Disclosed is a
coating composition comprising: (a)
hydroxy group-containing
inorganic particles having an average particle
diameter of between 5 and 30 nm; (b)
hydroxy group- containing
inorganic particles having an average particle
diameter of between 0.2 and 5 [mu]m; (c) an organosilane compound represented by the formula of RnSi(OR') 4-n (wherein R is a C1-C8 aminoalkyl group, glycidoxyalkyl group or isocyanatoalkyl group; R'is a C1-C6 lower
alkyl group; and n is an integer of between 0 and 3); and (d) a
solvent. A method for preparing the above
coating composition, a substrate such as film or structural exterior material, having excellent self-cleaning property and
staining resistance by using the above
coating composition and methods for producing the same are also disclosed. The coating composition using
hydroxy group-containing
inorganic particles can improve the initial hydrophilicity of conventional coating agents. Additionally, the coating composition can form a
hydrophilic coating layer having a
contact angle with water of 30 DEG or less by using two kinds of inorganic particles having a different particles
diameter. Particularly, the coating composition uses an
organic solvent having erosive property to a substrate to be coated and a low
boiling point, and thus can be applied to a conventional
production line for structural exterior materials without adding a separate coating line. Therefore, the coating composition can provide structural materials having hydrophilicity, excellent self-cleaning property and long service life, when coated on substrates such as vinyl sidings.