METHOD OF SECURING BULK FLOWABLE GOODS IN PAPERBOARD CONTAINER

Abstract

A paperboard container filled with flowable goods is secured with first, second and third sets of wrapping material wrapped about the exterior of the container. The wrapping material can be a pretensioned film. The first set is an open film, the second set is a cord and the third set is an open film. The cord extends from a bottom portion of the container to a top portion. The use of the wrapping material allows the container to have a reduced amount of paper content, thereby saving on material costs, and secures the container to a base member.

Description

FIELD OF THE INVENTION

The present invention relates to reinforcing and securing bulk flowable goods in containers made of corrugated paperboard.

BACKGROUND OF THE INVENTION

Transporting goods on pallets is an economical manner of shipping. The goods are loaded onto the pallet and the pallet can be moved from place to place by a forklift, truck, railcar, etc.

Many goods are pre-packaged in boxes, cartons and such. For example, a camera is typically packaged in a box. The boxes and cartons are made of paperboard. The paperboard can be noncorrugated or corrugated. In general, a small box may utilize noncorrugated paperboard, while a large box or carton, which contains a heavier load, utilizes corrugated paperboard. Continuing with the example, to transport the cameras, the boxes, if small enough, may be loaded into larger boxes, which larger boxes are then stacked onto a pallet. If the camera boxes are large enough, the boxes are stacked directly onto a pallet. Once stacked on a pallet, the boxes (and cartons) are self-supporting. To secure the stack of boxes to the pallet and create a single unit, the stack of boxes is often wrapped in a film, such as shrink wrap. Once wrapped, the pallet and its stack of boxes can be moved.

Transporting flowable goods requires a different packaging arrangement. Flowable goods include liquids and semi-solids such as animal protein. Animal protein can range in consistency from toothpaste, such as is used in hot dogs, to bone-in products such as shoulders and roasts.

Flowable goods are frequently shipped in bulk. One common manner to ship flowable goods is in a corrugated paper bulk container. Such a container has a bottom and side walls made of corrugated paper. Corrugated paper has plural paper liners and corrugated or fluted medium located between the pairs of liners. The liners are glued to the adjacent corrugated medium. The containers can be cylindrical, rectangular, or octagonal.

The containers are made from flat sheets of corrugated paperboard. The sheets are cut to size and folded to form the side walls and bottom wall of the container. The ends of the side walls are overlapped and glued together to make a complete, circumferential side wall that forms an interior.

The tops of the containers are open. Plastic liners are located inside of the containers. The liner has an open top.

The flowable goods are loaded into the plastic liner inside of the container, and the liner top is closed. The top of the paperboard container typically remains open.

The container is typically made for one time use. After the flowable goods have been removed from the container, the container is typically disposed of. Disposal can include recycling the components.

The paperboard container must contain the flowable goods before, during and after shipment. However, the container may fail, wherein the side wall breaks. Failures can occur at the glue joint of the overlapping side wall ends. Once the container fails, the plastic liner is unable to contain the flowable goods and the goods leak out. Once the goods leak out of the container, they spill onto the floor and other structure and may become unsuitable for the intended use. This results in a loss of the goods. In addition, the spilled goods must be cleaned up.

Corrugated paperboard is inherently hygroscopic material. Exposure of the paperboard to moisture, including ambient humidity, tends to weaken the paperboard significantly and shorten the service life of the container. Though difficult to quantify and highly variable, the overall strength of corrugated containers can easily be reduced by double digit percentages from exposure to the variations and humidity. Studies have shown that subjecting a corrugated paperboard container to relative humidity levels that fluctuate between 50-80% will reduce the service life by over 50%. Direct exposure of the paperboard to water or other liquids has an even greater effect.

In addition, to further increase the strength of the container, corrugated paperboard containers are commonly made with several reinforcing bands imbedded in their corrugated substrate. Such bands are typically contained between the outermost liner and the corrugated medium. Reinforcing bands represent the most common means to increase the overall tensile strength of the corrugated board and increase resistance to wall bulging. However, the overall strength is still limited by the overlapping glue joint. Furthermore, reinforcing bands add substantially to the cost and complexity of the manufacturing process.

