WO2024117228A1 - 遷移金属ドープシリカゾル及びその製造方法 - Google Patents

遷移金属ドープシリカゾル及びその製造方法 Download PDF

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WO2024117228A1
WO2024117228A1 PCT/JP2023/042962 JP2023042962W WO2024117228A1 WO 2024117228 A1 WO2024117228 A1 WO 2024117228A1 JP 2023042962 W JP2023042962 W JP 2023042962W WO 2024117228 A1 WO2024117228 A1 WO 2024117228A1
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silica sol
transition metal
doped
mass
colored silica
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French (fr)
Japanese (ja)
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和敏 関口
友貴 奥永
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Nissan Chemical Corp
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Nissan Chemical Corp
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
    • C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
    • C09C1/28—Compounds of silicon
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic

Definitions

  • the present invention relates to a colored silica sol containing colloidal silica particles, the colloidal silica particles being doped with a transition metal (hereinafter referred to as a transition metal-doped colored silica sol), and a method for producing the same.
  • a transition metal-doped colored silica sol a transition metal-doped colored silica sol
  • pigments have been widely used as colorants for inks, paints, plastics, rubber, fibers, toners, and other applications. These pigments are broadly classified into two types: organic pigments and inorganic pigments. In general, organic pigments are superior in color clarity, coloring power, and chemical resistance compared to inorganic pigments, but tend to have lower light resistance, heat resistance, and solvent resistance (see Non-Patent Document 1). In addition, for applications such as color filters and inkjet inks, high transparency is required for pigments as colorants, and the particle size of organic pigments is reduced by various methods to reduce light scattering and increase transparency (see Non-Patent Documents 2 and 3).
  • one of the known methods for coloring glass whose main component is silica is to dope the glass with a transition metal.
  • Many of these colored glasses have high light resistance, and are used, for example, in highly decorative crafts such as stained glass and cut glass, decorative items, containers, furniture, and building materials (see Non-Patent Document 4).
  • Patent Document 1 discloses a method of adding an active silicic acid aqueous solution as a feed liquid to a heel liquid of silica/alkali (molar ratio) 44.9, which is obtained by adding an active silicic acid aqueous solution and Cu(NO 3 ) 2.3H 2 O to a sodium silicate aqueous solution, to obtain a silica sol with a mass ratio of Cu to silica (Cu/silica) of about 0.0007.
  • Patent Document 2 discloses a method of obtaining a silica sol with an average particle diameter of 89 nm and a mass ratio of Cu to silica (Cu/silica) of about 0.0005 by coating a silica sol with an average particle diameter of 76 nm that does not contain transition metals as a core with a mixed layer in which Cu is dispersed in silica using an active silicic acid aqueous solution containing CuSO 4.
  • Patent Document 3 discloses a method of obtaining amorphous silica particles with a volume average particle diameter of 0.15 ⁇ m and a mass ratio of Fe to silica (Fe/silica) of about 0.009 by burning metal silicon and an Fe source in an atmosphere containing oxygen.
  • Patent Document 4 discloses a method for obtaining silica particles having a mass ratio of Cu to silica (Cu/silica) of about 0.04 by contacting silica particles having an average particle size of 0.75 ⁇ m produced by a sol-gel method with an aqueous CuSO 4 solution.
  • Patent Document 5 discloses a method for obtaining a porous silica powder having a specific surface area of more than 1000 m 2 /g and a mass ratio of Co to silica (Co / silica) of about 0.01.
  • Patent Document 6 discloses a method for obtaining silica particles having a mass ratio of Cu to silica (Cu/silica) of about 0.05 by contacting a hollow silica sol having an average particle size of 61 nm with an aqueous CuSO 4 solution.
  • the transparency of organic pigments increases with decreasing particle size, but in that case, lightfastness also tends to decrease, making it difficult to achieve both transparency and lightfastness.
  • the transition metal-containing silica particles proposed in the above Patent Documents 1 and 2 have a small amount of transition metal and insufficient coloring power.
  • the transition metal-containing silica particles proposed in the above Patent Documents 3 and 4 have a large particle size, which causes significant light scattering and insufficient transparency.
  • the transition metal-containing silica particles proposed in the above Patent Documents 5 and 6 tend to have insufficient coloring power because the transition metal, which serves as a coloring component, cannot exist in the pores of the porous or hollow structure.
  • the present invention has been made to solve the above problems, and aims to provide a transition metal-doped colored silica sol with excellent transparency, light resistance, and colorability, a method for producing the same, and a pigment composition, paint, ink, glaze, film, or molded body that contains at least the transition metal-doped colored silica sol.
  • the present invention provides a transition metal-doped colored silica sol that satisfies the following (1) to (4): (1) the mass ratio of the transition metal T to silica (T/silica) is 0.0001 or more and 0.05 or less; (2) the number average particle diameter (D1) of the particles in the silica sol calculated by image analysis of an electron microscope image is 5 nm or more and less than 50 nm; (3) the BET particle diameter (D2) of the particles in the silica sol calculated by a nitrogen adsorption method is 5 nm or more and less than 50 nm; (4) the ratio of the number average particle size to the BET particle size (D1/D2) is 1.5 or less; As a second aspect, the transition metal-doped colored silica sol according to the first aspect, wherein the transition metal T is one or more selected from the group consisting of V, Cr, Mn, Fe, Co, Ni,
  • the transition metal-doped colored silica sol according to any one of the first to third aspects in which the particle density PD of particles in the sol is at least 2.10 g/cm 3 or more.
  • the transition metal-doped colored silica sol according to any one of the first to fourth aspects wherein a dried powder obtained by drying the transition metal-doped colored silica sol at 100° C. under air is amorphous.
  • the transition metal-doped colored silica sol according to any one of the first to fifth aspects characterized in that particles in the sol are dispersed in an aqueous dispersion medium at a silica concentration of 1 mass % or more and 50 mass % or less.
  • the transition metal-doped colored silica sol according to any one of the first to sixth aspects in which an average particle diameter (D3) of particles in the silica sol measured by a dynamic light scattering method is 5 nm or more and less than 100 nm.
  • an apparent concentration of the transition metal T present in a dispersion medium of the transition metal-doped colored silica sol is less than 0.002 mass%.
  • the method comprises the steps of: (a) step, (b) step, (c) step, (d) step, and (e) step; (a) contacting an aqueous alkali silicate solution with a cation exchange
  • the method for producing a transition metal-doped colored silica sol according to the tenth aspect further comprising a step (f) of concentrating the transition metal-doped colored silica sol to obtain a concentrated solution after the step (e);
  • the method for producing a transition metal-doped colored silica sol according to the tenth or eleventh aspect in which the aqueous alkali silicate solution is one or more selected from an aqueous lithium silicate solution, an
  • the method for producing a transition metal-doped colored silica sol according to any one of the tenth to fifteenth aspects in which the particle density of particles in the transition metal-doped colored silica sol is at least 2.10 g/cm 3 or more;
  • the method for producing a transition metal-doped colored silica sol according to any one of the tenth to sixteenth aspects in which a dried powder obtained by drying the transition metal-doped colored silica sol at 100° C. under air is amorphous.
  • the method for producing a transition metal-doped colored silica sol according to any one of the tenth to seventeenth aspects, wherein the transition metal-doped colored silica sol is characterized in that particles in the sol are dispersed in an aqueous dispersion medium at a silica concentration of 1 mass % or more and 50 mass % or less.
  • the method for producing a transition metal-doped colored silica sol according to any one of the tenth to eighteenth aspects in which the transition metal-doped colored silica sol has an average particle size (D3) of particles in the silica sol measured by a dynamic light scattering method of 5 nm or more and less than 100 nm;
  • the method for producing a transition metal-doped colored silica sol according to any one of the tenth to nineteenth aspects in which an actual concentration of the transition metal T dissolved in a dispersion medium of the transition metal-doped colored silica sol is less than 0.002 mass %;
  • a pigment composition including at least the transition metal-doped colored silica sol according to any one of the first to ninth aspects;
  • a paint, ink, or glaze containing at least the pigment composition according to the twenty-first aspect;
  • a printed matter a printed matter
  • the present invention provides a transition metal-doped colored silica sol with excellent transparency, light resistance, and colorability, and a method for producing the same.
  • the transition metal-doped colored silica sol of the present invention can be made into a pigment composition as a colorant for various applications. By blending this pigment composition with a resin or the like, it is possible to manufacture paints, inks, glazes, printed matter, films, or molded bodies. Furthermore, the transition metal-doped colored silica sol of the present invention has high light resistance and is therefore resistant to discoloration and fading, and is expected to be used for a long time in a variety of applications.
  • FIG. 1 shows transmission electron microscope images (observation magnification: 100,000 times) of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the silica sol obtained in Comparative Example 1.
  • FIG. 1 shows transmission electron microscope images (observation magnification: 100,000 times) of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the silica sol obtained in Comparative Example 1.
  • FIG. 1 shows transmission electron microscope images (observation magnification: 100,000 times) of the Co-doped colored silica sol obtained in Example 1, the Cr
  • FIG. 2 shows the appearance of the UF concentrate of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the UF concentrate of the silica sol obtained in Comparative Example 1.
  • FIG. 1 shows the appearance of the UF concentrate of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the UF concentrate of the silica sol obtained in Comparative Example 1.
  • FIG. 1 shows the appearance of the UF concentrate of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in
  • FIG. 3 shows the appearance of powders obtained by drying the UF concentrates of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the silica sol obtained in Comparative Example 1 at 100° C. in air.
  • FIG. 4 shows X-ray diffraction patterns of powders obtained by drying the UF concentrates of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the silica sol obtained in Comparative Example 1 at 100° C. in air.
  • FIG. 1 shows X-ray diffraction patterns of powders obtained by drying the UF concentrates of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the silica sol obtained in Comparative Example 1 at 100° C. in air.
  • FIG. 1 shows X-ray
  • FIG. 5 shows the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum of the UF concentrate of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the UF concentrate of the silica sol obtained in Comparative Example 1.
  • FIG. 1 shows the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum of the UF concentrate of the Co-doped colored silica sol obtained in Example 1, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, the Ni-doped colored silica sol obtained in Example 16, and the UF concentrate of the silica sol obtained in Comparative Example 1.
  • FIG. 6 is an evaluation of the light resistance of each of the Co-doped colored silica sols obtained in Examples 1 to 4, the Cr-doped colored silica sol obtained in Example 13, the Mn-doped colored silica sol obtained in Example 14, the Cu-doped colored silica sol obtained in Example 15, and the Ni-doped colored silica sol obtained in Example 16, showing the transition of the rate of change in absorbance at each absorption wavelength when exposed to UV irradiation for 500 hours.
  • FIG. 7 is an evaluation of the light resistance of each of the PGME-diluted organic pigment dispersions of Comparative Examples 2 to 5, showing the transition of the rate of change in absorbance at each absorption wavelength after 500 hours of UV irradiation.
  • FIG. 7 is an evaluation of the light resistance of each of the PGME-diluted organic pigment dispersions of Comparative Examples 2 to 5, showing the transition of the rate of change in absorbance at each absorption wavelength after 500 hours of UV irradiation.
  • FIG. 8 shows a) the appearance of the colored film containing the Co-doped colored silica sol obtained in Example 18, b) a cross-sectional SEM image (magnification: 2000 times), and c) a visible-ultraviolet transmission spectrum.
  • FIG. 9 shows the appearances of the molded body containing the Co-doped colored silica sol obtained in Example 20, the molded body containing the silica sol obtained in Comparative Example 14, and the molded body obtained in Comparative Example 15.
  • the present invention relates to a transition metal-doped colored silica sol that satisfies the following (1) to (4).
  • the mass ratio of the transition metal T to silica (T/silica) is 0.0001 or more and 0.05 or less;
  • the number average particle diameter (D1) of the particles in the silica sol calculated by image analysis of an electron microscope image is 5 nm or more and less than 50 nm;
  • the BET particle diameter (D2) of the particles in the silica sol calculated by a nitrogen adsorption method is 5 nm or more and less than 50 nm;
  • the ratio of the number average particle size to the BET particle size (D1/D2) is 1.5 or less.
