Ground calcium carbonate composites for storage articles and method of making same

Abstract

The present invention is directed to an environmentally friendly composite structure and storage article fabricated therefrom. The composite structure includes a fiber-containing layer, such as a fiberboard layer or other layer having fibers from natural and/or synthetic sources, and a ground calcium carbonate-containing layer covering the fiber-containing layer. The ground calcium carbonate-containing layer is substantially continuously bonded to the fiber-containing layer along the surface of the fiber-containing layer. The fiber-containing layer and ground calcium carbonate-containing layer can be shaped, sized and manufactured such that the composite structure formed therefrom is capable of being shaped to form the storage article. The composite structure has advantages in that it has a high degree of pliability and flexibility that is increased over the pliability of the fiber-containing layer alone, which renders it highly attractive to consumers. The composite structure further has tensile strength and other characteristics that allow it to be readily machined into desired storage article forms, such as box and carton forms.

1 . A composite structure comprising;
 (a) a fiber-containing layer comprising at least one of natural and synthetic fiber, the fiber-containing layer having a surface; and   (b) a ground calcium carbonate-containing layer applied to the fiber-containing layer, the ground calcium carbonate-containing layer being bonded to the fiber-containing layer substantially continuously across the surface of the fiber-containing layer.   
   
   
       2 . The composite structure according to  claim 1 , wherein the composite structure has a pliability that is increased over that of the fiber-containing layer alone. 
   
   
       3 . The composite structure according to  claim 2 , wherein the composite structure has a pliability that is at least 20% higher than that of the fiber-containing layer alone. 
   
   
       4 . The composite structure according to  claim 1  wherein the ground calcium carbonate-containing layer comprises:
 (a) ground calcium carbonate particles sized from about 10 to about 20 microns, the ground calcium carbonate particles being present in an amount of from about 50% to about 85% by weight; and   (b) a bonding agent selected from at least one of high density polyethylene, bio-polymers and polylactic acids, the bonding agent being present in an amount of from about 15% to about 50% by weight.   
   
   
       5 . The composite structure according to  claim 1  wherein the ground calcium carbonate-containing layer comprises a basis weight of from about 15 to about 240 lbs/1000 sqft, a density of from about 54 to about 900 g/m 2 , and a thickness of from about 2.6 to about 30 mils. 
   
   
       6 . The composite structure according to  claim 1  wherein the fiber-containing layer comprises at least one of bleached or unbleached kraft board, recycled folding boxboard, folding box board, coated recycled board and uncoated recycled board. 
   
   
       7 . The composite structure according to  claim 6  wherein the fiber-containing layer has a basis weight of from about 53 to about 128 lbs/1000 sqft, a density of from about 210 to about 420 g/m 2  and a thickness of from about 14 mils to about 28 mils, and a tensile strength of from about 125 to about 900 MD and about 55 to about 400 CD. 
   
   
       8 . The composite structure according to  claim 7  comprising a basis weight of from about 66 to about 175 lbs/1000 sqft, a density of from about 216 to about 880 g/m 2 , a thickness of from about 12 mils to about 32 mils, and a tensile strength of from about 125 to about 900 MD and about 55 to about 400 CD. 
   
   
       9 . The composite structure according to  claim 6  comprising a basis weight of from about 198 to about 525 lbs/1000 sqft, a density of from about 648 to about 2640 g/m 2 , a thickness of from about 45 mils to about 80 mils, and a tensile strength of from about 375 to about 2700 MD and about 648 to about 2640 CD. 
   
   
       10 . The composite structure according to  claim 1 , wherein the fiber-containing layer and ground calcium carbonate-containing layer are shaped, sized and manufactured such that the composite structure formed therefrom is capable of being shaped to form a storage article. 
   
   
       11 . The composite structure according to  claim 10 , wherein the composite structure is formed by the steps of:
 (a) milling the fiber-containing layer;   (b) extruding the ground calcium carbonate-containing layer; and   (c) bonding the ground calcium carbonate-containing layer to the fiber-containing layer, by performing either:
 i. a hot application process comprising bonding the layers with an adhesive having a viscosity of from about 660 cP to about 1,480 cP at a temperature of from about 300° F. to about 385° F.; or 
 ii. a cold application process comprising bonding the layers with an adhesive having a viscosity of from about 1,000 cP to about 2,100 cP at a temperature of from about 27.5° C. to about 30° C., 
   
     thereby providing the composite structure capable of being shaped to form the storage article. 
   
   
       12 . The composite structure according to  claim 10  wherein the composite structure is formed into the shape of at least one of a retail box and a shipping box. 
   
   
       13 . The composite structure according to  claim 10  wherein the composite structure is formed into the shape of a pallet sheet. 
   
   
       14 . A method of making a composite structure containing ground calcium carbonate, the method comprising the steps of:
 (a) providing a fiber-containing layer comprising at least one of synthetic and natural fibers;   (b) providing a ground calcium-carbonate layer; and   (c) adhering the ground calcium-carbonate containing layer to the fiber-containing layer, the ground calcium carbonate-containing layer being bonded to the fiber-containing layer substantially continuously across a surface of the fiber-containing layer, thereby forming the composite structure.   
   
