Abstract:
Packaging insulation for insertion into a packaging container, which includes an air laid thermoplastic fibrous batt having foldable thermoplastic film material adhered to both sides of the batt. Preferably the thermoplastic material of which the fibers and film are made is the same, and most preferably it is PET. The resulting method and product provides packaging insulation which can be shipped flat and compressed, which expands when unpacked and which can be readily folded to match the interior configuration of a shipping container, such as a cardboard box.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of packaging insulation. 
       PRIOR ART 
       [0002]    Packaging insulation is used for shipping perishable items which must be kept cold during shipping. Individualized packages in which such items are shipped are lined with insulation to maintain the shipped item or items at the appropriate temperature. Current packaging insulation products comprise semi rigid expanded styrene panels, polymer bags stuffed with cotton, or Kraft paper bags stuffed with cotton. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention comprises packaging insulation for insertion into a packaging container, which includes a fibrous batt comprised of thermoplastic polymer fibers, having foldable thermoplastic polymer film adhered to both sides of the batt. The resulting method and product provides packaging insulation which can be shipped flat and compressed, which expands when unpacked and which can be readily folded to match the interior configuration of a shipping container, such as a cardboard box. Preferably the same thermoplastic polymer is used for the polymer fibers and the polymer film, and preferably it is PET, and most preferably recycled and recyclable. 
         [0004]    These and other features, advantages and objects of the invention will be more readily understood and appreciated by reference to the drawings, description of the preferred embodiments, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a perspective view of a preferred embodiment packaging insulation; 
           [0006]      FIG. 2  is a perspective view of two pieces of packaging insulation cut to fit within a particular shipping container; 
           [0007]      FIG. 3  is a perspective view of a cardboard shipping container without packaging insulation; 
           [0008]      FIG. 4  is a perspective view of the container of  FIG. 3  lined with the packaging insulation pieces of  FIG. 2 ; 
           [0009]      FIG. 5  is a plan view of the compression equipment used to form the packaging insulation of the preferred embodiment; and 
           [0010]      FIG. 6  is a top plan view of the compression equipment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]    In the preferred embodiment, laminated packaging insulation  1  comprises a fibrous polyethylene terephthalate (PET) fiber batt  10 , laminated between two layers of PET film material  20  ( FIG. 1 ).  FIG. 2  shows a sheet of the packaging insulation  1  which has been cut into pieces  1   a  and  1   b  to fit within the cardboard shipping container  30  of  FIG. 3 . Packaging insulation  1  is readily foldable into appropriate shipping container configurations. As shown in  FIG. 4 , piece  1   b  has been folded to cover the bottom, one side and the lid of container  30 . Piece  1   a  has been folded to cover the remaining three sides of container  30 . Preferably, the fibrous batt is non-woven, most preferably air-laid. While other thermoplastic polymers can be used for the fibers and film, preferably the same thermoplastic polymer is used for the polymer fibers and the polymer film, preferably it is PET, and most preferably recyclable and recycled. By using the same thermoplastic material for the fibers, the binder fibers and the film, the packaging insulation material may be readily recycled in commercial recycle centers. Recycled PET is the most preferable thermoplastic material. 
         [0012]    The non-woven PET fiber batt  10  is formed of PET staple fibers, preferably fibers made from recycled PET (recycled PET fibers), having a length between 20-72 mm, preferably between 20 to 60 mm. The denier of the recycled PET fibers substantially falls between about 1 to about 10, preferably about 2 to about 8, and most preferably about 4-6 denier. Thickness of the PET fibers varies with denier, but finer fibers are preferred. From about 5 to about 30% thermoplastic binder fibers, more preferably about 10-25%, and most preferably about 15-20%, are mixed in with the PET fibers. Binder fibers may be lower melting point resinous fibers such as polyolefin, PVA or PVOH; or may be bi-component fibers including a higher melting point thermoplastic component associated with a lower melting point thermoplastic material. The bi-component fiber may comprise side by side strands of the two materials, or a higher melting point core encased in a lower melting point sheath, or a higher melting point strand with lower melting point beads scattered along its length. The binder fibers have lengths within the ranges discussed above. As above, preferably the same thermoplastic polymer is used for the polymer binder fibers, the batt fibers and the polymer film, preferably it is PET, and most preferably recycled and recyclable. 
         [0013]    The PET film material used is preferably made from recycled PET (recycled PET film). It is preferably bi-axially oriented polyester film having a thickness of from about 2 to about 20 microns, most preferably about 12 microns. A clear PET film is preferred, having a haze of only about 3-4%. It is substantially impervious to moisture. 
         [0014]    The PET fibers are normally shipped in bales, which are “opened” using a bale opening machine and process, which separates the fibers. They are mixed with the binder fibers and delivered by the flow of air into an air lay machine that forms a continuous batt and delivers it to a continuously moving conveyor belt. The fibers will be air laid to a thickness which is appropriate to the final thickness desired. The fibers will be air laid to a thickness which is greater than, but appropriate to the final thickness desired. A batt as air laid on the conveyor may vary widely, but from about 3 to about 6 inch thicknesses are typical. The basis weight is between about 400 gsm to about 1200 gsm (0.08 pounds/square foot to about 0.25 pound/square foot.) The batt is conveyed through an oven which is maintained at a temperature of from about from about 160 to about 185° C., typically about 165 to 175° C. The heat of the oven tackifies the sheath of the binder fibers to assist in binding the natural and binder fibers together and give the batt cohesion. The heat of the oven tackifies the sheath of the binder fibers to assist in binding the PET and binder fibers together and give the batt cohesion. 
