Pigment, method for producing the same, solution, method for evaluating metal hydroxyl group amount, method for evaluating metal hydroxyl treatment rate

Abstract

The pigment of the present application is a compound represented by the following general formula (1) or the following general formula (2). (In the following formulae, M is Sn or Ge, X is C or N, R1 is an alkyl group or a phenyl group, Y1 and Y2 are each hydrogen, a halogen group, a methyl group, an alkoxy group, a phenyl group, a diphenyl amido group, a thio phenyl group, or a phenyl ethynyl group, Z is represented by a single bond or the following formula (3). R2 is an alkyl group or a phenyl group.)

Description

Technical Field

[0001] This invention relates to a pigment and its manufacturing method, a solution containing the pigment, a method for evaluating the amount of metal hydroxyl groups, and a method for evaluating the metal hydroxyl group treatment rate and the metal hydroxyl group residual rate.

[0002] This application claims priority based on Japanese Patent Application No. 2022-026890 filed on February 24, 2022, the contents of which are incorporated herein by reference. Background Technology

[0003] To impart functions such as ultraviolet shielding or gas barrier properties, metal oxide particles such as zinc oxide particles are added to various compositions.

[0004] When metal oxide particles are used in a composition, the surface of the metal oxide particles is treated with a surface treatment agent in order to make the surface of the metal oxide particles conform to the properties of the composition or to inhibit the catalytic activity of the metal oxide particles.

[0005] For example, when zinc oxide particles are formulated in the oil phase of oily cosmetics or emulsions, zinc oxide particles that have been surface-treated with silane coupling agents having alkoxy groups are used (for example, see Patent Document 1 and Patent Document 2).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 130632

[0009] Patent Document 2: Japanese Patent Application Publication No. 2007-51188 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] Previously, by improving the dispersibility of metal oxide particles such as zinc oxide particles in the oil phase, it was possible to confirm that the metal oxide particles had been surface-treated by surface treatment agents such as silane coupling agents. However, there was no way to quantitatively and accurately determine the extent to which the surface treatment of the metal oxide particles had occurred.

[0012] Previously, Fourier transform infrared (FT-IR) was known as a method for quantifying hydroxyl groups on the surface of metal oxide particles. However, FT-IR is easily affected by the moisture content in the sample, thus introducing errors. Furthermore, quantifying only the hydroxyl peak is difficult when it overlaps with the peaks of other functional groups. Therefore, it is challenging to easily and accurately evaluate hydroxyl groups on the surface of metal oxide particles in FT-IR.

[0013] Furthermore, the Grignard reaction is a known method for quantifying hydroxyl groups on the surface of metal oxide particles. However, the Grignard reaction requires highly reactive reagents and specialized equipment, and is performed under an inert atmosphere, making the evaluation process cumbersome. Moreover, since atmospheric moisture reacts with the reagents, it is difficult to accurately determine the amount of hydroxyl groups on the surface of metal oxide particles.

[0014] Furthermore, the limiting ethanol method is a method for evaluating the hydrophobicity state of the surface of metal oxide particles. While the limiting ethanol method can be used for simple evaluation, it is difficult to provide a quantitative evaluation.

[0015] Therefore, a simple and accurate method is needed to evaluate the state of the surface of metal oxide particles.

[0016] The present invention was made in view of the above circumstances, and its object is to provide a pigment capable of adsorbing onto hydroxyl groups (hereinafter, sometimes simply referred to as "metallic hydroxyl groups") bonded to metal atoms, a method for manufacturing the same, a solution containing the pigment, and a method for evaluating the amount of metallic hydroxyl groups in the pigment and the metallic hydroxyl group treatment rate.

[0017] Solution for solving the problem

[0018] That is, the pigment of the first aspect of the present invention is a compound represented by the following general formula (1) or the following general formula (2).

[0019] [Chemical Formula 1]

[0020]

[0021] (In formula (1), M is Sn or Ge, X is C or N, R1 is alkyl or phenyl, Y1 and Y2 are hydrogen, halogen, methyl, alkoxy, phenyl, diphenylamide, thiophenyl or phenylethynyl, respectively, and Z is represented by a single bond or the following formula (3).)

[0022] [Chemical Formula 2]

[0023]

[0024] (In formula (2), X is C or N, Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group respectively, and Z is a single bond or is represented by the following formula (3).)

[0025] [Chemical Formula 3]

[0026]

[0027] (In formula (3), R2 is an alkyl or phenyl group.)

[0028] The second method for manufacturing the pigment of the present invention is a method for manufacturing the pigment of the present invention, which includes the following steps: a mixing step, mixing a ligand represented by the following general formula (4) or a ligand represented by the following general formula (5), and mixing a metal source represented by the following general formula (6); and a coordination step, coordinating the metal source represented by the following general formula (6) with the ligand represented by the following general formula (4) or the ligand represented by the following general formula (5).

[0029] [Chemical Formula 4]

[0030]

[0031] (In formula (4), X is C or N, and Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group, respectively.)

[0032] [Chemical Formula 5]

[0033]

[0034] (In formula (5), X is C or N, Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group respectively, and R is alkyl or phenyl.)

[0035] [Chemical Formula 6]

[0036] R2-M=O (6)

[0037] (In formula (6), M is at least one selected from the group consisting of Sn, Ge and Bi, and R is an alkyl or phenyl group.)

[0038] The third-party method for manufacturing pigments of the present invention is a method for manufacturing pigments of the present invention, which includes the following steps: a mixing step, mixing a ligand represented by the following general formula (4) or a ligand represented by the following general formula (5), and mixing a metal source, an alkali and an organic solvent represented by the following general formula (7); and a coordination step, causing the metal source represented by the following general formula (7) to coordinate with the ligand represented by the following general formula (4) or the ligand represented by the following general formula (5).

[0039] [Chemical Formula 7]

[0040]

[0041] (In formula (4), X is C or N, and Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group, respectively.)

[0042] [Chemical Formula 8]

[0043]

[0044] (In formula (5), X is C or N, Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group respectively, and R is alkyl or phenyl.)

[0045] [Chemical Formula 9]

[0046] R2-M-A2 (7)

[0047] (In formula (7), M is at least one selected from the group consisting of Sn, Ge and Bi, R is an alkyl or phenyl group, and A is a halogen group.)

[0048] The solution of the fourth embodiment of the present invention contains the pigment and organic solvent of the first embodiment of the present invention.

[0049] The fifth method of the present invention for evaluating the amount of metal hydroxyl groups comprises the following steps: preparing a solution and a sample according to the fourth method of the present invention; evaluating the color x of the solution; adding the sample to the solution of the fourth method of the present invention to prepare a mixture A, and evaluating the color a of the mixture A; evaluating the difference between the obtained color x and the color a, and evaluating the amount of metal hydroxyl groups of the sample based on the obtained evaluation results.

[0050] The sixth embodiment of the present invention provides a method for evaluating the amount of metallic hydroxyl groups, comprising the following steps: preparing a solution of the fourth embodiment of the present invention, sample 1, and sample 2; adding sample 1 to the solution of the fourth embodiment of the present invention to prepare a mixture A, and evaluating the color a of the mixture A; adding sample 2 to the solution of the fourth embodiment of the present invention to prepare a mixture B, and evaluating the color b of the mixture B; evaluating the difference between the obtained color a and color b, and evaluating the difference between the amount of metallic hydroxyl groups a of sample 1 and the amount of metallic hydroxyl groups b of sample 2 based on the obtained evaluation results.

[0051] The seventh method for evaluating the amount of metallic hydroxyl groups of the present invention comprises the following steps: preparing a solution of the fourth method of the present invention, sample 1, and sample 2; evaluating the color x of the solution of the fourth method of the present invention; adding sample 1 to the solution of the fourth method of the present invention to prepare a mixture A, and evaluating the color a1 of the mixture A; adding sample 2 to the solution of the fourth method of the present invention to prepare a mixture B, and evaluating the color b1 of the mixture B; evaluating the difference between the obtained color x and the color a1, and evaluating the amount of metallic hydroxyl groups a of sample 1 based on the obtained evaluation result; evaluating the difference between the obtained color x and the color b1, and evaluating the amount of metallic hydroxyl groups b of sample 2 based on the obtained evaluation result; and evaluating the difference between the amount of metallic hydroxyl groups a and the amount of metallic hydroxyl groups b.

[0052] The method for evaluating the metal hydroxyl removal rate of the eighth aspect of the present invention is a method for evaluating the removal rate of metal hydroxyl groups on the surface of metal oxide particles when surface-treating metal oxide particles with a surface treatment agent. The method comprises the following steps: preparing a solution according to the fourth aspect of the present invention, metal oxide particles 1 before surface treatment, and surface-treated metal oxide particles 2 after surface treatment of the metal oxide particles 1; measuring the absorbance x of the solution according to the fourth aspect of the present invention; adding the surface-treated metal oxide particles 1 to the solution according to the fourth aspect of the present invention to prepare a mixture A, and measuring the absorbance a1 of the mixture A; adding the surface-treated metal oxide particles 2 to the solution according to the fourth aspect of the present invention to prepare a mixture B, and measuring the absorbance b1 of the mixture B; calculating the reduction rate a2 of the absorbance of the mixture A by subtracting the absorbance a1 from the absorbance x and dividing by the absorbance x ((x-a1) / x); and calculating the reduction rate a2 of the absorbance of the mixture A by subtracting the absorbance b1 from the absorbance x and dividing by the absorbance b1. The absorbance reduction rate b2 of the mixture B is calculated using the absorbance x ((x-b1) / x); the adsorption amount a3 (mol / g) of the pigment on the metal oxide particles 1 is calculated by multiplying the number of moles of the pigment contained in the mixture A by the absorbance reduction rate a2 and dividing by the amount of metal oxide particles 1 added to the solution A (a2 × number of moles of pigment contained in the mixture A / amount of metal oxide particles 1 added to the solution A); the adsorption amount a3 (mol / g) of the pigment on the metal oxide particles 1 is calculated by multiplying the number of moles of the pigment contained in the mixture B by the amount of metal oxide particles 1 added to the solution A. The amount of pigment adsorbed on the metal oxide particles 2 is calculated by multiplying the number by the rate of decrease in absorbance b2 and dividing by the amount of metal oxide particles 2 added to the solution B (b2 × number of moles of pigment contained in the mixture B / amount of metal oxide particles 2 added to the solution B); and the metal hydroxyl treatment rate based on the surface treatment is calculated by subtracting the value obtained by multiplying the adsorption amount b3 by the adsorption amount a3 by 100 (100 - ((b3 / a3) × 100)).

