Soil and/or moisture resistant secure document
View Patent ↗A soil and/or moisture resistant secure document and a method for producing such a secure document, are provided. The inventive method preferably employs a size press or other similar device to force a soil and/or moisture resistant formulation into the pores of the substrate and to remove excess formulation from opposing surfaces thereof. Soil and/or moisture resistant formulations when applied this way instead of by way of standard coating techniques do not obscure optically variable effects generated by non-porous OVDs that may be employed on or within these secure documents. In addition, thin layers of fibers (e.g., papermaking fibers) overlying and thus embedding portions of security devices in windowed secure documents that have been rendered soil and/or moisture resistant in accordance with this invention demonstrate increased durability.
1. A soil and/or moisture resistant secure document, which comprises at least one porous substrate having a thickness, an effective amount of a soil and/or moisture resistant formulation contained within the pores and on opposing surfaces of the porous substrate(s), wherein the soil and/or moisture resistant formulation is distributed throughout the thickness of the porous substrate(s), and one or more non-porous, optically variable security devices contained on and/or partially within the substrate(s), wherein the one or more non-porous, optically variable security devices have exposed surfaces that are substantially free of the soil and/or moisture resistant formulation.
2. The soil and/or moisture resistant secure document of claim 1 , wherein the secure document is a windowed secure document having the one or more security devices partially embedded therein and exposed in one or more windows, wherein areas of the secure document overlying the one or more security devices demonstrate increased durability in the form of reduced cracking or tearing as compared to a secure document that does not contain the soil and/or moisture resistant formulation.
3. The secure document of claim 2 , wherein the one or more security devices are one or more non-porous, optically variable security strips or threads having surfaces that are substantially free of the soil and/or moisture resistant formulation.
4. The soil and/or moisture resistant secure document of claim 1 , which has a porosity ranging from about 15,000 to about 300,000 seconds, determined in accordance with TAPPI Test Method No. T-460 om-06 (2006).
5. The soil and/or moisture resistant secure document of claim 4 , which has a porosity ranging from about 40,000 to about 150,000 seconds.
6. The soil and/or moisture resistant secure document of claim 1 , wherein the one or more non-porous, optically variable security devices is selected from the group of thin films, holograms, gratings, micro-prisms, photochromics, and microlens-based film structures.
7. The soil and/or moisture resistant secure document of claim 6 , wherein the one or more non-porous, optically variable security devices is a microlens-based film structure in the form of a security strip or thread that is partially embedded within the document, with the film structure being visible in one or more clearly defined windows on one or both surfaces of the document.
8. The soil and/or moisture resistant secure document of claim 1 , wherein the soil and/or moisture resistant formulation is an aqueous formulation containing thermoplastic resins selected from the group of resins having an ester bond, polyurethane resins, functionalized polyurethane resins, and copolymers and mixtures thereof.
9. The soil and/or moisture resistant secure document of claim 8 , wherein the soil and/or moisture resistant formulation is an aqueous polymer dispersion comprising dispersed particles having average particle sizes ranging from about 50 to about 150 nanometers.
10. The soil and/or moisture resistant secure document of claim 9 , wherein the aqueous polymer dispersion comprises from about 10 to about 40% by dry weight of resin particles or solids selected from the group of polyurethane resins, polyether-urethane resins, urethane-acrylic resins, and mixtures thereof.
11. The soil and/or moisture resistant secure document of claim 10 , wherein the aqueous polymer dispersion further comprises one or more pigments, and optionally one or more crosslinking agents.
12. A soil and/or moisture resistant secure document, which comprises at least one porous substrate having a thickness, an effective amount of a soil and/or moisture resistant formulation contained within the pores and on opposing surfaces of the porous substrate(s), and one or more non-porous, optically variable security devices having a microstructured surface contained on and/or partially within the substrate(s), wherein the one or more non-porous devices have exposed surfaces that are substantially free of the soil and/or moisture resistant formulation.
13. The soil and/or moisture resistant secure document of claim 12 , wherein the one or more non-porous, optically variable security devices is selected from the group of thin films, holograms, gratings, micro-prisms, photochromics, and microlens-based film structures.
14. The soil and/or moisture resistant secure document of claim 13 , wherein the one or more non-porous, optically variable security devices is a microlens-based film structure.
15. A windowed soil and/or moisture resistant secure document, which comprises at least one porous substrate having a thickness, one or more security devices partially embedded therein and exposed in one or more windows, and an effective amount of a soil and/or moisture resistant formulation contained on opposing surfaces and distributed throughout the thickness of the porous substrate(s), wherein areas of the porous substrate overlying the one or more security devices demonstrate increased durability in the form of reduced cracking or tearing as compared to a secure document that does not contain the soil and/or moisture resistant formulation.