Patent Publication Number: US-2009238501-A1

Title: Pallet Hood Tear Tape

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to tear tapes on shrink hoods and stretch hoods for products on a pallet. 
     2. Description of the Related Art 
     Tear strips comprising a thin thread or string of fiber placed within the container at its top are shown in U.S. Pat. No. 3,543,343 to Staller, as a means to open sealed containers along a single tear line. The drawback of such tear strips is that the tear line may deviate from the top of the bag and propagate into other container elements and compromise its strength, shape and operation. U.S. Pat. No. 3,827,427 to Uramoto defines two tear lines, one on each lip of a bag mouth, between pairs of ribs to contain the propagating tear. In U.S. Pat. No. 5,022,530 to Zieke, a tear strip comprised of a bead of thermoplastic material is provided to define a tear line generally along the top edge of the flexible container. 
     Tear strips are typically comprise weakened lines for tearing across sealed webs, for example to gain access to the mouth of a bag. U.S. Pat. No. 3,198,228 to Naito and U.S. Pat. No. 3,780,781 to Uramoto both describe tear strips having such weakened regions. U.S. Pat. 2002/0162766 to Saso et al. describes a shipping case alternative having an opaque film and a clear film shrink wrapped around packages and the clear film having a tear strip comprising parallel lines of zipper perforations extending along one of the shrink films. The zipper perforations are designed such that reasonable manual force applied to the shrink wrap will split open the shrink wrap along the perforations as a result of tears extending from one perforation to the next and so on. U.S. Pat. 2001/0025800 to Marco describes a single piece carrier for a six pack of cans having a tear or removal strip that separates the ring carrier from the film sleeve. 
     Various processes have been developed for securing product packages on a pallet. One such process is the so-called spiral wrapping process where a packaging material dispenser is kept in a fixed position while the load and the pallet rotates around a central vertical axis or oppositely: the load is fixed and the dispenser is circulated around the load while dispensing packaging material. The packaging material is dispensed onto the load by the rotation of the load that pulls the packaging material from the dispenser, as described in U.S. Pat. No. 5,005,335 to Yourgalite et al. An alternative process is the shrink process. Initially, the load is confined in a plastic hood, usually pulled down on the load by an appropriate frame surrounding the load in a horizontal plane, and subsequently the plastic hood is made to shrink by applying a fast heating process. The shrunk plastic hood serves the dual purpose of resiliently confining and holding the load units together and protecting the load units against the environment during transport, e.g. water and dust. Yet, another process is the stretch hood wrapping. A rectangular frame with four holding means-one in every corner-stretches the opening of a plastic hood to a larger horizontal projection than the load on the pallet to be wrapped and pulls down the hood on the load. 
     Suppliers are increasing shipping goods to retails stores on pallets with the products protected by shrink hoods or stretch hoods. At the retail store, the product pallet is typically opened by slicing the shrink hood with a knife to remove the shrink hood. This can cause inadvertent product damage. PCT App. WO2005/042346 to Nielsen et al. describes stretch hoods for packaging bulk goods. In order to facilitate the unwrapping at the destination point of the load, the method preferably comprises a further packaging step, wherein perforating means, e.g. a knife or a punching machine, is applied to perforate the packaging material in selected points or areas. However, these perforations could lead to weakening the stretch hood or to product damage during the perforation step. 
     In order to solve this problem, a tear tape can be attached to interior or exterior of the shrink hood or stretch hood to facilitate removal of the shrink hood without product damage. Although a variety on tear tape technologies have been applied to individual containers and small combinations of containers, tear tapes have not been applied to shrink hoods or stretch hoods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and others will be readily appreciated by the skilled artisan from the following description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a one embodiment of the invention; 
         FIG. 2  is a perspective view of a one embodiment of the invention; 
         FIG. 3  is a perspective view of a one embodiment of the invention; 
         FIG. 4  is a front view a portion of one embodiment of the invention; 
         FIG. 5  is a front view a portion of one embodiment of the invention; 
         FIG. 6  is a perspective view of a portion of one embodiment of the invention; 
         FIG. 7  is a top view of a portion of one embodiment of the invention; 
         FIG. 8  is a front view of a portion of one embodiment of the invention; 
         FIG. 9  is a front view of a portion of one embodiment of the invention; and 
         FIGS. 10   a - d  are perspective views of embodiments of the invention. 