  • the transition metal-doped colored silica sol of the present invention is a sol of particles in which a transition metal T is doped into colloidal silica particles, and the silica sol is doped with a mass ratio of the transition metal T to the silica (T/silica) of 0.0001 or more and 0.05 or less.
  • the mass ratio (T/silica) is 0.001 or 0.005 or more and 0.02 or less. If the mass ratio (T/silica) is less than 0.0001, the coloring property becomes insufficient, and if it is more than 0.05, it is difficult to dope the transition metal T into the silica particles, which is not preferable.
  • the doping amount of the transition metal T can be quantified by analyzing the silica sol by inductively coupled plasma optical emission spectroscopy (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AA), X-ray fluorescence spectrometry (XRF), or the like after performing a known appropriate pretreatment.
  • the transition metal T may be doped unevenly in the colloidal silica particles, or may be doped uniformly.
  • the particle diameter of the particles in the transition metal-doped colored silica sol is a number average particle diameter (D1) calculated from an electron microscope image by image analysis, which is 5 nm or more and less than 50 nm.
  • the number average particle diameter (D1) is 7 nm or more and 30 nm or less. If the number average particle diameter (D1) is smaller than 5 nm, the particles tend to aggregate with each other, resulting in poor dispersibility when made into a dispersion, and if it is larger than 50 nm, it is not preferable because the transparency is deteriorated due to strong light scattering such as Rayleigh scattering and Mie scattering.
  • the number average particle diameter (D1) of the particles in the silica sol can be obtained by the following procedure. That is, the silica sol is subjected to a known appropriate pretreatment, and then observed with a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM), and the area of the particles is calculated from the obtained electron microscope image of the silica sol by image analysis, and a circle equivalent diameter, which is the diameter of a perfect circle equal to the area, is obtained.
  • the number average value of this circle equivalent diameter can be the number average particle diameter (D1).
  • the particle diameter of the particles in the transition metal-doped colored silica sol is further calculated by the nitrogen adsorption method (BET method) as a BET particle diameter (D2) of 5 nm or more and less than 50 nm.
  • the BET particle diameter (D2) is 7 nm or more and 30 nm or less. If the BET particle diameter (D2) is smaller than 5 nm, the particles tend to aggregate with each other, resulting in poor dispersibility when made into a dispersion, and if it is larger than 50 nm, it is not preferable because the light scattering such as Rayleigh scattering and Mie scattering becomes strong, resulting in poor transparency.
  • the transition metal-doped colored silica sol has a ratio of the number average particle size to the BET particle size (D1/D2) of 1.5 or less.
  • D1/D2 is 1.3 or less.
  • the lower limit of D1/D2 can be selected from the range of 0.1 or more, 0.3 or more, 0.5 or more, 0.8 or more, or 1.0 or more.
  • the silica particles in the silica sol are preferably non-porous and non-hollow, and are essentially solid particles.
  • D1/D2 is greater than 1.5, the porosity or hollowness of the silica particles will be high, and the transition metal, which is the coloring component, will not be present in the pores of the porous or hollow structure, and the coloring power will be insufficient, which is undesirable. It is considered that the smaller the number-average particle size/BET particle size (D1/D2) ratio, the more solid the particles will be.
  • solid particles can be distinguished from porous or hollow particles by the difference in particle contrast when observed with a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • the particle shape of the silica particles in the silica sol is not particularly limited. Examples include spherical, ellipsoidal (rugby ball), cocoon, confetti, chain, and dice shapes. Among these, spherical particles are preferred because they have high dispersibility and little light scattering.
  • the particle size distribution of the silica particles in the silica sol is not particularly limited.
  • a particle size distribution with one peak, a particle size distribution with two or more peaks, a particle size distribution with a narrow half-value width, and a particle size distribution with a wide half-value width are possible.
  • a particle size distribution with one peak and a narrow half-value width is preferred because it causes less light scattering.
  • the transition metal T is preferably one or more types selected from elements present in Groups 3 to 11 of the periodic table, and can be appropriately selected according to the absorption wavelength band.
  • the transition metal T may be doped singly into colloidal silica particles in the silica sol, or multiple transition metals T may be doped simultaneously into colloidal silica particles in the silica sol.
  • a silica sol in which one type of transition metal T is doped singly into colloidal silica particles may be produced, and then multiple silica sols doped with another type of transition metal T may be mixed.
  • the transition metal T is preferably one or more types selected from the first transition series transition metals, and more preferably one or more types selected from V, Cr, Mn, Fe, Co, Ni, and Cu.
  • the transition metal-doped colored silica sol has a specific surface area SSA of 50 m 2 /g or more and 550 m 2 /g or less of the particles in the silica sol obtained by the nitrogen adsorption method.
  • the specific surface area SSA is preferably 90 m 2 /g or more and 400 m 2 /g or less. If the specific surface area is smaller than 50 m 2 /g, the transparency is likely to be lost when the silica sol is used in a resin composite material or the like. On the other hand, if the specific surface area is larger than 550 m 2 /g, the dispersibility in a dispersion medium or a resin is likely to decrease, and it is concerned that it is difficult to add at a high concentration. In addition, there is a risk that the silica particles have a porous structure.
  • the particle density PD of the particles in the transition metal-doped colored silica sol is preferably at least 2.10 g/cm 3 or more.
  • the upper limit of the particle density PD can be selected from the range of 3.0 g/cm 3 , or 2.80 g/cm 3 , or 2.70 g/cm 3 , or 2.60 g/cm 3 , or 2.50 g/cm 3 , or 2.40 g/cm 3 , or 2.30 g/cm 3 , or 2.25 g/cm 3 .
  • the true density of bulk silica is generally 2.2 to 2.3 g/cm 3 , so if it is less than 2.10 g/cm 3 , closed pores due to the porous structure or hollow structure are present, and the transition metal, which is the coloring component, cannot be present, which is undesirable because the coloring power is likely to be insufficient.
  • This particle density PD can be obtained, for example, by subjecting the silica sol to heat treatment (drying) at 100° C. in the air and measuring the particle density with a dry automatic density meter (AccuPycII 1340TEC, manufactured by Micromeritics) using He gas.
  • the transition metal-doped colored silica sol is preferably heat-treated (dried) at 100°C in air to produce an amorphous dried powder.
  • the crystallinity of the dried powder can be confirmed by X-ray diffraction, and if no crystalline phase derived from the transition metal T can be confirmed by X-ray diffraction, the transition metal T is considered to be doped in the silica particles.
  • cristobalite, tridymite, quartz, etc. are known as crystalline phases derived from silica, but crystalline silica is toxic, and from the standpoint of safety, it is preferable that these crystalline phases cannot be confirmed (the powder is amorphous).
  • the transition metal-doped colored silica sol is preferably a silica sol in which transition metal-doped colloidal silica particles are dispersed in an aqueous dispersion medium at a silica concentration of 1% by mass or more and 50% by mass or less.
  • the silica concentration is preferably 2% by mass or more and 40% by mass or less. If it is lower than 1% by mass, the productivity may be low and the transportation cost may be low, and if it is higher than 50% by mass, the dispersibility may be easily deteriorated due to the increase in the number of particles.
  • the silica concentration can be calculated by removing metal elements such as transition metal T in oxide form from the solid residue obtained by heat-treating (drying) the transition metal-doped colored silica sol at a specified temperature and time.
  • the water can be pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or ultrapure water, and can be appropriately selected depending on the application.
  • the transition metal-doped colored silica sol is preferably such that the average particle diameter (D3) of the particles in the silica sol measured by dynamic light scattering is 5 nm or more and less than 100 nm.
  • the average particle diameter (D3) is preferably 10 nm or more and less than 80 nm.
  • the measurement principle of the average particle diameter (D3) by dynamic light scattering is dynamic light scattering.
  • the silica sol can be measured by a dynamic light scattering particle diameter measuring device (Spectris, Zetasizer Nano) after performing a known appropriate pretreatment. If it is smaller than 5 nm, the dispersibility in the dispersion medium or resin is likely to decrease. On the other hand, if it is larger than 100 nm, it is not preferable because the transparency is deteriorated due to the strong light scattering such as Rayleigh scattering and Mie scattering.
  • the transition metal-doped colored silica sol desirably has a pH of 2 or more and 12 or less.
  • the pH is preferably 2 or more and 4 or less, or 8 or more and 11 or less. If the pH of the silica sol is less than 2, the dispersibility may be easily deteriorated, and in addition, the transition metal T may be easily dissolved into the dispersion medium. If the pH is higher than 12, the silica may be easily dissolved and gelled, and in addition, the dissolved silica may be easily dissolved into the dispersion medium.
  • the transition metal-doped colored silica sol desirably has an apparent concentration of the transition metal T dissolved in the dispersion medium of the transition metal-doped colored silica sol of less than 0.002% by mass (less than 20 ppm by mass).
  • the apparent concentration is preferably less than 0.0002% by mass (less than 2 ppm by mass). More preferably, it is less than 0.0001% by mass (less than 1 ppm by mass). If the apparent concentration is greater than 0.002% by mass, there are concerns about safety to the body and environmental impact.
  • the apparent concentration of the transition metal T dissolved in the dispersion medium of the silica sol can be quantified by analyzing the filtrate obtained by treating the silica sol with an ultrafiltration (UF) membrane or reverse osmosis (RO) membrane having an appropriate molecular weight cutoff, and then analyzing it with inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AA), or the like after performing a known appropriate pretreatment.
  • UF ultrafiltration
  • RO reverse osmosis
  • the transition metal-doped colored silica sol desirably has an absorbance change rate of 50 to 100 % , as represented by the following formula (3), at an absorption wavelength that causes coloring of the colored silica sol, determined by visible-ultraviolet spectrum analysis before and after a UV irradiation test using a UVA-340 lamp under conditions of a UV irradiation intensity of 0.89 W/m2, a temperature of 50°C, and an irradiation time of 500 hours (corresponding to 3.6 months of sunlight).
  • Absorbance change rate (%) [absorbance after UV irradiation / absorbance before UV irradiation] ⁇ 100 (3)
  • the rate of change in absorbance before and after the UV irradiation test is preferably 60 to 100%, 70 to 100%, 75 to 100%, or 80 to 100%.
  • the UV irradiation test can be carried out, for example, by placing the transition metal-doped colored silica sol in a quartz cell with a lid having an optical path length of 10 mm, placing the cell in a QUV accelerated weathering tester (manufactured by Q-Lab Co., Ltd., product name QUV/se), and using a UVA-340 type lamp.
  • the absorption wavelengths for comparing the absorbance change vary depending on the color of the colored silica sol, that is, the type of transition metal T doped into the silica particles.
  • the absorption wavelengths to be compared may be appropriately selected in consideration of the small influence of absorption due to other factors and the magnitude of absorption.
  • the absorbance can be compared at absorption wavelengths of around 640 nm for Co, around 590 nm for Cr, around 455 nm for Mn, around 640 nm for Cu, around 670 nm for Ni, around 425 nm and around 625 nm for V, and around 400 nm for Fe.
  • the rate of change in absorbance can be calculated from the obtained absorbance using the following formula (3).
  • the transition gold-doped colored silica sol has an absorbance change rate of 50 to 100%, which makes it a suitable silica sol that can maintain its color even when used in an environment exposed to sunlight.
  • the silica particles in the transition metal-doped colored silica sol may have a shell layer formed on the particle surface (in this case, the silica particles may be referred to as core particles).
  • the shell layer is a shell layer coated with a metal oxide that does not intentionally contain a transition metal T (excluding unavoidable impurities).
  • the "shell layer formed on the particle surface” includes both an embodiment in which the surface of the silica particle is coated with a shell layer and an embodiment in which the components constituting the shell layer are bonded to the surface of the silica particle.
