Methods for producing overt security features exhibiting one or more indicia
AssigneeSicpa Holding SA
InventorsHervé Pittet, Patrick Veya, Mélissa Bersier
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Abstract
Methods for producing eye-catching overt security features exhibiting one or more indicia for anti-counterfeit purposes on value documents or articles as well as decorative purposes are disclosed. In particular, the present invention provides methods for producing security features that can be easily, directly and unambiguously authenticated by the human without any external device or tool, wherein the security features comprised a cured ink and one or more cured indicia, the ink comprising cured cationically curable compounds or cured hybrid curable compounds and silver nanoplatelets.
Claims20
A method for producing a security feature exhibiting one or more indicia on a substrate comprising:
- a step a) of applying on a substrate surface a UV-Vis radiation curable ink, said UV-Vis radiation curable ink being in a first, liquid state so as to form a coating layer and said UV-Vis radiation curable ink comprising:
- i) from about 7.5 wt-% to about 20 wt-% of silver nanoplatelets bearing a surface stabilizing agent of general formula (V)
- wherein the residue RA is a C2-C4-alkyl group substituted with a hydroxy group;
- the residue RB is selected from a C1-C4-alkyl group, and a C2-C4-alkyl group substituted with a hydroxy group;
- and Cat+ is an ammonium cation of general formula +NH2RCRD,
- wherein the residue RC is a C2-C4-alkyl group substituted with a hydroxy group;
- and
- the residue RD is selected from a C2-C4-alkyl group, and a C2-C4-alkyl group substituted with a hydroxy group;
- ii) from about 45 wt-% to about 80 wt-% of either a cycloaliphatic epoxide, or a mixture of a cycloaliphatic epoxide and one or more UV-Vis radiation curable compounds;
- iii) one or more cationic photoinitiators;
- iv) a perfluoropolyether surfactant functionalized with one or more functional groups selected from the group consisting of hydroxyl, acrylate, methacrylate, and trialkoxysilyl;
- v) from about 3 wt-% to about 12 wt-% of a polyvinyl chloride copolymer containing at least 60 wt-% of vinyl chloride;
- and optionally
- vi) up to about 25 wt-% of one or more organic solvents;
- the weight percents being based on the total weight of the UV-Vis radiation curable ink,
- subsequently to the step a), a step b) of applying by a contactless fluid microdispensing technology a top coating composition at least partially on top of the coating layer, wherein said top coating composition is applied in the form of one or more indicia, wherein said one or more indicia have an ink deposit greater than about 0.8 g/m2;
- subsequently to step b), a step c) of curing the coating layer and the one or more indicia with one or more curing units,
- wherein the time between steps b) and c) is less than 5 seconds.
Dependencies are inferred from the claim text.