     
    
    
     Reference will now be made to the drawings wherein like numerals refer to like parts throughout. As used herein, positional terms, such as “bottom” and “top” and the like, and directional terms, such as “up”, “down” and the like, are employed for ease of description in conjunction with the drawings. Further, the terms “inner”, “interior”, “inwardly” and the like, refer to positions and directions toward the geometric center of embodiments of the present invention and designated parts thereof. The terms “outer”, “exterior”, “outwardly”, and the like, refer to positions and directions away from the geometric center. None of these terms is meant to indicate that the described components must have a specific orientation except when specifically set forth. 
     Figures illustrating the components of this invention and the container show some conventional mechanical elements that are known and that will be recognized by one skilled in the art. The detailed descriptions of such elements are not necessary to an understanding of the invention, and accordingly, are herein presented only to the degree necessary to facilitate an understanding of the novel features of the present invention. 
     SUMMARY OF THE INVENTION 
     In accordance with the above objects and those that will be mentioned and will become apparent below, one aspect of the present invention comprises a package shipment system comprising a base comprising a pallet or slipsheet; one or more products supported by the base; a hood fitting over the one or more products comprising a containment selected from the group consisting of a shrink hood or a stretch hood; wherein the hood comprises a tear tape attached to the interior of the hood. 
     In accordance with the above objects and those that will be mentioned and will become apparent below, another aspect of the present invention comprises a package shipment system comprising; a base comprising a pallet or slipsheet; one or more products supported by the base; a hood fitting over the one or more products comprising a containment selected from the group consisting of a shrink hood or a stretch hood; wherein the hood comprises a tear tape having a rough edge for tearing the hood and the tear tape attached to the interior of the hood. 
     In accordance with the above objects and those that will be mentioned and will become apparent below, another aspect of the present invention comprises package shipment system comprising a base comprising a pallet or slipsheet; one or more products supported by the base; a hood fitting over the one or more products comprising a containment selected from the group consisting of a shrink hood or a stretch hood; wherein the hood comprises a tear tape for tearing the hood and the tear tape is attached to the interior of the hood and covers a line of laser perforations. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified systems that may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to limit the scope of the invention in any manner. 
     All publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference. The citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. 
     As used herein, forms of the words “comprise”, “have”, and “include” are legally equivalent and open-ended and do not exclude additional unrecited elements, compositional components, or method steps. Accordingly, the term “comprising” encompasses the more restrictive terms “consisting essentially of” and “consisting of”. 
     It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a “surfactant” includes two or more such surfactants. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although a number of methods and materials similar or equivalent to those described herein can be used in the practice of the present invention, only exemplar materials and methods are described herein. 
     In the application, effective amounts are generally those amounts listed as the ranges or levels of ingredients in the descriptions, which follow hereto. All percentages, ratios and proportions are by weight, and all temperatures are in degrees Celsius (° C.), unless otherwise specified. All measurements are in SI units, unless otherwise specified. It should be understood that every limit given throughout this specification will include every lower, or higher limit, as the case may be, as if such lower or higher limit was expressly written herein. Every range given throughout this specification will include every narrower range that falls within such broader range, as if such narrower ranges were all expressly written herein. 
     The term “plastic” is defined herein as any polymeric material that is capable of being shaped or molded, with or without the application of heat. The term “thermoplastic” is defined herein as a high polymer that softens when exposed to heat and returns to its original condition when cooled. Usually plastics are a homo-polymers or co-polymers of high molecular weight. Plastics fitting this definition include, but are not limited to, polyolefins, polyesters, nylon, vinyl, acrylic, polycarbonates, polystyrene, and polyurethane. 
