Universal printable topcoat for graphics
Coated substrates comprising a topcoat are disclosed. The coated substrate may be substantially free of PVC while having performance comparable to a coated substrate comprising PVC. The topcoat may comprise a base polymer comprising a polyvinylpyrrolidone copolymer, such as polyvinylpyrrolidone/vinyl acetate. The base polymer may also comprise a cationic acrylic resin. The topcoat may also comprise a pigment system and optionally, a crosslinking system.
1. A topcoat comprising a base polymer and a pigment system, wherein the base polymer comprises a polyvinylpyrrolidone copolymer and a cationic acrylic resin; and wherein the polyvinylpyrrolidone copolymer comprises polyvinylpyrrolidone and vinyl acetate, wherein the topcoat comprises at least 35 wt. % cationic acrylic resin, based on the total weight of components other than water in the topcoat, wherein the topcoat comprises from 0.01 to 40 wt. % pigment system, based on the total weight of the components other than water in the topcoat.
2. The topcoat of claim 1 , wherein the topcoat is substantially free of polyvinyl chloride.
3. The topcoat of claim 1 , wherein the topcoat comprises from 25 to about 65 wt. % base polymer, based on the total weight of the topcoat.
4. The topcoat of claim 1 , wherein the topcoat comprises from 1 to 20 wt. % polyvinylpyrrolidone copolymer, based on the total weight of the topcoat.
5. The topcoat of claim 1 , wherein the cationic acrylic resin does not have hydroxyl functionality and further wherein the topcoat does not comprise a crosslinker.
6. The topcoat of claim 1 , wherein the cationic acrylic resin is a high molecular weight cationic stabilized polymer with hydroxyl functionality.
7. The topcoat of claim 1 , wherein the base polymer comprises from 35 to 60 wt. % cationic acrylic resin, based on the total weight of the topcoat.
8. The topcoat of claim 1 , wherein the pigment system comprises a pigment, a filler, and a binding agent.
9. The topcoat of claim 8 , wherein the filler is a silica.
10. The topcoat of claim 8 , wherein the binding agent is a metal oxide.
11. The topcoat of claim 1 , wherein the pigment system comprises from 0.01 to 30 wt. % pigment, based on the total weight of the pigment system.
12. The topcoat of claim 1 , wherein the pigment system comprises from 0.01 to 30 wt. % filler, based on the total weight of the pigment system.
13. The topcoat of claim 1 , wherein the pigment system comprises from 0.01 to 30 wt. % metal oxide, based on the total weight of the pigment system.
14. The topcoat of claim 1 , further comprising: a crosslinking system.
15. A coated substrate comprising a substrate having a topcoat according to claim 1 on at least one surface of the substrate.
16. The coated substrate of claim 15 , wherein the topcoat comprises printed or image indicia thereon.
17. A method of forming the coated substrate of claim 15 , the method comprising:
providing a substrate; providing the topcoat formulation;
applying the topcoat formulation onto at least one surface of the substrate; and
drying the topcoat formulation on the substrate to form a coated substrate;
wherein the topcoat formulation is coated onto the substrate from 1 to 20 gsm.
18. The method of claim 17 , wherein the topcoat formulation is applied to the substrate by gravure coating, knife coating or mayer bar coating onto the substrate.
19. The method according claim 17 , wherein the topcoat formulation is corona treated prior to applying the topcoat formulation to the substrate.
20. The method according to claim 17 , further comprising printing text or an image on the topcoat.