[0053] The method for evaluating the residual rate of metal hydroxyl groups in the ninth aspect of the present invention is a method for evaluating the treatment rate of metal hydroxyl groups on the surface of metal oxide particles when surface-treating metal oxide particles with a surface treatment agent. The method comprises the following steps: preparing a solution according to the fourth aspect of the present invention, metal oxide particles 1 before surface treatment, and surface-treated metal oxide particles 2 after surface treatment of the metal oxide particles 1; measuring the absorbance x of the solution according to the fourth aspect of the present invention; adding the surface-treated metal oxide particles 1 to the solution according to the fourth aspect of the present invention to prepare a mixture A, and measuring the absorbance a1 of the mixture A; adding the surface-treated metal oxide particles 2 to the solution according to the fourth aspect of the present invention to prepare a mixture B, and measuring the absorbance b1 of the mixture B; calculating the reduction rate a2 of the absorbance of the mixture A by subtracting the absorbance a1 from the absorbance x and dividing by the absorbance x ((x-a1) / x); and subtracting the absorbance a1 from the absorbance x. The reduction rate b2 of absorbance of the mixture B is calculated by dividing the value of b1 by the absorbance x ((x-b1) / x); the adsorption amount a3 (mol / g) of the pigment on the metal oxide particles 1 is calculated by multiplying the number of moles of the pigment contained in the mixture A by the reduction rate a2 of absorbance and dividing by the amount of metal oxide particles 1 added to the solution A ((a2×number of moles of pigment contained in the mixture A) / amount of metal oxide particles 1 added to the solution A); the adsorption amount a3 (mol / g) of the pigment on the metal oxide particles 1 is calculated by multiplying the number of moles of the pigment contained in the mixture A by the amount of metal oxide particles 1 added to the solution A; the adsorption amount a3 (mol / g) of the pigment on the metal oxide particles 1 is calculated by multiplying the number of moles of the pigment contained in the mixture B by the amount of metal oxide particles 1 added to the solution A. The amount of pigment adsorbed on the metal oxide particles 2 is calculated by multiplying the number of moles of the pigment contained in the solution by the rate of decrease in absorbance b2 and dividing by the amount of metal oxide particles 2 added to the solution B (particle b2 × number of moles of pigment contained in the mixture B / amount of metal oxide particles 2 added to the solution B), and the amount of metal hydroxyl residue based on the surface treatment is calculated by multiplying the adsorption amount b3 by the value of the adsorption amount a3 by 100 ((b3 / a3) × 100).

[0054] The effects of the invention

[0055] According to the pigment of the present invention, the pigment can be adsorbed onto metal hydroxyl groups, thus enabling determination of whether a sample contains metal hydroxyl groups.

[0056] The pigment of the present invention can be obtained by the method for manufacturing the pigment according to the present invention.

[0057] The solution according to the present invention, because it contains the pigment of the present invention, enables the evaluation of whether a sample contains metallic hydroxyl groups.

[0058] According to the method for evaluating the amount of metal hydroxyl groups of the present invention, the amount of metal hydroxyl groups contained in a sample can be evaluated qualitatively and quantitatively.

[0059] According to the method for evaluating the metal hydroxyl removal rate of the present invention, when metal oxide particles are surface treated with a surface treatment agent, the removal rate of metal hydroxyl groups on the surface of metal oxide particles can be quantitatively evaluated. Attached Figure Description

[0060] Figure 1 It is a diagram showing the compounds represented by general formula (1) and the compounds represented by general formula (2) side by side.

[0061] Figure 2 This is a diagram showing an example of the synthesis of ligands represented by general formula (4).

[0062] Figure 3 This is a diagram showing an example of the synthesis of ligands represented by general formula (5).

[0063] Figure 4 This refers to the pigment obtained in Example 1. 1 A graph showing the results of H-NMR measurements.

[0064] Figure 5 This is a schematic diagram illustrating the reaction mechanism between the red pigment of Example 1 and the metallic hydroxyl groups present on the surface of the active alumina particles.

[0065] Figure 6 This is a schematic diagram illustrating the reaction mechanism between the yellow pigment of Example 2 and the metal hydroxyl groups present on the surface of the active alumina particles.

[0066] Figure 7 This is a graph showing the treatment rate of metallic hydroxyl groups on the surface of zinc oxide particles relative to the content of octyltriethoxysilane in Example 10. Detailed Implementation

[0067] The embodiments of the pigment and its manufacturing method, the solution containing the pigment, the method for evaluating the amount of metal hydroxyl groups, and the method for evaluating the metal hydroxyl group treatment rate of the present invention will be described.

[0068] Furthermore, this embodiment has been specifically described to better understand the spirit of the invention, and is not limited to this invention unless otherwise specified. Changes, omissions, or additions can be made to the numbers, quantities, positions, values, ratios, types, orders, etc., without departing from the scope of the invention.

[0069] [pigment]

[0070] The pigment in this embodiment is a compound represented by the following general formula (1) or the following general formula (2).

[0071] [Chemical Formula 10]

[0072]

[0073] (In formula (1), M is Sn or Ge, X is C or N, R1 is alkyl or phenyl, Y1 and Y2 are hydrogen, halogen, methyl, alkoxy, phenyl, diphenylamide, thiophenyl or phenylethynyl, respectively, and Z is represented by a single bond or the following formula (3).)

[0074] [Chemical Formula 11]

[0075]

[0076] (In formula (2), X is C or N, Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group respectively, and Z is a single bond or is represented by the following formula (3).)

[0077] [Chemical Formula 12]

[0078]

[0079] (In formula (3), R2 is an alkyl or phenyl group.)

[0080] When R1 and / or R2 are alkyl groups, they are not particularly limited as long as they do not hinder the coordination reaction between the pigment and the metal hydroxyl group in this embodiment. The number of carbon atoms in the alkyl group is preferably 1 or more, more preferably 1 or more and 20 or less, even more preferably 2 or more and 15 or less, and particularly preferably 3 or more and 10 or less. The number of carbon atoms can be 1 to 8, 2 to 6, 4 to 5, etc. Specifically, examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, etc., but the group is not limited to these examples.

[0081] In this embodiment, Y1 and Y2 are respectively exemplified as hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl, or phenylethynyl group. Y1 and Y2 are not particularly limited as long as they are groups whose color changes according to electron-withdrawing, electron-donating, or conjugation expansion. That is, if Y1 and Y2 are color-capable groups, they can be any groups.

[0082] For example, the number of carbon atoms in the alkoxy group can be arbitrarily chosen, for example, it can be 1 to 10, 2 to 5, 3 to 4, but is not limited to these examples.

[0083] The halogen group mentioned above is selected from the group consisting of F, Cl, Br, and I. The halogen group is preferably F and / or Br, but is not limited to these examples.

[0084] Y1 and Y2 can be the same group or different groups.

[0085] As a specific example of a compound represented by the above general formula (1), pigments represented by the following formulas (8) to (14) can be cited.

[0086] [Chemical Formula 13]

[0087]

[0088] The pigment represented by the above formula (8) is red and is a pigment that absorbs light with a wavelength around 545 nm. In the formula, Ph represents phenyl.

[0089] [Chemical Formula 14]

[0090]

[0091] The pigment represented by the above formula (9) is yellow and is a pigment that absorbs light with a wavelength around 453 nm. In the formula, Ph represents phenyl.

[0092] [Chemical Formula 15]

[0093]

[0094] The pigment represented by the above formula (10) is dark reddish-purple.

[0095] [Chemical Formula 16]

[0096]

[0097] The pigment represented by the above formula (11) is yellow. In the formula, Ph represents phenyl.

[0098] [Chemical Formula 17]

[0099]

[0100] The pigment represented by the above formula (12) is dark purple. In the formula, IPr represents isopropyl.

[0101] [Chemical Formula 18]

[0102]

[0103] The pigment represented by the above formula (13) is dark purple. In the formula, Ph represents phenyl.

[0104] As a specific example of a compound represented by the above formula (2), a pigment represented by the following formula (14) can be cited.

[0105] [Chemical Formula 19]

[0106]

[0107] The pigment represented by the above formula (14) is brown.

[0108] The pigment of this embodiment adsorbs onto metal hydroxyl groups on one hand, and does not react with the hydroxyl groups of water or alcohol on the other. Therefore, if the pigment of this embodiment comes into contact with a sample containing metal hydroxyl groups, the pigment adsorbs onto the metal hydroxyl groups. Then, the color of the pigment changes from its original color to the color of the shorter wavelength side.

[0109] There are no particular limitations on the method for contacting the pigment with the sample. Dried sample and / or dried pigment, or other substances, can be used. For example, the pigment and sample can be directly mixed to bring them into contact. Alternatively, dried pigment and dried sample can be mixed and brought into contact. Or, the sample can be added to a solution obtained by dissolving the pigment in an organic solvent to bring them into contact. From the viewpoint of achieving uniform contact, it is preferable to add the sample to the solution in which the pigment is dissolved in an organic solvent to bring the pigment into contact with the sample.

[0110] In this embodiment, the metal hydroxyl group is not particularly limited as long as it is the metal hydroxyl group adsorbed by the pigment of this embodiment; Si-OH is also included in this example. The metal of the metal hydroxyl group can be a typical metal element, a transition metal element, a lanthanide element, or an actinide element.

[0111] In this embodiment, the metal hydroxyl group can be any hydroxyl group bonded to a metal atom, and the bonded metal can take any form. For example, it can be a metal or a compound such as an oxide.

[0112] The pigment in this embodiment can react with the metal hydroxyl groups on the surface of metal oxide particles or the metal hydroxyl groups contained in the hydrolyzed silane coupling agent.

[0113] In the pigment represented by the above general formula (1), the five-coordinate M, i.e., M with a coordination number of 5, becomes six-coordinated through reaction with a metal hydroxyl group. This change in coordination number increases the electron density of M, verticalizes the R1 group, and thus decreases electron-withdrawing properties. Consequently, the LUMO energy level rises, resulting in a wider bandgap. That is, the five-coordinate M in the above general formula (1) becomes six-coordinated through reaction with a metal hydroxyl group, thereby shifting the absorption peak to a shorter wavelength. Therefore, if the above pigment adsorbs onto a metal hydroxyl group, the red pigment changes to an orange color, and the yellow pigment changes to a green color. By utilizing this color change of the above pigment, the amount of metal hydroxyl in the sample can be quantitatively evaluated.

[0114] In the pigments represented by the above general formula (2), the metal corresponding to M in the above general formula (1) is bismuth. For example... Figure 1As shown, bismuth is a group 15 element, therefore the isolated electron pair plays the same role as R1 in the above general formula (1). Therefore, as a complex structure, the above general formula (1) and the above general formula (2) form similar structures. That is, in the pigment represented by the above general formula (2), the color of the pigment changes through the five-coordinate of the four-coordinate organobismuth compound. The mechanism of its color change is the same as that of the pigment represented by the above general formula (1).

