Patent ID: 7361394

Claim:
An optical disk of a system wherein a substrate, a recording layer and a thin film cover layer (V) with a thickness of from 5 to 200 μm, are laminated in this order, and the recording layer is to be irradiated through the thin film cover layer (V) with a blue laser beam to be used for recording and/or retrieving data, wherein a hard coating layer (W) is formed on the thin film cover layer (V), and the hard coat layer (W) is made of a cured product of a coating composition (X) comprising a polyfunctional compound (A) having at least two active energy ray curable polymerizable functional groups, a water and oil repellency-imparting agent (B), an active energy ray polymerization initiator (C) and a colloidal silica (D) having an average particle size of from 1 to 200 nm, provided that the water and oil repellency-imparting agent (B) is a water and oil repellency-imparting agent (B-T) having, in one molecule, a moiety (b-1) exerting water and oil repellency and selected from the group consisting of portions represented by the following formulae (6) to (8), a moiety (b-2) made of at least one portion selected from the group consisting of portions represented by the following formulae (1) to (4), and an active energy ray curable functional group (b-3): —R 1 — Formula (1) —(CH 2 CH 2 O) x — Formula (2) —(CH 2 CH(CH 3 )O) y — Formula (3) —(C(═O)C u H 2u O) t — Formula (4) wherein R 1 is a C 6-20 alkylene group, each of x and y is an integer of from 5 to 100, u is an integer of from 3 to 5, and t is an integer of from 1 to 20, —(CF 2 CF 2 O) p — Formula (6) —(CF 2 CF(CF 3 )O) q — Formula (7) —(CF 2 CF 2 CF 2 O) r — Formula (8) wherein each of p,q, and r is an integer of from 1 to 100.