Figure 26 The combination shown selects solid particles and non-aqueous liquid, mixes these solid particles, non-aqueous liquid, and aluminum hydroxide with water, and prepares the clay for the second honeycomb structure. Among the solid particles used in the manufacture of the dispersion (specifically, the clay for the exhaust gas purification filter) of this example, the raw material with the largest amount (mass ratio) is aluminum hydroxide, and the second largest raw material is talc. In addition, the solid particle with the largest HSP distance from water in the solid particle candidate group is porous silica, and the second largest solid particle is talc A.

[0173]

[0174] As shown in Table 25, the HSP distance Ra between porous silica and water is 39.0, which is the largest value among the solid particles used. Figure 23 to Figure 26 As shown in Table 25, the Hansen spheres S1 of both solid particles overlap with the Hansen spheres S2 of the non-aqueous liquid in Examples 12 to 15. Therefore, the clay of the Examples can be said to have good dispersibility based on the results of Experimental Example 2. Figure 19 to Figure 22 As shown, in Comparative Examples 5 to 8, at least one of the two types of solid particles, Hansen spheres S1, did not overlap with the non-aqueous liquid Hansen spheres S2. Therefore, based on the results of Experimental Example 2, the clays of Comparative Examples 5 to 8 were poor in dispersibility.

[0175] The present disclosure is not limited to the above-mentioned embodiments and examples, and can be applied to various embodiments without departing from the main purpose thereof. In the embodiments and examples, the green clay used in the manufacture of the honeycomb structure is mainly described as a dispersion, but the present disclosure can also be applied to other technical fields of mixed solid particles such as ceramic raw materials, water and non-aqueous liquids. Specifically, gas sensors, solid batteries, spark plugs, etc. can be exemplified. The present technology can be widely used in products including sintered bodies such as ceramics.

[0176] The present disclosure is described in accordance with the embodiments, but it should be understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes a variety of modifications and modifications within the scope of equality. Moreover, a variety of combinations and methods, as well as other combinations and methods including only one element, above or below the elements, are also within the scope and concept of the present disclosure.

Claims

1. A method for producing a dispersion, which is a method for producing a dispersion by mixing a plurality of solid particles, water and a liquid other than water, wherein: The solid particles are powders composed of inorganic substances, and the liquid is a non-aqueous liquid composed of liquid organic substances. The solid particles and the liquid are selected for producing the dispersion in such a manner that the Hansen spheres of at least two of the solid particles overlap with the Hansen spheres of at least one of the liquids, and the Hansen solubility parameter distance Ra between one of the solid particles overlapping with the Hansen sphere of the liquid and water is the largest among all the solid particles used in producing the dispersion, The Hansen solubility parameter distance Ra is defined as follows: When the HSP value of solute A is (δ dA ,δ pA ,δ hA ), the HSP value of solvent B is (δ dB ,δ pB ,δ hB ), Ra can be represented by the following formula I, Ra = {4·(δ dA -δ dB ) 2 +(δ pA -δ pB ) 2 +(δ hA -δ hB ) 2 } 1 / 2 Formula I.

2. The method for producing a dispersion according to claim 1, wherein: The solid particles are selected and used for producing the dispersion so that the mixing ratio of one of the solid particles overlapping with the Hansen spheres of the liquid is the largest in terms of mass ratio among all the solid particles used for producing the dispersion.

3. The method for producing a dispersion according to claim 1, wherein: The solid particle having the largest Hansen solubility parameter distance Ra is the first solid particle, and the first solid particle is selected from a candidate group of solid particles that can be used in the manufacture of the dispersion as the solid particle having the largest Hansen solubility parameter distance Ra, and is used to manufacture the dispersion.

4. The method for producing a dispersion according to claim 2, wherein: The solid particle having the largest Hansen solubility parameter distance Ra is the first solid particle, and the first solid particle is selected from a candidate group of solid particles that can be used in the manufacture of the dispersion as the solid particle having the largest Hansen solubility parameter distance Ra, and is used to manufacture the dispersion.

5. The method for producing a dispersion according to claim 3, wherein: A second solid particle, which is a solid particle other than the first solid particle among the solid particles overlapping the Hansen sphere of the liquid, is selected from the solid particle candidate group as a solid particle having the second largest Hansen solubility parameter distance Ra for use in producing the dispersion.

6. The method for producing a dispersion according to claim 4, wherein: A second solid particle, which is a solid particle other than the first solid particle among the solid particles overlapping the Hansen sphere of the liquid, is selected from the solid particle candidate group as a solid particle having the second largest Hansen solubility parameter distance Ra for use in producing the dispersion.

7. The method for producing a dispersion according to claim 3, wherein: Among the solid particles overlapping with the Hansen spheres of the liquid, second solid particles other than the first solid particles are selected as solid particles having the first or second largest blending ratio in terms of mass ratio among all the solid particles used for preparing the dispersion.

8. The method for producing a dispersion according to claim 4, wherein: Among the solid particles overlapping with the Hansen spheres of the liquid, second solid particles other than the first solid particles are selected as solid particles having the first or second largest blending ratio in terms of mass ratio among all the solid particles used for preparing the dispersion.

9. A method for producing a dispersion by mixing a plurality of solid particles, water and a liquid other than water, wherein: The solid particles are powders composed of inorganic substances, and the liquid is a non-aqueous liquid composed of liquid organic substances. The Hansen solubility parameter distance from water is Ra 28MPa. 1 / 2 At least two solid particles are selected from the above solid particle candidate group, and the Hansen spheres of the solid particles overlap with the Hansen spheres of at least one liquid in the liquid candidate group, and the solid particles and the liquid are selected to produce the dispersion, The Hansen solubility parameter distance Ra is defined as follows: When the HSP value of solute A is (δ dA ,δ pA ,δ hA ), the HSP value of solvent B is (δ dB ,δ pB ,δ hB ), Ra can be represented by the following formula I, Ra = {4·(δ dA -δ dB ) 2 +(δ pA -δ pB ) 2 +(δ hA -δ hB ) 2 } 1 / 2 Formula I.

10. The method for producing a dispersion according to claim 9, wherein: The solid particles are selected for use in producing the dispersion so that the mixing ratio of at least one of the solid particles selected from the solid particle candidate group becomes the largest in terms of mass ratio among all the solid particles used in producing the dispersion.

11. A method for producing a ceramic sintered body, comprising forming and sintering the dispersion obtained by the production method according to any one of claims 1 to 10, wherein: The solid particles are ceramic raw materials.

12. The method for producing a ceramic sintered body according to claim 11, wherein: The ceramic sintered body has a honeycomb structure.

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