Water based printing ink

A rapidly drying aqueous printing ink containing a gel forming polymer soluble in the ink but which rapidly gels upon application of the ink to a substrate during a printing process.

BACKGROUND OF THE INVENTION 

The present invention relates to printing inks. More specifically the present invention relates to printing inks wherein the principal solvent or vehicle is water, hereinafter denoted water-based and/or aqueous printing inks. 

Printing inks are employed in the graphic arts as the medium by which desired colored representations are formed on a surface. The printing ink forms a colored coating in predetermined fashion on the selected substrate. Mechanical means carrying out a printing process applies the ink to the selected surface. 

One way to offset printing inks are according to the type of printing process to be carried out. Certain types of printing processes require relatively sheetfed offset inks of a paste-like consistency while others demand inks of an oleophilic nature; still others entail the employment of relatively fluid, offset inks. Letter press, gravure and flexographic printing processes, among others, usually necessitate fast drying inks. 

SUMMARY OF THE INVENTION 

An object of the present invention is to provide an improved printing ink. 

Another object of this invention is to provide a quick sheetfed offset ink not requiring a volatile organic solvent vehicle. 

Still another object of this invention is to provide a quick drying water based printing ink. 

Further, an object of this invention is to provide a printing ink suitable for letter press, flexographic, gravure and other types of printing processes wherein a relatively fluid hydrophilic ink can be employed. 

Another object of this invention is to provide an aqueous printing ink containing a polymeric additive which remains in solution in the ink prior to printing but rapidly gels after application of the ink to a substrate. 

Other objects of the invention will be apparent to the skilled artisan from the detailed description of the invention hereinafter.