| 摘要 |
PURPOSE:To form oleophilic unexposed areas serviceable as an offset printing plate by forming a photosensitive layer contg. at least a diazonium salt and a water-soluble binder on a water-proof support and coupling it with a coupler compd. having an oleophilic group using an aq. alkaline soln. contg. this coupler. CONSTITUTION:An especially suitable diazonium salt used for a diazo copying material is compds. represented by formulae I , II, and III in which R1, R2 are each 1-5C alkyl, alkoxy oxyalkyl, benzyl, or the like; Y, Z are each halogen, 1-5C alkyl, carboxy, or the like; m, n are each an integer of 0-4; X is an anion, such as Cl<->, Br<->, SO4<2->, ClO4<->, or PF6<->, or an adduct consisting of one of said anions and one of ZnCl2, CdCl2, SnCl4, etc. As said hydrophilic binder, a water- soluble resin is suitable. |