[0115] Furthermore, the amount of metal hydroxyl groups in the pigment of this embodiment is evaluated by the change in color, so the approximate amount of metal hydroxyl groups can also be evaluated visually.

[0116] The pigment of this embodiment has high stability and is easy to handle, and can be easily and accurately evaluated for whether the sample contains metal hydroxyl groups and the amount of metal hydroxyl groups contained therein.

[0117] The pigment of this embodiment has the above-described characteristics, and therefore has the potential for various applications.

[0118] For example, the pigment of this embodiment can quantitatively evaluate the amount of metal hydroxyl groups reacted by evaluating the amount of metal hydroxyl groups before and after the reaction in a reaction involving metal hydroxyl groups.

[0119] For example, when metal oxide particles are surface treated with a surface treatment agent, the amount of metal hydroxyl groups of the metal oxide particles before and after surface treatment can be evaluated by using the pigment of this embodiment, and the extent to which the surface of the metal oxide particles has been surface treated can be evaluated.

[0120] Furthermore, in the reaction of hydrolyzing the silane coupling agent, the extent of the hydrolysis reaction of the silane coupling agent can be evaluated by using the pigment of this embodiment to evaluate the amount of metal hydroxyl groups of the silane coupling agent before and after the hydrolysis reaction.

[0121] [Methods for manufacturing pigments]

[0122] A preferred example of a method for manufacturing pigments will be described.

[0123] (First Embodiment)

[0124] The method for manufacturing pigments according to this embodiment includes the following steps: a mixing step, mixing a ligand represented by the following general formula (4) or a ligand represented by the following general formula (5) and a metal source represented by the following general formula (6); and a coordination step, coordinating the metal source represented by the following general formula (6) with the ligand represented by the following general formula (4) or the ligand represented by the following general formula (5).

[0125] [Chemical Formula 20]

[0126]

[0127] (In formula (4), X is C or N, and Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group, respectively.)

[0128] [Chemical Formula 21]

[0129]

[0130] (In formula (5), X is C or N, Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group respectively, and R is alkyl or phenyl.)

[0131] [Chemical Formula 22]

[0132] R2—M=O (6)

[0133] (In formula (6), M is at least one selected from the group consisting of Sn, Ge and Bi, and R is an alkyl or phenyl group.)

[0134] The examples of Y1 and Y2 in equation (4) or (5) above can be the same as the examples of Y1 and Y2 in equation (1) or (2). The example of R in equation (5) above can be the same as the example of R2 in equation (3). The examples of the two Rs in equation (6) above can be the same as the examples of R1 in equation (1) or R2 in equation (3).

[0135] Both the ligands represented by general formula (4) and general formula (5) can be synthesized via the condensation reaction of the corresponding aldehyde and amine. Examples of the synthesis of the ligand represented by general formula (4) are shown below. Figure 2 The synthesis of ligands represented by the above general formula (5) is illustrated in the figure. Figure 3 middle.

[0136] In the manufacturing method of this embodiment, a ligand represented by general formula (4) or a ligand represented by general formula (5) and a metal source represented by general formula (6) are first prepared and then mixed.

[0137] There are no particular limitations on the method for coordinating the metal source to the ligand. For example, the ligand and the metal source can be mixed to allow them to react and coordinate.

[0138] From the viewpoint of obtaining homogeneous reactants, in the mixing process, it is preferable to perform a coordination process in which the ligand, the metal source, and an organic solvent, such as an organic solvent having 3 or more carbon atoms, are mixed, and the metal source is coordinated with the ligand in the mixture.

[0139] Examples of reactions between a ligand represented by the above general formula (4) or a ligand represented by the above general formula (5) and a metal source represented by the above general formula (6) are described in detail.

[0140] The method for manufacturing pigment according to this embodiment includes the following steps: a mixing step in which a ligand represented by the above general formula (4) or a ligand represented by the above general formula (5), a metal source represented by the above general formula (6), and an organic solvent with 3 or more carbon atoms are mixed in a container to form a mixture; and a coordination step in which the metal source represented by the above general formula (6) is coordinated with the ligand represented by the above general formula (4) or the ligand represented by the above general formula (5) by a dehydration reaction.

[0141] In the mixing process, mixing can be performed using any method chosen. For example, the mixing process can be carried out at room temperature. Stirring can also be performed using any method chosen.

[0142] Next, in the mixing process, the atmosphere in the container, such as air, can be replaced with another atmosphere. This other atmosphere can be, for example, a nitrogen atmosphere, an inert atmosphere, or a reduced-pressure atmosphere. From the viewpoint of reaction efficiency, a nitrogen atmosphere or an inert atmosphere is preferred.

[0143] There are no particular limitations on the method for carrying out the dehydration reaction; for example, heating the mixture can be used. If the mixture contains an organic solvent with three or more carbon atoms, it can be circulated. The dehydration reaction can be carried out while stirring.

[0144] In this embodiment, since a dehydration reaction is performed, there is no particular limitation on the type of organic solvent with 3 or more carbon atoms, as long as it is miscible with water. From the viewpoint of removing unreacted substances by filtration, the organic solvent with 3 or more carbon atoms is more preferably an organic solvent that does not dissolve the ligand and the metal source.

[0145] Examples of such organic solvents include methanol, ethanol, 1-propanol, acetone, tetrahydrofuran, acetonitrile, and pyridine. Among these, acetone is preferred from the viewpoint of ease of handling.

[0146] The amount of organic solvent added to the above mixture is not particularly limited, as long as it is sufficient to uniformly mix the ligand and the metal source. For example, the content of the organic solvent in the above mixture may be 0% by mass or more and 99% by mass or less, or 10% by mass or more and 99% by mass or less, or 30% by mass or more and 99% by mass or less, or 50% by mass or more and 99% by mass or less, or 70% by mass or more and 99% by mass or less, or 80% by mass or more and 99% by mass or less.

[0147] For the purpose of carrying out the dehydration reaction, the heating temperature of the above mixture is not particularly limited as long as the dehydration reaction is carried out. For example, it can be above 50°C and below 100°C, or above 60°C and below 90°C.

[0148] The heating time for the above mixture is not particularly limited, as long as the metal source coordinates with the ligand to produce the pigment. For example, it can be more than 1 hour and less than 24 hours, or more than 2 hours and less than 13 hours. Since the ability to produce the pigment can be confirmed by the color of the reactants, the heating time can be adjusted while observing the color of the reactants.

[0149] When the above mixture is heated to carry out a dehydration reaction, the pigment of this embodiment can be obtained by distilling the organic solvent from the mixture after the dehydration reaction. The method of distilling the organic solvent is not particularly limited; for example, simply drying the mixture is sufficient.

[0150] From the viewpoint of removing unreacted products, the mixture after the dehydration reaction can be filtered, and the organic solvent can be distilled from the filtrate to obtain the pigment of this embodiment.

[0151] The pigment manufacturing method of this embodiment can include a washing step after the dehydration reaction.

[0152] When it is desired to remove organic solvents with 3 or more carbon atoms used in the process of mixing the above-mentioned ligands and the above-mentioned metal sources by washing, hexane, toluene, chloroform, etc. can be preferably used as organic solvents for washing.

[0153] The cleaned pigment can be obtained by mixing the cleaning organic solvent with the pigment obtained above and distilling the organic solvent from the mixture.

[0154] The method of distilling organic solvents is not particularly limited as long as it can remove the organic solvent; for example, it can be removed by heating and drying or vacuum drying.

[0155] To remove unreacted substances, the above-mentioned cleaning organic solvent is mixed with the obtained pigment, the mixture is filtered, and the organic solvent is distilled from the filtrate, thereby removing the unreacted substances.

[0156] (Second Implementation)

[0157] The method for manufacturing pigment according to this embodiment includes: a mixing step, which mixes a ligand represented by the above general formula (4) or a ligand represented by the above general formula (5), a metal source represented by the following general formula (7), an alkali, and an organic solvent; and a coordination step, which coordinates the ligand represented by the above general formula (4) or the ligand represented by the above general formula (5) with the metal source represented by the following general formula (7).

[0158] [Chemical Formula 23]

[0159] R2-M-A2 (7)

[0160] (In formula (7), M is at least one selected from the group consisting of Sn, Ge and Bi, R is an alkyl or phenyl group, and A is a halogen group.)

[0161] The two R examples in equation (7) above can be the same as R1 in equation (1) or R2 in equation (3).

[0162] In the manufacturing method of this embodiment, a ligand represented by general formula (4) or a ligand represented by general formula (5) and a metal source represented by general formula (7) are first prepared and then mixed.

[0163] Examples of reactions between a ligand represented by the above general formula (4) or a ligand represented by the above general formula (5) and a metal source represented by the above general formula (7) are described in detail.

[0164] The method for manufacturing pigments according to this embodiment includes: a mixing step in which a ligand represented by the above general formula (4) or a ligand represented by the above general formula (5), a metal source represented by the above general formula (7), an alkali, and an organic solvent are added to a container and mixed to form a mixture; and a coordination step in which the metal source represented by the above general formula (7) is coordinated with the ligand represented by the above general formula (4) or the ligand represented by the above general formula (5) through a deoxygenation reaction.

[0165] In the mixing process, similar to the second embodiment, mixing can be performed by any chosen method.

[0166] Next, in the mixing process, the atmosphere in the container, such as air, can be replaced with another atmosphere. This other atmosphere can be, for example, a nitrogen atmosphere, an inert atmosphere, or a reduced-pressure atmosphere. From the viewpoint of reaction efficiency, a nitrogen atmosphere or an inert atmosphere is preferred.

[0167] There are no particular limitations on the method of deoxidation, as long as the base can capture the acid. The deoxidation reaction can be carried out while stirring. For example, simply stirring the mixture at room temperature is sufficient. Only the amount of base required for the deoxidation reaction needs to be used. Therefore, for example, the base only needs to be mixed in a quantity 2 to 20 times the molar amount of the metal source.

[0168] As a base, it is not particularly limited as long as it can capture acid, but tertiary amines are preferred, and tertiary alkylamines are more preferred.

[0169] As a base, for example, trimethylamine, triethylamine, diisopropylethylamine, tributylamine, trioctylamine, diazabicycloundecene, diazabicyclononene, pyridine, etc., can be used. Among these, triethylamine, which is easy to handle, is preferred.

[0170] There are no particular limitations on the type of organic solvent, as long as it does not hinder the deoxygenation reaction and does not dissolve the salts of the byproducts. For example, tetrahydrofuran can be preferably used as such an organic solvent.