     Shrink Hoods and Stretch Hoods 
     U.S. Pat. No. 6,012,266 and U.S. Pat. No. 5,544,472 to Koskinen et al. and U.S. Pat. App. 2005/0284783 to May describe shrink hoods for packaging bulk goods and are hereby incorporated in their entirety herein. PCT App. WO2005/042346 to Nielsen describes stretch hoods, and is hereby incorporated in its entirety herein. Suitable film materials are described in U.S. Pat. App. 2006/0094824 to Roulin et al., U.S. Pat. App. 2005/0037219 to Ohlsson et al., PCT App. WO2007/129078 to Nilsen et al, PCT App. WO2006/076917 to Erikson and PCT App. WO2007/044544 to Parkinson et al, and are hereby incorporated in their entirety herein. These technologies generally use plastic films that are resistant to formation of holes and tear propagation, therefore traditional tear strip technology, such as simple parallel lines of zipper perforations, is not suitable. The shrink hoods or stretch hoods of the invention preferably lack zipper perforations running the length of the tear tape. The emphasis in the development of shrink hoods and stretch hoods has been to provide product security on a pallet, for example, rather than to create convenience for accessing these products at a later time. 
     Tear tapes may be applied in a variety of ways. The tear tapes may be extruded into the thermoplastic film of the shrink hood or stretch hood or extruded or otherwise formed separately and then attached to the surface thereof. Examples of tear tapes are disclosed in U.S. Pat. No. 6,513,657 to Sheehan, Jr., which is hereby incorporated in its entirety herein. Tear tapes could be applied to the interior of the hood during the process by which the bag for the shrink or stretch hood is made on a extruding machine, as the bag is tubed, or as flat material that is then converted to a hood. The tear tape could also be post applied, by adhesive or other means, to the interior or exterior of the shrink or stretch hood before the hood is fitted to the palletized products or already on the palletized products. The tear tape tears the material of the hood when pulled outwards, and the tear tape could optionally weaken the hood material when applied either through mechanical or other active means, such as the chemical activity of an adhesive. The tape application equipment could create a line of perforation, for example laser perforation, as the tape is applied. The application equipment could locally alter the film properties of the hood adjacent to the tear tape by mechanical, electrical (e.g. corona), thermal or chemical means to enhance the tape application and subsequent tearing process. The tear tape itself could also alter these properties and modify the film surface or structure of the stretch or shrink hood and impart properties desirable to the functionality of the tear tape, for example strength in a horizontal direction and weakness in a vertical direction. The tear tape could be colored or printed to bring attention to its presence or function. 
       FIG. 1  shows a shrink or stretch hood  10  being applied over a plurality of unitized products  12  on a pallet or slipsheet  14 . The hood  10  contains a single tear tape  16 , consisting of tape, bead, line of material, or seam, on the interior of the hood and running vertically from top to bottom of the hood  10 . The hood  10  can have a cutout or perforation  18  with allows the user to grab and pull the tear tape  16  and remove or partially remove the hood  10 . 
       FIG. 2  shows a shrink or stretch hood  20  fully covering the top and sides of a plurality of unitized products on a pallet or slipsheet  24 . The tear tape  26  extends from the hood seam  27  at the top of the hood  20  to the bottom of the hood  20  at the pallet or slipsheet  24 . 
       FIG. 3  shows a shrink or stretch hood  30  covering the sides and part of the top of a plurality of unitized products  32  on a pallet or slipsheet  34 . The tear tape  36  extends from the open top  38  of the hood  30  to the bottom  39  of the hood  30  at the pallet or slipsheet  34 . 
       FIG. 4  is an exploded view of one embodiment of the cutout or perforation  18  of  FIG. 1 . There is a slit  40  in the hood  42  across and through the tear tape  44  and there are perforations  46  extending from the ends of the slit  48 . The slit  40  allows access for opening the hood. 
