Readily configurable plastic foam packaging

An efficient means for providing packaging materials comprises foam sheets which have been at least partially cut into regular segments which may be configured by hand into nearly any shape to fit a void space which may surround an article to be packaged in a container. The sheets may be stacked into a cube for ease of transport and storage. The foam sheets may be easily separated into segments by hand by snapping (rigid) or tearing (flexible) the foam into a custom shape which best fits the void space. In one particular embodiment, the segments may comprise a thermoplastic foam which may be configured into corner pads for supporting an article within an outer container.

FIELD OF INVENTION

The present invention relates to packaging materials for protecting articles during transportation or storage. More particularly, the invention relates to sheets of plastic foam which may be readily configured by hand into shapes to customize the packaging of an article.

BACKGROUND OF THE INVENTION

Various types of packaging materials are known for packaging and shipping perishable or fragile articles. In some cases a box containing an article is suspended within another package or box for protection during shipping or storage. Loose fill packaging materials may be used to space and protect the inner articles within an outer box.

Of particular interest is the efficient packaging of fragile devices or articles such that vibration and shock due to impact do not harm the device or article. This is particularly true of electronic devices, medical devices, glassware, etc. Shipping and transport of smaller articles has resulted in the formation of an industry dedicated to serving the public in this area. For instance, the United Parcel Service, Federal Express and the United States Postal Service have all evolved to fill this need.

Particularly popular is the use of “loose fill” materials such as expanded plastic beads (polystyrene, polyethylene, polypropylene, etc.) which may be extruded and cut into a variety of shapes (peanuts, H-shaped, S-shaped, V-shaped, star-shaped, saddle-shaped, FIG. 8-shaped, etc.) which can be used to fill a void and surround an article placed inside a shipping container or box to cushion the article against damage. The loose fill provides a low weight “resilient envelope”, however, it has been found that heavier articles may wander or settle within the loose fill medium over time due to vibration during transportation. While loose fill materials may have “good pourability” for filling a void or space between an article and its container, they are particularly difficult to dispose of, as the low density and high volume provide tremendous quantities of loose beads which the consumer must deal with and which many waste management companies do not see as “recyclable”. A further disadvantage of loose fill materials is that the low density and large volume make storing and transporting the materials before use very inefficient. Other “loose-fill” materials may comprise shredded fiber board or paper, however these materials tend to settle or become compressed and are not as resilient as the aforementioned plastic foams.

Foam-in-place materials provide another option to package articles. Thermoset two-component urethane precursors may be reacted together and poured or sprayed to expand and fill an open space to provide cushioning.

Thermoplastic beads may be expanded in shaped molds to form customized sections of packaging for the protection of contents. Often these are used as “clam shell” protectors on each end of an article to “suspend” the article in a packaging container. These materials, once formed to shape, are specific to an application or shaped article and are not readily reusable for packaging other articles, particularly of other shapes. In addition, these molded sections are bulky to transport and store before use. Further, these materials are particularly difficult to dispose of due to their odd or complex shapes. In attempting to efficiently dispose of these odd shapes, the shapes are often broken into pieces causing a lot of loose dust or “fluff”.

An alternate means to provide packing materials has been to cut a block or sheet of, for instance, a foamed material to shape. That is, however an extremely wasteful process as a lot of scrap is generated from the material that is removed from the blank and usually a lot of dust or debris is generated.

“Bubble-wrap” is another type of packaging for articles, where a sheet of plastic bubbles can be wrapped around an article having a regular shape. However, the ability of “bubble-wrap” to fill irregular shaped spaces or voids is poor and, once again, disposal is difficult, unless one wants to crush all the bubbles to reduce the volume to a practical level.

In the packaging of heavy products, appliances and the like, corner and top support pads may be provided between a corner of the appliance and an outer container. These pads provide impact protection as well as stacking strength. Often these support pads are formed to shape of paper board and adhesive. They are not however generally reusable in a different configuration.

What is needed is a product which provides an easily configurable shape that may be customized to efficiently package a given article and which may be readily reusable and more easily disposed of.

