Multiple ply paperboard material having improved oil and grease resistance and stain masking properties and method for forming same

Abstract

A multiple-ply paperboard material having improved oil and grease resistance properties, and improved stain masking properties to minimize the appearance of oil and grease stains in the paperboard material, and a method for forming same. The multiple-ply paperboard includes a substantially paperboard substrate having at least two plies, including at least a top ply and a bottom ply formed of substantially paperboard material, a grease resistant coating, a pigment-based pre-coating and a pigment-based top coating. The grease resistant coating includes a fluorochemical component applied to the outer surface of the top ply and to the outer surface of the bottom ply to hinder the penetration and migration of grease and oil into said substantially paperboard substrate through both the top ply and the bottom ply. The pigment-based pre-coating is applied to the top ply over the grease resistant coating, while the top coating is applied over the pre-coating. The pre-coating and top coating both include an opacity enhancing component, such as titanium dioxide, to minimize the appearance of grease and oil stains in the paperboard material. A separate masking agent may also be coated onto the top ply, integrated into the grease resistant coating and/or added to at least one of the pigment based coatings to help mask grease and oil stains.

What is claimed is:  
     
         1 . A multiple-ply paperboard material having improved oil and grease resistance properties, said multiple-ply paperboard material comprising: 
 a substantially paperboard substrate having at least two plies, including at least a top ply and a bottom ply, wherein the top ply and bottom ply are both formed of a substantially paperboard material,    said top ply having an outer surface and an inner surface, such that the inner surface of the top ply is attached to at least one other ply of said at least two plies,    said bottom ply also having an outer surface and an inner surface, such that the inner surface of the bottom ply is attached to at least one other ply of said at least two plies;    a grease resistant coating applied to at least a portion of the outer surface of the top ply and to at least a portion of the outer surface of the bottom ply,    said grease resistant coating including a fluorochemical component and a surfactant component to hinder the penetration and migration of grease and oil into said substantially paperboard substrate through both the top ply and the bottom ply to, in turn, increase the overall oil and grease resistance of the multiple-ply paperboard material.    
     
     
         2 . The multiple-ply paperboard material according to  claim 1  further including at least one additional ply positioned between the top ply and the bottom ply.  
     
     
         3 . The multiple-ply paperboard material according to  claim 1  wherein the fluorochemical component of the grease resistant coating includes a fluorinated salt.  
     
     
         4 . The multiple-ply paperboard material according to  claim 1  wherein the fluorochemical component of the grease resistant coating includes a fluorinated polymer.  
     
     
         5 . The multiple-ply paperboard material according to  claim 1  wherein the surfactant component of the grease resistant coating includes at least one of an isopropyl alcohol and an ethoxylated diol.  
     
     
         6 . The multiple-ply paperboard material according to  claim 1  wherein the grease resistant coating includes a solvent to facilitate application of the fluorochemical component to the top and bottom plies.  
     
     
         7 . The multiple-ply paperboard material according to  claim 1  further including at least one pigment-based coating applied to at least a portion of at least one of the outer surface of the top ply and the outer surface of the bottom ply over at least a portion of the grease resistant coating.  
     
     
         8 . The multiple-ply paperboard material according to  claim 7  wherein the pigment-based coating includes a pigment component and a binder component, the pigment component including a clay component and an opacity enhancing component, said opacity enhancing component minimizing the appearance of grease and oil stains in the paperboard material.  
     
     
         9 . The multiple-ply paperboard material according to  claim 8  wherein the opacity enhancing component of the pigment component is selected from the group consisting of titanium dioxide and calcium carbonate.  
     
     
         10 . The multiple-ply paperboard material according to  claim 9  wherein the opacity enhancing component includes titanium dioxide, said pigment component including approximately 25-70 parts by weight titanium dioxide.  
     
     
         11 . The multiple-ply paperboard material according to  claim 10  wherein titanium dioxide comprises approximately 50 parts by weight of the pigment component.  
     