       FIG. 5  is another exploded view of another embodiment of the cutout or perforation  18  of  FIG. 1 . An opening  50  is cut in the hood  52  in a shape to create pull tabs  54  having a portion of the tear tape  56  for pulling and removing the tear tape  56 . 
       FIG. 6  is a perspective view of a portion of a pallet  60  containing bags  62  of material. A hood  64  fits over the pallet  60  and the bags  62  and a tear tape  66  extends vertically centered in the space between the bags  62 . 
       FIG. 7  is a top view of a portion of  FIG. 6  showing the hood  64 , the interior tear tape  66  and the bags  62 . 
       FIG. 8  is a front view of a tear tape  80  having straight sides  82  and underneath the hood film  81 . 
       FIG. 9  is a front view of a shearing tear tape  90  having saw blade edges or cutting edges  92  and underneath the hood film  91 . The tear tape  90  might have advantages in shearing extremely tough film material. 
       FIGS. 10   a - 10   d  show alternative embodiments of the tear tape on a palletized product.  FIG. 10   a  shows multiple tear tapes  101  on adjacent sides of the shrink or stretch hood.  FIG. 10   b  shows a multi-piece tear tape  102  extending from the bottom to the top of the hood.  FIG. 10   c  shows an angular tear tape  103  extending across two sides of the hood.  FIG. 10   d  shows a combination tear tape  104  extending horizontally and vertically on multiple sides and the top of the hood. 
     Shearing Tear Tape 
     The shearing tear tape  90  in  FIG. 9  might have rough or jagged edges, like a saw blade, to induce shearing the shrink hood or stretch hood. The shearing tear tape can be constructed out of a variety of materials including a tougher plastic or nonwoven having greater tensile strength or orientation, a plastic or nonwoven material having an abrasive edge, or a metallic material. The shearing tear tape might have a rough edge or edges that incorporate hard abrasive materials (e.g., having a Mohs&#39; hardness greater than about 8) to provide the tear tape with a more aggressive abrasive surface and aid in shearing the hood. Suitable abrasive materials include, without limitation, aluminum oxide including ceramic aluminum oxide, heat-treated aluminum oxide and white-fused aluminum oxide; as well as silicon carbide, alumina zirconia, diamond, ceria, cubic boron nitride, garnet, and combinations of the foregoing. The average particle sizes of the foregoing abrasives can range from about 1 to about 2000 microns. 
     Laser Perforation 
     The shrink hood or stretch hood may have a line of perforations, formed for example by laser perforations as described in PCT App. WO2006/063609 to Groeneweg et al. and PCT App. WO2007/050559 to Wiker et al. also describing appropriate film technology, both of which are incorporated herein in their entirety. The laser perforations, as opposed to mechanical perforations, may provide a line for tearing the hood without weakening the hood that would induce tearing during the process of forming the hood on the palletized product or during shipping, etc. The tear tape  80  may cover or extend on both sides of the laser perforations  84  in the hood film  81  as in  FIG. 8 , so that the film tears along the laser perforations as the tear tape is pulled. The tear tape  90  may be adjacent to the laser perforations  94  in the hood film  91  as in  FIG. 9 , where the edge  92  of the shearing tear tape may interact with the perforations during the removal process. The laser perforations can go completely through the hood film or only partially go through the film to weaken the hood film. 
     Products 
     This invention can be applied to all palletized products shipped in shrink hood and stretch hoods. These products can include single or multiple units in the form of boxes, bags, items, or any other satisfactory unit form for conveying on pallets. It may also allow fragile products that might be damaged in the normal process of removing a shrink hood to be shipped that way. Palletized products include boxes, bags, bottles, cans, any packaging form, bricks, blocks, construction materials, or anything shipped in this general form. 
     While this detailed description includes specific examples according to the invention, those skilled in the art will appreciate that there are many variations of these examples that would nevertheless fall within the general scope of the invention and for which protection is sought in the appended claims.