Optically variable water-based inks
View Patent ↗Optically variable water-based inks, methods of providing security information, and documents are provided. The optically variable water-based inks are suitable for flexographic printing processes, and the optically variable water-based inks display a viewing angle dependent color shift between at least a first color and at least a second color. The optically variable water-based inks may be used to provide security information and to flexographically print documents.
1. A method of providing security information, comprising:
providing a water-based ink comprising:
about 5 to about 50 percent by weight of at least one optically variable pigment;
at least one binder; and
water;
printing at least a portion of a substrate with said water-based ink utilizing flexographic printing, wherein:
said portion of said substrate printed with said water-based ink displays a viewing angle dependent color shift between at least a first color and a second color;
said portion of said substrate printed with said water-based ink comprises security information; and said security information is not reproducible via photocopying; and
printing said substrate utilizing laser printing subsequent to printing at least a portion of said substrate with said water-based ink wherein said security information remains intact during said laser printing.
2. The method as claimed in claim 1 wherein said at least one optically variable pigment comprises about 10 to about 20 percent by weight of said water-based ink.
3. The method as claimed in claim 1 wherein said substrate comprises a paper substrate.
4. The method as claimed in claim 1 wherein said substrate comprises a plastic substrate.
5. The method as claimed in claim 1 wherein said substrate comprises a security document.
6. The method as claimed in claim 1 wherein said water-based ink is printed on said substrate such that said substrate is spot-coated.
7. The method as claimed in claim 1 wherein said water-based ink is printed on said substrate such that said substrate is flood coated.
8. The method as claimed in claim 1 wherein said water-based ink is printed on said substrate such that at least one indicia is formed thereon.
9. The method as claimed in claim 1 wherein said substrate comprises a security document selected from a check, a money order, a certificate, an auto title, a bearer bond, a stamp, a postal order, and a lottery tickets.
10. The method as claimed in claim 1 wherein said substrate comprises a check.