     
         12 . The multiple-ply paperboard material according to  claim 8  wherein the pigment component comprises approximately 80% by weight of the pigment-based coating.  
     
     
         13 . The multiple-ply paperboard material according to  claim 7  wherein the pigment based coating further includes a masking agent to minimize the appearance of oil and grease stains in the paperboard material.  
     
     
         14 . The multiple-ply paperboard material according to  claim 13  wherein the masking agent comprises at least one of a dye and a tint.  
     
     
         15 . The multiple-ply paperboard material according to  claim 7  wherein the pigment-based coating further includes a fluorochemical component to enhance the grease resistance of the multiple-ply paperboard material.  
     
     
         16 . The multiple-ply paperboard material according to  claim 1  further including: 
 a pigment-based pre-coating applied to at least a portion of at least one of the outer surface of the top ply and the outer surface of the bottom ply over at least a portion of the grease resistant coating, said pre-coating including a pigment component and a binder component, and  
 a pigment-based top coating applied to at least one of the top ply and the bottom ply over at least a portion of the pre-coating, said top coating including a pigment component and a binder component.  
 
     
     
         17 . The multiple-ply paperboard material according to  claim 16  wherein the precoating includes approximately 80% by weight of the pigment component, and wherein the top coating includes approximately 70%-80% by weight of the pigment component.  
     
     
         18 . The multiple-ply paperboard material according to  claim 16  wherein the pigment component of both the pre-coating and the top coating includes both a clay component and an opacity enhancing component, said opacity enhancing component minimizing the appearance of grease and oil stains in the paperboard material.  
     
     
         19 . The multiple-ply paperboard material according to  claim 18  wherein the opacity enhancing component of both the pre-coating and the top coating includes titanium dioxide, 
 said pigment component of the pre-coating including approximately 10-50 parts by weight titanium dioxide, and  
 said pigment component of the top coating including approximately 25-70 parts by weight titanium dioxide.  
 
     
     
         20 . The multiple-ply paperboard material according to  claim 19  wherein 
 the pigment component of the pre-coating includes approximately 10 parts by weight titanium dioxide and  
 the pigment component of the top coating includes approximately 50 parts by weight titanium dioxide.  
 
     
     
         21 . The multiple-ply paperboard material according to  claim 16  wherein at least one of the pre-coating and the top coating further includes a fluorochemical component to enhance the grease resistance of the multiple-ply paperboard material.  
     
     
         22 . The multi-ply paperboard according to  claim 1  wherein the grease resistant coating further includes a masking agent to minimize the appearance of grease and oil stains from the exterior of at least one of the top ply and the bottom ply of the multiple-ply paperboard material.  
     
     
         23 . The multiple-ply paperboard material according to  claim 22  wherein the grease resistant coating further includes a polyvinyl alcohol component, said masking agent including at least one of a dye and a tint mixed with the polyvinyl alcohol component to pre-darken the appearance of the outer surface of at least one of the top ply and the bottom ply to, in turn, minimize the appearance of grease and oil stains in the multiple-ply paperboard material.  
     
     
         24 . A multiple-ply paperboard material having improved oil and grease resistance properties, and improved stain masking properties to minimize the appearance of oil and grease stains in the paperboard material, said multiple-ply paperboard comprising: 
 a substantially paperboard substrate having at least two plies, including at least a top ply and a bottom ply, wherein the top ply and bottom ply are both formed of a substantially paperboard material,    said top ply having an outer surface and an inner surface, such that the inner surface of the top ply is attached to at least one other ply of said at least two plies,    said bottom ply also having an outer surface and an inner surface, such that the inner surface of the bottom ply is attached to at least one other ply of said at least two plies;    a grease resistant coating applied to at least a portion of the outer surface of the top ply and to at least a portion of the outer surface of the bottom ply,    said grease-resistant coating including a fluorochemical component to hinder the penetration and migration of grease and oil into said substantially paperboard substrate through both the top ply and the bottom ply to, in turn, increase the overall oil and grease resistance of the multiple-ply paperboard material;    at least one pigment-based coating applied to at least a portion of at least one of the outer surface of the top ply and the outer surface of the bottom ply over at least a portion of the grease resistant coating,    said at least one pigment-based coating including a pigment component and a binder component, said pigment component including a clay component and an opacity enhancing component, said opacity enhancing component minimizing the appearance of grease and oil stains in the paperboard material.    
     
