Moisture-setting printing ink

Claim 1

A PRINTING INK COMPOSITION RESPONSIVE TO MOISTURE SETTING TREATMENTS COMPRISING A SOLVENT COMPONENT AND A BINDER COMPONENT; SAID SOLVENT COMPONENT COMPRISING A MAJOR PROPORTION OF DIPROPYLENE GLYCOL AND A MINOR PROPORTION OF DIMETHYL PHTHALATE IN SUCH RELATIVE AMOUNTS AS TO PROVIDE A COMPOSITE SOLVENT COMPONENT HAVING HYGROSCOPIC CHARACTERISTICS SUCH THAT A MIXTURE OF SAID SOLVENT COMPONENT WITH WATER IN THE RATIO OF APPROXIMATELY 30% WATER TO APPROXIMATELY 70% SOLVENT COMPONENT WILL BE IN MOISTURE EQUILIBRIUM WITH CONTIGUOUS ATMOSPHERE AT 79% RELATIVE HUMIDITY AND A TEMPERATURE BETWEEN 20* C.-30* C.; SAID BINDER COMPONENT COMPRISING INK BINDING MATERIAL INCLUDING NITROCELLULOSE HAVING A NITROGEN CONTENT OF NOT LESS THAN 11.15% AND NOT MORE THAN 11.75% AND A 100% PHENOL-ALDEHYDE NOVOLAC RESIN, SAID BINDER COMPONENT BEING FREELY SOLUBLE IN THE SOLVENT COMPONENT AND HAVING THE FURTHER PROPERTY OF BEING SUBSTANTIALLY COMPLETELY SOLUBLE IN A MIXTURE OF SAID SOLVENT COMPONENT WITH THE MAXIMUM AMOUNT OF WATER PRESENT IN SUCH MIXTURE WHEN IT IS IN MOISTURE EQUILIBRIUM WITH ATMOSPHERE AT RELATIVE HUMIDITIES OF APPROXIMATELY 50%-65% RH; SAID INK BEING STABLE ON THE PRESS ROLLS UNDER USUAL PRESSROOM CONDITIONS AND HAVING THE PROPERTY OF SETTING WITH SUFFICIENT RAPIDITY TO MEET HIGH SPEED PRESS REQUIREMENTS WHEN SUBJECTED TO A MOISTURE SETTING TREATMENT AFTER PRINTING.