Method of producing aluminum substrate for planographic printing plate and method of recycling planographic printing plate

Abstract

A method of producing an aluminum substrate for a planographic printing plate is provided in which a recycled material including a used planographic printing plate having a planographic printing plate support obtained by treating an aluminum substrate is prepared, a recycled bare metal is obtained from the recycled material, and a new aluminum bare metal and a trace-metal master alloy of necessary amounts are mixed into the recycled bare metal to produce a new aluminum substrate.

1 . A method of producing an aluminum substrate for a planographic printing plate, the method sequentially comprising:
 preparing a recycled material including a used planographic printing plate having a planographic printing plate support obtained by treating an aluminum substrate;   producing a recycled bare metal by introducing the obtained recycled material into a melting furnace, melting the recycled material at a temperature of from 680° C. to 900° C. to obtain a recycled material melt, and shaping the recycled material melt into a predetermined shape with a predetermined weight;   analyzing the aluminum purity and a trace metal content of the obtained recycled bare metal;   comparing analysis values of the aluminum purity and the trace metal content of the obtained recycled bare metal with a desired aluminum purity and a desired trace metal content predetermined for a planographic printing plate support in order to calculate differences therebetween, and determining a mixture ratio of a new aluminum bare metal and a trace-metal master alloy with a determined purity with respect to the recycled bare metal on the basis of the calculated differences;   producing a pre-rolling melt by introducing the recycled bare metal, the new aluminum bare metal, and the trace-metal master alloy into a pre-rolling melting furnace at amounts corresponding to the determined mixture ratio, and heating and melting; and   producing a strip-shaped aluminum substrate by rolling the obtained pre-rolling melt.   
     
     
         2 . The method of producing an aluminum substrate for a planographic printing plate according to  claim 1 , wherein the planographic printing plate support is obtained by sequentially performing a roughening treatment, an anodization treatment, and a hydrophilizing treatment using an aqueous solution including polyvinyl phosphonic acid on the aluminum substrate. 
     
     
         3 . The method of producing an aluminum substrate for a planographic printing plate according to  claim 2 , wherein the recycled material further includes at least one of cut pieces of the aluminum substrate or cut pieces of the planographic printing plate, which are generated during producing the planographic printing plate. 
     
     
         4 . The method of producing an aluminum substrate for a planographic printing plate according to  claim 1 , wherein the planographic printing plate support is obtained by sequentially performing a roughening treatment and an anodization treatment using an electrolytic solution including phosphoric acid on the aluminum substrate. 
     
     
         5 . The method of producing an aluminum substrate for a planographic printing plate according to  claim 4 , wherein the recycled material further includes at least one of cut pieces of the aluminum substrate or cut pieces of the planographic printing plate, which are generated during producing a planographic printing plate precursor. 
     
     
         6 . The method of producing an aluminum substrate for a planographic printing plate according to  claim 4 , wherein a content of the phosphoric acid in the electrolytic solution is in a range of from 10% by mass to 50% by mass. 
     
     
         7 . A method of recycling a planographic printing plate, the method sequentially comprising:
 producing a planographic printing plate support obtained by treating an aluminum substrate for the planographic printing plate;   producing a planographic printing plate precursor by forming an image recording layer on the treated surface of the planographic printing plate support;   processing the obtained planographic printing plate precursor to obtain a planographic printing plate and performing a desired printing on the obtained planographic printing plate;   recovering the used planographic printing plate generated after printing; and   recycling the recovered planographic printing plate by providing the recovered planographic printing plate as the recycled material of an aluminum substrate in the method of producing an aluminum substrate for a planographic printing plate of  claim 1 .   
     
     
         8 . The method of recycling a planographic printing plate according to  claim 7 , wherein the planographic printing plate support is obtained by sequentially performing a roughening treatment, an anodization treatment, and a hydrophilizing treatment using an aqueous solution including polyvinyl phosphonic acid on at least one surface of an aluminum substrate for the planographic printing plate. 
     
     
         9 . The method of recycling a planographic printing plate according to  claim 8 , wherein the aluminum substrate for the planographic printing plate is the aluminum substrate for the planographic printing plate obtained by the method of producing an aluminum substrate for a planographic printing plate according to  claim 2 . 
     
     
         10 . The method of recycling a planographic printing plate according to  claim 7 , wherein the planographic printing plate support is obtained by sequentially performing a roughening treatment and an anodization treatment using an electrolytic solution including phosphoric acid on at least one surface of an aluminum substrate for the planographic printing plate. 
     
     
         11 . The method of recycling a planographic printing plate according to  claim 10 , wherein the aluminum substrate for the planographic printing plate is the aluminum substrate for the planographic printing plate obtained by the method of producing an aluminum substrate for a planographic printing plate according to  claim 4 .