Oil/grease resistant paper products
Oil and grease resistant paper products are disclosed that include a substrate and, on at least one side of the substrate, a continuous layer of a barrier coating, the barrier coating comprising a binder system and a pigment. The barrier coating, when applied to the substrate and dried to form a barrier layer, has a Pigment Volume Concentration (PVC) that is below a Critical Pigment Volume Concentration (CPVC) of the barrier coating, providing a continuous three-dimensional film of the binder system. In some implementations the binder system comprising a latex and a natural binder and/or the paper product further includes a topcoat disposed on a side of the barrier coating opposite the substrate.
1. A paper product comprising:
a substrate; and
on at least one side of the substrate, a continuous layer of a barrier coating, the barrier coating comprising a binder system, the binder system comprising a latex and a natural binder, and a pigment,
wherein the barrier coating, when applied to the substrate and dried to form a barrier layer, has a Pigment Volume Concentration (PVC) that is below a Critical Pigment Volume Concentration (CPVC) of the barrier coating, providing a continuous three-dimensional film of the binder system.
2. The paper product of claim 1 , further comprising a topcoat disposed on the surface of the barrier layer.
3. The paper product of claim 2 wherein the topcoat has a PVC that is above a CPVC of the topcoat.
4. The paper product of claim 2 wherein the topcoat includes a pigment blend comprising an ultrafine clay and/or an ultrafine ground calcium carbonate.
5. The paper product of claim 2 wherein the topcoat comprises a natural binder.
6. The paper product of claim 1 wherein the barrier coating includes from about 40 to 750 parts of the binder system per 100 parts pigment by weight.
7. The paper product of claim 1 wherein the paper product exhibits >99% repulpability.
8. The paper product of claim 1 further comprising a precoat disposed between the substrate and the barrier layer.
9. The paper product of claim 8 wherein the precoat includes a pigment blend comprising a platy pigment and a coarse pigment with an average particle size of at least about 2 μm.
10. The paper product of claim 8 wherein the precoat is calendered.
11. The paper product of claim 1 wherein the paper product is free of fluorocarbon-containing materials.
12. The paper product of claim 1 wherein the binder system includes from about 2 to 250 parts of polyvinyl alcohol.
13. The paper product of claim 1 wherein the binder system includes from about 0.01 to 2 parts of calcium stearate.
14. The paper product of claim 1 wherein the storage modulus on the TMA (thermomechanical analysis) curve of the latex is less than 50 MPa at room temperature (25° C.).
15. The paper product of claim 14 wherein the storage modulus on the TMA curve of the latex is less than 30 MPa at room temperature (25° C.).
16. A paper product comprising:
a substrate;
on at least one side of the substrate, a continuous layer of a barrier coating, the barrier coating comprising a binder system and a pigment, and
a topcoat disposed on a side of the barrier coating opposite the substrate,
wherein the barrier coating, when applied to the substrate and dried to form a barrier layer, has a Pigment Volume Concentration (PVC) that is below a Critical Pigment Volume Concentration (CPVC) of the barrier coating, providing a continuous three-dimensional film of the binder system.
17. The paper product of claim 16 wherein the topcoat includes a pigment blend comprises ultrafine clay and/or an ultrafine ground calcium carbonate.
18. The paper product of claim 17 wherein the topcoat further comprises a coarse pigment.
19. The paper product of claim 18 wherein the ratio of fine pigment to coarse pigment is from about 1:10 to 10:1.
20. The paper product of claim 16 wherein the topcoat includes a binder system comprising a latex.
21. The paper product of claim 20 wherein the topcoat binder system further comprises a natural binder.
22. The paper product of claim 21 wherein the natural binder comprises starch.
23. The paper product of claim 16 further comprising a precoat disposed between the substrate and the barrier coating.
24. The paper product of claim 23 wherein the precoat is calendered.
25. A method of making a paper product comprising:
applying, to at least one side of a substrate, a continuous layer of a barrier coating, the barrier coating comprising a binder system, the binder system comprising a latex and a natural binder, and a pigment,
drying the barrier coating to form a barrier layer, the dried barrier layer having a Pigment Volume Concentration (PVC) that is below a Critical Pigment Volume Concentration (CPVC) of the barrier coating, providing a continuous three-dimensional film of the binder system, and
applying a topcoat to the barrier layer.
26. The method of claim 25 , wherein the topcoat is a graphical topcoat.
27. The method of claim 26 further comprising calendering the topcoat.
28. The method of claim 25 further comprising applying a precoat to the substrate prior to applying the barrier coating, on the same side of the substrate.
29. The method of claim 25 wherein applying the barrier coating is performed using a non-contact coater.
30. The method of claim 28 further comprising calendering the substrate after applying the precoat and before applying the barrier coating.
31. The method of claim 25 further comprising calendering the substrate prior to applying the barrier coating.