[0171] The amount of organic solvent added is not particularly limited as long as it is sufficient to uniformly mix the ligand, the metal source, and the alkali. For example, the content of the organic solvent in the mixture may be 1% or more and 99% or less by mass, 10% or more and 99% or less by mass, 30% or more and 99% or less by mass, 50% or more and 99% or less by mass, 70% or more and 99% or less by mass, or 80% or more and 99% or less by mass.

[0172] The stirring time in the deoxidation process is not particularly limited as long as the aforementioned pigment is being produced. For example, it can be more than 1 hour and less than 24 hours, or more than 2 hours and less than 13 hours. Since the ability to produce the aforementioned pigment can be confirmed by observing the color of the reactants, the stirring time can be adjusted while observing the color of the reactants.

[0173] The pigment manufacturing method of this embodiment preferably includes a step of removing the byproduct, namely salt, after the deoxygenation reaction. The method for salt removal is not particularly limited; for example, filtration can be used.

[0174] The pigment of this embodiment can be obtained by distilling the organic solvent in the mixture after the deoxygenation reaction or the filtrate after filtering the mixture after the deoxygenation reaction.

[0175] The pigment manufacturing method of this embodiment may include a pigment separation step or a recrystallization step to improve the purity of the pigment after removing the by-product, i.e., salt.

[0176] According to the pigment manufacturing method of this embodiment, the pigment of the above embodiment can be obtained through the above steps.

[0177] [Solution]

[0178] The solution in this embodiment contains the pigments and organic solvents described in the above embodiments.

[0179] The solution in this embodiment contains the aforementioned pigment, so when the organic solvent is colorless and transparent, the coloring is a color of the same family as the pigment.

[0180] As for the organic solvent, there are no particular limitations as long as it can dissolve the aforementioned pigments. Examples include methanol, ethanol, propanol, butanol, pentanol, hexanol, toluene, tetrahydrofuran, xylene, hexane, chloroform, benzene, methyl ethyl ketone, methyl isobutyl ketone, acetone, propylene glycol monomethyl ether, ethyl acetate, and butyl acetate. Furthermore, from the viewpoint of solution concentration stability, a high boiling point is preferred for the organic solvent. In the solution of this embodiment, any organic solvent that readily dissolves the pigments can be appropriately selected.

[0181] The concentration of the pigment contained in the solution of this embodiment is not particularly limited as long as the molar number of the pigment is greater than the molar number of the metal hydroxyl groups contained in the evaluation sample.

[0182] When quantitatively evaluating the amount of metal hydroxyl groups, the amount of pigment can be sufficiently increased within the range of pigment dissolution in this embodiment. When simply performing a qualitative evaluation of the adsorption of metal hydroxyl groups by visual inspection, the concentration of the pigment can be adjusted to a concentration where color change is easily observed.

[0183] The concentration of the pigment contained in the solution of this embodiment can be, for example, 1 × 10⁻⁶. -10 Above 1 mol / L and below 1 mol / L.

[0184] When evaluating the amount of metal hydroxyl groups on the surface of metal oxide particles, the concentration of the aforementioned pigment contained in the solution of this embodiment is preferably 1 × 10⁻⁶. -3 mol / L or higher and 1×10 -7 Below mol / L, more preferably 1×10 -4 mol / L or higher and 1×10 -6 Below mol / L.

[0185] The solution in this embodiment may consist only of the pigment and the organic solvent described above, but may also contain other components besides the pigment and the organic solvent described above without impairing the effect of the present invention.

[0186] The pigment contained in the solution of this embodiment selectively adsorbs the metal hydroxyl groups contained in the sample and does not react with hydroxyl groups such as water or alcohol. Therefore, the amount of metal hydroxyl groups contained in the sample can be qualitatively and quantitatively evaluated without the influence of moisture. Moreover, since the pigment of this embodiment does not react with hydroxyl groups such as water or alcohol, the solution of this embodiment exhibits excellent stability even in the atmosphere and is easy to store.

[0187] When an evaluation sample is added to the solution of this embodiment, there are cases where the sample precipitates in the solution and cases where it does not precipitate.

[0188] When an evaluation sample is added to the solution of this embodiment, and the sample precipitates in the solution, the amount of pigment contained in the solution decreases by adsorption onto the precipitated sample. Therefore, the color of the solution lightens. Then, the pigment adsorbed onto the sample changes from its original color to the color of the shorter wavelength side.

[0189] Therefore, to evaluate the amount of metallic hydroxyl groups contained in a sample, it can be evaluated based on the color of the pigment before and after adsorption, or based on the color of the solution before and after the addition of the sample. Alternatively, both methods can be used.

[0190] When an evaluation sample is added to the solution of this embodiment, and the sample does not precipitate in the solution but mixes uniformly, the color of the pigment dissolved in the solution changes. Therefore, the color of the solution changes to the color of the shorter wavelength side.

[0191] Therefore, to evaluate the amount of metallic hydroxyl groups contained in a sample, it can be evaluated based on the color of the solution before and after the addition of the sample. The evaluation can be performed by any method, for example, as described later, by visual observation or measurement using a device, by inferring differences based on observations, or by performing arithmetic calculations using these results as needed.

[0192] [Methods for evaluating the amount of metallic hydroxyl groups]

[0193] A preferred example of a method for evaluating the amount of metal hydroxyl groups is described.

[0194] (First Embodiment)

[0195] The method for evaluating the amount of metallic hydroxyl groups in this embodiment includes: evaluating the color x of the above solution; adding a sample to the above solution to prepare a mixture A, and evaluating the color a of the mixture A; and evaluating the difference between the color x and the color a and evaluating the amount of metallic hydroxyl groups a of the sample.

[0196] The evaluation of colors x and a can be done visually or by measuring color-related physical quantities such as absorbance. Specifically, examples include the calculation of the amount of metal hydroxyl groups using absorbance.

[0197] Furthermore, in this invention, the sample can be any sample, as long as evaluation can be performed. For example, the sample can be composed of powder or particles, and the evaluation can also assess the amount of metallic hydroxyl groups present on the surface of the powder or particles. Depending on the need, the sample can be a solid substance, or it can be a liquid or fluid sample. Moreover, in this invention, evaluation can refer to measurement, observation, comparison, or calculation, etc.

[0198] An example of a method for accurately evaluating the amount of metallic hydroxyl groups 'a' on the surface of a sample by absorbance will be described. To simplify the explanation, an evaluation method using metal oxide particles as the sample and a red pigment represented by the above general formula (8) that absorbs light at 545 nm will be described.

[0199] Furthermore, the amount of pigment in the above solution is defined as n (mol), and the amount of metal oxide particles added to the above solution is defined as h (g). The specific surface area of ​​the metal oxide particles is defined as S (m²). 2 / g).

[0200] The absorbance of the above solution at 545 nm was measured using an absorbance meter, and the value of its absorbance was set as x (color x).

[0201] Metal oxide particles are added to the above solution and mixed to prepare mixture A. From the viewpoint of improving the reaction between the pigment and the metal hydroxyl group, heating is preferred during mixing. The heating temperature is preferably a temperature at which the organic solvent in the solution does not volatilize; for example, mixing is preferably carried out at 40°C to 70°C. The heating temperature only needs to be adjusted to be below the boiling point of the organic solvent.

[0202] The mixing time should continue until the color change of the solution disappears; for example, mixing can be carried out for 1 to 12 hours.

[0203] The amount of metal oxide particles added to the above solution is not particularly limited, as long as it results in a color change that is easily understood. For example, the concentration of the pigment can be 1 × 10⁻⁶. -3 mol / L~1×10 -7 Add 1 mg to 10 mg of the sample to 3 mL to 10 mL of the above solution with a concentration of mol / L.

[0204] When evaluating by the color of the solution, if metal oxide particles are precipitated in mixture A, it is preferable to remove the adsorbed pigment metal oxide particles from mixture A by centrifugation or filtration, and then evaluate the absorbance of mixture A.

[0205] The absorbance of the above mixture A at 545 nm was measured using an absorbance meter, and the value of its absorbance was set as a (color a).

[0206] The following is a detailed explanation of an example of a method for evaluating (visual comparison or calculation, etc.) the amount of metal hydroxyl groups a of the above-mentioned sample based on the difference between color x and color a. Furthermore, regarding the amount of metal hydroxyl groups a, it is possible to use visual observation, absorbance a1, reduction rate a2, adsorption amount a3 (mol / g), and adsorption amount a4 (mol / m²) as described below. 2 Adsorption capacity a4' (cells / m) 2 ), value a5 (pieces / g or pieces / m 2 The preferred methods for evaluation include using [various methods].

[0207] (Calculation 1 using evaluation results)

[0208] The absorbance of the above mixture A at 545 nm was measured, and its absorbance value was set as a (a1).

[0209] The rate of decrease in absorbance a2 is calculated using the following formula (21).

[0210] The rate of decrease in absorbance of mixture A is a2 = (x - a1) / x (21)

[0211] Since the decrease in absorbance is the result of the reaction between the metal hydroxyl groups and the pigment, it can be considered that the rate of decrease in absorbance a2 = the adsorption rate of the pigment on the metal oxide particles.

[0212] (Calculation 2 using evaluation results)

[0213] The amount of pigment adsorbed per 1g of metal oxide particles, a3 (mol / g), can be calculated using the following formula (22).

[0214] The amount of pigment adsorbed per 1g of metal oxide particles, a3 (mol / g), = adsorption rate of pigment on metal oxide particles × amount of pigment (mol) / mass of metal oxide particles (g) = a2 × n (mol) / h (g) (22)

[0215] The above pigments react with metal hydroxyl groups in a 1:1 molar ratio, so the value calculated by the above formula (22) represents the amount of metal hydroxyl groups contained in 1g of metal oxide particles.

[0216] (Calculation 3 using evaluation results)

[0217] To eliminate the influence of the size of the metal oxide particles, the adsorption amount a3 of the pigment can be divided by the specific surface area S of the metal oxide particles. That is, in the following formula (23), the adsorption amount a3 of each metal oxide particle can be calculated. 2 The adsorption capacity of the pigment a4 (mol / m 2 ). 1m per metal oxide particle2 The adsorption capacity of the pigment, a4, represents the amount of pigment adsorbed per 1m of metal oxide particles. 2 The amount of metallic hydroxyl groups contained therein.

[0218] 1m per metal oxide particle 2 The adsorption capacity of the pigment a4 (mol / m 2 )=a3(mol / g) / S(m 2 / g)(23)

[0219] Furthermore, if necessary, the adsorption amount (units / m²) can also be obtained by dividing the amount of metal hydroxyl groups (units / g) converted from the number obtained by calculation 4 below using the result of calculation 2 by the specific surface area S of the metal oxide particles. 2 ).