         [0015]    From the oven, the batt is conveyed along to compressor  50  ( FIGS. 5 and 6 ). Compressor  50  comprises a series of upper and lower compression rollers  51   a - b,    53   a - b,    55   a - b,    57   a - b  and  59   a - b  which respectively carry a conveyor belt  50   a  and  50   b,  made of a low friction material such as Teflon. Located between the compression rollers, are compression plates  52   a - b,    54   a - b,    56   a - b  and  58   a - b,  which press against the upper and lower Teflon conveyor belts  50   a  and  50   b.  The Teflon conveyor belts  50   a  and  50   b  slide over and past the compression plates. 
         [0016]    As fibrous batt  10  is fed between the upper and lower Teflon conveyor belts  50   a  and  50   b,  at upper and lower starter rolls  51   a  and  51   b,  the PET film facing stock is fed from one of the upper rolls  40   a  under the upper Teflon conveyor belt  50   a  at top roll  51   a  and from one of the lower rolls  40   b  over the lower Teflon conveyor belt  50   b  at bottom roll  51   b  so as to be applied to both opposite sides of the passing fibrous batt  10  ( FIG. 5 ). Two separate top feed stock rolls  40   a  can carry the same full width paper rolls and used in the alternative, or can carry paper rolls of two different widths and used in the alternative, or can carry two narrower paper rolls and used simultaneously to feed two side by side rolls of paper, which overlap slightly during the lamination process. The same is true for the two separate bottom feed stock rolls  40   b.    
         [0017]    The batt continues to pass between the upper and lower Teflon conveyor belts, carried by alternating upper and lower compression rollers and compression plates, which gradually reduce the thickness of the laminated batt to the target thickness. Compression rolls  51   a - b,  and  53   a - b  are heated to from about 170° C. to about 190° C., while rolls  55   a - b,    57   a - b  and  59   a - b  are cooled to about 40° F. to about 55° F. Similarly, compression plates  52   a - b  and  54   a - b  are heated to from about 170° C. to about 190° C., while plates  56   a - b  and  58   a - b  are cooled to about 40° F. to about 55° F. In this manner, binding fibers in the fibrous batt continue to be adhering and tacky, and the PET film stock becomes heated and tacky, through the heated compression rollers and heated compression plates. When the batt reaches the cooling rollers and cooling compression plates, the heated and tacky binder fabrics and the tackified PET film stock begin to solidify and complete the adherence process, both between fibers in the batt, and between the batt and the PET film laminated to each opposing face of the batt. 
         [0018]    As the laminated batt passes the final compression rolls  59   a  and  59   b,  it passes through longitudinal cutters  60  adjustably mounted on a support  61 . This cuts the batt to desired widths. The batt so cut then passes a guillotine cutter blade  70  which cross-cuts the batt to desired lengths. 
         [0019]    The resulting packaging insulation products  1  are cut to desired dimensions for specific packaging insulation requirements, and are from about ¼ to about 3 inches thick, and have a density of from about one to about seven pounds per cubic foot. The packaging insulation products can be shipped flat and compressed for economy of shipment. Surprisingly, the laminated PET product can be compressed to a greater degree than other types of fibrous batts used in packaging insulation, making it more economical to ship to the customer. When the laminated PET batts are unpacked at the customer&#39;s location, they expand back to at least near their original thickness, and can be folded to fit the packaging container in which product is to be shipped. Preferably, two panels are provided for each package ( FIG. 2 ), one of which can be folded to cover the bottom, rear side and top of the container, and the other of which can be folded to cover the two ends and front side of the container ( FIGS. 3 and 4 ). 
       EXAMPLE 
       [0020]    A 1.5 inch thick all recycled PET fiber and film product, with a density of one pound/cubic foot, was assembled in a cardboard shipping container in the manner shown in  FIG. 4 . Each payload consisted of two 6-oz gel packs with a thermocouple on top, in between (middle), and bottom of the assembly. The assemblies were held together with duct tape. 
         [0021]    The gel packs were placed into an environmental chamber for freezing to −18° C. at least 6 hours prior to the official initiation of the test. Concurrently the shipping container fitted with the PET insulation material conditioned to 22° C. in a separate chamber for a minimum of 24 hours. 
         [0022]    The gel pack assemblies were placed in the shipping container and the closed container was subjected to 35° C. (95° F.) for more than 72 hours. The temperatures were logged at 15 minute intervals. The gel packs inside the container remained below 39° F. for more than 35 hours. 
         [0023]    Of course it is understood that the above are preferred embodiments of the invention, and that various changes and alterations can be made without departing from the spirit and scope of the invention, as set forth in the appended claims.