  • the former "embodiment in which the surface of the silica particle is covered with a shell layer” may be any embodiment in which the shell layer covers at least a part of the surface of the silica particle, that is, it includes an embodiment in which the shell layer covers a part of the surface of the silica particle (an embodiment in which the shell layer exists on a part of the surface of the silica particle) and an embodiment in which the shell layer covers the entire surface of the silica particle (an embodiment in which the shell layer exists on the entire surface of the silica particle). In this embodiment, it does not matter whether the shell layer is bonded to the surface of the silica particle or not.
  • the component constituting the shell layer is bonded to the surface of the silica particle
  • the thickness of the shell layer can be, for example, 0.3 nm or more and 5 nm or less, and the shell thickness can be, for example, 0.4 nm or more and 4 nm or less.
  • the shell thickness for example, 0.3 nm or more
  • the core region doped with the transition metal can be sufficiently covered, which can lead to the realization of improved light resistance.
  • the shell thickness for example, 5 nm or less, it is possible to ensure the coloring power of the transition metal doped in the core region, which can lead to the realization of a sol with excellent coloring properties.
  • the surface of the silica particles may be partially or completely covered with a shell layer, but it is preferable that the surface is completely covered and has a non-porous structure.
  • the shell thickness may be calculated using the BET particle size (D2) instead of the number average particle size (D1).
  • the transition metal-doped silica sol of the present invention can be produced based on a silica sol production method generally called the water glass method, specifically, the following steps (a), (b), (c), (d) and (e); (a) contacting an aqueous alkali silicate solution with a cation exchange resin to prepare an aqueous activated silicic acid solution; (b) mixing one or more selected from an aqueous alkali silicate solution, an aqueous active silicic acid solution, an aqueous alkali solution, and a transition metal salt compound to prepare a heel liquid having a silica/alkali (molar ratio) of less than 30; (c) preparing a feed liquid comprising one or more kinds selected from an active silicic acid aqueous solution, a transition metal salt compound, and an alkaline aqueous solution; (d) adding the heel liquid in the vessel, and while maintaining the heel liquid at
  • transition metal salt compound is added during preparation of the heel solution, during preparation of the feed solution, or during preparation of both, and/or the transition metal salt compound is contained in at least one of the aqueous alkali silicate solution, the aqueous active silicic acid solution, and the aqueous alkali solution; It can be manufactured.
  • the aqueous alkali silicate solution used in step (a) is preferably one or more selected from an aqueous lithium silicate solution, an aqueous sodium silicate solution, and an aqueous potassium silicate solution.
  • the aqueous alkali silicate solution may be used alone or in combination of two or more. From the viewpoint of economy, an aqueous sodium silicate solution known as water glass is preferred. These aqueous alkali silicate solutions may be used after diluting with water as necessary.
  • the cation exchange resin used in step (a) can be appropriately selected from known cation exchange resins and is not particularly limited.
  • a strongly acidic cation exchange resin is preferable.
  • the aqueous solution of the alkaline silicate is diluted with water to a silica concentration of 1% by mass or more and less than 10% by mass, and the aqueous solution is contacted with a strongly acidic cation exchange resin for decationization (dealkalization).
  • the aqueous solution can be contacted with a strongly basic anion exchange resin before or after contact with the cation exchange resin for deanionization.
  • Various details of the contact conditions have already been proposed in the past, and any of these known conditions can be adopted in the present invention.
  • strongly acidic cation exchange resins include Amberlite IR-120B (trade name), Amberjet 1020 (trade name, manufactured by Organo Corporation), DOWEX MARATHON GH (trade name, manufactured by The Dow Chemical Company), Diaion SK104 (trade name), Diaion PK208 (trade name, manufactured by Mitsubishi Chemical Group Corporation), and Duolite C20J (trade name, manufactured by Sumika Chemtex Corporation).
  • strongly basic anion exchange resins include Amberlite IRA400J, Amberlite IRA410J, Amberjet 4400 (manufactured by Organo Corporation), Diaion SA10A, Diaion SA20A (manufactured by Mitsubishi Chemical Group Corporation), and Duolite UBA120 (manufactured by Sumika Chemtex Corporation).
  • the concentration of the active silicic acid aqueous solution obtained in step (a) is preferably 1% by mass or more and 6% by mass or less, and more preferably 3% by mass or more and 4% by mass or less, as silica. If the concentration is less than 1% by mass as silica, productivity will deteriorate, and if it is higher than 6% by mass, the active silicic acid aqueous solution will become unstable and will tend to gel.
  • the pH of the active silicic acid aqueous solution is preferably 1 or more and 5 or less, or pH 7 or more and 12 or less, and more preferably 2 or more and 4 or less, or pH 8 or more and 11 or less. If the pH is outside this range, the active silicic acid aqueous solution will become unstable and will tend to gel.
  • the heel liquid obtained in step (b) is prepared by mixing one or more selected from an aqueous alkali silicate solution, an aqueous active silicic acid solution, an aqueous alkali solution, and a transition metal salt compound so that the silica/alkali (molar ratio) is less than 30. If the silica/alkali (molar ratio) is greater than 30, the particles in the silica sol tend to fuse together during particle synthesis, which is undesirable as it tends to reduce dispersibility.
  • the aqueous alkali silicate solution and the aqueous active silicic acid solution in step (b) may be the same as or different from those used and prepared in step (a).
  • the alkaline aqueous solution used in step (b) is preferably one or more types selected from aqueous solutions of lithium hydroxide, sodium hydroxide, potassium hydroxide, and ammonia.
  • the alkaline aqueous solution may be used alone or in combination of two or more types.
  • Aqueous alkaline solutions are commercially available in various concentrations, and these commercially available products may be used, or may be diluted with water as necessary.
  • the transition metal salt compound used in step (b) is not particularly limited and may be an organic salt or an inorganic salt, but is preferably at least one selected from chloride salts, nitrates, sulfates, borates, and phosphates.
  • One type of transition metal salt compound may be used alone, or two or more types may be used.
  • the transition metal salt compound is preferably used after being dissolved in water.
  • the metal of the transition metal salt compound used in step (b) is preferably one or more selected from V, Cr, Mn, Fe, Co, Ni, and Cu.
  • the metal of these transition metal salt compounds may be used alone or in combination of two or more.
  • the feed liquid obtained in the step (c) is composed of one or more selected from an active silicic acid aqueous solution, a transition metal salt compound, and an alkaline aqueous solution. They may be used alone or in combination of two or more.
  • the order of mixing these aqueous solutions is not particularly limited as long as it does not adversely affect the effects of the present invention.
  • an acid aqueous solution such as hydrochloric acid, nitric acid, or sulfuric acid, or the alkaline aqueous solution may be added to adjust the pH of the active silicic acid aqueous solution to a stable level.
  • the aqueous active silicic acid solution in step (c) may be the same as or different from those used and prepared in step (a) and/or step (b), and the aqueous alkali solution and transition metal salt compound in step (c) may be the same as or different from those used in step (b).
  • the transition metal salt compound may be added during preparation of the heel solution or feed solution, or may be originally contained in the aqueous alkali silicate solution, the aqueous active silicic acid solution, or the aqueous alkali solution, or both.
  • the transition metal salt compound is added during preparation of the heel solution in step (b), during preparation of the feed solution in step (c), or during preparation of both, and/or the transition metal salt compound is contained in at least one of the aqueous alkali silicate solution, the aqueous active silicic acid solution, and the aqueous alkali solution.
  • the liquid temperature of the heel liquid in the step (d) is from 60° C. to 105° C., preferably from 70° C. to 100° C. If it is less than 60° C., the reactivity of particle synthesis is low, which is not preferable.
  • this step when multiple feed liquids are used, one type may be added alone, or two or more types may be added simultaneously. The rate at which the feed liquids are added to the heel liquid can be appropriately set.
  • a step of adding an aqueous solution of active silicic acid to the heel liquid while maintaining the heel liquid in the vessel at 60°C or higher and 105°C or lower to form a silica shell layer on the surface of the particles in the transition metal-doped colored silica sol may be included.
  • the liquid temperature of the heel liquid is 60°C or more and 105°C or less, preferably 70°C or more and 100°C or less.
  • the rate at which the active silicic acid aqueous solution is added to the heel liquid can be appropriately set.
  • the mixture may be cooled to room temperature once and then heated again to form a shell layer.
  • the acid aqueous solution or the alkali aqueous solution may be further added to adjust the pH to a level at which a shell layer is easily formed on the particle surface, and then the shell layer may be formed.
  • step (e) after step (d), the mixture is maintained at a temperature of 60°C or more and 105°C or less for a certain period of time to obtain a sizing liquid.
  • the maintenance time is preferably between 0.5 and 24 hours. If it is shorter than 0.5 hours, unreacted active silicic acid remains in the system, which tends to deteriorate dispersibility, and this is not preferred. If it is longer than 24 hours, this is not preferred from the viewpoint of productivity.
  • the pH may be adjusted by adding an aqueous acid solution such as hydrochloric acid, nitric acid, or sulfuric acid, or the aforementioned aqueous alkali solution.
  • a step (f) of concentrating the silica sol to obtain a concentrated liquid can be included.
  • the concentration step (f) can adjust the silica concentration to 1% by mass or more and 50% by mass or less, for example, by concentration using an ultrafiltration (UF) membrane or by evaporation concentration under reduced pressure or normal pressure.
  • UF ultrafiltration
  • the pigment composition of the present invention is not particularly limited as long as it contains at least the transition metal-doped colored silica sol of the present invention.
  • the pigment composition may be prepared as a pigment composition in the form of a dispersion liquid by using the transition metal-doped colored colloidal silica particles in the transition metal-doped colored silica sol as a pigment as it is, or may be prepared as a pigment composition in the form of a powder by using the solid residue obtained by heat-treating (drying) the transition metal-doped colored silica sol at an appropriate treatment temperature and for an appropriate treatment time.
  • the powder may be pulverized by a known technique and further classified before use.
  • the pigment composition may be color-matched by mixing a plurality of transition metal-doped colored silica sols having different elements in an arbitrary mixing ratio, or may be color-matched by adding another type of pigment.
  • pigments include inorganic pigments and organic pigments.
  • examples of the above pigments include inorganic white pigments such as titanium oxide, zinc oxide, and mica; inorganic black pigments such as carbon black, graphite, iron black, copper-chrome black, cobalt-chrome black, and copper-manganese-iron black; inorganic red and orange pigments such as red iron oxide; inorganic yellow pigments such as yellow iron oxide, titanium yellow, and titanium-antimony-chrome yellow; inorganic green pigments such as chrome green, dichromium trioxide, cobalt green, cobalt-titanium-nickel-zinc green, and cobalt-aluminum-chrome blue-green; inorganic blue pigments such as ultramarine blue, Berlin blue, and cobalt blue; permanent red 4R, brilliant carmine FB, permanent red F5RK, pyrazolone orange, pyrazolone red, benzimidazolone orange, permanent red 2B, lake red R, Bordeaux 10B, Bon
  • organic yellow pigments such as fast yellow FGL, benzimidazolone yellow H3G, benzimidazolone yellow H4G, diarylide yellow HR, isoindoline yellow, anthrapyrimidine yellow, nickel azo yellow, and quinophthalone yellow
  • organic green pigments such as chlorinated phthalocyanine green and brominated phthalocyanine green
  • organic blue pigments such as phthalocyanine blue ⁇ , metal-free phthalocyanine blue, and threne blue
  • organic purple pigments such as dioxane violet and quinacridone violet
  • extender pigments such as calcium carbonate, kaolin, diatomaceous earth, silica, talc, barium sulfate, and bar
  • the pigment composition can be mixed with a dispersion medium such as water and/or a water-soluble organic solvent, a resin (plastic), glass raw materials, additives, etc. as necessary.
  • a dispersion medium such as water and/or a water-soluble organic solvent, a resin (plastic), glass raw materials, additives, etc.
  • the order of mixing can be any order as long as it does not affect the effects of the present invention.