Even with reinforcing bands, failures of the container commonly occur. One typical failure mechanism includes side wall bulging. The flowable goods produce outward, normal forces on the container side walls. Due to hydrostatic pressure, the pressure at the bottom of the side walls is greater than the pressure near the top of the side walls. As a consequence, the base of the side walls bulge out. The base or bottom of the container can fail due to these forces. Another failure mechanism of the side walls involves uneven loading on the walls and corners, where the loading may be applied more heavily to one side wall than to another. Contributing to uneven loading is off-center positioning of the container on the pallet. The result of such uneven loading can be collapse of the wall base. Still another failure mechanism is wall base collapse due to inertial forces of the container during transport. For example, a container transported in a truck is subjected to the same starting and stopping forces and turning forces that the truck experiences. Each time the vehicle accelerates (such as by starting or speeding up), or decelerates (such as by stopping), the flowable contents surge against the respective side wall or walls. A sudden stop results in a sudden and relatively strong surge of the goods against a side wall. In addition, the loaded container can shift or slide off of the pallet. Once the container is off the pallet, moving the container, with its soft, non-load bearing paperboard bottom, is difficult.

Another prior art technique is to use a corrugated insert sleeve. However, these containers may fail during transport due to internal forces against the base of the walls. Alternatively, in the prior art, an external perimeter sleeve may be used, made of woven polymer material. However, the same type of failure mechanism is encountered during transport as with the insert sleeve. In addition, both the sleeve insert and perimeter sleeve add substantial costs to the container.

The above failure mechanisms are commonly found in containers of 1800-2000 pounds total content weight, with paperboard fiber weights of 260-300 pounds per MSF (thousand square feet). In the case of containers using insert or perimeter sleeves, the paperboard fiber weights can be lighter, 240-300 pounds/MSF. The corrugated insert sleeve is typically 160-180 pounds per MSF.

The primary cost component of corrugated paperboard bulk containers is material, specifically the paperboard comprising each layer. Paperboard typically accounts for 55-65% of the total cost of a container. Reducing the overall paperboard content (fiber weight) is the most cost effective way to improve the economics and cost effectiveness of containers.

In bulk containers, overall strength is primarily a function of fiber weight. That is the use of more and/or heavier paperboard results in a stronger container as more fiber equals more strength. Designing an effective bulk container is thereby an exercise in balancing two opposing criteria, namely maximizing strength while minimizing fiber content and its associated costs.

SUMMARY OF THE INVENTION

A method secures bulk flowable goods in a paperboard container. The container comprises side walls of paperboard, the walls enclosing an interior. The method comprises loading the flowable goods into the interior of the container. Applying a first set of pretensioned wrapping material to an exterior of the container in a circumferential manner, the wrapping material comprising a film, the film of the first set being an open web. Applying a second set of the pretensioned wrapping material to the exterior of the container in a circumferential manner, the film of the second set being a cord, the cord being wrapped between a bottom portion of the container and a top portion of the container. Applying a third set of the pretensioned wrapping material to the exterior of the container in a circumferential manner, the film of the third set being an open web.

In one aspect, before loading the flowable goods into the interior of the container, placing the container on a base member. The step of applying the first set of pretensioned wrapping material to an exterior of the container in a circumferential manner further comprises the step of applying the first set of pretensioned wrapping material to an exterior of the container and to the base member in a circumferential manner.

In another aspect, wherein the steps of applying first, second and third sets of the pretensioned wrapping material further comprises the step of applying the first, second and third sets of wrapping material in a continuous length about the exterior of the container.

In still another aspect, further comprising the step of assembling the container before loading the flowable goods into the interior of the container, the step of assembling the container further comprising the step of folding the paperboard to form the side walls into an enclosure and joining ends of the sidewalls at a seam.

In still another aspect, wherein the step of joining the end walls at a seam further comprises the step of overlapping the ends of the side walls.

In still another aspect, wherein the step of assembling the container further comprises the step of folding bottom flaps to form a bottom wall.

In still another aspect, wherein the step of loading the flowable goods into the interior of the container further comprises the step of allowing the side walls of the container to bulge outwardly.

In still another aspect, wherein the steps of applying the first, second and third sets of the pretensioned wrapping material to an exterior of the container in a circumferential manner further comprises the step of applying the pretensioned wrapping material to the container by a film applicator and rotating one of the container or the film applicator relative to the other of the film applicator or container.