SUMMARY OF THE INVENTION

It is thus an object of the present invention to provide packaging materials, particularly void fillers, which are supplied efficiently in sheet form and which may be readily separated and configured into shapes which closely match the void or areas being filled.

According to this invention, the objective is obtained by providing foamed plastic sheets which have been partially cut through in a regular pattern such that segments may be readily separated by hand to substantially conform the packaging to the space to be filled. This provides for the efficient use of packaging materials both in their supply chain and in use. Once used, the sections may be reconfigured for another application or may be disposed of efficiently and cleanly.

In a first embodiment, the invention is directed at a sheet of rigid, preferably polystyrene, foam which has been cut nearly through its thickness in a regular pattern such that the sheet may be fractured along the cut line into shapes to closely fit a packaging space. Additionally, the bottom of the cut line is radiused to prevent the creation of dust when the segments are separated.

In a second embodiment, the invention is directed at sheets of flexible, preferably polyurethane, foam which has been convoluted. The sheets are die cut into regular segments, however, small connecting tab sections remain uncut around the periphery of each segment to provide a sheet that is efficient to handle, yet easily separated by hand into custom shapes.

In a third embodiment, the invention is directed at a preferably laminated sheet of low density thermoplastic foam. The sheet may be die cut in an intermittent pattern to form a three-segmented L-shaped section which may be hinged around uncut portions to form three-dimensional corner pieces for rectangular objects packed within another box or carton. The corner pieces may provide spacing as well as impact protection and are reusable.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed at the efficient use of packaging materials for protecting articles during storage or transport. The packaging materials, which may be of various hardnesses, densities, impact strengths and resiliencies, may be supplied in sheet form preferably stacked in a space efficient cube. The sheets may be partially cut into standard size segments that may be separated into shapes by hand which may closely match the void space between an article and its shipping or storage container to efficiently protect the article against damage. Since the sheets may be pre-scored into regular shaped segments, the segments may be reused in other packaging applications by further separating or re-combining the segments. Disposal efficiency is improved since the regular shaped segments are not so small, like loose fill materials, to take up large volumes or create dust, yet the segments are small enough, preferably 1 to 3 inches wide by 1 to 3 inches long, to be contained in a small space.

FIG. 1is a plan view of a first embodiment of the readily configurable foam packaging according to the present invention. A rigid foamed plastic foam sheet10is shown which preferably may have dimensions of about 24 inches (A) by 24 inches (B) by about 1 inch thick.

The foam may preferably comprise polystyrene foam of about 1.0 pounds per cubic foot density, but may be any rigid or semi-rigid foam composition of any density suitable for packaging articles to protect them in storage or in transport. For instance, the foam may comprise, but not be limited to, polystyrene, polyolefin, epoxy and polyurethane, and blends, alloys and copolymers thereof. For efficient packaging, the density range may comprise, but not be limited to, about 0.4 to about 10 pounds per cubic foot. Since packaging should not contribute substantially to the weight of the article being shipped, densities in the range of about 0.4 to about 2.0 pounds per cubic foot may be preferred, providing they furnish sufficient protection.

The rigid plastic foamed sheet10may be manufactured by the expansion of beads as is known in the art, or in the case of rigid urethane or epoxy, may be a poured in place, reacted thermoset composition.

To provide an efficiently sized segment, readily configurable into various shapes for filling void spaces around articles in a container, the sheet10may be segmented into regular shaped preferably rectangular segments16each preferably having a width of about 1 inch to 2 inches (C) by a length of about 1 inch to 2 inches (D). A sheet10may comprise a mixture of sizes as shown inFIG. 1where C×D may be 2 inches by 2 inches and C×D′ having dimensions of 2 inches by 1 inch.

The foam sheet10may be only partially cut through using, preferably, a heated wire to provide the segments16which may be easily separated by hand, but still retain the sheet10in an space efficient single piece which may be stacked into a cube for shipping and storage of the packaging material. While rectangular shaped segments are preferred for ease of handling, the segments may comprise any shape, including but not limited to, triangular, octagonal, hexagonal, pentagonal, rhomboid, curved or combinations thereof.