     
         25 . The multiple-ply paperboard material according to  claim 24  wherein the fluorochemical component of the grease-resistant coating includes a fluorinated polymer.  
     
     
         26 . The multiple-ply paperboard material according to  claim 24  wherein the opacity enhancing component of the at least one pigment-based coating includes titanium dioxide, and wherein the pigment component of the pigment-based coating includes approximately 25-70 parts by weight titanium dioxide.  
     
     
         27 . The multiple-ply paperboard material according to  claim 24  wherein the at least one pigment based coating further includes a masking agent to minimize the appearance of stains in the paperboard material.  
     
     
         28 . The multiple-ply paperboard material according to  claim 24  wherein the at least one pigment-based coating comprises two pigment-based coatings, including 
 a pre-coating including a pigment component and a binder component, said pre-coating being applied to at least a portion of the outer surface of the top ply over at least a portion of the grease resistant coating, and  
 a top coating including a pigment component and a binder component, said top coating being applied over at least a portion of the pre-coating,  
 said pigment component of both the pre-coating and the top coating including both a clay component and an opacity enhancing component,  
 said opacity enhancing component comprising titanium dioxide,  
 the pigment component of the pre-coating including approximately 10-50 parts by weight titanium dioxide and  
 the pigment component of the top coating including approximately 25-70 parts by weight titanium dioxide.  
 
     
     
         29 . A multi-ply paperboard material having improved oil and grease resistance properties, and improved stain masking properties to minimize the appearance of oil and grease stains in the paperboard material, said multiple-ply paperboard material comprising: 
 a substantially paperboard substrate having at least two plies, including at least a top ply and a bottom ply, wherein the top ply and bottom ply are each formed of a substantially paperboard material,    said top ply having a outer surface and an inner surface, such that the inner surface of the top ply is attached to at least one other ply of said at least two plies,    said bottom ply also having an outer surface and an inner surface, such that the inner surface of the bottom ply is attached to at least one other ply of said at least two plies;    said top ply and said bottom ply each including a fluorochemical component integrally bonded therein to hinder penetration of grease and oil into said substantially paperboard substrate through both the top ply and the bottom ply to, in turn, increase the overall oil and grease resistance of the multi-ply paperboard;    at least one pigment-based coating applied to at least a portion of the outer surface of the top ply over at least a portion of the grease resistant coating,    said at least one pigment-based coating including a pigment component and a binder component, said pigment component including a clay component and a opacity enhancing component, said opacity enhancing component minimizing the appearance of grease and oil stains in the paperboard material.    
     
     
         30 . A process for improving the resistance of multiple-ply paperboard material to the penetration and migration of oil and grease to, in turn, minimize the appearance of oil and grease staining in the paperboard material, said process including the steps of: 
 forming a substantially paperboard substrate having at least two plies, including at least a top ply and a bottom ply, said top ply being formed from a substantially paperboard material and having an outer surface and an inner surface, said bottom ply also being formed from a substantially paperboard material and having an outer surface and an inner surface;    attaching the inner surface of the top ply to at least one other ply, thereby leaving the outer surface of the top ply exposed;    attaching the inner surface of the bottom ply to at least one other ply, thereby leaving the outer surface of the bottom ply exposed;    applying a grease-resistant coating to at least a portion of the outer surface of the top ply and to at least a portion of the outer surface of the bottom ply,    said grease-resistant coating including a fluorochemical component and a surfactant component to hinder the penetration and migration of grease and oil into said substantially paperboard substrate through both the top ply and the bottom ply to, in turn, increase the overall oil and grease resistance of the multi-ply paperboard.    
     