In still another aspect, wherein the steps of applying the first, second and third sets of the pretensioned wrapping material to an exterior of the container in a circumferential manner further comprises the step of applying the pretensioned wrapping material to the container by a film applicator, and pretensioning the wrapping material with the film applicator.

In still another aspect, further comprising the step of changing the film from the open web to the cord with the film applicator.

In still another aspect, wherein the step of applying a third set of the pretensioned wrapping material to the exterior of the container in a circumferential manner further comprises the step of overlaying the second set of wrapping material with the third set of wrapping material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D show cross-sectional views of corrugated constructions. FIG. 1A shows single wall (SW) corrugated paperboard. FIG. 1B shows double wall (DW) corrugated paperboard. FIG. 1C shows triple wall (TW) corrugated paperboard. FIG. 1D shows laminated double wall/double wall (DW/DW) corrugated paperboard.

FIG. 2 shows a prior art corrugated paperboard bulk container and flat form, prior to be folded and glued.

FIG. 3 is a cross-sectional view of the prior art corrugated paperboard, taken through lines III-III of FIG. 2.

FIG. 4 is a perspective view of the prior art corrugated paperboard of FIG. 2, folded and grouped into a container.

FIG. 5 shows a corrugated paperboard bulk container in open configuration, prior to being folded and glued.

FIG. 6 is a perspective view of the single wall container of FIG. 5, folded, glued and filled with flowable goods and loaded on a pallet, ready for wrapping.

FIG. 7 is the container of FIG. 6, wrapped according to the present invention.

FIG. 8 shows a side view of the container on a wrapping apparatus.

FIG. 9 is a top view of a tensioner.

FIG. 10A is a side view of the corder, shown with the film in an open configuration.

FIG. 10B is a side view of the corder, shown with the film in a corded configuration.

FIG. 11 shows a wrapping pattern of the container of FIGS. 6 and 7, in accordance with a preferred embodiment.

FIG. 12 is a cross-sectional view taken through line XII of a portion of the wrapped container of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides a filled and wrapped bulk flowable goods container 11 (see FIG. 7) made of corrugated paperboard. The paperboard is reinforced with an external wrapping of wrapping material. The external wrapping allows for a reduced amount of paper in the container, resulting in a cost savings. For example, where, in the prior art, a triple wall type corrugated paperboard may be used to contain the flowable goods, with the present invention, a double wall corrugated paperboard container with the external wrapping can be used for the same quantity and type of flowable goods. Said double wall corrugated paperboard has less paper fiber than does the triple wall corrugated paperboard and is thus less costly, even with the external wrapping.

Before describing the method and the container, a brief description is provided of various types of corrugated paperboard, as well as some example containers. In the description, like reference numbers indicate like components.

FIGS. 1A-1D illustrate cross-sectional views of various types of corrugated paperboard. FIG. 1A shows a single wall (SW) corrugated paperboard 13, having a first liner 15, a second liner 17 and an intermediate corrugated or fluted medium 19 located between the two liners 15, 17. The liners 15, 17 and corrugated medium 19 are all made of paperboard.

Paperboard is a heavyweight paper made from virgin or recycled wood fiber and is a well-known material. Paperboard is typically brown, but may be colors such as white. The paperboards used in the liner and corrugated medium are classified by their respective bases weights and pounds per thousand square feet (LB/MSF). For example, the liner typically ranges between 26-90 pounds per MSF and the corrugated medium is typically 26 pounds per MSF. Lighter or heavier versions of the paperboard can be obtained. As an example, when using a single wall for a container, a typical average basis weight of the combined corrugated paperboard 15, 17, 19 is approximately 120 pounds per MSF.

FIG. 1B shows the typically stronger double wall (DW) corrugated paperboard 21 construction, having first and second outermost liners 15, 17, an intermediate liner 23 and a first corrugated medium 19 between the first and intermediate liners 15, 23 and a second corrugated medium 19 between intermediate and second liners 23, 17.

FIG. 1C shows the typically even stronger triple wall (TW) corrugated paperboard 25 construction with three corrugated mediums 19 and their associated liners 15, 17, 23.

FIG. 1D shows the typically even stronger laminated double wall/double wall (DW/DW) corrugated paperboard 27 construction, which is two double walls laminated together with adhesive 28 between adjacent outer liners.