FIG. 2is an enlarged side view of the foam sheet10illustrating how the segments16are formed.

In one preferred embodiment a heated nickel-chromium wire may be held tautly and pressed into the sheet10to about three-quarters of the thickness of the sheet. The wire may be preferably about 0.014 inches in diameter and heated by applying a voltage of about15volts to generate the heat. Pressing the hot wire into the sheet10may melt the foam to form a narrow slit12.

As further shown inFIG. 2, the wire preferably may form a slit only part way through the thickness of the sheet to allow the sheet to be easily handled as a single article after being slit. The preferably rectangular segments16thus formed may then be separated by hand into whatever shape most closely resembles the void space to be filled around an article to be supported inside a container. For instance, the segments may form an end cap for each article to be packaged by removing the center portion of the sheet (forming a clam shell package). Or the segments may be broken apart to form an “L” shape such as for the corner of a rectangular article. The segments may be readily broken apart by hand as shown inFIG. 5by bending the sheet along one of the slits12over a sharp edge such as a table or counter.

To ensure a clean break without the creation of dust or debris, the slit12formed in the sheet10may terminate at a smooth radius14formed at the bottom of the slit. This may be accomplished by having a dwell period in the slitting process, letting the hot wire pause momentarily at the bottom of the slit to form a preferably, smooth sided nearly circular region around the wire. The additional melting of the foam in this area preferably may form a semi-circle of about 0.060 inches in diameter using a dwell time of about 0.5 seconds with the aforementioned process parameters. Preferably the semi-circle14may be located at about 75 percent to about 85 percent of the thickness of the sheet.

Thus, the rigid foam sheet10may provide an efficiently packaged packaging material which may protect and cushion articles without adding weight and may easily be configured to a desired size and shape by hand without the need to cut the foam or create a mess. Further, the material may provide insulation (R value of 4.0 per inch), if needed. With the segmented sheet there may be essentially no waste as every segment may be used in some packaging application and more often than not may be reused by further separating or re-combining the segments into a new shape which fills the void between an article and its container.

In a second embodiment, the foam packaging material may be a flexible foam, preferably a polyurethane, of around 1.0 pounds per cubic foot density. This softer flexible foam may be more suitable for packaging fragile or odd-shaped articles. As with the rigid foam of the first embodiment, the flexible foam may likewise be supplied for efficient storage and transport in a 24 inch (A) by 24 inch (B) sheet (seeFIG. 3), preferably stacked in a cube.

FIG. 3shows a plan view of the flexible foam sheet20. The sheet20may be preferably die cut into 2 inch (C) by 2 inch (D) segments which have uncut sections or tabs22at the corners and at the center of each edge to retain the segments26in sheet form until they are used. At that point, the segments26may easily be torn apart by hand to form whatever shape or configuration fits the void space between an article to be protected and its container.

The separation process is shown inFIG. 6. As with the first embodiment of the present invention, the segments26may be separated to form shapes (“L”, “H”, “I”, “T”, for instance) or even hollow shapes with the center removed for use as end caps in clam shell packaging.

To form the segmented sheet which comprises the second embodiment of the present invention, a sheet of flexible foam may be provided by skiving a bun to shape or pouring-in-place a shape as is known in the art. The foam may preferably be of low density, in a range of about 0.5 pounds per cubic foot to about 10 pounds per square foot, more preferably of about 0.8 pounds per cubic foot to about 1.8 pounds per cubic foot. The sheet20may preferably be about 2 inches thick and have an ILD (Indentation Load Deflection) of about 32 to about 40 pounds according to ASTM test method number (D3574-86, 25% deflection).

The foam sheet may preferably be convoluted as in known in the art to form a surface of matching protrusions and depressions which may be separated into two matching sections. This is shown inFIG. 4with the cut line between the foam sections28,30shown as reference numeral24.

