Planographic printing plate and preparation method and use thereof

A planographic printing plate consisting of:

• a metal substrate;
• and
• a hydrophobic priming coat formed on a surface of the metal substrate and a hydrophilic graphic layer formed on the priming coat, wherein the hydrophobic priming coat is formed by a hydrophobic primer liquid through curing, the hydrophilic graphic layer is formed by inkjet-printing and curing a printing plate-making ink onto the hydrophobic priming coat, wherein:
• based on a total weight of the printing plate-making ink, the components of the printing plate-making ink and their contents are:
• 0.5-20 wt. % of a first film-forming resin,
• 0.1-15 wt. % of a second film-forming resin,
• 0.01-5 wt. % of a nanoscale or micron-scale dye,
• 0-5 wt. % of an additive, and
• a solvent,
• wherein, the first film-forming resin is selected from the group consisting of a homopolymer of (meth)acrylic acid and a copolymer of (meth)acrylic acid with C1-4 alkyl (meth)acrylate;
• the second film-forming resin is selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyoxyethylene, polyvinylpyrrolidone, urea resin, polyacrylamide, polyamine, polymaleic anhydride, water soluble epoxy resin, water soluble phenolic resin water soluble polyurethane, and combinations thereof;
• and
• based on a total weight of the hydrophobic primer liquid, the components of the hydrophobic primer liquid and their contents are:
• 0.01-20 wt. % of a polyolefin,
• 0.2-2 wt. % of a metal adhesion promoter, and
• a solvent;
• the polyolefin contains a polymer represented by the following formula
• wherein R3 is selected from the group consisting of hydrogen, phenyl, chlorine, alkyl with 1-4 carbon atoms, aryl with at least one benzene ring, bromine or chlorine, p is at least 5;
• the metal adhesion promoter is selected from the group consisting of silane coupling agent, titanate coupling agent, aryl phosphate, hyperphosphate polyester polymer, alkyl phosphate, zirconium aluminate, zirconate, and combinations thereof.