Ink composition for waterless lithography and methods of printing therefrom

In an ink composition for waterless lithography consisting essentially of about 15 to about 35 percent by weight of a vehicle resin, said vehicle resin being selected from the group consisting of a rosin-modified phenolic resin, a phenolic resin, an alkyd resin, a rosin ester resin, a petroleum resin, a maleic resin and mixtures thereof, about 5 to about 25 percent by weight of a drying or semi-drying oil, about 15 to about 45 percent by weight of a mineral oil and about 1 to about 40 percent by weight of a coloring material, the improvement in that said mineral oil comprises high-boiling petroleum solvent mixtures having a boiling point higher than 200.degree. C. and contains less than 5 percent by volume of aromatic components, and in which all or a part of said drying or semi-drying oil is replaced by a member selected from the group consisting of an aliphatic acid ester, an aliphatic dibasic acid ester, a phosphoric acid ester and mixtures thereof, said aliphatic acid ester being selected from the esters prepared by the esterification reaction of saturated aliphatic acids having 4 to 10 carbon atoms, oleic acid and elaidic acid with saturated monohydroxy alcohols having 1 to 8 carbon atoms, said aliphatic dibasic acid ester being selected from the diesters prepared by the esterification reaction of saturated dibasic acids having 2 to 10 carbon atoms, maleic acid and fumaric acid with saturated monohydroxy alcohols having 1 to 8 carbon atoms, said member having a boiling point higher than 200.degree. C. and a coagulating point less than -5.degree. C.

A litographic printing method comprising putting the following ink composition on a waterless lithographic printing plate in the absence of any kind of water fountain system to mask the non-image area, and transferring the ink to the printing material;

• the ink composition for waterless lithography consisting essentially of about 15 to about 35 percent by weight of a vehicle resin, said vehicle resin being selected from the group consisting of a rosin-modified phenolic resin, a phenolic resin, an alkyd resin, a rosin ester resin, a petroleum resin, a maleic resin and mixtures thereof, about 5 to about 25 percent by weight of a drying or semi-drying oil, about 15 to about 45 percent by weight of a mineral oil and about 1 to about 40 percent by weight of a coloring material, said mineral oil comprising high-boiling petroleum solvent mixtures with a boiling point higher than 200.degree. C. and containing less than 5 percent by volume of aromatic components, and all or a part of said drying or semi-drying oil being replaced by a member selected from the group consisting of an aliphatic acid ester, an aliphatic dibasic acid ester, a phosphoric acid ester and a mixture thereof, said aliphatic acid ester being selected from the esters prepared by the esterification reaction of saturated aliphatic acids having 4 to 10 carbon atoms, oleic acid and elaidic acid with saturated monohydroxy alcohols having 1 to 8 carbon atoms, said aliphatic dibasic acid ester being selected from the diesters prepared by the esterification reaction of saturated dibasic acids having 2 to 10 carbon atoms, maleic acid and fumaric acid with saturated monohydroxy alcohols having 1 to 8 carbon atoms, said member having a boiling point higher than 200.degree. C. and a coagulating point less than -5.degree. C.