Abstract: The object of the present invention is to provide an ink composition for heatset offset printing which has an excellent drying property, does not cause skinning during storage of ink composition, and has excellent stability on press in printing. The present invention is an ink composition for heatset offset printing containing a pigment, a binder resin, a petroleum solvent, and at least one kind of vegetable oil component selected from the group consisting of a vegetable oil and a fatty acid ester thereof, the content of the vegetable oil component being 20% by mass or less, and the ink composition further containing: 0.008 to 0.7% by mass of a metal soap drier based on the mass of the metal contained in the drier; 0.008 to 12% by mass of at least one kind selected from the group consisting of a polyvalent carboxylic acid, a derivative thereof, tocopherol, and tocotrienol; and 0.08 to 12% by mass of a phenolic antioxidant.

Abstract: The present invention provides a method of producing an ink composition for offset printing with use of a crude copper phthalocyanine pigment and/or an active crude copper phthalocyanine pigment and without use of a pigment dispersion resin that requires additional cost, to produce an ink composition which provides a highly tinted and bright image. The method includes the steps of: premixing a premix component through stirring so as to obtain a pigment mixture, the premix component containing a crude copper phthalocyanine pigment and/or an active crude copper phthalocyanine pigment, at least one binder resin selected from the group consisting of a rosin-modified phenolic resin, a rosin-modified maleic acid resin, a petroleum resin, and an alkyd resin, and an oil component; grinding and milling the pigment mixture obtained by the premixing, using a bead mill with grinding media of beads each having a size of 0.1 mm or larger and smaller than 1.5 mm, at a temperature within the range of 0° to 180° C.

Abstract: The object of the present invention is to provide an ink composition for heatset offset printing which has an excellent drying property, does not cause skinning during storage of ink composition, and has excellent stability on press in printing. The present invention is an ink composition for heatset offset printing containing a pigment, a binder resin, a petroleum solvent, and at least one kind of vegetable oil component selected from the group consisting of a vegetable oil and a fatty acid ester thereof, the content of the vegetable oil component being 20% by mass or less, and the ink composition further containing: 0.008 to 0.7% by mass of a metal soap drier based on the mass of the metal contained in the drier; 0.008 to 12% by mass of at least one kind selected from the group consisting of a polyvalent carboxylic acid, a derivative thereof, tocopherol, and tocotrienol; and 0.08 to 12% by mass of a phenolic antioxidant.

Abstract: It is an object of the present invention to provide a method of producing an ink composition for offset printing, which can improve the productivity of inks considerably, and the ink composition for offset printing obtained by the production method. The present invention pertains to a method of producing an ink composition for offset printing, including the steps of wetting 300 parts by mass of a neutral carbon black with 30 to 900 parts by mass of a wetting agent containing at least water, performing flushing of the wetted neutral carbon black using an oil-based varnish for a printing ink containing at least one component of four components consisting of gilsonite, an aliphatic hydrocarbon resin having a softening point of 120 to 125° C., extracted from gilsonite, a petroleum resin and a heavy oil, and then removing the wetting agent.

Abstract: The present invention aims to provide a method of producing an ink composition for offset printing, which can improve the productivity of inks considerably, and in which the printing quality of printed substances obtained in using the foregoing ink composition for offset printing for sheet-fed printing is equal to or higher than that of printed substances obtained with the acid powder carbon black, while using the acid carbon black, particularly an acid bead carbon black. The present invention pertains to a method of producing an ink composition for offset printing, including the steps of wetting 100 parts by mass of an acid carbon black having a pH value of 2.0 to 6.0 with 25 to 400 parts by mass of a wetting agent containing at least water, using an oil-based varnish for a printing ink containing an alkyd resin having an acid value of 30 KOH mg/g or less to perform flushing of the wetted acid bead carbon black, and then removing the wetting agent.

Abstract: The present invention aims to provide a method of producing an ink composition for offset printing, which can improve the productivity of inks considerably while using a neutral carbon black and in which the printing quality of printed substances obtained by using the ink obtained by the method to perform sheet-fed printing is higher than that of printed substances using an acid carbon black, and an ink composition for offset printing prepared by the production method. The present invention pertains to a method of producing an ink composition for offset printing, including the steps of wetting 300 parts by mass of a neutral carbon black with 100 to 900 parts by mass of a wetting agent containing at least water, using an oil-based varnish for a printing ink containing an alkyd resin having an acid value of 30 KOH mg/g or less to perform flushing of the foregoing wetted neutral carbon black, and then removing the wetting agent.

Abstract: An offset printing ink composition is provided which has further improved drying characteristics to satisfy performances required for offset printing, such as anti-blocking properties including primary blocking resistance and secondary blocking resistance, while aiming at compatibility with the environment. The ink composition comprises mainly a coloring agent, a binder resin and a solvent containing a vegetable oil component and is characterized by further containing as a drying characteristic improver at least one member selected from the group consisting of (A) a polymer which is obtained by polymerizing at least one of olefin monomers and diene monomers, and has a solubility parameter of less than 19 (MPa)1/2 and is compatible with the solvent; and (B) a liquid paraffin, wherein the total amount of the improver is 0.1 to 10% by weight in the ink composition.