  • the pigment composition after mixing may be used while maintaining the state of a dispersion liquid (liquid state), or may be used in powder form after heat treatment (drying) at an appropriate treatment temperature and treatment time.
  • the transition metal-doped colored silica sol may first be made into a powder form, and then the resin, additives, etc. may be mixed therewith, and the powder form may be used as it is, or the dispersion medium, etc. may be added thereto, followed by a dispersion treatment, and the powder may be used as a dispersion liquid. From the viewpoint of transparency, it is particularly preferred that
  • the water-soluble organic solvent may be an alcohol, ether, ester, or ketone.
  • the water-soluble organic solvent include monoalcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, tert-butanol, and diacetone alcohol; polyhydric alcohol solvents such as ethylene glycol and propylene glycol; aromatic alcohol solvents such as furfuryl alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono tert-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ...
  • the solvent examples include ether/ester solvents such as ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 3-methoxybutanol, 3-methyl-3-methoxybutanol, ethylene glycol monomethyl ether acetate, ethyl 2-hydroxypropionate, ethyl hydroxyacetate, ⁇ -butyrolactone, tetrahydrofuran, and 1,4-dioxane; ketone solvents such as acetone and 4-hydroxy-4-methyl-2-pentanone; and nitrogen-containing solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. These may be used
  • the resin (plastic) may be any known resin, such as a thermoplastic resin, a thermosetting resin, or a photocurable resin.
  • thermoplastic resins include polyvinyl chloride (PVC) resin, polyethylene (PE) resin, polypropylene (PP) resin, polystyrene (PS) resin, acrylonitrile butadiene styrene (ABS) resin, acrylonitrile styrene (AS) resin, thermoplastic acrylic (e.g., polymethyl methacrylate: PMMA) resin, polyvinyl alcohol (PVA) resin, vinyl acetate (PVAc) resin, polyvinylidene chloride (PVDC) resin, polyethylene terephthalate (PET) resin, polyamide (PA) resin, polyacetal (POM) resin, polycarbonate (PC) resin, modified polyphenylene ether (m-PPE) resin, polybutylene terephthalate (PBT) resin, ultra-high molecular weight polyethylene (U-PE
  • polyimide resins examples include polyphenylene polystyrene (PPS) resins, polyarylate (PAR) resins, polyamideimide (PAI) resins, polyetherimide (PEI) resins, polyetheretherketone (PEEK) resins, thermoplastic polyimide (TPI) resins, liquid crystal polymer (LCP) resins, polytetrafluoroethylene (PTFE) resins, polymethylterpene (PMP) resins, polyphenylene oxide (noryl, PPO) resins, thermoplastic polyurethane (TPU) resins, coumarone resins, ionomer (ION) resins, polyester-based thermoplastic elastomers, rosin, cellulose acetate (CA) resins, polylactic acid (PLA) resins, polybutylene succinate (PBS) resins, polycaprolactone (PCL) resins, polyglycolic acid (PGA) resins, polyhydroxyalkanoic acid (PHA) resins,
  • thermosetting resins examples include phenol (PF) resin, urea (UF) resin, melamine (MF) resin, unsaturated polyester (UP) resin, epoxy (EP) resin, silicone (SI) resin, polyurethane (PU) resin, diallyl phthalate (PDAP) resin, polyimide (PI) resin, thermosetting acrylic (TPA) resin, liquid polybutadiene, silicone rubber, shellac, furan resin, casein resin, etc.
  • photocurable resins examples include vinyl-based photocurable resins, acrylic-based photocurable resins, epoxy-based photocurable resins, urethane-based photocurable resins, polyester-based photocurable resins, etc. These resins may be used alone or in combination of two or more types, or may be used as copolymers or modified products of two or more types.
  • the resin is preferably a soluble resin that dissolves in water and/or a water-soluble organic solvent, or a dispersed resin that is dispersed in a colloid or emulsion.
  • the glass raw materials may be any known glass raw material. Examples include silica sand, feldspar, cullet, sodium silicate, calcium carbonate, lithium carbonate, sodium carbonate, sodium sulfate, sodium nitrate, potassium carbonate, potassium nitrate, barium carbonate, barium nitrate, limestone, dolomite, magnesium oxide, borax, boric acid, phosphoric acid, aluminum hydroxide, red lead, litharge, fluorite, creolite, sodium silicofluoride, zinc oxide, titanium oxide, zirconium oxide, and the like. These may be used alone or in combination of two or more.
  • the glass raw materials may also be used as raw materials for glazes.
  • the additives may be any known additive.
  • the additives include wetting agents, dispersants, penetrants, drying agents, drying inhibitors, defoamers, viscosity adjusters, pH adjusters, chelating agents, plasticizers, crosslinking agents, curing catalysts, radical generators, acid generators, sensitizers, polymerization inhibitors, antioxidants, UV absorbers, leveling agents, lubricants, flame retardants, antistatic agents, rust inhibitors, preservatives, algae inhibitors, antibacterial agents, antifungal agents, and antiviral agents. These additives may be used alone or in combination of two or more.
  • mixing and dispersion processes can be carried out in a container using a mixing and dispersing machine such as a stirring blade, paint shaker, bead mill, ball mill, dissolver, or kneader. If mixing or dispersing is poor at room temperature, heating may be performed as necessary.
  • a mixing and dispersing machine such as a stirring blade, paint shaker, bead mill, ball mill, dissolver, or kneader. If mixing or dispersing is poor at room temperature, heating may be performed as necessary.
  • this pigment composition may be subjected to classification using a sieve, centrifugation, filtration, etc. before or after mixing to remove unnecessary foreign matter.
  • the concentration of the pigment (the transition metal-doped colored colloidal silica particles in the transition metal-doped colored silica sol, and other pigments as desired) in the pigment composition can be 1% by mass or more and 50% by mass or less, based on 100% by mass of the pigment composition. It is preferably 2% by mass or more and 40% by mass or less. If the pigment concentration in the pigment composition (dispersion) is less than 1% by mass, the coloring properties are low due to the small amount of coloring components, and if it is more than 50% by mass, the dispersibility is likely to deteriorate due to the increase in the number of particles, which is not preferable.
  • the pigment concentration can be 1% by mass or more and 100% by mass or less, preferably 5% by mass or more and 90% by mass or less, based on 100% by mass of the pigment composition. If the pigment concentration in the pigment composition (powder) is less than 1% by mass, the coloring properties are low due to the small amount of coloring components, which is not preferred.
  • the proportion of dispersing media such as water and water-soluble organic solvents in the pigment composition can be 50% by mass or more and 99% by mass or less, based on 100% by mass of the pigment composition, when the pigment composition is used as a dispersion liquid.
  • the pigment composition when used as a powder, it is preferable that the pigment composition contains as few of these dispersing media as possible.
  • the proportion of resin in the pigment composition is not particularly limited, but is from 0 to 50% by mass, based on 100% by mass of the pigment composition. Preferably, it is from 1 to 50% by mass. If a resin is blended into the pigment composition, it is preferably at least 1% by mass.
  • the mass ratio of the pigment to the resin is 1/99 or more and 99/1 or less. Preferably, it is 5/95 or more and 95/5 or less.
  • the proportion of additives in the pigment composition is the remainder in 100% by mass of the pigment composition, specifically, 0% by mass or more and 10% by mass or less in 100% by mass of the pigment composition.
  • the pigment composition of the present invention can be used as a paint, ink, or glaze. That is, the present invention is also directed to the paint, ink, or glaze that contains at least the pigment composition.
  • the present invention also relates to a printed matter, a film, or a molded article that contains at least the pigment composition.
  • the printed matter or film of the present invention is not particularly limited as long as it contains at least the pigment composition of the present invention.
  • the printed matter refers to an item on which images such as letters, pictures, photographs, etc. are printed with ink on a substrate.
  • the film may be a coating film applied to a substrate or a free-standing film.
  • the coating film means a film formed by applying a coating material or the like onto a substrate, and the free-standing film means a film that does not require the support of a substrate.
  • the thickness of the film is not particularly limited, but can be selected from the range of about 0.01 ⁇ m to 10 mm.
  • the thickness of the coating film is 0.05 ⁇ m or more and 20 ⁇ m or less.
  • it is 0.1 ⁇ m or more and 10 ⁇ m or less.
  • the thickness of the free-standing film is 5 ⁇ m or more and 10 mm or less.
  • it is 50 ⁇ m or more and 1 mm or less.
  • the pigment composition of the present invention may be applied to a substrate by brush coating, roller coating, spatula coating, aerosol coating, air spray coating, airless spray coating, dip coating, electrostatic coating, powder coating, flow coating, curtain coating, shower coating, spray coating, roll coating, bar coating, gravure coating, slit coater method, dipping, spin coating, casting, screen printing, inkjet coating, etc.
  • the pigment composition may be applied once or twice or more.
  • the pigment composition and/or the substrate may be applied while being heated, or may be heated after application. After drying, the substrate to which the pigment composition has been applied may be subjected to a heat treatment (post-baking).
  • a light source of an appropriate wavelength may be irradiated at a predetermined intensity for a predetermined time.
  • the substrate may be a known substrate.
  • the substrate include metal, ceramics, glass, pottery, porcelain, refractory materials, concrete, mortar, slate, wood, paper, cotton, hemp, silk, wool, and plastics.
  • Preferred substrates are transparent in the visible range, such as glass, polyethylene terephthalate resin, acrylic resin, polycarbonate resin, cellulose acetate resin, vinyl chloride resin, polyethylene resin, polyolefin resin, fluororesin, and polyimide resin.
  • the shape of the substrate is not particularly limited and includes any shape. Examples include fibers, mesh fabrics, knitted fabrics, woven fabrics, nonwoven fabrics, films, sheets, plates, rods, pipes, plates, bowls, cups, boxes, etc.
  • the molded article of the present invention is not particularly limited as long as it contains at least the pigment composition of the present invention.
  • the term "molded body" refers to a material obtained by processing a raw material into a desired shape, surface, or design, and may be various shaped bodies including, but not limited to, resin, metal, glass, etc.
  • Examples of methods for molding the pigment composition of the present invention include injection molding, blow molding, extrusion molding, cast molding, hand lay-up molding, press molding, compression molding, vacuum molding, compressed air molding, T-die method, inflation method, calendar molding, droplet molding method, direct dissolution method, marble melt method, overflow method, float method, etc.
  • the shape of the molded product is not particularly limited, and any shape is included. Examples include fibers, mesh fabrics, knitted fabrics, woven fabrics, nonwoven fabrics, films, sheets, plates, rods, pipes, plates, bowls, cups, boxes, etc.
  • silica particles may be referred to simply as “silica particles” or “silica sol” regardless of whether or not they have a shell layer or are doped with a transition metal.
  • ⁇ pH> The pH of the sample was measured at room temperature (20 ⁇ 5° C.) using a pH meter (manufactured by DKK-Toa Corporation).
  • the silica concentration of the sample was measured by mass method.Specifically, the mass of the calcination residue when a predetermined mass of the silica sol to be measured is calcined in an electric furnace at 1000°C is subtracted from the mass of the calcination residue when the metal elements of 0.0001 mass% or more (1 mass ppm or more) are converted into oxides, except for silica (measured as silicon in the analysis and converted into oxides) among the inorganic elements measured by the metal element analysis described below, to obtain the silica mass, and the silica concentration (%) is calculated by [(silica mass/silica sol mass) x 100].
  • Metal element analysis (including silica) was performed using an inductively coupled plasma optical emission spectrometer (ICP-OES, Agilent Technologies, product name Agilent 5110). Specifically, the sample was treated with a microwave decomposition device, then appropriately diluted and measured with ICP-OES. A calibration curve was prepared using a calibration solution prepared in the range of 0-1 ppm by mass. The mass ratio of the transition metal T to silica (T/silica) was calculated from the measured amounts of metal elements and the above-mentioned silica mass.
