PURPOSE: To provide an ink compsn. which does not stain non-image areas, gives a sufficient density to image areas, hardly cause emulsification and makes it possible to carry out litho printing using dampering water, containing an organopolysiloxane contg. two specified kinds of substituents.
CONSTITUTION: An ink compsn. for litho printing contains an organopolysiloxane contg. at least one subsituent of formula I (wherein X is 0W4; a is 1W50; b is 0W50; R' is H, alkyl, acyl) and at least one substituent of formula II or III(wherein Y is 0W4; R", R''' are each a 1W30C hydrocarbon group contg. no unsaturated bonds at its terminal; Z is 2W30). The ink compsn. can be obtd. by mixing or kneading a conventional vehicle for ink compsn., said organopolysiloxane, a pigment and optionally other additives with a solvent or diluent.
KONDOU TOSHIROU
ISOBE KENICHI
SHINETSU CHEM IND CO
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