     
         31 . The process according to  claim 30  further including the step of applying a pigment-based coating having a pigment component and a binder component to at least a portion of the outer surface of the top ply over at least a portion of the grease resistant coating, the pigment component including a clay component and an opacity enhancing component to minimize the appearance of grease and oil stains in the paperboard material.  
     
     
         32 . The process according to  claim 31  wherein the step of applying a pigment based coating having a pigment component and a binder component to at least a portion of the outer surface of the top ply over at least a portion of the grease resistant coating further includes the step of mixing a masking agent with the pigment based coating before applying the pigment based coating to at least a portion of the grease resistant coating to minimize the appearance of grease and oil stains in the multiple-ply paperboard material.  
     
     
         33 . The process according to  claim 30  further including the steps of: 
 applying a pre-coating, including a pigment component and a binder component, to at least a portion of the outer surface of the top ply over at least a portion of the grease resistant coating, and  
 applying a top coating, including a pigment component and a binder component, over at least a portion of the pre-coating.  
 
     
     
         34 . The process according to  claim 33  wherein the step of applying the pre-coating includes applying the pre-coating in a ratio of approximately 80% by weight of the pigment component to approximately 20% by weight of the binder component, and wherein the step of applying the top coating includes the step of applying the top coating in a ratio of approximately 70%-80% by weight of the pigment component to approximately 20-30% by weight of the binder component.  
     
     
         35 . The process according to  claim 33  wherein the pigment component of both the pre-coating and the top coating includes both a clay component and an opacity enhancing component to minimize the appearance of grease and oil stains in the paperboard material.  
     
     
         36 . The process according to  claim 35  wherein the opacity enhancing component includes titanium dioxide, the pigment component of the pre-coating including approximately 10-50 parts by weight titanium dioxide and the pigment component of the top coating including approximately 25-70 parts by weight titanium dioxide.  
     
     
         37 . The process according to  claim 30  further including the step of mixing a fluorochemical component with the pre-coating before applying the pre-coating to at least a portion of the top ply over at least a portion of the grease resistant coating.  
     
     
         38 . The process according to  claim 30  further including the step of mixing a masking agent with the grease-resistant coating before applying the grease resistant coating to at least one of the top and bottom plies of the paperboard material to minimize the appearance of grease and oil stains in the multiple-ply paperboard material.  
     
     
         39 . The process according to  claim 30  further including the step of coating the outer surface of the top ply with a masking agent before the step of applying the grease-resistant coating to at least a portion of the outer surface of the top ply, to minimize the appearance of grease and oil stains in the multiple-ply paperboard material.  
     
     
         40 . A process for minimizing the appearance of oil and grease stains in multiple-ply paperboard material, said process including the steps of: 
 forming a substantially paperboard substrate having at least two plies, including at least a top ply and a bottom ply, said top ply being formed from a substantially paperboard material and having an outer surface and an inner surface, said bottom ply also being formed from a substantially paperboard material and having an outer surface and an inner surface;    forming at least one of the top and bottom plies with a fluorochemical component integrally bonded therewithin to hinder the penetration and migration of grease and oil into said substantially paperboard substrate through both the top ply and the bottom ply to, in turn, increase the overall oil and grease resistance of the multiple-ply paperboard;    attaching the inner surface of the top ply to at least one other ply, thereby leaving the outer surface of the top ply exposed;    attaching the inner surface of the bottom ply to at least one other ply, thereby leaving the outer surface of the bottom ply exposed;    applying a pre-coating, including a pigment component and a binder component, to at least a portion of the outer surface of the top ply over at least a portion of the grease resistant coating, said pigment component including approximately 50-90 parts by weight of a clay component and approximately 10-50 parts by weight of an opacity enhancing component; and    applying a top coating, including a pigment component and a binder component, over at least a portion of the pre-coating, said pigment component including approximately 30-75 parts by weight of a clay component and approximately 25-75 parts by weight of an opacity enhancing component to minimize the appearance of grease and oil stains in the multiple-ply paperboard material.