  • ICP-OES inductively coupled plasma optical emission spectrometer
  • ⁇ BET particle size (D2) calculated by nitrogen adsorption method The specific surface area SSA (m 2 /g) was measured by the nitrogen adsorption method (BET method) using a nitrogen adsorption specific surface area measuring device (manufactured by Yuasa Ionics Co., Ltd., product name Monosorb MS-22).
  • the sample used was a powder obtained by contacting the silica sol to be measured with a hydrogen-type strongly acidic cation exchange resin, drying it at 300°C in air for 1 hour, and then pulverizing it in a mortar.
  • BET particle diameter D2 (nm) was calculated from the specific surface area SSA (m 2 /g) measured by the nitrogen adsorption method (BET method) and the particle density PD (g/cm 3 ) shown below according to formula (1).
  • BET particle diameter D2 (nm) 6000/[particle density PD (g/cm 3 ) ⁇ specific surface area SSA (m 2 /g)] (1)
  • ⁇ Number average particle size/BET particle size (D1/D2) ratio was calculated by taking the ratio of the above-mentioned number average particle size (D1) to the BET particle size (D2).
  • ⁇ Average particle size (D3) measured by dynamic light scattering method The average particle size (D3) measured by a dynamic light scattering method was measured using a dynamic light scattering particle size measuring device (manufactured by Spectris Co., Ltd., product name: Zetasizer Nano S).
  • Shell thickness (number average particle size (D1) of particles after forming shell layer ⁇ number average particle size (D1) of particles before forming shell layer) ⁇ 2 (2)
  • the shell thickness may be calculated using the BET particle size (D2) instead of the number average particle size (D1).
  • ⁇ Dispersibility> The silica sol to be evaluated was irradiated with a green laser pointer having a wavelength of 532 nm, and the occurrence of the Tyndall phenomenon was visually confirmed to evaluate the dispersibility of the silica particles. If the Tyndall phenomenon was observed and no precipitate was generated, the dispersibility was evaluated as ⁇ , and if the Tyndall phenomenon was not observed or precipitate was generated, the dispersibility was evaluated as ⁇ .
  • the crystal phase was identified using a desktop X-ray diffractometer (XRD, manufactured by Rigaku Corporation, product name MiniFlex600).
  • the sample was dried at 100°C in air and then ground in a mortar to obtain a powder.
  • the visible-ultraviolet spectrum of the silica sol to be measured was measured using an ultraviolet-visible-near infrared spectrophotometer (manufactured by Shimadzu Corporation, product name UV-3600). Specifically, a quartz cell with a lid and an optical path length of 10 mm was used, and water or propylene glycol monomethyl ether (PGME) was used as a control. The visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum were measured in the measurement wavelength range of 250-800 nm.
  • an ultraviolet-visible-near infrared spectrophotometer manufactured by Shimadzu Corporation, product name UV-3600
  • PGME propylene glycol monomethyl ether
  • the light resistance of the transition metal-doped colored silica sol was evaluated using a QUV accelerated weathering tester (manufactured by Q-Lab Co., Ltd., product name QUV/se). Specifically, the target silica sol, which was a sample, was placed in a covered quartz cell with an optical path length of 10 mm, and placed in the QUV accelerated weathering tester. The measurement was performed under the following conditions: UVA-340 lamp, UV irradiation intensity of 0.89 W/m 2 , temperature of 50° C., and irradiation time of 500 h (equivalent to 3.6 months of sunlight).
  • the mass loss rate of the sample after 500 h of UV irradiation was less than 1%, and there was no problem with the airtightness of the covered quartz cell.
  • UV irradiation of the target silica sol was similarly performed under conditions where only the UV irradiation time was 100 hours or 250 hours. After UV irradiation for a predetermined period of time (100 hours, 250 hours, 500 hours), the absorption spectrum of the silica sol was measured by visible-ultraviolet spectrum analysis, and the rate of change in absorbance before and after UV irradiation at any absorption wavelength was calculated from the following formula (3).
  • Absorbance change rate (%) [absorbance after UV irradiation / absorbance before UV irradiation] ⁇ 100 (3) The closer the absorbance change rate (%) is to 100%, the less the absorbance changes upon UV irradiation, and the higher the light resistance is determined to be.
  • This diluted sodium silicate aqueous solution was passed through a column packed with 1 L of hydrogen-type strongly acidic cation exchange resin (manufactured by Organo Corporation, trade name Amberlite IR-120B) at a rate of 250 mL/min to contact with the cation exchange resin, thereby preparing 1684 g of an active silicic acid aqueous solution with a silica concentration of 3.5% by mass and a pH of 2.9.
  • the concentrations of V, Cr, Mn, Fe, Co, Ni, and Cu in this active silicic acid aqueous solution were all below the lower detection limit (less than 0.0001% by mass).
  • the obtained aqueous solution of active silicic acid was used appropriately in preparing the feed liquid or heel liquid, and in coating the silica particles (shell layer) in each of the silica sol production processes described below.
  • Example 1 ⁇ Preparation of Co-doped colored silica sol> 28 g of commercially available JIS No. 3 sodium silicate aqueous solution (silica concentration 28.8 mass%, Na2O concentration 9.5 mass%, silica/ Na2O molar ratio 3.1) was added to 780 g of pure water and mixed uniformly to prepare 808 g of heel liquid with a silica concentration of 1.0 mass%, Na2O concentration of 0.33 mass%, silica/ Na2O molar ratio of 3.1, and pH 11.0.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.4, a silica concentration of 2.7% by mass, an average particle size (D3) of 13 nm by dynamic light scattering, a Co concentration of 0.012% by mass (120 ppm by mass), and a mass ratio of Co to silica (Co/silica) of 0.0044. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The electron microscope image is shown in Figure 1. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 9.3 ⁇ 2.8 nm.
  • the UF concentrated solution of the obtained Co-doped colored silica sol had a pH of 9.9, a silica concentration of 26.1 mass%, a Co concentration of 0.12 mass% (1200 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0046.
  • the UF filtrate obtained during UF concentration had a pH of 10.4 and a Co concentration of 0.0004 mass% (4 mass ppm). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.6 and a silica concentration of 22.1% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent, blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 377 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 7.3 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.27.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum are shown in Figure 5.
  • Example 2 ⁇ Preparation of Co-doped colored silica sol> After the end of the supply of the feed liquid, the step of maintaining the liquid temperature in the vessel at 80° C. under stirring for 6 hours was changed to 1 hour, and the same operation as in Example 1 was performed to obtain 2,500 g of a sized liquid of Co-doped colored silica sol.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.5, a silica concentration of 2.7% by mass, an average particle size (D3) of 13 nm as determined by dynamic light scattering, a Co concentration of 0.012% by mass (120 ppm by mass), and a mass ratio of Co to silica (Co/silica) of 0.0045. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 9.5 ⁇ 2.6 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.4 and a Co concentration of 0.0003 mass% (3 mass ppm). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. under air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. The powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.13 g/cm 3. Similarly, the crushed powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.4 and a silica concentration of 22.1% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent, blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 372 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 7.6 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.26.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • Example 3 ⁇ Preparation of Co-doped colored silica sol>
  • the heel liquid was changed to 808 g of a heel liquid (silica concentration 1.0 mass%, NH3 concentration 1.1 mass%, silica/ NH3 molar ratio 0.28, pH 10.9) prepared by uniformly mixing 544 g of pure water, 231 g of the active silicic acid aqueous solution (silica concentration 3.5 mass%, pH 2.9), and 33 g of ammonia water (ammonia concentration 27 mass%) , and the same operation as in Example 1 was performed to obtain 2,500 g of a sized liquid of Co-doped colored silica sol.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.4, a silica concentration of 2.7% by mass, an average particle size (D3) of 17 nm as determined by dynamic light scattering, a Co concentration of 0.013% by mass (130 ppm by mass), and a mass ratio of Co to silica (Co/silica) of 0.0049. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 11.6 ⁇ 4.3 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.5 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. under air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. The powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.18 g/cm 3. Similarly, the crushed powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.4 and a silica concentration of 25.2% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 271 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 10.1 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.14.
  • the resulting sized liquid of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the sized liquid of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 525 nm, 580 nm, and 640 nm.
  • Example 4 ⁇ Preparation of Co-doped colored silica sol>
  • 7.9 g of the 10% by mass CoSO4 aqueous solution was changed to 35.3 g, and 1719 g of the prepared feed solution was used.
  • the same procedure as in Example 3 was repeated, except that 2527 g of a sized solution of Co-doped colored silica sol was obtained.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.3, a silica concentration of 2.7% by mass, an average particle size (D3) of 27 nm as measured by dynamic light scattering, a Co concentration of 0.054% by mass (540 ppm by mass), and a mass ratio of Co to silica (Co/silica) of 0.020. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 9.6 ⁇ 3.0 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.2 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. under air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. The powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.21 g/cm 3. Similarly, the crushed powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.8 and a silica concentration of 20.0 mass%.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 282 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 9.6 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.00.
  • the resulting sized liquid of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the sized liquid of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 525 nm, 580 nm, and 640 nm.
  • Example 5 ⁇ Preparation of Co-doped colored silica sol>
  • the heel liquid was changed to 808 g of a heel liquid (silica concentration 1.0 mass%, Na2O concentration 0.32 mass%, NH3 concentration 0.50 mass%, silica/alkali molar ratio 0.48, pH 11.2) prepared by uniformly mixing 765 g of pure water, 28 g of a commercially available JIS No. 3 sodium silicate aqueous solution, and 15 g of ammonia water, and the same procedure as in Example 1 was repeated to obtain 2,500 g of a sized liquid of Co-doped colored silica sol.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.7, a silica concentration of 2.7% by mass, an average particle size (D3) of 20 nm as measured by dynamic light scattering, a Co concentration of 0.012% by mass (120 ppm by mass), and a mass ratio of Co to silica (Co/silica) of 0.0045. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 9.2 ⁇ 3.0 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.8 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. under air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. The powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.18 g/cm 3. Similarly, the crushed powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.5 and a silica concentration of 19.4% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 332 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 8.3 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.11.
  • the resulting sized liquid of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the sized liquid of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 525 nm, 580 nm, and 640 nm.
  • Example 6 ⁇ Preparation of Co-doped colored silica sol> 10 g of commercially available JIS No. 3 sodium silicate aqueous solution was added to 284 g of pure water and mixed uniformly to prepare 294 g of heel liquid with a silica concentration of 1.0 mass%, a Na 2 O concentration of 0.33 mass%, a silica/Na 2 O molar ratio of 3.1, and a pH of 11.0. Next, 10.3 g of a 10 mass% CoSO 4 aqueous solution was added to 2205 g of the activated silicic acid aqueous solution and mixed uniformly to prepare 2215 g of feed liquid.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 9.4, a silica concentration of 3.2 mass%, an average particle size (D3) of 16 nm as determined by dynamic light scattering, a Co concentration of 0.0066 mass% (66 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0020. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 9.7 ⁇ 3.2 nm.
  • the UF filtrate obtained during UF concentration had a pH of 9.2 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. in air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. Thereafter, the powder was further pulverized in a mortar, and the particle density PD was measured with a dry densitometer, which was 2.17 g/cm 3. Similarly, the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.1 and a silica concentration of 23.2% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent, blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 313 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 8.8 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.10.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • Example 7 ⁇ Preparation of Co-doped colored silica sol (with shell layer)> The synthesis of Co-doped colored silica sol particles was carried out under the same conditions as in Example 1. That is, 10 g of a commercially available JIS No. 3 aqueous sodium silicate solution was first added to 284 g of pure water and mixed uniformly to prepare 294 g of heel liquid with a silica concentration of 1.0 mass %, a Na 2 O concentration of 0.32 mass %, a silica/Na 2 O molar ratio of 3.1 and a pH of 11.0.
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 9.7, a silica concentration of 3.1 mass%, an average particle size (D3) of 14 nm as determined by dynamic light scattering, a Co concentration of 0.0043 mass% (43 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0014. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 12.9 ⁇ 3.8 nm.
