Patent ID: 7306850

Claim:
A substrate for a planographic printing plate, the substrate comprising aluminum and including a hydrophilic surface formed by a hydrophilic polymer including a functional group that chemically bonds to the aluminum substrate directly or is chemically bindable to the aluminum substrate via structural component having a crosslinking structure, wherein the hydrophilic polymer includes the functional group at the terminal of the main chain, and wherein the hydrophilic surface comprises a polymer compound represented by the general formula (III), the polymer compound represented by the general formula (III) being a polymer compound comprising the following units (i′) to (iii′), and a silane coupling group represented by unit (iii′) is a terminal and bonded to at least one of the units (i′) and (ii′); in the general formula (III), each of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms; m is an integer of 0 to 2; x and y are numbers showing a ratio of compositions when x+y=100, and a ratio of x to y=100:0 to 1:99; each of L 1 , L 2 and L 3 represent a single bond or an organic linking group; each of Y 1 and Y 2 represents —N(R 7 )(R 8 ), —OH, —NHCOR 7 —, —CO 2 M—, or —SO 3 M; each of R 7 and R 8 independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; and M represents one of a hydrogen atom, an alkali metal, an alkaline earth metal and an onium.