Such convoluted sections may comprise a dimpled surface on one side of the foam section, such dimpled surface being formed by passing a flat sheet through a convoluting machine which has a pair of rolls with opposed spaced projecting members arranged in a pattern, and while the sheet is compressed between the rollers, subjecting the sheet to the action of a transverse saw, splitting the sheet to form a pair of convoluted sections each having the dimpled surface on one side. The dimpled surface in cross-section may thus be formed in a generally sinuous configuration.

While shown as sinusoidal in shape (FIG. 4), the pattern generated in the matching surface of the foam sheet sections may vary widely according to the pattern which forms the outer surface of the rolls of the convoluter which feeds the foam to the splitter. Shapes that may form the peaks and troughs (projections and depressions) include, but are not limited to; square, hexagonal, octagonal, round and oval.

The foam sheet preferably may comprise a thermoset urethane having a polyether, polyester or graft copolymer polyol component, although other expanded polymers which may be easily compressed are also contemplated.

To create a sheet of segments26which are easily separated and configurable to form a void space, the foam sheet20after being convoluted, as shown inFIG. 4, may be die cut into preferably 2 inch by 2 inch segments26using preferably a steel rule die. Other methods such as laser cutting or water jet trimming are also contemplated.

FIG. 7illustrates an essentially full size view of a portion of the outer surface of the foam sheet20ofFIG. 3. The steel die may be pressed into the foam to sever the sheet into segments but leave connecting tab portions22, preferably at the corners and the center of each edge of each segment26.

The connecting tabs may be preferably formed by having a segmented die which allows a portion of the sheet to be cut through, while other portions are not cut, as the matching portion of the die has been removed in that area. The connecting tabs22may be preferably about 0.060 inches in width and may extend through the thickness of the sheet20for a distance of from about 0.060 inches thick to the full thickness of the sheet (about 2 inches). Thus, the flexible foam sheet20may provide an efficiently packaged packaging material which may protect and cushion articles without adding weight and may easily be customized to a desired size and shape without the need for knives to cut the foam or creating debris. There may be no waste as every segment may be used in some packing application and most can be used by further separating or recombining the segments into a new shape which fills the void between an article and its container.

In a third embodiment, the foam packaging material may be a relatively flexible thermoplastic such as polyethylene, polypropylene, other polyolefins and blends, alloys and copolymers with polystyrene. The foam may be cross-linked by radiation, graft initiator, cross-linking agent, etc. The thermoplastic foam may be provided by extruding a sheet of about 0.5 inches in thickness. Preferably, the foam has a density in the range of about 0.5 pounds per cubic foot to about 10 pounds per cubic foot, more preferably about 1.2 pounds per cubic foot. This sheet may then be heat laminated to other like sheets to form a sheet or “plank” of preferably about 1.0 inches to about 3.0 inches in thickness. The sheets may be laminated together using hot air (about 1000° F.) applied to facing surfaces and then compressing the sheets together through the nip of a set of rollers, bonding the heating surfaces together upon cooling. Replication of this process may build the sheet thickness to the desired end use thickness.

Generally when packaging an article within a container, a thickness of about 2 inches of protective packaging between the article and container is recommended. This provides cushioning as well as some protection from penetration. For heavy articles, especially those having defined corners, such as appliances, furniture, etc., corner pads may be configured from the aforementioned laminated sheets or planks of thermoplastic foam to yield a dent resistant, somewhat resilient, cushioning segment having a reasonably high level of stiffness. This material may fill the need between a relatively rigid non-conformable packaging material, like polystyrene foam and the like, and a relatively soft configurable packaging material, like flexible polyurethane foam, and the like.

Thermoplastic foams as used in this third embodiment may generally be closed celled, useful over a wide range of temperatures, with excellent tensile and tear strength and not easily abraded. The resilient, closed cell structure may effectively absorb shock and vibration and recover the foam to its original shape if deflected.

FIG. 8is a plan view of a sheet or plank of thermoplastic foam, as described above, laminated to about 2.0 inches in thickness.

The plank30may preferably be supplied in sections of about 18 inches wide by 18 inches long, or multiples thereof such that the section may be die cut into sub-segments of about 3 inches by 3 inches. These 3 inch square sub-segments may then be separated from the plank30as an L-shaped segment36(seeFIG. 9A) which may be configured into a corner pad (or cap or support)38as shown inFIG. 9B.

