Developer for photopolymerizable presensitized plate for use in making lithographic printing plate

Abstract

A developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate characterized in that it comprises an alkali silicate and a nonionic compound represented by the following general formula (I), it has a molar ratio: SiO 2 /M 2 O (wherein M represents an alkali metal or an ammonium group) ranging from 0.75 to 4.0, a pH value ranging from 11.5 to 12.8 and a conductivity ranging from 3 to 30 mS/cm: A-W  (I) wherein A represents a hydrophobic organic group whose logP as determined for A-H is not less than 1.5 and W represents a nonionic hydrophilic organic group whose logP as determined for W-H is less than 1.0. The developers according to the present invention can prevent scumming during printing and simultaneously attain sufficient printing durability without impairment of image-forming performance, and the developer can dissolve or disperse stably for a long period of time the compounds which are not soluble in the developer, and therefore the running performance of the developer can be excellent and stabilized.

1 . A developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate characterized in that it comprises an alkali silicate and a nonionic compound represented by the following general formula (1), it has a molar ratio: SiO 2 /M 2 O (wherein M represents an alkali metal or an ammonium group) ranging from 0.75 to 4.0, and a pH value ranging from 11.5 to 12.8:  
         A-W  (I)  
       wherein A represents a hydrophobic organic group whose logP as determined for A-H is not less than 1.5 and W represents a nonionic hydrophilic organic group whose logP as determined for W-H is less than 1.0.  
     
     
         2 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein the alkali silicate is selected from the group consisting of sodium silicate, potassium silicate, lithium silicate and ammonium silicate.  
     
     
         3 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein the molar ratio: SiO 2 /M 2 O ranges from 1.0 to 3.0.  
     
     
         4 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein the content of the alkali silicate ranges from 0.1 to 3% by weight as expressed in terms of the amount of silicon dioxide (SiO 2 ).  
     
     
         5 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein the content of the nonionic compound ranges from 0.1 to 15% by weight.  
     
     
         6 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein the nonionic compound is at least one member selected from the group consisting of nonionic aromatic ether type surfactants represented by the following general formula (I-A) and nonionic aromatic ether type surfactants represented by the following general formula (I-B):  
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  each represents H or an alkyl group having 1 to 100 carbon atoms and n and m each represents an integer ranging from 0 to 100, provided that n and m are not simultaneously zero.  
     
     
         7 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein it comprises carbonic acid or a carbonate.  
     
     
         8 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein it comprises an alkaline agent selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium tertiary phosphate, potassium tertiary phosphate, ammonium tertiary phosphate, sodium secondary phosphate, potassium secondary phosphate, ammonium secondary phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium borate, potassium borate and ammonium borate, potassium citrate, sodium citrate, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and mixture thereof.  
     
     
         9 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , wherein it comprises a chelating agent for divalent metals.  
     
     
         10 . The developer for a photopolymerizable presensitized plate for use in making a lithographic printing plate of  claim 1 , which has a conductivity ranging from 3 to 30 mS/cm.  
     
     
         11 .- 26 . (canceled)