| abstract |
This invention pertains to aqueous-based ink formulations for inkjet printing of invisible markings on the surface of articles for identification, authentication, sorting, etc. The ink formation contain at least one near infrared monomeric (as opposed to copolymerized) dye which has been previously dispersed or dissolved in water, glycols, aliphatic alcohols, and are useful for printing by both Continuous inkjet (CIP) and Drop-on-demand (DOD) method. This invention also demonstrates the enhanced ability to formulate said inkjet ink formulations when a small amount of water-dissipatible sulfopolyester/amide is added. Also, melt extrusion blending is demonstrated to be an alternative manufacturing process for premixing current Eastman ClirCodeTM copolymerizable dyes with the water-dissipatible sulfopolyesters without need for more expensive polymer process manufacturing steps. |