  • the shell thickness was calculated from formula (2) using the number average particle diameter (D1) of the particles in Example 1, which was 9.5 ⁇ 2.6 nm, and was found to be 1.7 nm.
  • the obtained UF concentrate of Co-doped colored silica sol had a pH of 8.9, a silica concentration of 32.8 mass%, a Co concentration of 0.046 mass% (460 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0014.
  • the UF filtrate obtained during UF concentration had a pH of 9.7 and a Co concentration of 0.0001 mass% (1 mass ppm). Since Co was almost absent on the UF filtrate side and present on the UF concentrate side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. in air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. Thereafter, the powder was further pulverized in a mortar, and the particle density PD was measured with a dry densitometer, which was 2.21 g/cm 3. Similarly, the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.2 and a silica concentration of 26.2% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 255 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 10.6 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.21.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • Example 8 ⁇ Preparation of Co-doped colored silica sol (with shell layer)> After synthesizing the particles in Example 7, in order to form a shell layer on the particle surface, the liquid temperature in the vessel when the active silicic acid aqueous solution was continuously supplied at a constant rate was changed from 80°C to 100°C, and further, after the supply of the active silicic acid aqueous solution was completed, the liquid temperature in the vessel was also changed from 80°C to 100°C. Except for this, the same operation as in Example 7 was performed to obtain 2,503 g of a sized liquid of Co-doped colored silica sol (with shell layer).
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 9.7, a silica concentration of 3.3 mass%, an average particle size (D3) of 12 nm as determined by dynamic light scattering, a Co concentration of 0.0044 mass% (44 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0013. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 12.7 ⁇ 2.9 nm.
  • the shell thickness was calculated from formula (2) using the number average particle diameter (D1) of the particles in Example 1, which was 9.5 ⁇ 2.6 nm, and was found to be 1.6 nm.
  • the UF filtrate obtained during UF concentration had a pH of 9.5 and a Co concentration of 0.0001 mass% (1 mass ppm). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. in air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. Thereafter, the powder was further pulverized in a mortar, and the particle density PD was measured with a dry densitometer, which was 2.22 g/cm 3. Similarly, the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.1 and a silica concentration of 27.9% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent, blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 252 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 10.7 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.19.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • Example 9 ⁇ Preparation of Co-doped colored silica sol (with shell layer)> A 3 L glass reaction vessel equipped with a stirrer and a condenser was charged with 343 g of the sized solution of the Co-doped colored silica sol prepared in Example 1 and 9.2 g of a 10 mass % NaOH aqueous solution, and the liquid temperature in the vessel was kept at 80° C. in an oil bath. Next, 2,029 g of the active silicic acid aqueous solution was continuously supplied to the vessel under stirring at a constant rate over 900 minutes to form a shell layer on the particle surfaces. After the supply of the active silicic acid solution was completed, the liquid temperature in the vessel was maintained at 80° C. for 6 hours with stirring to obtain 2,381 g of a sized liquid of Co-doped colored silica sol (with a shell layer).
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.0, a silica concentration of 3.4 mass%, an average particle size (D3) of 17 nm as measured by dynamic light scattering, a Co concentration of 0.0017 mass% (17 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0005. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 16.8 ⁇ 3.7 nm.
  • the shell thickness was calculated from formula (2) using the number average particle diameter (D1) of the particles in Example 1, which was 9.5 ⁇ 2.6 nm, and was found to be 3.7 nm.
  • the UF filtrate obtained during UF concentration had a pH of 9.8 and a Co concentration of 0.0001 mass% (1 mass ppm). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. in air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. Thereafter, the powder was further pulverized in a mortar, and the particle density PD was measured with a dry densitometer, which was 2.23 g/cm 3. Similarly, the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.2 and a silica concentration of 25.4% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent, blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 186 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 14.5 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.16.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • Example 10 ⁇ Preparation of Co-doped colored silica sol (with shell layer)>
  • the liquid temperature in the vessel when the active silicic acid aqueous solution was continuously supplied at a constant rate was changed from 80°C to 100°C, and further, after the supply of the active silicic acid aqueous solution was completed, the liquid temperature in the vessel was also changed from 80°C to 100°C. Except for this, the same operation as in Example 9 was performed to obtain 2,381 g of a sized liquid of Co-doped colored silica sol (with shell layer).
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.1, a silica concentration of 3.6 mass%, an average particle size (D3) of 25 nm as determined by dynamic light scattering, a Co concentration of 0.0017 mass% (17 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0005. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 17.3 ⁇ 4.1 nm.
  • the shell thickness was calculated from formula (2) using the number average particle diameter (D1) of the particles in Example 1, which was 9.5 ⁇ 2.6 nm, and was found to be 3.9 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.0 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. in air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. Thereafter, the powder was further pulverized in a mortar, and the particle density PD was measured with a dry densitometer, which was 2.24 g/cm 3. Similarly, the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.1 and a silica concentration of 24.2% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 174 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 15.4 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.13.
  • the obtained UF concentrate of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 540 nm, 590 nm, and 640 nm.
  • Example 11 ⁇ Preparation of Co-doped colored silica sol> 745 g of pure water, 317 g of the above-mentioned aqueous activated silicic acid solution, and 46 g of aqueous ammonia were added and uniformly mixed to prepare 1,108 g of heel liquid (silica concentration 1.0 mass%, NH3 concentration 1.1 mass%, silica/ NH3 molar ratio 0.26, pH 10.8).
  • the resulting Co-doped colored silica sol sieve liquid was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Co-doped colored silica sol sieve liquid had a pH of 10.4, a silica concentration of 2.4 mass%, an average particle size (D3) of 27 nm as measured by dynamic light scattering, a Co concentration of 0.045 mass% (450 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.019. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 10.5 ⁇ 3.3 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.4 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. under air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. The powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.21 g/cm 3. Similarly, the crushed powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.0 and a silica concentration of 20.5% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 296 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 9.2 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.14.
  • the resulting sized liquid of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the sized liquid of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 525 nm, 580 nm, and 640 nm.
  • Example 12 ⁇ Preparation of Co-doped colored silica sol (with shell layer)> The synthesis of Co-doped colored silica sol particles was carried out under the same conditions as in Example 11. That is, first, 315 g of pure water, 134 g of the above-mentioned aqueous activated silicic acid solution, and 19 g of aqueous ammonia were added and uniformly mixed to prepare 468 g of heel liquid (silica concentration 1.0 mass%, NH3 concentration 1.1 mass%, silica/ NH3 molar ratio 0.26, pH 10.8).
  • 1,454 g of the above aqueous active silicic acid solution was continuously fed at a constant rate over 144 minutes at 80° C. to form a shell layer on the particle surfaces.
  • the liquid temperature in the vessel was maintained at 80° C. for 6 hours with stirring to obtain 2,519 g of a sized liquid of Co-doped colored silica sol (with a shell layer).
  • the granulation liquid of the Co-doped colored silica sol was highly transparent and blue-purple, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the granulation liquid of the Co-doped colored silica sol obtained had a pH of 10.1, a silica concentration of 3.0 mass%, an average particle size (D3) of 24 nm by dynamic light scattering method, a Co concentration of 0.019 mass% (190 mass ppm), and a mass ratio of Co to silica (Co/silica) of 0.0063. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The number average particle size (D1) calculated by image analysis from the electron microscope image of the particles was 11.1 ⁇ 3.8 nm.
  • the shell thickness was calculated from formula (2) using the number average particle diameter (D1) of the particles in Comparative Example 2, which was 10.5 ⁇ 3.3 nm, and was found to be 0.3 nm.
  • the UF filtrate obtained during UF concentration had a pH of 10.2 and a Co concentration below the lower detection limit (less than 0.0001 mass%). Since almost no Co was present in the UF filtrate side, but was present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Co and colored.
  • the obtained UF concentrated solution of the Co-doped colored silica sol was dried at 100° C. in air to obtain a transparent blue-purple powder of the Co-doped colored silica sol. Thereafter, the powder was further pulverized in a mortar, and the particle density PD was measured with a dry densitometer, which was 2.20 g/cm 3. Similarly, the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the resulting UF concentrate of the Co-doped colored silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Co-doped colored silica sol having a pH of 2.2 and a silica concentration of 21.5% by mass.
  • This acidic Co-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-purple acidic Co-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 275 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 9.9 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.12.
  • the resulting sized liquid of Co-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the sized liquid of Co-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Co was confirmed at wavelengths of 525 nm, 580 nm, and 640 nm.
  • Example 13 ⁇ Preparation of Cr-doped colored silica sol> 543 g of pure water, 231 g of the active silicic acid aqueous solution (silica concentration 3.5 mass%, pH 2.9), and 34 g of ammonia water (ammonia concentration 27 mass%) were added and uniformly mixed to prepare 808 g of heel liquid (silica concentration 1.0 mass%, NH3 concentration 1.1 mass%, silica/ NH3 molar ratio 0.26, pH 10.9).
  • the granulation liquid of the obtained Cr-doped colored silica sol was highly transparent and blue-green, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the granulation liquid of the obtained Cr-doped colored silica sol had a pH of 10.4, a silica concentration of 2.7 mass%, an average particle size (D3) of 23 nm by dynamic light scattering method, a Cr concentration of 0.012 mass% (120 mass ppm), and a mass ratio of Cr to silica (Cr/silica) of 0.0044.
  • the particles When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles.
  • the electron microscope image is shown in Figure 1.
  • the number average particle size (D1) calculated by image analysis from the electron microscope image of the particles was 9.3 ⁇ 3.0 nm.
  • the UF concentrated solution of the obtained Cr-doped colored silica sol had a pH of 9.7, a silica concentration of 30.1 mass%, a Cr concentration of 0.13 mass% (1300 mass ppm), and a mass ratio of Cr to silica (Cr/silica) of 0.0043.
  • the UF filtrate obtained during UF concentration had a pH of 10.5 and a Cr concentration below the lower detection limit (less than 0.0001 mass%). Since Cr was almost absent on the UF filtrate side and present on the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Cr and colored.
  • the obtained UF concentrated solution of Cr-doped colored silica sol was dried at 100°C under air to obtain a transparent blue-green Cr-doped colored silica sol powder.
  • the appearance of this Cr-doped colored silica sol powder is shown in Figure 3.
  • the powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.16 g/ cm3 .
  • the crushed powder was measured by X-ray diffraction method, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the XRD pattern is shown in Figure 4.
  • the UF concentrate of the Cr-doped colored silica sol obtained was contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Cr-doped colored silica sol having a pH of 2.5 and a silica concentration of 21.2 mass %.
  • This acidic Cr-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent blue-green acidic Cr-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 307 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 9.0 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.07.
  • the UF concentrate of the obtained Cr-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of the Cr-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Cr was confirmed at wavelengths of 425 nm and 590 nm.
  • the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum are shown in Figure 5.
  • the obtained Cr-doped colored silica sol was placed in a quartz cell with a lid having an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rate before UV irradiation was 100%
  • the absorbance change rate after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 590 nm was 99%, 98%, and 97%, respectively.
  • the results are shown in Table 2 and Figure 6.
  • Example 14 ⁇ Preparation of Mn-doped colored silica sol> 543 g of pure water, 231 g of the active silicic acid aqueous solution (silica concentration 3.5 mass%, pH 2.9), and 34 g of ammonia water (ammonia concentration 27 mass%) were added and uniformly mixed to prepare 808 g of heel liquid (silica concentration 1.0 mass%, NH3 concentration 1.1 mass%, silica/ NH3 molar ratio 0.26, pH 10.9).
  • the obtained Mn-doped colored silica sol sieve liquid was highly transparent and reddish brown, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the obtained Mn-doped colored silica sol sieve liquid had a pH of 10.4, a silica concentration of 2.7 mass%, an average particle size (D3) of 19 nm by dynamic light scattering method, a Mn concentration of 0.012 mass% (120 mass ppm), and a mass ratio of Mn to silica (Mn/silica) of 0.0045.