FIGS. 2-4 show a prior art bulk goods container 31 made of a double wall corrugated paperboard 21A with embedded reinforcing bands 33. The corrugated paperboard 21A is similar to the double wall corrugated paperboard 21 of FIG. 1B, but has additional bands 33. The bands 33 are between the outermost liner 15 and the adjacent corrugated medium 19 (see FIG. 3). The container is of a common rectangular type. There are four side walls 35, and flaps 37 that overlap one another to form a bottom wall. The walls 35 and flaps 37 are cut from a single sheet of the double wall paperboard and provided with fold lines 39. The container has beveled corners 41. The cut sheet (FIG. 2) has ends 43, 45. One of the ends is a glue tab 45 with glue applied thereon, and which is overlapped by the opposite end 43, typically at a beveled corner. To form the container, the side walls 35 are folded at the corners to make a generally rectangular shape and the flaps 37 are folded inward to overlap one another and make a bottom. The ends 43, 45 are overlapped to close and complete the rectangular shape. The flaps may be provided with fold lines. FIG. 4 shows the assembled container. For illustrative purposes, the reinforcing bands 33 are shown in FIG. 4, as is the glue tab 45 (they normally are not respectively visible). The container has an interior 47 surrounded by the side walls 35 and the bottom flaps 37. The top end of the container is open, with the side walls having exposed upper edges 49.

FIGS. 5-6 show another container 51. The container 51 is made of single wall corrugated paperboard, although another type of corrugated paperboard could be used (for example, double wall, triple wall, etc.). FIG. 5 shows the container flat, cut and with fold lines 39. The container 51 is cut and folded in the same manner as is the container 31 of FIG. 2. FIG. 6 shows the container 51 of FIG. 5 formed, with the ends 43, 35 glued together. The container 51 of FIG. 6 has an interior 47 shown as being nearly filled with flowable goods 55. To prevent the flowable goods from directly contacting the paperboard, the interior 47 is typically lined with a plastic liner 57. Typically, the liner is a plastic bag with a closed bottom and an open top and sized to fit inside the assembled container. The top of the liner overlaps the upper edges 49 of the side walls, and consequently spills over for a distance. In FIGS. 6 and 7, plastic liner 57 and said overlap is not shown to better see the container itself as well as the flowable goods 55. The liner 57 is shown in FIG. 12. Once the container is filled with flowable goods, the top end of the liner 57 is closed. However, the top end of the corrugated container is open.

The container 51 is located on a base member 61. The base member supports the bottom wall flaps 37. A commonly used base member is a pallet. As an alternative, the container need not be used on a pallet but can be used on some other base member. In addition, the container 51 need not be rectangular but can be another shape such as cylindrical or octagonal.

Flowable goods 55 include liquids, animal protein, dried grains, and various beaded materials such as polymer resins. Animal protein can be provided in paste, solid or some other form. Solid animal protein includes bone-in and de-boned animal parts. The side walls 35 of the container provide form and shape to the flowable goods contained therein. If the side walls were removed or breached, the flowable goods would flow out of the container. Liquid of course would likely completely empty from the container. Animal protein or other solid or semi-solid type of flowable goods would flow out of the container, with some quantity remaining inside of the container. Animal protein is flowable in a manner analogous to concrete slump. With concrete slump, the concrete is loaded into a container with side walls. The container holds the concrete at some height X. When the container, which has no bottom, is lifted away from the concrete, the mass of concrete slumps out to the side and down, lowering the overall height of the concrete mass to Y. The difference in heights X minus Y is slump. Likewise, slump is used in geology to describe a mass of soil that shifts down and away from the slope.

Because the goods in the container are flowable, the goods exert pressure on the container side walls. This pressure causes the bottom portions of the side walls to bulge out.

In contrast to flowable goods, stacked goods behave differently. Examples of stacked goods include goods in boxes and cartons. Such boxes and cartons can be stacked on top of each other and on a pallet. A container is not needed to stack or maintain the goods onto the pallet, as the goods, once stacked, are self-supporting. If the same boxes are stacked in a store or other retail environment, the boxes will remain stable and stacked. Such stackings occur in aisles, at end caps, etc. to display the boxed goods to customers.

FIG. 6 shows an idealized drawing of the container 51. In reality, the side walls 35 of the container bulge out, particularly near the bottom. This is due to the weight or pressure of the flowable goods pushing out against the side walls.

