Manufacture method of metal plate substrate for computer-to-plate of inkjet printing

A method for preparing a metal substrate for inkjet Computer-To-Plate (CTP), the method selected from the group consisting of an anodization method, a non-anodizing method, and a direct method;

• (1) the anodization method consisting of:
• (a) treating the metal substrate by anodization;
• (b) applying uniformly a hydrophilic polymer paint on a surface of the anodized metal substrate;
• and
• (c) drying the surface;
• (2) the non-anodizing method consisting of:
• (a) treating the metal substrate directly by sandpaper burnishing, sand blasting, polishing, or brushing;
• (b) applying uniformly the hydrophilic polymer paint on the surface of the treated metal substrate;
• and
• (c) drying the surface;
• and
• (3) the direct method consisting of directly applying uniformly the hydrophilic polymer paint on
• the metal substrate;
• wherein the hydrophilic polymer paint used in the anodization method, the non-anodizing method, and the direct method consists of
• a hydrophilic polymer having a concentration from 0.95 weight % to 15 weight %;
• nano-size or micron-size oxide particles having a concentration from 0.05 weight % to 15 weight %;
• at least one additive having a concentration from 0% weight % to weight %;
• and
• at least one solvent remaining;
• wherein the hydrophilic polymer is
• (a) at least one selected from polyvinyl alcohol, polyvinyl acetal, gelatin, polyacrylamide resin, and polyvinylpyrrolidone;
• or
• (b) at least one selected from water-soluble phenolic resin, polyacrylic resin, polyacrylic resin ester, polymethacrylic resin, polymethacrylic resin ester, polyethylene glycol, polyethylene glycol acetal, cellulose polymer, copolymer of acrylic acid and acrylate, copolymer of methacrylic acid and methacrylic ester, copolymer of acrylic acid and methacrylic ester, and copolymer of methacrylic acid and acrylate;
• wherein each of the nano-size or micron-size oxide particles (a) has a particle size from 10 nanometers to 3,000 nanometers and (b) is one selected from one of silica, alumina, or titania;
• wherein the coating amount of the hydrophilic polymer paint on the metal substrate from 1 g/m2 to 2.5 g/m2 and wherein the at least one additive is at least one of a cationic fixing agent, an anti-foaming agent, or an antioxidant.