  • the particles When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles.
  • the electron microscope image is shown in Figure 1.
  • the number average particle size (D1) calculated by image analysis from the electron microscope image of the particles was 10.0 ⁇ 2.8 nm.
  • the UF concentrated solution of the obtained Mn-doped colored silica sol had a pH of 9.8, a silica concentration of 26.5 mass%, a Mn concentration of 0.12 mass% (1200 mass ppm), and a mass ratio of Mn to silica (Mn/silica) of 0.0045.
  • the UF filtrate obtained during UF concentration had a pH of 10.5 and a Mn concentration below the lower detection limit (less than 0.0001 mass%). Since Mn was almost absent in the UF filtrate side and present in the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Mn and colored.
  • the obtained UF concentrated solution of Mn-doped colored silica sol was dried at 100°C under air to obtain a transparent reddish brown powder of Mn-doped colored silica sol.
  • the powder appearance of this Mn-doped colored silica sol is shown in Figure 3.
  • the powder was then crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.18g /cm3.
  • the crushed powder was measured by X-ray diffraction method, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the XRD pattern is shown in Figure 4.
  • the UF concentrate of the obtained Mn-doped colored silica sol was contacted with a hydrogen-type strong acid cation exchange resin to obtain an acidic Mn-doped colored silica sol having a pH of 2.3 and a silica concentration of 19.6 mass %.
  • This acidic Mn-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent reddish brown acidic Mn-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 271 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 10.2 nm, and the number average particle size/BET particle size (D1/D2) ratio was 0.98.
  • the obtained UF concentrate of Mn-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Mn-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Mn was confirmed at a wavelength of 455 nm.
  • the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum are shown in Figure 5.
  • the obtained Mn-doped colored silica sol was placed in a quartz cell with a lid having an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rate before UV irradiation was 100%
  • the absorbance change rate after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 455 nm was 100%, 100%, and 100%, respectively.
  • the results are shown in Table 2 and Figure 6.
  • Example 15 ⁇ Preparation of Cu-doped colored silica sol> 543 g of pure water, 231 g of the active silicic acid aqueous solution (silica concentration 3.5 mass%, pH 2.9), and 34 g of ammonia water (ammonia concentration 27 mass%) were added and uniformly mixed to prepare 808 g of heel liquid (silica concentration 1.0 mass%, NH3 concentration 1.1 mass%, silica/ NH3 molar ratio 0.26, pH 10.9).
  • the resulting Cu-doped colored silica sol sieve liquid was highly transparent and sky blue, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the resulting Cu-doped colored silica sol sieve liquid had a pH of 10.4, a silica concentration of 2.7 mass%, an average particle size (D3) of 19 nm by dynamic light scattering, a Cu concentration of 0.011 mass% (110 mass ppm), and a mass ratio of Cu to silica (Cu/silica) of 0.0041. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The electron microscope image is shown in Figure 1. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 9.7 ⁇ 2.9 nm.
  • the UF concentrated solution of the obtained Cu-doped colored silica sol had a pH of 9.7, a silica concentration of 30.5 mass%, a Cu concentration of 0.13 mass% (1300 mass ppm), and a mass ratio of Cu to silica (Cu/silica) of 0.0043.
  • the UF filtrate obtained during UF concentration had a pH of 10.6 and a Cu concentration below the lower detection limit (less than 0.0001 mass%). Since Cu was almost absent on the UF filtrate side and present on the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Cu and colored.
  • the obtained UF concentrated solution of Cu-doped colored silica sol was dried at 100°C under air to obtain a transparent sky blue powder of Cu-doped colored silica sol.
  • the powder appearance of this Cu-doped colored silica sol is shown in Figure 3.
  • the powder was then further crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.17 g/ cm3 .
  • the crushed powder was measured by X-ray diffraction method, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the XRD pattern is shown in Figure 4.
  • the obtained Cu-doped colored silica sol was contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic Cu-doped colored silica sol having a pH of 2.2 and a silica concentration of 19.8% by mass.
  • This acidic Cu-doped colored silica sol was dried in air at 300° C. for 1 hour to obtain a transparent sky blue acidic Cu-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 280 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 9.9 nm, and the number average particle size/BET particle size (D1/D2) ratio was 0.98.
  • the obtained UF concentrated solution of Cu-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrated solution of Cu-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Cu was confirmed at a wavelength of 640 nm.
  • the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum are shown in Figure 5.
  • the obtained Cu-doped colored silica sol was placed in a quartz cell with a lid having an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rate before UV irradiation was 100%
  • the absorbance change rate after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 640 nm was 99%, 99%, and 99%, respectively.
  • the results are shown in Table 2 and Figure 6.
  • Example 16 ⁇ Preparation of Ni-doped colored silica sol> 284 g of pure water, 10 g of a commercially available JIS No. 3 sodium silicate aqueous solution, and 10 g of a sodium hydroxide aqueous solution (NaOH concentration 10 mass%) were mixed uniformly to prepare 304 g of heel liquid (silica concentration 1.0 mass%, N2O concentration 0.57 mass%, silica/ N2O molar ratio 1.8, pH 12.0).
  • the Ni-doped colored silica sol sieve liquid obtained was highly transparent and green, and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good.
  • the Ni-doped colored silica sol sieve liquid obtained had a pH of 9.4, a silica concentration of 3.1 mass%, an average particle size (D3) of 14 nm as measured by dynamic light scattering, a Ni concentration of 0.031 mass% (310 mass ppm), and a mass ratio of Ni to silica (Ni/silica) of 0.0099. When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The electron microscope image is shown in Figure 1. The number-average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 11.3 ⁇ 2.4 nm.
  • Ni-doped colored silica sol was concentrated by pressure filtration with compressed air at room temperature under stirring using an ultrafiltration (UF) membrane with a molecular weight cutoff of 200,000, and 236 g of a highly transparent and green Ni-doped colored silica sol UF concentrate and 2104 g of a colorless and transparent UF filtrate were recovered.
  • UF ultrafiltration
  • the UF concentrated solution of the Ni-doped colored silica sol obtained had a pH of 8.8, a silica concentration of 30.7 mass%, a Ni concentration of 0.29 mass% (2900 mass ppm), and a mass ratio of Ni to silica (Ni/silica) of 0.0095.
  • the UF filtrate obtained during UF concentration had a pH of 9.1 and a Ni concentration of 0.0002 mass% (2 mass ppm). Since Ni was almost absent on the UF filtrate side and present on the UF concentrated solution side, it was confirmed that the colloidal silica particles were doped with Ni and colored.
  • the obtained UF concentrated solution of Ni-doped colored silica sol was dried at 100°C under air to obtain a transparent green Ni-doped colored silica sol powder.
  • the powder appearance of this Ni-doped colored silica sol is shown in Figure 3.
  • the powder was then further crushed in a mortar and the particle density PD was measured with a dry densitometer, which was 2.17g/ cm3 .
  • the crushed powder was measured by X-ray diffraction method, and the XRD pattern was broad, indicating that the crystallinity of the powder was amorphous.
  • the XRD pattern is shown in Figure 4.
  • the UF concentrate of the Ni-doped colored silica sol obtained was contacted with a hydrogen-type strong acid cation exchange resin to obtain an acidic Ni-doped colored silica sol having a pH of 2.3 and a silica concentration of 24.0 mass %.
  • This acidic Ni-doped colored silica sol was dried in air at 300°C for 1 hour to obtain a transparent green acidic Cr-doped colored silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 262 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 10.6 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.07.
  • the obtained UF concentrate of Ni-doped colored silica sol was filtered through a nylon membrane filter with a pore size of 0.45 ⁇ m, and then the visible-ultraviolet spectrum of the UF concentrate of Ni-doped colored silica sol was measured using pure water as a control. As a result, absorption due to Ni was confirmed at wavelengths of 395 nm, 670 nm, and 750 nm.
  • the visible-ultraviolet transmission spectrum and the visible-ultraviolet absorption spectrum are shown in Figure 5.
  • the obtained Ni-doped colored silica sol was placed in a quartz cell with a lid having an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rates after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 670 nm were 100%, 100%, and 100%, respectively.
  • the results are shown in Table 2 and FIG. 6.
  • the silica sol sieving liquid obtained was highly transparent and no sediment was generated. Furthermore, when a green laser pointer with a wavelength of 532 nm was irradiated, the Tyndall phenomenon was observed, and the dispersibility was good. Although a slight colloidal color was observed, the liquid was colorless and transparent and not colored.
  • the silica sol sieving liquid obtained had a pH of 10.1, a silica concentration of 3.3 mass%, and an average particle size (D3) of 20 nm as measured by dynamic light scattering. The transition metal compound was below the lower detection limit (less than 0.0001 mass%). When the particles were observed with an electron microscope in TEM mode, they were solid spherical particles. The electron microscope image is shown in Figure 1. The number average particle size (D1) calculated from the electron microscope image of the particles by image analysis was 12.5 ⁇ 3.7 nm.
  • silica sol sized liquid obtained was concentrated by pressure filtration with compressed air at room temperature under stirring using an ultrafiltration (UF) membrane with a molecular weight cutoff of 200,000, and 265 g of a colorless and transparent silica sol UF concentrate and 2034 g of a colorless and transparent UF filtrate were recovered.
  • the appearance of this silica sol UF concentrate is shown in Figure 2.
  • the obtained UF concentrated solution of silica sol had a pH of 9.5 and a silica concentration of 28.6% by mass.
  • the transition metal T was below the lower detection limit (less than 0.0001% by mass). No precipitate was generated in the UF concentrated solution of the obtained silica sol.
  • the UF filtrate obtained during UF concentration had a pH of 9.9.
  • the transition metal T was below the lower detection limit (less than 0.0001% by mass).
  • the obtained UF concentrated solution of silica sol was dried at 100° C. in air to obtain a colorless and transparent silica sol powder.
  • the appearance of this silica sol powder is shown in FIG.
  • the powder was then further pulverized in a mortar and the particle density PD was measured with a dry densitometer, which was 2.26 g/ cm3 .
  • the powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the powder was amorphous.
  • the XRD pattern is shown in FIG.
  • the resulting silica sol was then contacted with a hydrogen-type strongly acidic cation exchange resin to obtain an acidic silica sol having a pH of 2.4 and a silica concentration of 24.1% by mass.
  • the acidic silica sol was dried in air at 300° C. for 1 hour to obtain a colorless and transparent acidic silica sol powder.
  • the powder was pulverized in a mortar and measured by nitrogen adsorption to find that the specific surface area (SSA) was 224 m2 /g.
  • the BET particle size (D2) calculated by the nitrogen adsorption method using formula (1) was 11.9 nm, and the number average particle size/BET particle size (D1/D2) ratio was 1.05.
  • the visible-ultraviolet spectrum of the silica sol UF concentrate was measured using pure water as a control. As a result, in the measurement wavelength range of 250 nm to 800 nm, nothing was observed other than absorption due to light scattering by colloidal silica particles with wavelengths of 400 nm or less.
  • the visible-ultraviolet transmission spectrum and visible-ultraviolet absorption spectrum are shown in Figure 5.
  • a red organic pigment dispersion (manufactured by TOKUSHIKI CORPORATION, product name MT-120 Red, pigment Pigment Violet 19, pigment concentration 15% by mass) was diluted with propylene glycol monomethyl ether (PGME) to a pigment concentration of 0.01% by mass to prepare a PGME-diluted red organic pigment dispersion.
  • PGME propylene glycol monomethyl ether
  • the visible-ultraviolet spectrum of this PGME diluted red organic pigment dispersion was measured using PGME as a control, and absorption was confirmed at wavelengths of 490 nm, 525 nm, and 560 nm.
  • the PGME diluted red organic pigment dispersion was placed in a quartz cell with a lid and an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rates after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 560 nm were 35%, 0.3%, and 0.2%, respectively.
  • the results are shown in Table 3 and Figure 7.
