OIL-BASE INK FOR INK JET PROCESS PRINTING PLATE AND METHOD FOR FORMING PRINTING PLATE BY USING SAME

摘要

PROBLEM TO BE SOLVED: To provide an oil-base ink improved in dispersion stability, re-dispersibility, storage stability, image reproducibility, and plate wear by selecting an ink for forming a printing plate composed of a water-resistant support and an image receptive layer formed thereon and containing zinc oxide and a binder resin, wherein the resin is prepared by polymerizing a solution containing (A) a monofunctional monomer, (MA) a monofunctional macromonomer, and (P) a dispersion stabilizing resin and granulating the polymer. SOLUTION: A printing plate is provided in which the angle of contact of the surface of an image receptive layer with water is 30 deg. or greater, and the non-image area is desensitized. The ink is prepared by dispersing resin particles in a nonaqueous carrier fluid having an electric resistance of 10<9>Ωcm or above and a permittivity of 3.5 or below. Component A is a monomer which is miscible with the carrier fluid, is soluble in a nonaqueous solution, and is insolubilized therein when polymerized, component MA is a macromonomer having a weight-average molecular weight of 2×10<4> or below and having a main chain represented by formula I (V<0> is -COO- or the like) and having a polymerizable double bond group of formula II (V<1> is -COO- or the like) at either terminal, and component P is a resin being soluble in a nonaqueous solution and containing a comonomer component of formula III (R<1> is a 10-32C alkyl or the like).