| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical disk which has transparency, surface hardness and durability and is free from warpage and by which writing and/or reading are performed. SOLUTION: The optical disk is obtained by forming a hardened material layer of a protective coating material composition for the optical disk, containing a urethane (metha)acrylate compound (A) having at least two radically polymerizable (metha)acryloyloxy groups, at least one amide group and at least two urethane groups in the molecule thereof, an ethylenically unsaturated compound (B) except the (A) component and a photopolymerization initiator (C). |
