Flexible printed material
Described herein is a process for preparing a flexible printed material. The process may comprise providing a flexible print substrate comprising a primer on a surface of the print substrate, the primer comprising a primer resin; printing an ink composition comprising a thermoplastic resin onto the primer on the surface of the print substrate; and depositing a cross-linking composition comprising a cross-linker onto the printed ink composition disposed on the primer such that the thermoplastic resin of the ink composition is crosslinked and the primer resin of the primer is crosslinked.
1. A process for preparing a printed material comprising:
providing a print substrate comprising a primer on a first surface of the print substrate, the primer comprising a polyethylene imine;
printing an ink composition comprising a thermoplastic resin onto the primer on the first surface of the print substrate;
depositing a cross-linking composition comprising a cross-linker-onto the printed ink composition disposed on the primer such that the thermoplastic resin of the ink composition is crosslinked and the polyethylene imine of the primer is crosslinked; and
depositing a sealant layer directly on a second surface of the print substrate, wherein the second surface is opposing the first surface of the print substrate.
2. The process according to claim 1 , wherein the thermoplastic resin of the ink composition is selected from the group consisting of alkylene acrylic acid resins, alkylene methacrylic acid resins, polyurethane resins, polyethylene imine resins, polyamide resins, polyvinyl alcohol, and combinations thereof.
3. The process according to claim 1 , wherein the thermoplastic resin of the ink composition comprises a polymer having acidic side groups.
4. The process according to claim 1 , wherein the ink composition is a liquid electrophotographic ink composition and the thermoplastic resin comprises a copolymer of an alkylene monomer and a monomer selected from acrylic acid and methacrylic acid.
5. The process according to claim 1 , wherein the cross-linking composition comprises an epoxy cross-linker, an aziridine cross-linker, an isocyanate cross-linker or a carbodiimide cross-linker.
6. The process according to claim 5 , wherein the cross-linker composition comprises 0.5 wt. % to 10 wt. % of the cross-linker by total weight of the cross-linker composition, the remaining wt. % being a carrier solvent.
7. The process according to claim 1 , wherein the thermoplastic resin comprises a polymer having acidic side groups and the cross-linker is an epoxy cross-linker.
8. The process according to claim 1 , wherein the cross-linking composition is provided in an amount such that the coat weight of the cross-linker deposited on the printed ink composition is at least 0.05 gm −2 .
9. The process according to claim 1 , wherein the cross-linker is an epoxy cross-linker of the formula (I)
(X)—(Y—[Z—F] m ) n
wherein, in each (Y—[Z—F] m ), Y, Z and F are each independently selected, such that:
F is an epoxy group of the formula —CH(O)R 1 H, wherein R 1 is selected from H and alkyl;
Z is alkylene;
Y is selected from a single bond, —O—, —C(═O)—O—, —O—C(═O)—;
m is 1;
n is at least 1; and
X is an organic group.
10. The process according to claim 1 comprising depositing an overprint varnish on the print substrate such that the overprint varnish is disposed on the cross-linking composition.
11. The process according to claim 1 wherein the print substrate is selected from the group consisting of a paper/aluminum/polyethylene laminate, a polyethylene terephthalate/aluminum/polyethylene laminate, an axially oriented polypropylene/metalized-axially oriented polypropylene laminate, and a polyethylene terephthalate/polyethylene laminate.
12. The process according to claim 1 wherein the print substrate is less than 600 μm in thickness.
13. The process according to claim 1 wherein the sealant layer comprises a copolymer of an alkylene monomer and a monomer selected from acrylic acid and methacrylic acid.
14. The process according to claim 1 , wherein the cross-linking composition comprises an isocyanate cross-linker or a carbodiimide cross-linker.
15. The process according to claim 1 , wherein the cross-linking composition comprises a carbodiimide cross-linker.
16. The process according to claim 1 , further comprising at least one of:
applying a corona treatment to the primer disposed on the surface of the print substrate before printing the ink composition on to the primer; or
applying a corona treatment to the printed ink composition disposed on the primer before depositing the cross-linking composition onto the printed ink composition.
17. The process according to claim 1 , further comprising activating the cross-linking composition after depositing the cross-linking composition on the printed ink composition such that the thermoplastic resin of the ink composition is crosslinked and the polyethylene imine of the primer is crosslinked, wherein activating the cross-linking composition comprises heating the cross-linking composition to a temperature of at least 50° C.
18. The process according to claim 1 , wherein the sealant layer comprises a thin film of a polymer, and wherein the film is less than 100 μm in thickness.