The present invention reinforces the paperboard container 51 by wrapping the exterior of the container with wrapping material 63. FIG. 7 shows the filled and wrapped container 65.

In the preferred embodiment, the wrapping material 63 is stretch wrap film. The stretch wrap film is conventional and commercially available.

Stretch wrap film is commonly used in packaging such as wrapping a number of boxes stacked on a pallet to bind the boxes and pallet into one unit for transport. Stretch wrap film is typically made of polyethylene, such as linear low density polyethylene (LLDPE) or very low density polyethylene (VLDPE), although other types of polymers may be used. Stretch wrap film is stretchable and may be clingy, so that it clings to itself and other objects. Stretch wrap film comes in several varieties such as cast and blown.

Stretch wrap film comes in a variety of thicknesses and widths. Typical thicknesses range from 40-150 gauge. Typical widths are 2-5 inches banding, 12-20 inch hand grade and 20-30 inch machine grade. Greater widths may be used as well. Stretch wrap film has cling, which is the ability to stick to itself and other objects. The cling can be on one or both sides of the film.

Stretch wrap film can be stretched or tensionized. When applying stretch wrap film to a pallet of containers, the film is typically stretched in its longitudinal direction.

The stretch wrap film 63 is wrapped around the container 51 with the wrapping apparatus. The wrapping apparatus supplies the film. Typically, the width of the film is less than the height of the container. As a consequence, the wrapping apparatus positions the film at the desired height relative to the container.

The film is wrapped around the container using relative motion between the container and the wrapping apparatus. In one version, the wrapping apparatus is stationary and the container rotates on a turntable. In another version, the container is stationary and the wrapping apparatus moves about the container.

FIG. 8 shows the wrapping apparatus 71, which has a turntable 73 for the container 51, and a spool 75 of the stretch wrap film 63. When the spool is exhausted of film, it is replaced with a fresh spool. The spool is located near the container. The turntable 73 rotates the container 51 relative to the spool 75.

Because the container 51 is typically higher than the width of the stretch wrap film 63, the spool is moved vertically so as to be able to wrap the container from bottom to top (or vice versa). The spool 75 is mounted on a vertical track 77. One or more motors are provided to move the spool vertically along the track and to rotate the container on the turntable 73. The track 77 is in turn mounted to a support structure 78. The support structure can be fixed or mobile.

The wrapping material 63 unwinds from the spool and enters a dispensing apparatus 79. The dispensing apparatus 79 has a tensioner 81 (see FIG. 9) and a corder 83 (see FIGS. 10A, 10B). The film passes through the tensioner 81 first and then through the corder 83.

Referring to FIG. 9, the tensioner 81 has a series of tensioning rollers 85. The film is wrapped around the rollers and exits the tensioner. The tensioning rollers apply tension or stretch to the film before the film is contacted with a container. The amount of tension applied to the film can be adjusted by adjusting the distance between rollers 85. For example, as shown in FIG. 9, one side of the film contacts a first roller 85 and the other side of the film contacts a second roller 86. The second roller 86 is located downstream of the first roller, with downstream being in the direction the film travels. The second roller is located at a distance from, or is spaced apart from, the first roller. The distance or spacing is varied to vary the tension on the film.

The corder 81 shapes the film. The corder has rollers 87, which rollers have concave surfaces and contact the edges of the film. The film can vary from an open web 63A as shown in FIG. 10A, to a cord 63B as shown in FIG. 10B. For the open web 63A, the cording rollers 87 are expanded to a distance equal to the width of the film. Thus, the film is not crimped or corded as it exits the corder and retains its full width or height (FIG. 10A). To cord the film, the cording rollers 87 move closer together to narrow the distance therebetween and push the edges of the film to form the cord 63B (see FIG. 10B).

The wrapping procedure will now be described.

The container 51 is formed and placed on a pallet 61 or other base member. A plastic liner is located in the container interior, with the top of the liner being open and folded over the top of the container. Flowable goods 55 are then loaded into the liner and the container interior 47 (see FIG. 6). As the container fills, the side walls 35 bulge out from the pressure of the flowable goods. The container is filled to the desired level, which is below the top edge of the side walls. The top of the liner is closed and the container and its pallet are placed in the wrapping area, next to the wrapping apparatus 71.