  • the PGME diluted yellow organic pigment dispersion was placed in a quartz cell with a lid and an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rates after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 440 nm were 35%, 0.4%, and 0.4%, respectively.
  • the results are shown in Table 3 and Figure 7.
  • a green organic pigment dispersion (manufactured by TOKUSHIKI CORPORATION, product name MT-160 Green, pigment Pigment Green 7, pigment concentration 25% by mass) was diluted with propylene glycol monomethyl ether (PGME) to a pigment concentration of 0.01% by mass to prepare a PGME-diluted green organic pigment dispersion.
  • PGME propylene glycol monomethyl ether
  • the visible-ultraviolet spectrum of this PGME diluted green organic pigment dispersion was measured using PGME as a control, and absorption was confirmed at wavelengths of 320 nm, 365 nm, and 650 nm.
  • the PGME diluted green organic pigment dispersion was placed in a quartz cell with a lid having an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance before UV irradiation was taken as 100%
  • the absorbance change rates after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 650 nm were 74%, 33%, and 5%, respectively.
  • the results are shown in Table 3 and Figure 7.
  • the results are shown in Table 3 and Figure 7.
  • a blue organic pigment dispersion (manufactured by TOKUSHIKI CORPORATION, product name MT-170 Blue, pigment Pigment Blue 15, pigment concentration 15% by mass) was diluted with propylene glycol monomethyl ether (PGME) to a pigment concentration of 0.01% by mass to prepare a PGME-diluted blue organic pigment dispersion.
  • PGME propylene glycol monomethyl ether
  • the visible-ultraviolet spectrum of this PGME diluted blue organic pigment dispersion was measured using PGME as a control, and absorption was confirmed at wavelengths of 345 nm, 630 nm, and 710 nm.
  • the PGME diluted blue organic pigment dispersion was placed in a quartz cell with a lid and an optical path length of 10 mm, and placed in a QUV accelerated weathering tester to evaluate light resistance.
  • the absorbance change rates after 100 hours, 250 hours, and 500 hours of UV irradiation at an absorption wavelength of 630 nm were 77%, 31%, and 6%, respectively.
  • the results are shown in Table 3 and Figure 7.
  • the organic pigments of Comparative Examples 2 to 5 showed an absorbance change rate of 0.2-6% after 500 hours of UV irradiation, meaning that absorption had almost completely disappeared.
  • the transition metal-doped colored silica sols of Examples 1 to 16 showed an absorbance change rate of 64-100% after 500 hours of UV irradiation, meaning that there was no decrease (100%) or only a decrease of about 40%, making it clear that the transition metal-doped silica sol of the present invention has excellent light resistance.
  • Examples 7 to 10 and 12 it was confirmed that light resistance was improved by forming a shell layer on the particle surface.
  • Comparative Example 8 To 10 g of the UF concentrated solution of the silica sol obtained in Comparative Example 1 (silica concentration: 28.6% by mass), 0.48 g of a 10% by mass MnSO4 aqueous solution was added under stirring so that the mass ratio of Mn to silica (Mn/silica) was 0.005. The silica nanoparticles were aggregated to generate a precipitate, which then gelled.
  • Comparative Example 10 To 10 g of the UF concentrated solution of the silica sol obtained in Comparative Example 1 (silica concentration: 28.6% by mass), 0.54 g of a 10% by mass NiSO4 aqueous solution was added under stirring so that the mass ratio of Ni to silica (Ni/silica) was 0.005. As a result, the silica nanoparticles aggregated and a precipitate was generated, followed by gelation.
  • Example 17 ⁇ Preparation of pigment composition containing Co-doped colored silica sol>
  • the UF concentrated solution of the Co-doped colored silica sol obtained in Example 1 was dried at 100°C under air, and then heat-treated at 600°C for 1 hour to obtain a transparent blue-purple Co-doped colored silica sol powder.
  • the powder was then pulverized in a mortar to obtain a powder.
  • the pulverized powder was measured by X-ray diffraction, and the XRD pattern was broad, indicating that the powder was amorphous. 1 g of this pulverized powder was mixed with 4 g of a commercially available aqueous solution of sodium silicate (JIS No. 3) to obtain a pigment composition.
  • JIS No. 3 commercially available aqueous solution of sodium silicate
  • Example 18 ⁇ Preparation of pigment composition containing Co-doped colored silica sol> 2.7 g of the UF concentrate of the Co-doped colored silica sol obtained in Example 4 (silica concentration: 27.5% by mass), 2.1 g of an aqueous polyester-based urethane resin (product name: Hydran HW-171, manufactured by DIC Corporation, solid content: 35% by mass) and 0.2 g of water were mixed to obtain 5.0 g of a pigment composition consisting of a blue-purple dispersion having a silica concentration of 15% by mass, a solid content of the aqueous polyester-based urethane resin of 15% by mass, and a total solid content of 30% by mass, relative to 100% by mass of the pigment composition.
  • a pigment composition consisting of a blue-purple dispersion having a silica concentration of 15% by mass, a solid content of the aqueous polyester-based urethane resin of 15% by mass, and a total solid content of 30% by mass, relative
  • Example 19 ⁇ Preparation of pigment composition containing Co-doped colored silica sol> 2.4 g of the UF concentrate of the Co-doped colored silica sol obtained in Example 3 (silica concentration 30.9% by mass), 2.1 g of an aqueous polyester-based urethane resin (product name Hydran AP-40N, manufactured by DIC Corporation, solid content 35% by mass) and 0.5 g of water were mixed to obtain 5.0 g of a pigment composition consisting of a blue-purple dispersion having a silica concentration of 15% by mass, a solid content of the aqueous polyester-based urethane resin of 15% by mass, and a total solid content of 30% by mass, relative to 100% by mass of the pigment composition.
  • a pigment composition consisting of a blue-purple dispersion having a silica concentration of 15% by mass, a solid content of the aqueous polyester-based urethane resin of 15% by mass, and a total solid content of 30% by mass, relative to 100%
  • ⁇ Preparation of a colored film containing Co-doped colored silica sol> 3 g of the obtained pigment composition was used as a coating material, and applied to a 125 ⁇ m thick PET film at 4 m/s with a bar coater to a wet film thickness of 150 ⁇ m, and heat-treated at 100° C. for 5 minutes to form a blue-purple transparent film.
  • the film thickness was measured with a scanning electron microscope (SEM) and found to be 35 ⁇ m.
  • SEM scanning electron microscope
  • the visible-ultraviolet spectrum of the obtained film was measured using air as a control. As a result, absorption was confirmed at wavelengths of 525 nm, 580 nm, and 640 nm.
  • Example 20 ⁇ Preparation of pigment composition containing Co-doped colored silica sol> 2.4 g of the UF concentrate of the Co-doped colored silica sol obtained in Example 3 (silica concentration 30.9% by mass), 2.1 g of an aqueous polyester-based urethane resin (product name Hydran AP-40N, manufactured by DIC Corporation, solid content 35% by mass) and 0.5 g of water were mixed to obtain 5.0 g of a pigment composition consisting of a blue-purple dispersion having a silica concentration of 15% by mass, a solid content of the aqueous polyester-based urethane resin of 15% by mass, and a total solid content of 30% by mass, relative to 100% by mass of the pigment composition.
  • a pigment composition consisting of a blue-purple dispersion having a silica concentration of 15% by mass, a solid content of the aqueous polyester-based urethane resin of 15% by mass, and a total solid content of 30% by mass, relative to 100%
  • Example 20 As shown in Figure 9, the molded product obtained in Example 20 was colored, whereas the molded products obtained in Comparative Examples 14 and 15 were not colored. As described above, it has become clear that the transition metal-doped colored silica sol of the present invention has excellent coloring properties.
  • pigment compositions containing the transition metal-doped colored silica sol of the present invention include bicycles, motorbikes, automobiles, railroad vehicles, ships, aircraft, rockets, buildings, building materials, roofing materials, exterior wall materials, wall materials, flooring materials, ceiling materials, undercoats, signs, bulletin boards, signs, traffic lights, utility poles, electric wires, street lights, mailboxes, roads, bridges, window glass, glasswork, industrial electrical appliances, household electrical appliances, furniture, kitchen equipment, sanitary equipment, cooking utensils, tableware, containers, stationery, clothing, decorative items, etc. In particular, it is preferably used in applications where transparency and light resistance are required.
  • a pigment composition containing the transition metal-doped colored silica sol of the present invention can be applied to glass and then heated and cooled, or added to a glass raw material and then melted, cooled, and vitrified, thereby producing colored glass.
  • the pigment composition containing the transition metal-doped colored silica sol of the present invention can also be used in various other products for the purpose of coloring.

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  • Wood Science & Technology (AREA)
  • Inorganic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Silicon Compounds (AREA)
  • Pigments, Carbon Blacks, Or Wood Stains (AREA)
  • Paints Or Removers (AREA)
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118788340A (zh) * 2024-06-11 2024-10-18 南平青华科技有限公司 一种用于合成柠檬烯-4-醇的催化剂及其应用

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003267720A (ja) * 2002-03-15 2003-09-25 Mitsubishi Chemicals Corp 異元素含有シリカゲル
JP2005022897A (ja) * 2003-06-30 2005-01-27 Mitsubishi Chemicals Corp 異元素含有シリカゲル
JP2005022896A (ja) * 2003-06-30 2005-01-27 Mitsubishi Chemicals Corp 異元素担持シリカゲル
JP2006342023A (ja) * 2005-06-09 2006-12-21 Asahi Kasei Corp 中空シリカゾル及び中空シリカ微粒子
WO2007007751A1 (ja) * 2005-07-12 2007-01-18 Nissan Chemical Industries, Ltd. 表面処理シリカゾル、その製造方法及びインクジェット記録媒体
WO2009101974A1 (ja) * 2008-02-12 2009-08-20 Nissan Chemical Industries, Ltd. シリカコロイド粒子及びその製造方法、並びにその有機溶媒分散シリカゾル、重合性化合物分散シリカゾル及びジカルボン酸無水物分散シリカゾル
JP5389374B2 (ja) * 2008-04-23 2014-01-15 株式会社アドマテックス 着色非晶質シリカ微粒子及びその製造方法並びに着色非晶質シリカ微粒子含有樹脂組成物
JP2021187732A (ja) * 2020-05-27 2021-12-13 東洋製罐グループホールディングス株式会社 金属がドープされた多孔質シリカを含むスラリーの製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003267720A (ja) * 2002-03-15 2003-09-25 Mitsubishi Chemicals Corp 異元素含有シリカゲル
JP2005022897A (ja) * 2003-06-30 2005-01-27 Mitsubishi Chemicals Corp 異元素含有シリカゲル
JP2005022896A (ja) * 2003-06-30 2005-01-27 Mitsubishi Chemicals Corp 異元素担持シリカゲル
JP2006342023A (ja) * 2005-06-09 2006-12-21 Asahi Kasei Corp 中空シリカゾル及び中空シリカ微粒子
WO2007007751A1 (ja) * 2005-07-12 2007-01-18 Nissan Chemical Industries, Ltd. 表面処理シリカゾル、その製造方法及びインクジェット記録媒体
WO2009101974A1 (ja) * 2008-02-12 2009-08-20 Nissan Chemical Industries, Ltd. シリカコロイド粒子及びその製造方法、並びにその有機溶媒分散シリカゾル、重合性化合物分散シリカゾル及びジカルボン酸無水物分散シリカゾル
JP5389374B2 (ja) * 2008-04-23 2014-01-15 株式会社アドマテックス 着色非晶質シリカ微粒子及びその製造方法並びに着色非晶質シリカ微粒子含有樹脂組成物
JP2021187732A (ja) * 2020-05-27 2021-12-13 東洋製罐グループホールディングス株式会社 金属がドープされた多孔質シリカを含むスラリーの製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118788340A (zh) * 2024-06-11 2024-10-18 南平青华科技有限公司 一种用于合成柠檬烯-4-醇的催化剂及其应用

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