FY 91 Syntheses of Liquid Prototype Air Dry Resins for Use in BEP Intaglio Inks

摘要

The objective of the work described in the report was to design and synthesizeair-drying resins at the National Institute of Standards and Technology (NIST) for intaglio cylinder-wipe inks to be used in printing currency at the Bureau of Engraving and Printing (BEP). Tung oil fatty acids were used in alkyd syntheses to improve the rate and extent of air-dry cure of inks made from these alkyd resins so that the resistance to aqueous alkali solutions would be improved to the point of becoming satisfactory. Because tung oil fatty acids are not commercially available, the synthesis procedure was more involved than the relatively simple synthesis of alkyds based on linseed oil fatty acids. Moreover, the tung oil fatty acid-containing resins were not better than the linseed oil containing alkyd resins. Linseed oil fatty acid-containing alkyd resins which passed laboratory tests for washing (ability to emulsify in Dalmar solution) and chemical resistance were successfully designed and synthesized. The key was to increase the average molecular size of the alkyd resin molecules. At least three of the resins produced inks which are promising candidates for production intaglio inks. Because of acid numbers of the resins are designed to be about 100 (mg KOH per gram resin), no solubilizing amines are needed. Because of the designed viscosity of the resins, no solvent is needed. Therefore, the resins should meet the requirements of air pollution regulations for the foreseeable future.