[0220] (Calculation 4 using evaluation results)

[0221] When you want to determine the amount of metallic hydroxyl groups in terms of quantity rather than moles, you can use Avogadro's constant (6.02 × 10⁻⁶). 23 The value a5 (pieces / g or pieces / m) is obtained by multiplying the product of the above calculation result (22) or (23). 2 ).

[0222] In addition, when performing calculations 3 and 4, either calculation can be performed first.

[0223] According to the method for evaluating the amount of metallic hydroxyl groups in this embodiment, the amount of pigment adsorbed on the sample can be determined based on the change in color of the solution. Therefore, the amount of metallic hydroxyl groups contained in the sample can be evaluated qualitatively and quantitatively.

[0224] (Second Implementation)

[0225] The method for evaluating the amount of metallic hydroxyl groups in this embodiment includes the following steps: adding sample 1 to the above solution to prepare a mixture A, and evaluating the color a of the mixture A; adding sample 2 to the above solution to prepare a mixture B, and evaluating the color b of the mixture B; and evaluating the difference between the color a and the color b, and evaluating the difference between the amount of metallic hydroxyl groups in sample 1 and the amount of metallic hydroxyl groups in sample 2.

[0226] To evaluate the differences, comparisons can be made based on visual observation, measurement, and calculations of the measurement results.

[0227] Similar to the first embodiment, the samples (sample 1, sample 2) use metal oxide particles, and the pigment uses a pigment represented by the above general formula (8). Sample 1 and sample 2 can be selected arbitrarily as needed. For example, at least one of the following can be the same or different: material, composition, characteristics, manufacturing conditions, processing conditions, physical properties, size, shape, and / or storage conditions of sample 1 and sample 2. These may be unknown at the time of measurement. Sample 1 and sample 2 can be the same or different types of samples, but are preferably the same type of samples.

[0228] In the same manner as in the first embodiment, metal oxide particles, serving as sample 1, were added to the above solution and mixed to prepare mixture A. Furthermore, in the same manner as in the first embodiment, metal oxide particles, serving as sample 2, were added to the above solution and mixed to prepare mixture B.

[0229] The absorbance of the above mixture A at 545 nm was measured using an absorbance meter, and the value of its absorbance was designated as a (color a). Furthermore, the absorbance of the above mixture B at 545 nm was measured using an absorbance meter, and the value of its absorbance was designated as b (color b).

[0230] By evaluating the difference between color a and color b, for example by comparing these values, the difference in the amount of metallic hydroxyl groups a in sample 1 and b in sample 2 is evaluated, that is, whether there is a difference or the degree of difference is determined. The method for evaluating the amount of metallic hydroxyl groups in this embodiment only measures color a and color b. Therefore, the difference in the amount of metallic hydroxyl groups a in sample 1 and b in sample 2 can be easily and qualitatively evaluated, for example, by visual inspection.

[0231] (Third Implementation)

[0232] The method for evaluating the amount of metallic hydroxyl groups in this embodiment includes the following steps: evaluating the color x of the above solution; adding sample 1 to the above solution to prepare a mixture A, and evaluating the color a1 of the mixture A; adding sample 2 to the above solution to prepare a mixture B, and evaluating the color b1 of the mixture B; evaluating the difference between the color x and the color a1, and evaluating the amount of metallic hydroxyl groups a(a2) of the sample 1; evaluating the difference between the color x and the color b1, and evaluating the amount of metallic hydroxyl groups b(b2) of the sample 2; and evaluating the difference between the amount of metallic hydroxyl groups a(a2) and the amount of metallic hydroxyl groups b(b2).

[0233] Similar to the first embodiment, the samples (sample 1, sample 2) use metal oxide particles, and the pigment uses a pigment represented by the above general formula (8). Furthermore, the examples of sample 1 and sample 2 may be the same as those described in the first or second embodiment. In order to evaluate the differences, comparisons can be made based on visual observation, measurement, or calculations of the measurement results.

[0234] In the same manner as in the first embodiment, metal oxide particles, serving as sample 1, were added to the above solution and mixed to prepare mixture A. Furthermore, in the same manner as in the first embodiment, metal oxide particles, serving as sample 2, were added to the above solution and mixed to prepare mixture B.

[0235] In this embodiment, similarly to the first embodiment, the amount of metallic hydroxyl groups a(a2) of sample 1 is obtained by evaluating the difference between color x and color a1, and the amount of pigment adsorbed on sample 1, i.e., the amount of hydroxyl groups contained in the metal oxide particles of sample 1, can be determined. Furthermore, in the same manner as the first embodiment, the amount of metallic hydroxyl groups b(b2) of sample 2 is obtained by evaluating the difference between color x and color b1, and the amount of pigment adsorbed on sample 2, i.e., the amount of hydroxyl groups contained in the metal oxide particles of sample 2, can be determined. In this embodiment, calculations 1 to 4 described in the first embodiment are preferably used. Therefore, the amount of metallic hydroxyl groups contained in sample 1 and sample 2 can be evaluated qualitatively and quantitatively. That is, the difference between the amount of metallic hydroxyl groups a(a2) of sample 1 and the amount of metallic hydroxyl groups b(b2) of sample 2 can be evaluated.

[0236] [Evaluation method for metal hydroxyl group treatment rate]

[0237] The method for evaluating the metal hydroxyl removal rate in this embodiment is as follows: when surface-treating metal oxide particles with a surface treatment agent, the removal rate of metal hydroxyl groups on the surface of the metal oxide particles is evaluated. In the evaluation method of this embodiment, the calculation described in the first embodiment above can also be preferably used. The evaluation method of this embodiment includes the following steps: measuring the absorbance x of the above solution; adding surface-treated metal oxide particles 1 to the above solution to prepare a mixture A, and measuring the absorbance a1 of the mixture A; adding surface-treated metal oxide particles 2 to the above solution to prepare a mixture B, and measuring the absorbance b1 of the mixture B; calculating the reduction rate a2 of the absorbance of the mixture A by subtracting the absorbance a1 from the absorbance x and dividing by the absorbance x ((x-a1) / x); calculating the reduction rate b2 of the absorbance of the mixture B by subtracting the absorbance b1 from the absorbance x and dividing by the absorbance x ((x-b1) / x); and multiplying the number of moles of the pigment contained in the mixture A by the reduction rate a2 of the absorbance and dividing by the number of metal oxide particles. 1. The amount of pigment adsorbed on the metal oxide particles 1 is calculated as a3 (mol / g) relative to the amount of solution A added (a2 × number of moles of pigment contained in mixture A / amount of metal oxide particles 1 added relative to solution A); the amount of pigment adsorbed on the metal oxide particles 2 is calculated as b3 (mol / g) by multiplying the number of moles of pigment contained in mixture B by the rate of decrease in absorbance b2 and dividing by the amount of metal oxide particles 2 added relative to solution B (b2 × number of moles of pigment contained in mixture B / amount of metal oxide particles 2 added relative to solution B); and the metal hydroxyl treatment rate based on the surface treatment is calculated by subtracting the value obtained by multiplying the adsorption amount b3 by the adsorption amount a3 by 100 (100 - (b3 / a3 × 100)).

[0238] An example of the method for evaluating the metal hydroxyl treatment rate in this embodiment will be described in detail.

[0239] Prepare metal oxide particles 1 (sample 1) before surface treatment. Also prepare metal oxide particles 2 (sample 2) after surface treatment of metal oxide particles 1 with a silane coupling agent, etc. Prepare the above-mentioned solution as well.

[0240] Metal oxide particles 1 were added to the above solution and stirred to prepare mixture A1. Metal oxide particles 1 were removed from mixture A1 by centrifugation to obtain evaluation mixture A2.

[0241] Furthermore, metal oxide particles 2 were added to the above solution and stirred to prepare mixture B1. Metal oxide particles 2 were removed from mixture B1 by centrifugation to obtain evaluation mixture B2.

[0242] The absorbance of the above solution and mixtures A2 and B2 at 545 nm was measured.

[0243] The reduction rate of absorbance of mixture A2 and mixture B2 is calculated using the following formula (equivalent to calculation 1).

[0244] The decrease rate of absorbance of mixture A2, a2 ​​= adsorption rate of pigment on metal oxide particles 1 contained in mixture A2 = (absorbance of the above solution - absorbance of mixture A2) / absorbance of the above solution

[0245] The decrease rate of absorbance of mixture B2, b2 = adsorption rate of pigment on metal oxide particles 2 contained in mixture B2 = (absorbance of the above solution - absorbance of mixture B2) / absorbance of the above solution

[0246] The decrease in absorbance of red pigment at 545nm indicates pigment adsorption, and therefore can be converted into the absorption reduction rate = pigment adsorption rate.

[0247] The adsorption amount of pigment per 1g of particles in mixture A and the adsorption amount of pigment per 1g of particles in mixture B are calculated using the following formulas (equivalent to calculation 2).

[0248] The amount of pigment adsorbed on metal oxide particles 1, a3 (mol / g), = the adsorption rate of pigment on metal oxide particles 1 (the decrease rate of absorbance mentioned above, a2) × pigment amount (mol) / mass of metal oxide particles 1 (g).

[0249] The amount of pigment adsorbed on metal oxide particles 2, b3 (mol / g), = the adsorption rate of pigment on metal oxide particles 2 (the decrease rate of absorbance mentioned above, b2) × pigment amount (mol) / mass of metal oxide particles 2 (g).

[0250] Next, as shown in the following formula, the amount of pigment adsorbed (mol / g) can also be multiplied by Avogadro's constant (6.02 × 10⁻⁶). 23 (pcs / mol), converted to the amount of pigment adsorbed (pcs / g) (corresponding to calculation 4).

[0251] The amount of pigment adsorbed by metal oxide particles 1 (particles / g) = the amount of pigment adsorbed by metal oxide particles 1 (mol / g) × Avogadro's constant

[0252] The amount of pigment adsorbed by metal oxide particles 2 (particles / g) = the amount of pigment adsorbed by metal oxide particles 2 (mol / g) × Avogadro's constant

[0253] In this embodiment, the pigment reacts with the metal hydroxyl groups present on the surface of the metal oxide particles in a 1:1 ratio. Therefore, the amount of pigment adsorbed (particles / g) refers to the amount of metal hydroxyl groups present on the surface of metal oxide particle 1 or metal oxide particle 2, that is, the amount of untreated metal hydroxyl groups (particles / g) without surface treatment.

[0254] Therefore, the amount of untreated metal hydroxyl groups (cells / g) of metal oxide particles 1 = the amount of pigment adsorbed by metal oxide particles 1 (cells / g).