The free end of the wrapping material is pulled from the dispensing apparatus and stuck to the container and the pallet. If stretch wrap film 63 is used, the film adheres to the container and pallet. The container 51 and pallet 61 are then rotated by the turntable 73 relative to the spool 75. In the example shown in the drawings, the container and the pallet are rotated clockwise when viewed from the top in plan view. As the container rotates, it pulls the film off of the spool. The film is under tension, as provided by the tensioning device.

The film is wrapped in plural sets. In the preferred embodiment, the film is wrapped in a first set 91 of open film, a second set 93 of corded film and a third set 95 of open film. To illustrate the wrapping, FIG. 11 shows panoramic views of the circumference of the container during wrapping. Each view or block shows a complete 360 degree circumference of the container. Blocks 1-20 are in chronological order, with the wrapping illustrated in block 1 occurring before the wrapping illustrated in block 2 and so on.

As shown in blocks 1-5 of FIG. 11, the first set of wraps is with the open film 63 (the film wrapped during that particular block is shown as a dark band (when open) or dark line (corded)). The film is secured to the base of the container and the base member. The container and base member are rotated through several revolutions in order to provide several wraps of pre-stretched open film 63A. As shown, the open film is wrapped several revolutions around the bottom portion of the container and around the pallet.

Then, the second set of wraps is applied, wherein the cording rollers 87 converge to change the film from an open web configuration to a corded configuration 63B. This can be seen in block 5. The container is then wrapped from the bottom portion to the top portion of the container in a helical configuration, as shown by blocks 6-12 of FIG. 11. This is accomplished by moving the dispensing apparatus and spool 75 vertically up on the track 77. As with the open film and the first set of wraps, the corded film and the second set of wraps is under tension or prestretching. In practice, the cord is wrapped within a short distance of the bottom and top or upper edges of the container.

When the cord 63B nears the upper edge 49 of the container, the cording rollers spread apart to allow the film to open to its open web configuration 63A and the container is wrapped with the third set of wraps. In this third set of wraps, the open web 63A is wrapped from top to bottom, with the edges of the film overlapping (see blocks 13-20 of FIG. 11). When the film reaches the base of the container, the film is cut and the tail or free end is secured to the container. The wrapped container 11, shown in FIG. 7, is ready for transport.

The film 63, when both open in blocks 1-5 and 13-20, and when corded as in block 6-12, is prestretched or tensionized. This provides a tight wrap about the container that counteracts the pressure of the flowable contents on the side walls.

In general, the first set of wraps (blocks 1-5) serves to anchor the container to the pallet, the second set of wraps (blocks 6-12) applies the cord to the container, and the third set of wraps (blocks 13-20) secures the cording in place.

The vertical spacing of the wraps and the number of wraps varies according to the container and the contents. In general, the more dense the flowable goods, the more wraps in order to enforce the side walls. Also, in general, the weaker the side walls of the container, that is the less fiber, the more wraps. The vertical spacing of the wraps is controlled by the rotating speed of the container and the vertical movement of the spool. The faster the rotation of the container and the slower the vertical movement of the spool, the closer the wraps will be.

Thus, FIG. 11 shows an example. More or less wraps, whether open or corded, could be used. The open wraps 63A, particularly in the third set, can overlap more or overlap less. The cord 63B can be wrapped onto the container in plural passes; for example from bottom to top (one pass) and then top to bottom (another pass). Likewise, the open web 63A can be wrapped onto the container in plural passes.

The third set of wraps can be in a spiral, where the wraps overlap. Alternatively, the third set can provide one or more wraps at the upper portion of the cord and the one or more wraps at the lower portion of the cord.

As shown in FIG. 12, the wrapped container has flowable goods 55 inside, surrounded by the liner 57 and the paperboard side walls 35 and bottom wall 37 (which bottom wall is made from the folded flaps). The paperboard side walls 35, which continue to bulge under the weight of the flowable goods, are coupled to the pallet by the first set of wraps 91. The second set of corded wraps 93 contact the first set of wraps 91 and the exposed portions of the side walls 35 (which side walls are not covered by the first set of wraps, as shown in FIG. 11). The third set of wraps 95 contacts the exposed portions of the side walls 35, the second set of wraps 93 and the first set of wraps 91. In FIG. 12, the thicknesses of the liner 57 and the film is exaggerated relative to the paperboard thickness to better show these elements. The pretensioning of the film minimizes stretching of the wrapped film. Thus, the container walls are securely wrapped by the film. The top of the container remains open and unwrapped. The plastic liner at the top protects the goods from contamination.