   
       15 . The method according to  claim 14  further comprising the step of:
 (d) shaping the composite structure to form the component for the storage article, wherein the ground calcium carbonate-containing layer and fiber-containing layer   
     provided in steps (a) and (b) are shaped, sized and manufactured such that the composite structure formed therefrom is capable of being shaped to form the storage article. 
   
   
       16 . The method according to  claim 14 , wherein step (c) comprises bonding the ground calcium carbonate-containing layer to the fiber-containing layer by:
 i. a hot application process comprising bonding the layers with an adhesive having a viscosity of from about 660 cP to about 1,480 cP at a temperature of from about 300° F. to about 385° F.; or   ii. a cold application process comprising bonding the layers with an adhesive having a viscosity of from about 1,000 cP to about 2,100 cP at a temperature of from about 27.5° C. to about 30° C.,   
     thereby providing the composite structure. 
   
   
       17 . A method of shipping a product or displaying a product for retail, the method comprising the steps of:
 (a) providing a storage article comprising:
 a composite structure comprising: 
 (i) a fiber-containing layer comprising at least one of synthetic and natural fibers, the fiber-containing layer having a surface; and 
 (ii) a ground calcium carbonate-containing layer covering the fiber-containing layer, the ground calcium carbonate-containing layer being bonded to the fiber-containing layer substantially continuously across the surface of the fiber-containing layer, 
 wherein the fiber-containing layer and ground calcium carbonate-containing layer are shaped, sized and manufactured such that the composite structure formed therefrom is capable of being shaped to form the storage article; 
   (b) placing the product within the storage article; and   (c) shipping the storage article or displaying the storage article for retail.   
   
   
       18 . The method of shipping a product or displaying a product for retail according to  claim 17 , wherein the composite structure has a pliability that is increased over that of the paperboard layer alone. 
   
   
       19 . The method of shipping a product or displaying a product for retail according to  claim 17 , wherein step (a) comprises providing a storage article comprising a composite structure that is formed into the shape of at least one of a retail box and shipping box. 
   
   
       20 . A ground calcium carbonate-containing structure comprising:
 an extruded ground calcium carbonate-containing material comprising a mixture of ground calcium carbonate particles, a bonding agent, and at least one of a natural and synthetic fiber.   
   
   
       21 . The extruded ground calcium carbonate-containing structure according to  claim 20 , wherein the extruded ground calcium carbonate-containing material comprises from about 30% to about 60% by weight of ground calcium carbonate particles, from about 15% to about 20% by weight of the bonding agent, and from about 20% to about 50% by weight of fibers. 
   
   
       22 . The extruded ground calcium carbonate-containing structure according to  claim 21 , wherein the structure is shaped, sized and manufactured such that it is pliable. 
   
   
       23 . The extruded ground calcium carbonate-containing structure according to  claim 21 , wherein the structure is shaped, sized and manufactured such that it is capable of being shaped to form a storage article. 
   
   
       24 . A composite structure comprising:
 (a) a fiber-containing layer comprising a first fiber comprising at least one of a natural and synthetic fiber, the fiber-containing layer having a surface; and   (b) a ground calcium carbonate-containing layer bonded to the surface of the fiber-containing layer, the ground calcium carbonate-containing layer comprising an extruded ground calcium carbonate-containing material comprising a mixture of ground calcium carbonate particles, a bonding agent, and a second fiber comprising at least one of a natural and synthetic fiber.   
   
   
       25 . The composite structure according to  claim 24 , wherein the composite structure is shaped, sized and manufactured such that it is pliable. 
   
   
       26 . The composite structure according to  claim 24 , wherein the composite structure is shaped, sized and manufactured such that it is capable of being shaped to form a storage article. 
   
   
       27 . The composite structure according to  claim 24  wherein the fiber-containing layer comprises at least one of bleached or unbleached kraft board, recycled folding boxboard, folding box board, coated recycled board and uncoated recycled board. 
   
   
       28 . The composite structure according to  claim 24 , wherein the extruded ground calcium carbonate-containing material comprises from about 30% to about 60% by weight of ground calcium carbonate particles, from about 15% to about 20% by weight of the bonding agent, and from about 20% to about 50% by weight of the second fibers. 
   
   
       29 . A method of making a ground calcium carbonate-containing structure, the method comprising:
 (a) providing extrusion pellets comprising a ground calcium carbonate-containing material that is a mixture of ground calcium carbonate particles, a bonding agent, and at least one of synthetic and natural fibers; and   (b) applying at least one of heat and pressure to the extrusion pellets to extrude the ground calcium carbonate-containing material into a preselected shape corresponding to the ground calcium carbonate-containing structure.   
   
   
       30 . Extrusion pellets for the extrusion of ground calcium carbonate-containing materials, the extrusion pellets comprising a blend of ground calcium carbonate-containing particles, a bonding agent, and at least one of a natural and a synthetic fiber. 
   
   
       31 . The extrusion pellets according to  claim 30 , wherein the pellets comprise from about 30% to about 60% by weight of ground calcium carbonate particles, from about 15% to about 20% by weight of the bonding agent, and from about 20% to about 50% by weight of fibers.