[0255] Furthermore, the amount of untreated metal hydroxyl groups (cells / g) of metal oxide particles 2 is equal to the amount of pigment adsorbed by metal oxide particles 2 (cells / g).

[0256] Next, as shown in the following formula, the amount of untreated metal hydroxyl groups per unit area of ​​the metal oxide particles (number / m²) can be calculated by dividing the amount of untreated metal hydroxyl groups (number / g) by the specific surface area of ​​the metal oxide particles. 2 (Corresponds to calculation 3).

[0257] The amount of untreated metal hydroxyl groups per unit area of ​​metal oxide particle 1 (number / m²) 2 = Amount of untreated metal hydroxyl groups in metal oxide particle 1 (number / g) / Specific surface area of ​​metal oxide particle 1 (m²) 2 / g)

[0258] The amount of untreated metal hydroxyl groups per unit area of ​​metal oxide particles 2 (number / m) 2 = Amount of untreated metal hydroxyl groups in metal oxide particles 2 (number / g) / Specific surface area of ​​metal oxide particles 2 before surface treatment (m²) 2 / g)

[0259] After obtaining the amount of untreated metal hydroxyl groups on metal oxide particles 1 and 2, the treatment rate of metal hydroxyl groups present on the surface of the metal oxide particles is then calculated (equivalent to calculation 5) by the following calculation.

[0260] Treatment rate of metal hydroxyl groups in metal oxide particles 1 (%) = 100 - (Amount of untreated metal hydroxyl groups in metal oxide particles 1 (number / m)) 2 The amount of untreated metal hydroxyl groups in metal oxide particles 1 (number / m) 2 (×100)

[0261] Treatment rate of metal hydroxyl groups in metal oxide particles 2 (%) = 100 - (Amount of untreated metal hydroxyl groups in metal oxide particles 2 (number / m)) 2 The amount of untreated metal hydroxyl groups in metal oxide particles 1 (number / m) 2 (×100)

[0262] The higher the treatment rate of metal hydroxyl groups, the more the metal hydroxyl groups existing on the surface of the metal oxide particles are treated and hydrophobized.

[0263] When surface-treating metal oxide particles with a surface treatment agent, firstly, the amount of untreated metal hydroxyl groups on the metal oxide particles before surface treatment is calculated and used as a baseline value. Next, the amount of untreated metal hydroxyl groups on the metal oxide particles after surface treatment is calculated, divided by the baseline value, and multiplied by 100. This allows calculation of the percentage (%) of metal hydroxyl groups remaining on the surface of the metal oxide particles. Therefore, by subtracting the percentage (%) of the remaining hydroxyl groups from 100, it is possible to calculate whether the metal hydroxyl groups present on the surface of the metal oxide particles before surface treatment were treated, i.e., the treatment rate of metal hydroxyl groups before and after surface treatment.

[0264] Therefore, by using the pigment of the present invention, the residual rate of metal hydroxyl groups remaining on the surface of metal oxide particles can also be evaluated by the method of the amount of untreated metal hydroxyl groups of surface-treated metal oxide particles 2 / the amount of untreated metal hydroxyl groups of metal oxide particles 1 before surface treatment × 100.

[0265] Before surface treatment, the metal oxide particles are in a state where all untreated metal hydroxyl groups remain, therefore the metal hydroxyl group removal rate (%) is 0. On the other hand, when all the metal hydroxyl groups present on the surface of the metal oxide particles are surface treated, the metal hydroxyl group removal rate (%) becomes 100.

[0266] The amount of untreated metal hydroxyl groups is shown above using the value calculated as 3 as an example, but it can also be calculated in any of the units 2, 3, and 4.

[0267] According to the evaluation method for metal hydroxyl treatment rate of this embodiment, it is possible to quantitatively evaluate the extent to which the metal hydroxyl groups on the surface of metal oxide particles have been treated by the surface treatment agent.

[0268] Example

[0269] The present invention will be described in more detail below through embodiments and comparative examples, but the present invention is not limited to the following embodiments.

[0270] [Example 1]

[0271] "The Production of Red Pigment"

[0272] A mixture was prepared by mixing 1 mmol of 2,2'-dihydroxyazobenzene as a ligand, 1 mmol of diphenyltin oxide (IV) as a metal source, and 30 mL of acetone.

[0273] Next, the mixture was stirred at 70°C for 3 hours to carry out a dehydration reaction, allowing the metal source to coordinate with the ligand.

[0274] The mixture after the dehydration reaction was filtered, the filtrate was recovered, and the solvent was distilled from the filtrate, thereby obtaining the pigment of Example 1 represented by the above formula (8). The color of the obtained pigment was visually confirmed, and the pigment was red. The obtained pigment was then... 1 The H-NMR measurement results are shown in Figure 4 .

[0275] The red pigment obtained in Example 1 was mixed with water, but the color of the red pigment did not change. This confirms that the red pigment of Example 1 does not react with the hydroxyl groups of water.

[0276] The red pigment obtained in Example 1 was mixed with ethanol, but the color of the red pigment did not change. This confirms that the red pigment of Example 1 does not react with the hydroxyl groups of the alcohol.

[0277] The addition of the red pigment of Example 1 to commercially available activated alumina particles resulted in a yellow color change. This is believed to be due to the reaction of the red pigment of Example 1 with the hydroxyl groups present on the surface of the activated alumina particles, causing the Sn group of the red pigment of Example 1 to change from a five-coordinate state to a six-coordinate state, thus resulting in the color change. The reaction mechanism of the red pigment of Example 1 with the hydroxyl groups present on the surface of the activated alumina particles is shown below. Figure 5 .

[0278] Based on these evaluation results, it was confirmed that the red pigment in Example 1 does not adsorb onto the hydroxyl groups of water or alcohol, but selectively adsorbs onto the metal hydroxyl groups.

[0279] [Example 2]

[0280] "The Production of Yellow Pigment"

[0281] The pigment of Example 2, represented by the above formula (9), was obtained in the same manner as in Example 1, except that σ-salicylaminophenol was used instead of 2,2'-dihydroxyazobenzene. Visual confirmation of the obtained pigment's color revealed it to be a deep yellow.

[0282] The yellow pigment obtained in Example 2 was mixed with water, but the color of the yellow pigment did not change. This confirms that the yellow pigment of Example 2 does not react with the hydroxyl groups of water.

[0283] The yellow pigment obtained in Example 2 was mixed with ethanol, but the color of the yellow pigment did not change. This confirms that the yellow pigment of Example 2 does not react with the hydroxyl groups of the alcohol.

[0284] The addition of the yellow pigment from Example 2 to commercially available activated alumina particles confirmed that the yellow pigment turned pale yellow. This is believed to be due to the reaction between the yellow pigment from Example 2 and the hydroxyl groups present on the surface of the activated alumina particles, causing the Sn group of the yellow pigment from Example 2 to change from a five-coordinate state to a six-coordinate state, resulting in the color change. The reaction mechanism of the yellow pigment from Example 2 with the hydroxyl groups present on the surface of the activated alumina particles is shown below. Figure 6 middle.

[0285] Based on these evaluation results, it was confirmed that the yellow pigment of Example 2 does not adsorb onto the hydroxyl groups of water or alcohol, but selectively adsorbs onto the metal hydroxyl groups.

[0286] [Example 3]

[0287] The pigment of Example 3, represented by the above formula (10), was obtained in the same manner as in Example 1, except that 4,4'-dibromo-2,2'-dihydroxyazobenzene and dioctyltin oxide (IV) were used instead of 2,2'-dihydroxyazobenzene and diphenyltin oxide (IV). Visual confirmation of the obtained pigment's color revealed it to be a dark reddish-purple.

[0288] [Example 4]

[0289] "The Production of Yellow Pigment"

[0290] The pigment of Example 4, represented by the above formula (11), was obtained in the same manner as in Example 1, except that 4,4'-dibromo-3,3'-difluoro-2,2'-dihydroxyazobenzene was used instead of 2,2'-dihydroxyazobenzene. Visual confirmation of the obtained pigment's color revealed it to be a deep yellow.

[0291] [Example 5]

[0292] "The Production of Dark Purple Pigment"

[0293] A mixture was prepared by mixing 1 mmol of 4,4'-dibromo-2,2'-dihydroxyazobenzene as a ligand, 1 mmol of dichlorodiisopropylgermanium as a metal source, 4 mL of tetrahydrofuran, and 0.3 mL of triethylamine.

[0294] Next, the mixture was stirred at room temperature for 6 hours to carry out a deoxygenation reaction, allowing the metal source to coordinate with the ligand.

[0295] Next, the salt of the byproducts was removed by filtration, the filtrate was recovered, and the solvent was distilled from the filtrate, thereby obtaining the dark purple pigment of Example 5 represented by the above formula (12).

[0296] [Example 6]

[0297] "The Production of Dark Purple Pigment"

[0298] A mixture was prepared by mixing 0.1 mmol of 4,4'-dibromo-2,2'-dihydroxyazobenzene as a ligand, 0.1 mmol of dichlorodiphenylgermanium as a metal source, 20 mL of tetrahydrofuran, and 0.09 mL of triethylamine.

[0299] Next, the mixture was stirred at room temperature for 6 hours to carry out a deoxygenation reaction, allowing the metal source to coordinate with the ligand.

[0300] Next, the salt of the byproducts was removed by filtration, the filtrate was recovered, and the solvent was distilled from the filtrate, thereby obtaining the dark purple pigment of Example 6 represented by the above formula (13).

[0301] [Example 7]

[0302] "The Production of Brown Pigment"

[0303] A mixture of 0.5 mol triphenylbismuth, 1 mol trichlorobismuth, and 50 mL diethyl ether was prepared. The mixture was stirred at room temperature for 1 hour to prepare dichlorophenylbismuth as a metal source, resulting in a preparation solution containing dichlorophenylbismuth.

[0304] A mixture was prepared by mixing 0.7 mol of 4,4'-dibromo-2,2'-dihydroxyazobenzene (as ligand), 5 mL of triethylamine, and 20 mL of tetrahydrofuran. This mixture was then added to a preparative solution containing the obtained dichlorophenylbismuth, and the mixture was stirred at room temperature for 24 hours to carry out a deoxygenation reaction, thereby coordinating the metal source with the ligand.

[0305] Next, the salt of the byproducts was removed by filtration, the filtrate was recovered, and the solvent was distilled from the filtrate, thereby obtaining the brown pigment of Example 7 represented by the above formula (14).