A container wrapped with a wrapping material that is corded and open can hold a quantity of flowable goods with less fiber content in its paperboard than with an unwrapped container. For example, instead of using a triple wall corrugated paperboard, a double wall corrugated paperboard can be used. As an alternative, a triple corrugated paperboard could be used, which paperboard contains less fiber (for example 10-25% less fiber) than a prior art container.

The wrapping material minimizes the possibility that the container will fail or rupture. The container, with its pallet, can be transported and used in accordance with normal practice. The wrapped container maintains its integrity and confines the flowable goods even if the goods are unevenly loaded, or if the container is off-center of the pallet.

The pallet and container are loaded onto a transport vehicle, such as a truck, for shipment. After loading, as the truck moves, the flowable goods move under inertial forces, yet are constrained by the wrapped container. For example, if the truck accelerates from a stop in the forward direction, the flowable goods remain at rest until the wrapped side walls of the container move the goods. Likewise, if the truck, now traveling at a speed, should decelerate to a stop, the flowable goods remain at the speed until the wrapped side walls of the container stop the goods. If the truck travels along a curve, such as a highway curve, the flowable goods remain traveling along the forward direction until the wrapped side walls move the goods along the curve. In this manner, the flowable goods continue to exert forces along the container side walls. Despite the side walls being distorted by bulging, the wrapped side walls withstand the forces and remain intact.

The foregoing disclosure and showings made in the drawings are merely illustrative of the principles of this invention and are not to be interpreted in a limiting sense.

Claims

1. A method of securing bulk flowable goods in a paperboard container, the container comprising side walls of paperboard, the walls enclosing an interior, comprising the steps of:

a) loading the flowable goods into the interior of the container;

b) applying a first set of pretensioned wrapping material to an exterior of the container in a circumferential manner, the wrapping material comprising a film, the film of the first set being an open web;

c) applying a second set of the pretensioned wrapping material to the exterior of the container in a circumferential manner, the film of the second set being a cord, the cord being wrapped between a bottom portion of the container and a top portion of the container;

d) applying a third set of the pretensioned wrapping material to the exterior of the container in a circumferential manner, the film of the third set being an open web.

2. The method of claim 1, further comprising the steps of:

a) before loading the flowable goods into the interior of the container, placing the container on a base member;

b) the step of applying the first set of pretensioned wrapping material to an exterior of the container in a circumferential manner further comprises the step of applying the first set of pretensioned wrapping material to an exterior of the container and to the base member in a circumferential manner.

3. The method of claim 1, wherein the steps of applying first, second and third sets of the pretensioned wrapping material further comprises the step of applying the first, second and third sets of wrapping material in a continuous length about the exterior of the container.

4. The method of claim 1, further comprising the step of assembling the container before loading the flowable goods into the interior of the container, the step of assembling the container further comprising the step of folding the paperboard to form the side walls into an enclosure and joining ends of the sidewalls at a seam.

5. The method of claim 4, where the step of joining the end walls at a seam further comprises the step of overlapping the ends of the side walls.

6. The method of claim 4, wherein the step of assembling the container further comprises the step of folding bottom flaps to form a bottom wall.

7. The method of claim 1, wherein the step of loading the flowable goods into the interior of the container further comprises the step of allowing the side walls of the container to bulge outwardly.

8. The method of claim 1, wherein the steps of applying the first, second and third sets of the pretensioned wrapping material to an exterior of the container in a circumferential manner further comprises the step of applying the pretensioned wrapping material to the container by a film applicator and rotating one of the container or the film applicator relative to the other of the film applicator or container.

9. The method of claim 1, wherein the steps of applying the first, second and third sets of the pretensioned wrapping material to an exterior of the container in a circumferential manner further comprises the step of applying the pretensioned wrapping material to the container by a film applicator, and pretensioning the wrapping material with the film applicator.

10. The method of claim 9, further comprising the step of changing the film from the open web to the cord with the film applicator.

11. The method of claim 1, wherein the step of applying a third set of the pretensioned wrapping material to the exterior of the container in a circumferential manner further comprises the step of overlaying the second set of wrapping material with the third set of wrapping material.