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Paper characterized by insoluble basic surface properties is rendered selectively printing-ink receptive by application of alkenylsuccinic acid, its anhydride, or its soluble salt.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is concerned with offset printing of the kind which, on a venerable history, is oftentimes called lithography. Traditionally, lithography (the name is derived from the Greek lithos meaning stone and grapho meaning write) has involved the preparation to a smooth surface of a stone, usually limestone, which can be a dolomitic limestone, of very fine grain. Upon this stone, by a skilled artist working in mirror image with a lithographer's "crayon" of a waxy nature, a design to be printed is applied. Thereafter, the surface of the stone is definitively wetted with water, (characteristically in the absence of surface-active agents) and the wetted surface then coated with printer's ink from a roller, which has at times been a roller in a printing press. The ink, characteristically oil- or solvent-based in nature, "wets," that is to say, adheres by means of hydrogen bonds and by forces such as the forces of van der Waals, to only the waxy-coated surface where the lithographer's crayon was applied. The phenomenon has admitted of carrying out the practice with such delicacy that great artists from Benjamin West in 1801 to Picasso today have found the lithograph medium an artistic medium of great sensitivity. Other notable contributions to lithography as an artistic medium have been made by Currier and Ives, and mention should be made of a revival of the medium at the hands of James A. MacNeil Whistler. Daumier, Hassam, Signac, Degas, Renoir, Kollwitz, Rouault, Orozco, and Rivera are but a few artists who have found lithography a medium of virtuosity. It is widely used in commercial and industrial printing as well.
In more recent years, the method has been modified. The lithographer's stone has given way to papers and metal plate surfaces. The hydrophobic-hydrophilic balance of inks and of material in the stead of the lithographer's crayon have been carefully studied. Because the lithos, or stone has been largely displaced, the process has become known, in more recent years, as "offset" printing.
2. The Prior Art
As to offset printing or lithography assisted by an alkenyl succinic acid(cas:110-15-6) compound, applicant knows of no prior art whatsoever. The alkenyl succinic acid(cas:110-15-6), their anhydrides, and their soluble salts such as their alkali metal salts including notably the sodium and disodium salts are well known in the prior art. U.S. Pat. No. 2,770,077 is concerned with the use of an alkenylsuccinic compound in conditioning soil for agricultural use.
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