[0306] Evaluation of the adsorption capacity of pigments for metal hydroxyl groups in Examples 1 to 7

[0307] The pigments obtained in Examples 1 through 7 were dissolved in 0.1 g of toluene to obtain solutions. The color of the solutions was the same as the color of the pigments themselves. A specific surface area of ​​30 m² was added to the solutions. 2 / g of zinc oxide particles (manufactured by Sumitomo Osaka Cement Co., Ltd.) were used. As a result, it was observed that the pigment was adsorbed on the surface of the zinc oxide particles, and the color of the solution became lighter.

[0308] That is, it was confirmed that the pigments obtained in Examples 1 to 7 selectively adsorbed onto the surface of zinc oxide particles by metallic hydroxyl groups.

[0309] [Example 8]

[0310] Preparation of a solution containing red pigment

[0311] By dissolving 250 nmol (0.12 mg) of the red pigment from Example 1 in toluene to make a volume of 5 mL, 5 × 10⁻⁶ ppm of the pigment from Example 8 was obtained. -5 A solution of mol / L. The color of the obtained solution was visually confirmed; it was purplish-red.

[0312] Evaluation of the stability of the pigments in Examples 1 to 7 and the solution in Example 8

[0313] The pigments from Examples 1 to 7 and the solution from Example 8 were placed in spiral tubes and left at room temperature (25°C) for one month.

[0314] Before and one month after placement, the color of the pigments in Examples 1 to 7 and the color of the solution in Example 8 were visually confirmed, and the color of the pigments did not change.

[0315] Through this evaluation, it was confirmed that the pigments of Examples 1 to 7 are stable compounds that do not react with moisture in the atmosphere, and that the color of the pigments does not change even in the solution state, indicating that they are stable compounds that selectively adsorb onto metal hydroxyl groups.

[0316] [Example 9]

[0317] Qualitative evaluation of the amount of metal hydroxyl groups

[0318] Untreated zinc oxide particles (hereinafter referred to as "zinc oxide particles 1") were prepared.

[0319] Zinc oxide particles 1 were surface-treated with octyltriethoxysilane to prepare surface-treated zinc oxide particles (hereinafter referred to as "surface-treated zinc oxide particles 2"). The content of octyltriethoxysilane relative to the total amount (100% by mass) of surface-treated zinc oxide particles 2 was 6% by mass.

[0320] 3 mg of zinc oxide particles 1 were added to the solution of Example 8, and the mixture was stirred at 60°C for 4 hours to prepare mixture A. In mixture A, the red pigment was adsorbed onto the zinc oxide particles and precipitated, thus the solution turned light orange.

[0321] Furthermore, 3 mg of surface-treated zinc oxide particles 2 were added to the solution of Example 8, and the mixture was stirred at 60°C for 4 hours to prepare mixture B. In mixture B, the zinc oxide particles underwent surface treatment, resulting in a reduction of the metallic hydroxyl groups on the particle surface, thus the red pigment was hardly adsorbed. Therefore, the color of mixture B was a slightly lighter purplish-red compared to the solution of Example 8.

[0322] By comparing the colors of mixture A and mixture B, it was confirmed that the metallic hydroxyl groups on the surface of zinc oxide particles 1 before surface treatment were visually observed to have been surface-treated with octyltriethoxysilane, and a qualitative evaluation was performed.

[0323] [Example 10]

[0324] Evaluation of the treatment rate of metal hydroxyl groups

[0325] Prepared with a specific surface area of ​​35m² 2 / g of zinc oxide particles (hereinafter referred to as "zinc oxide particles 1").

[0326] Zinc oxide particles 1 were surface-treated with octyltriethoxysilane to prepare surface-treated zinc oxide particles (hereinafter referred to as "surface-treated zinc oxide particles 2"). The content of octyltriethoxysilane was 1% by mass relative to the total amount (100% by mass) of surface-treated zinc oxide particles 2.

[0327] 4.1 mg of zinc oxide particles 1 was added to the solution (solution C) of Example 8, and the mixture was stirred at 60°C for 4 hours to prepare mixture A1. Zinc oxide particles 1 were removed from mixture A1 by centrifugation to obtain evaluation mixture A2.

[0328] Furthermore, 4.0 mg of surface-treated zinc oxide particles 2 were added to the solution (solution C) of Example 8, and the mixture was stirred at 60°C for 4 hours to prepare mixture B1. The surface-treated zinc oxide particles 2 were removed from mixture B1 by centrifugation to obtain evaluation mixture B2.

[0329] The absorbance of mixtures A2 and B2 at 545 nm was measured using a spectrophotometer (model: V-770, manufactured by JASCO Corporation). The results showed that the absorbance of mixture A2 was 0.403 and that of mixture B2 was 0.444. Furthermore, the absorbance of the solution (solution C) in Example 8 was 0.74.

[0330] The reduction rate of absorbance of mixture A2 and mixture B2 was calculated respectively.

[0331] The decrease rate of absorbance of mixture A2 = adsorption rate of pigment on zinc oxide particles 1 contained in mixture A2 = (absorbance of solution C - absorbance of mixture A2) / absorbance of solution C = 0.455

[0332] The decrease rate of absorbance of mixture B2 = adsorption rate of pigment on surface-treated zinc oxide particles 2 contained in mixture B2 = (absorbance of solution C - absorbance of mixture B2) / absorbance of solution C = 0.400

[0333] The decrease in absorbance of red pigment at 545nm indicates pigment adsorption, and therefore can be converted into the absorption reduction rate = pigment adsorption rate.

[0334] The amount of pigment adsorbed per 1g of particles contained in mixture A was calculated (mol / g).

[0335] The amount of pigment adsorbed on zinc oxide particle 1 (mol / g) = adsorption rate of pigment on zinc oxide particle 1 × amount of pigment (mol) / mass of zinc oxide particle 1 (g) = 0.455 × 250 × 10 -9 mol / 4.1×10 -3 g = 2.77 × 10 -5 mol / g

[0336] The amount of pigment adsorbed on the surface-treated zinc oxide particles 2 (mol / g) = adsorption rate of pigment on the surface-treated zinc oxide particles 2 × pigment amount (mol) / mass of surface-treated zinc oxide particles 2 (g) = 0.400 × 250 × 10 -9 mol / 4.0×10 -3 g = 2.50 × 10 -5 mol / g

[0337] Next, the amount of pigment adsorbed (mol / g) was multiplied by Avogadro's constant (6.02 × 10⁻⁶). 23 (pcs / mol), which is converted into the amount of pigment adsorbed (pcs / g).

[0338] The amount of pigment adsorbed by zinc oxide particle 1 (particles / g) = the amount of pigment adsorbed by zinc oxide particle 1 (mol / g) × Avogadro's constant = 2.77 × 10⁻⁶ -5 ×6.02×10 23 pcs / mol = 1.67 × 10 19 (pieces / g)

[0339] The amount of pigment adsorbed by surface-treated zinc oxide particles 2 (particles / g) = the amount of pigment adsorbed by surface-treated zinc oxide particles 2 (mol / g) × Avogadro's constant = 2.50 × 10 -5 ×6.02×10 23(units / mol) = 1.51 × 10 19 (pieces / g)

[0340] like Figure 5 As shown, the red pigment in Example 1 reacts with the metallic hydroxyl groups present on the surface of the zinc oxide particles in a 1:1 ratio. Therefore, the amount of pigment adsorbed (cells / g) refers to the amount of metallic hydroxyl groups present on the surface of zinc oxide particle 1 or surface-treated zinc oxide particle 2, i.e., the amount of untreated metallic hydroxyl groups (cells / g).

[0341] Therefore, the amount of untreated metal hydroxyl groups (cells / g) of zinc oxide particles 1 = the amount of pigment adsorbed by zinc oxide particles 1 (cells / g) = 1.67 × 10⁻⁶ 19 (pieces / g)

[0342] Furthermore, the amount of untreated metallic hydroxyl groups (cells / g) in surface-treated zinc oxide particles 2 = the amount of pigment adsorbed by surface-treated zinc oxide particles 2 (cells / g) = 1.51 × 10⁻⁶ 19 (pieces / g)

[0343] Next, by dividing the amount of untreated metal hydroxyl groups (cells / g) by the specific surface area of ​​the zinc oxide particles, the amount of untreated metal hydroxyl groups per unit area of ​​the zinc oxide particles (cells / m²) was calculated. 2 ).

[0344] The amount of untreated metallic hydroxyl groups per unit area of ​​zinc oxide particles 1 (cells / m²) 2 = Amount of untreated metallic hydroxyl groups in zinc oxide particle 1 (number / g) / Specific surface area of ​​zinc oxide particle 1 (m²) 2 / g)=4.77×10 17 (pieces / m) 2 )

[0345] The amount of untreated metallic hydroxyl groups per unit area of ​​surface-treated zinc oxide particles 2 (number / m²) 2 = Amount of untreated metallic hydroxyl groups in surface-treated zinc oxide particles 2 (number / g) / Specific surface area of ​​zinc oxide particles 2 before surface treatment (m²) 2 / g)=4.30×10 17 (pieces / m) 2 )

[0346] Next, the treatment rate (surface treatment rate) of the metallic hydroxyl groups present on the surface of the zinc oxide particles is calculated through the following calculations.

[0347] Treatment rate of metal hydroxyl groups in zinc oxide particles 1 (%) = 100 - (Amount of untreated metal hydroxyl groups in zinc oxide particles 1 (number / m³)) 2 The amount of untreated metallic hydroxyl groups (cells / m) of zinc oxide particles 12 )×100)=0

[0348] Treatment rate (%) of metallic hydroxyl groups in surface-treated zinc oxide particles 2 = 100 - (Amount of untreated metallic hydroxyl groups in surface-treated zinc oxide particles 2 (number / m)) 2 The amount of untreated metallic hydroxyl groups (cells / m) of zinc oxide particles 1 2 ()×100)=9.8

[0349] The higher the treatment rate of metal hydroxyl groups, the more the metal hydroxyl groups existing on the surface of zinc oxide particles are treated and hydrophobized.

[0350] Surface-treated zinc oxide particles were prepared with a content of 2% by mass of octyltriethoxysilane relative to zinc oxide particles; 3. Surface-treated zinc oxide particles with a content of 4% by mass of octyltriethoxysilane relative to zinc oxide particles; 4. Surface-treated zinc oxide particles with a content of 6% by mass of octyltriethoxysilane relative to zinc oxide particles; 5. Surface-treated zinc oxide particles with a content of 8% by mass of octyltriethoxysilane relative to zinc oxide particles; 6.

[0351] Next, the evaluation was conducted in the same manner as for the surface-treated zinc oxide particles 2 described above, and the metal hydroxyl treatment rate on the surface of the zinc oxide particles was calculated. The evaluation results and calculation results are shown in Table 1. In Table 1, OTS represents octyltriethoxysilane used for surface treatment. Furthermore, a graph showing the metal hydroxyl treatment rate relative to the content of octyltriethoxysilane is presented. Figure 7 In. Figure 7 In Example 10, the metal hydroxyl treatment rate of surface-treated zinc oxide particles 2-6, as measured and calculated, is represented by black dots.