The specifics of forming the L-shape segments36from the plank30are as follows. A steel rule die may be used to “kiss cut” through the plank30, shown inFIG. 8, leaving selected portions of the sheet connected together locally to allow ease of handling the L-shaped sections36. The die may cut completely through the sheet at selected locations as indicated by the solid lines inFIG. 8, but leave a portion of the thickness of the plank30uncut (due to sections missing in the die blade) along common edges of interlocking L-shaped segments. These uncut tab sections are indicated by reference numeral32inFIGS. 8 and 9A).

These tabs32, which may generally be about 0.060 inches in width by 0.060 inches in thickness, may allow the sheet or plank to be handled as a single article and be stacked into a cube for efficient storage and shipment of the packaging prior to its intended end use, yet provide easy separation of the L-shaped segments by tearing. The vestiges of these tabs may be seen inFIG. 9Aalong the periphery of the L-shaped segment36and referenced as numeral32′.

When the L-shaped segment (36inFIG. 9A) is needed to provide a corner pad for a packaging application, an L-shaped segment may be manually separated from the plank30(FIG.8).

The L-shaped segment36(FIG. 9A) may then be configured into a corner pad by rotating each of the end sub-segments42,44in the direction of arrows A and A′ inFIG. 9A. This then may provide the corner pad38shown inFIG. 9B. Thus, a protective end cap having a thickness of about 1.5 inches to about 3 inches may be formed from 3 inch square sub-segments formed by partially die cutting the laminated plank section30.

To ensure that the sub-segments42and44remain essentially perpendicular to the base sub-segment46, a dovetail section40may be die cut into each of the sub-segments42,44. A connecting hinge portion34similar to tab32may be used to connect the sub- segments together and may be located on either side of the dovetail40to ensure that the sub-segments42and46and44and46remain connected and that each may be rotated to form a corner cap38. Preferably the size of the hinge portion34is controlled, and preferably may be relatively wider and thicker than tear tab32. By controlling of the width and thickness of the hinge portions34, it is important to note that one can therefore control the angle that may be formed as between first sub-segment42and base46and between sub-segment44and base46. For example, by reducing the width of the hinge portion34and/or its thickness, sub-segments42and44may be positioned and self-assemble to about a90degree angle with respect to base46.

By reference to dovetail section it should be understood that this relates to any geometry that, when the sub-segments42or44are rotated to a substantially perpendicular configuration relative to base46, such geometry is one that creates an interference as between base46and any one of sub-segments42or44, so that they remain in a position for use in packaging as a corner pad.

When the sub-segments42and44are rotated in the direction of arrows A and A′ (FIG. 9B) around hinge portions34relative to base46, the dovetail sections40of base46may be rotated through the body of sub-segment42and44until the dovetail sections40clear the inner wall of the sub-segment. At this point the ears of the dovetail40may clear the side wall and recover their original shape to act as a locking mechanism to ensure that the corner pad38retains its desired, essentially inside square corner, configuration. In other words, that sub-segments42and44may not return to their original flat sheet orientation but may be retained by the dovetail sections40in a position substantially perpendicular to base46. In one preferred embodiment the sub-segments42,44and46were each about 3 inches square and 2 inches thick and the dovetail extended about 0.75 inches into the sub-segments42,44and had a width about 1.5 inches across the ears and about 1.125 inches at its narrowest point. Retention of this “inside corner” shape for the pad may allow easy location of four corner pads in the bottom of a container with minimal adjustment. Another four pads may be located at the top corners of the article being packaged and covered by a container top.

All three embodiments of the present invention thus comprise a polymeric foam provided in sheet form which may be easily separated into segments to customize packaging for a multitude of applications.

The description and drawings illustratively set forth the presently preferred invention embodiments. We intend the description and drawings to describe the embodiments and not to limit the scope of the invention. Obviously, it is possible to modify these embodiments while remaining within the scope of the following claims. Therefore, within the scope of the claims one may practice the invention otherwise than as the description and drawings specifically show and describe.