Method for producing oxide particles with controlled color characteristics, oxide particles, and coating or film-like composition comprising the same

A coating or film-like oxide composition comprising the oxide particles composed of any one oxide of an iron oxide, a zinc oxide, and a cerium oxide,

• wherein at least a part of a surface of the oxide particles is coated with a silicon compound,
• wherein the silicon compound is able to change the color characteristics of the oxide particles by coating at least a part of the surface of the oxide particles, and
• wherein a combination of the oxide particles, a ratio of M-OH bonds contained in the oxide particles and color characteristics of the oxide particles, is any one of the following f1 to h1:
• f1:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 8% or more and 14.5% or less, the average reflectance of the oxide particles for light rays at wavelengths of 780 nm to 2500 nm is 50% or more;
• f2:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 10% or more and 15% or less, and the maximum reflectance of the oxide particles for light rays at a wavelength of 400 nm to 620 nm is 18% or less;
• f3:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 9.5% or more and 13% or less, and the average reflectance of the oxide particles for light rays at wavelengths of 620 nm to 750 nm is 22% or less;
• f4:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 8% or more and 15% or less, and hue H (=b*/a*) in an L*a*b* colorimetric system is in the range of 0.5 to 0.9;
• f5:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 9% or more and 15% or less, and, in a transmission spectrum of a dispersion in which the oxide particles are dispersed in a dispersion medium, the transmittance for light rays at a wavelength of 380 nm is 5% or less and the transmittance for light rays at a wavelength of 600 nm is 80% or more;
• f6:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 9% more and 15% or less, and, in a dispersion in which the oxide particles are dispersed in a dispersion medium, an average molar absorption coefficient for light rays at wavelengths of 190 nm to 380 nm is 2200 L/(mol·cm) or more;
• f7:
• the oxide particles are iron oxide particles, the oxide particles include ester bonds, and the ratio of M-OH bonds contained in the oxide particles is 9% or more and 13% or less, and the average reflectance of the oxide particles for light rays at wavelengths of 780 nm to 2500 nm is 50% or more;
• f8:
• the oxide particles are iron oxide particles, the ratio of M-OH bonds contained in the oxide particles is 8% or more and 9.3% or less, or 13.3% or more and 15% or less, and the average reflectance of the oxide particles for light rays at wavelengths of 620 nm to 750 nm is higher than 22%;
• g1:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 30% or more and 39% or less, and the average reflectance of the oxide particles for light rays at wavelengths of 780 nm to 2500 nm is 72% or more;
• g2:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 30% or more and 36% or less, and a wavelength at which the reflectance of the oxide particles is 15% is 375 nm or more;
• g3:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 38% or more and 42% or less, and an average reflectance for light rays at wavelengths of 380 nm to 780 nm is 86% or more;
• g4:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 31% or more and 39% or less, and a color saturation C(=((a*)2+(b*)2)1/2) in an L*a*b* colorimetric system is in the range of 0.5 to 13;
• g5:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 38% or more and 42% or less, and, in a transmission spectrum of a dispersion in which the oxide particles are dispersed in a dispersion medium, the transmittance for light rays at a wavelength of 340 nm is 10% or less and the average transmittance for light rays at wavelengths of 380 nm to 780 nm is 92% or more;
• g6:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 30% or more and 36% or less, and, in a transmission spectrum of a dispersion in which the oxide particles are dispersed in a dispersion medium, a wavelength at which the reflectance of the oxide particles is 15% is 365 nm or more;
• g7:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 30% or more and 42% or less, and, in a dispersion in which the oxide particles are dispersed in a dispersion medium, an average molar absorption coefficient for light rays at wavelengths of 200 nm to 380 nm is 700 L/(mol·cm) or more;
• g8:
• the oxide particles are zinc oxide particles, the ratio of M-OH bonds contained in the oxide particles is 31% or more and 39% or less, a color saturation C(=((a*)2+(b*)2)1/2) in an L*a*b* colorimetric system is in the range of 0.5 to 13, and an L* value in the L*a*b* colorimetric system is in the range of 95 to 97, and
• h1:
• the oxide particles are cerium oxide particles, the ratio of M-OH bonds contained in the oxide particles is 25% or more and 35% or less, and in a dispersion in which the oxide particles are dispersed in a dispersion medium, an average molar absorption coefficient for light rays at wavelengths of 200 nm to 380 nm is 4000 L/(mol·cm) or more.