[0352] [Comparative Example 1]

[0353] Evaluation of the metal hydroxyl treatment rate based on the limiting ethanol method

[0354] The surface-treated zinc oxide particles 3 to 6 used in Example 10 were also evaluated using the limiting ethanol method.

[0355] The limiting ethanol method involves preparing a solution of water and ethanol, adding a sample to this solution, and observing whether the sample precipitates. Furthermore, in the limiting ethanol method, if the sample does not precipitate, the ethanol ratio is increased; if the sample precipitates, the water ratio is increased. Thus, this method evaluates the hydrophobicity of the metal oxide particle surface based on the ethanol ratio required for sample precipitation (the limiting ethanol ratio). A higher ethanol ratio indicates greater hydrophobicity of the metal oxide particle surface and a higher metal hydroxyl group removal rate.

[0356] The mass ratio of surface-treated zinc oxide particles 3 to 6 precipitated in water / ethanol was evaluated by observation. The results are shown in Table 1. Furthermore, for reference only, the limiting ethanol ratios of surface-treated zinc oxide particles 3 to 6 obtained in Comparative Example 1 are shown in Table 1. Figure 7 Within the white square.

[0357] The water / ethanol mass ratio of surface-treated zinc oxide particles 5 with a content of 6% by mass of octyltriethoxysilane and surface-treated zinc oxide particles 6 with a content of 8% by mass of octyltriethoxysilane is 70:30, and it is impossible to quantitatively evaluate the difference in surface treatment state.

[0358] [Table 1]

[0359]

[0360] [Example 11]

[0361] 20 μL of methyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the solution of Example 8, and the mixture was stirred at 60°C for 4 hours to prepare mixture A. The color of mixture A was approximately the same as that of the solution of Example 8.

[0362] Hydrolysate was obtained by mixing 2g of methyltrimethoxysilane and 0.79g of water at 25°C for 3 hours to induce a hydrolysis reaction.

[0363] If the obtained hydrolysate is gradually added to the solution of Example 8, it is confirmed that the color of the solution changes from purplish-red to yellow.

[0364] Based on the results of Example 11, it was confirmed that the pigment of this example can not only evaluate the metal hydroxyl groups on the surface of metal oxide particles, but also evaluate the degree of hydrolysis reaction.

[0365] Industrial availability

[0366] This invention provides a pigment capable of adsorbing onto metal hydroxyl groups, a method for manufacturing the same, a solution containing the pigment, and methods for evaluating the amount of metal hydroxyl groups in the pigment and the metal hydroxyl group treatment rate. This invention provides a pigment capable of selectively adsorbing onto metal hydroxyl groups contained in a sample without reacting with the hydroxyl groups of water or alcohol. The pigment of this invention allows for a convenient evaluation of the amount of metal hydroxyl groups contained in a sample. Therefore, the pigment of this invention has significant industrial value when used as a testing reagent.

Claims

1. A solution for evaluating the amount of metallic hydroxyl groups, said solution comprising a pigment and an organic solvent. The pigment is a compound represented by the following general formula (1) or the following general formula (2). The concentration of the pigment is 1×10 -10 Above 1 mol / L and below 1 mol / L In formula (1), M is Sn or Ge, X is C or N, R1 is alkyl or phenyl, Y1 and Y2 are hydrogen, halogen, methyl, alkoxy, phenyl, diphenylamido, thiophenyl or phenylethynyl, respectively, and Z is represented by a single bond or the following formula (3). In formula (2), X is C or N, Y1 and Y2 are hydrogen, halogen group, methyl, alkoxy, phenyl, diphenylamide group, thiophenyl or phenylethynyl group respectively, and Z is a single bond or is represented by the following formula (3). In formula (3), R2 is an alkyl or phenyl group.

2. A method for evaluating the amount of metal hydroxyl groups, comprising the following steps: Prepare the solution and sample as described in claim 1; Evaluate the color x of the solution; The sample is added to the solution to prepare mixture A, and the color a of mixture A is evaluated; and The difference between color x and color a is evaluated, and the amount of metallic hydroxyl groups in the sample is evaluated based on the obtained evaluation results.

3. The method for evaluating the amount of metal hydroxyl groups according to claim 2, wherein, The color x and the color a are absorbance values.

4. A method for evaluating the amount of metal hydroxyl groups, comprising the following steps: Prepare the solution, sample 1, and sample 2 as described in claim 1; The sample 1 was added to the solution to prepare mixture A, and the color a of mixture A was evaluated. The sample 2 was added to the solution to prepare mixture B, and the color b of mixture B was evaluated. and The difference between the obtained color a and color b is evaluated, and the difference between the amount of metal hydroxyl groups a of sample 1 and the amount of metal hydroxyl groups b of sample 2 is evaluated based on the obtained evaluation results.

5. The method for evaluating the amount of metal hydroxyl groups according to claim 4, wherein, The colors a and b refer to absorbance.

6. A method for evaluating the amount of metal hydroxyl groups, comprising the following steps: Prepare the solution, sample 1, and sample 2 as described in claim 1; Evaluate the color x of the solution; The sample 1 was added to the solution to prepare mixture A, and the color a1 of mixture A was evaluated. The sample 2 was added to the solution to prepare mixture B, and the color b1 of mixture B was evaluated. The difference between the obtained color x and the obtained color a1 is evaluated, and the amount of metal hydroxyl groups a of the sample 1 is evaluated based on the obtained evaluation results; The difference between the obtained color x and the obtained color b1 is evaluated, and the amount of metallic hydroxyl groups b of the sample 2 is evaluated based on the evaluation results; and Evaluate the difference between the amount of metal hydroxyl groups a and the amount of metal hydroxyl groups b.

7. The method for evaluating the amount of metal hydroxyl groups according to claim 6, wherein, The color x, the color a1, and the color b1 are absorbance values.

8. A method for evaluating the metal hydroxyl removal rate, comprising evaluating the removal rate of metal hydroxyl groups on the surface of metal oxide particles after surface treatment with a surface treatment agent, the method comprising the following steps: Prepare the solution as described in claim 1, metal oxide particles 1 before surface treatment, and metal oxide particles 2 after surface treatment of the metal oxide particles 1; Measure the absorbance x of the solution; To prepare a mixture A, metal oxide particles 1 before surface treatment are added to the solution, and the absorbance a1 of the mixture A is measured. Add the surface-treated metal oxide particles 2 to the solution to prepare a mixture B, and measure the absorbance b1 of the mixture B. The reduction rate a2 of the absorbance of the mixture A is calculated by subtracting the absorbance a1 from the absorbance x and dividing by the absorbance x ((x-a1) / x); The reduction rate b2 of the absorbance of the mixture B is calculated by subtracting the absorbance b1 from the absorbance x and dividing by the absorbance x ((x-b1) / x). The amount of pigment adsorbed on the metal oxide particles 1 is calculated by multiplying the number of moles of the pigment contained in the mixture A by the rate of decrease in absorbance a2 and dividing by the amount of metal oxide particles 1 added to the solution A (a2 × number of moles of pigment contained in the mixture A / amount of metal oxide particles 1 added to the solution A). The unit of the adsorption amount a3 is mol / g. The adsorption amount b3 of the pigment on the metal oxide particles 2 is calculated by multiplying the number of moles of the pigment contained in the mixture B by the rate of decrease in absorbance b2 and dividing by the amount of metal oxide particles 2 added to the solution B (b2 × number of moles of pigment contained in the mixture B / amount of metal oxide particles 2 added to the solution B). The unit of the adsorption amount b3 is mol / g. The metal hydroxyl treatment rate based on the surface treatment is calculated by subtracting the value obtained by multiplying the adsorption amount b3 by the adsorption amount a3 by 100 (100 - ((b3 / a3) × 100)) from 100.

9. A method for evaluating the residual rate of metal hydroxyl groups, comprising the following steps: (1) When metal oxide particles are surface-treated with a surface treatment agent, the method evaluates the residual rate of metal hydroxyl groups on the surface of the metal oxide particles. Prepare the solution as described in claim 1, metal oxide particles 1 before surface treatment, and metal oxide particles 2 after surface treatment of the metal oxide particles 1; Measure the absorbance x of the solution; To prepare a mixture A, metal oxide particles 1 before surface treatment are added to the solution, and the absorbance a1 of the mixture A is measured. Add the surface-treated metal oxide particles 2 to the solution to prepare a mixture B, and measure the absorbance b1 of the mixture B. The reduction rate a2 of the absorbance of the mixture A is calculated by subtracting the absorbance a1 from the absorbance x and dividing by the absorbance x ((x-a1) / x); The reduction rate b2 of the absorbance of the mixture B is calculated by subtracting the absorbance b1 from the absorbance x and dividing by the absorbance x ((x-b1) / x). The amount of pigment adsorbed on the metal oxide particles 1 is calculated by multiplying the number of moles of pigment contained in the mixture A by the rate of decrease in absorbance a2 and dividing by the amount of metal oxide particles 1 added to the solution A ((a2 × number of moles of pigment contained in the mixture A) / amount of metal oxide particles 1 added to the solution A), where the unit of adsorption amount a3 is mol / g. The amount of pigment adsorbed on the metal oxide particles 2 is calculated by multiplying the number of moles of the pigment contained in the mixture B by the rate of decrease in absorbance b2 and dividing by the amount of metal oxide particles 2 added to the solution B ((b2 × number of moles of pigment contained in the mixture B) / amount of metal oxide particles 2 added to the solution B). The unit of the adsorption amount b3 is mol / g. and The residual rate of the metal hydroxyl groups based on the surface treatment is calculated by dividing the adsorption amount b3 by the value of the adsorption amount a3 and multiplying by 100 ((b3 / a3)×100).

10. The method for evaluating the amount of metal hydroxyl groups according to claim 2, wherein, The evaluation results were obtained by visually observing the solution and the mixture A.

11. The method for evaluating the amount of metal hydroxyl groups according to claim 3, wherein, In the step of evaluating the amount of metal hydroxyl groups in the sample, the absorbance is used to calculate the amount of metal hydroxyl groups.

12. The method for evaluating the amount of metal hydroxyl groups according to claim 4, wherein, The evaluation results are obtained by visually observing mixture A and mixture B.

13. The method for evaluating the amount of metal hydroxyl groups according to claim 7, wherein, In the steps of evaluating the amount of metal hydroxyl groups a and b, the absorbance is used to calculate the amounts of metal hydroxyl groups a and b.

Images