PURPOSE: To obtain a hard coating agent excellent in scratch resistance and high hardness, etc., and useful for plastic lens, etc., by blending a specific organosilicon compound with complex fine particles of tungsten oxide and tin oxide and aluminum perchlorate.
CONSTITUTION: The hard coating agent is obtained by blending (A) an organosilicon compound of the formula R1aSi(OR2)4-a (R1 is 2-8C epoxy, 1-6C alkyl, alkenyl, etc.; R2 is H, 1-4C alkyl, alkoxyalkyl or acyl; (a) is 1, 2 or 3), or partially hydrolyzed product thereof with (B) double oxide fine particles of tungsten oxide and tin oxide or double oxide fine particles of zirconium oxide and tin oxide and (C) aluminum perchlorate. Furthermore, as the double oxide fine particles of the component B, particles treated with a basic substance and stabilized under basic conditions are preferably used and the particle diameter is preferably 2-100mμ.
SATO KAZUHARU
YAMAMOTO KENJI
