Nanoparticle-containing solution and use thereof

Nanoparticle-containing resin particles comprising:

• a resin, and
• metal oxide nanoparticles dispersed within the resin,
• the metal oxide nanoparticles being hydrophobized with a phosphoric acid ester and a reactive group-containing carbonyl compound, wherein:
• the phosphoric acid ester is a compound represented by the following general formula (I):
• where:
• R1 is an alkyl group having 8 to 13 carbon atoms or an allyl group,
• R2 is H or CH3,
• n is 1 to 30, and
• the compound is a mixture in which a combination of a and b is a combination of 1 and 2 or 2 and 1;
• and
• the reactive group-containing carbonyl compound is selected from:
• a reactive group-containing carboxylic acid represented by the following general formula (II):
• CH2═CR3—Z—COOH (II)
• where:
• R3 is H or CH3, and
• Z is a divalent hydrocarbon group of 5 or more carbon atoms optionally containing an ester group;
• and
• a reactive group-containing cyclic ester represented by the following general formula (III):
• CH2═CR3—X-M (III)
• where:
• R3 is H or CH3,
• X is a divalent hydrocarbon group of 1 or more carbon atoms optionally containing an ester group, and
• M is a lactone or a lactide.