Patent ID: 8733070

Claim:
A method of making a clay coated paperboard packaging material, comprising: a. providing a grease, fat and oil permeable substrate suitable for use as a packaging material, the substrate having an inner surface and an outer surface; b. selecting a dark colored layer that is permeable to grease, fat and oil, the dark colored layer (i) including at least one non-metallic dark colorant, (ii) including no light colorant, and (iii) not capable when applied by itself to the substrate of masking stains from grease, fat or oil that have permeated the substrate and the dark colored layer; c. selecting a light colored layer that is permeable to grease, fat and oil, the light colored layer (i) including at least one non-metallic light colorant, (ii) including no dark colorant, (iii) including a natural or synthetic clay; and (iv) not capable when applied by itself to the substrate of masking stains from grease, fat or oil that have permeated the substrate and the light colored layer; d. applying in a coater of a paper manufacturing machine the dark colored layer on the outer layer of the substrate; e. applying in a coater of a paper manufacturing machine the light colored layer on the dark colored layer; f. wherein said steps (b) and (c) each include the step of selecting a dark colored layer and selecting a light colored layer that, when applied according to steps (d) and (e) in the paper manufacturing machine, result in a structure that masks stains from grease, fat and oil that have permeated the substrate, the dark colored layer, and the light colored layer.