Patent Application
20170369226
The present invention relates to the field of packaging insulation.
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.
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.
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.
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 (
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.
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.
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.
From the oven, the batt is conveyed along to compressor 50 (
As fibrous batt 10 is fed between the upper and lower Teflon conveyor belts 50a and 50b, at upper and lower starter rolls 51a and 51b, the PET film facing stock is fed from one of the upper rolls 40a under the upper Teflon conveyor belt 50a at top roll 51a and from one of the lower rolls 40b over the lower Teflon conveyor belt 50b at bottom roll 51b so as to be applied to both opposite sides of the passing fibrous batt 10 (
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 51a-b, and 53a-b are heated to from about 170° C. to about 190° C., while rolls 55a-b, 57a-b and 59a-b are cooled to about 40° F. to about 55° F. Similarly, compression plates 52a-b and 54a-b are heated to from about 170° C. to about 190° C., while plates 56a-b and 58a-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.
As the laminated batt passes the final compression rolls 59a and 59b, 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.
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'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 (
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
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.
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.
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.
