| abstract |
PURPOSE:To obtain a lithographic plate material superior in photosensitivity to the visible rays and physical properties for printing by forming a photosensitive resin layer composed of an additionally polymerizable compound having an ethylenically unsaturated double bond and a specified photopolymerization initiation system on the hydrophilic surface of a support. CONSTITUTION:The photosensitive resin layer containing the additionally polymerizable compound having an ethylenically unsaturated double bond, such as an unsaturated carboxylic acid, and as the photopolymerization initiation system, xanthene or its derivative represented by the formula shown on the right and a photosensitivity promotor is formed on the hydrophilic surface of the support, such as Al, Zn, or Ni. In that formula, A is halogen; Y is a C or 0 atom, and when it is a C atom, the bond expressed with a dotted line is a double bond; Z is an 0 atom combined with an adjacent C atom through a double bond, lower alkoxy, or lower alkanoyloxy; R<1> is lower alkyl, lower hydroxyalkyl, lower-alkoxylated lower alkyl, di-(lower alkylamino)-(lower alkyl), or aryl; and R<2> is lower alkoxy or lower dialkylamino. |