US 3670880 A
This disclosure relates to a package construction adapted for vertical stacking and shipment in which a flexible product is enclosed within a paperboard receptacle, and a paperboard cover is disposed atop the flexible product in such a fashion that the cover rests on the product and telescopes over the receptacle such that other package constructions disposed thereabove bear upon the flexible product and not the paperboard container. The package construction contains a plastic film on its outer surfaces which is shrunk wrapped thereover and is fused thereto, thereby providing weather resistant protection for the contents thereof.
Description (OCR text may contain errors)
United States Patent Burleson et a].
[451 June 20, 1972 PACKAGE FOR FLEXIBLE PRODUCTS Inventors: E. Richard Burleson, Reseda, Califi; Carl H. Davis, Seattle, Wash.
Dresser Industries, lnc., Dallas, Tex.
Aug. 7, 1970 Assignee:
US. Cl. ..206/65 S, 206/835, 229/DIG. 12, 53/30 Int. Cl. 865d 71/00, 865d 85/62 Field of Search ..206/65 R, 65 S, 65 B, 45.33, 206/835; 53/30; 229/3.l, DIG. 12
References Cited UNITED STATES PATENTS 5/1963 Fallert ..206/65 R 6/196] Tench et a]. ..229/3.l
3,508,375 4/1970 Myers ..206/45 .33
Primary Examiner-William T. Dixson, Jr.
Attorney-Robert W. Mayer, Thomas P. Hubbard, Jr., Daniel Rubin, Raymond T. Majesko, Roy L. Van Winkle, William E. Johnson, Jr. and Eddie E. Scott ABSTRACT This disclosure relates to a package construction adapted for vertical stacking and shipment in which a flexible product is enclosed within a paperboard receptacle, and a paperboard cover is disposed atop the flexible product in such a fashion that the cover rests on the product and telescopes over the receptacle such that other package constructions disposed thereabove bear upon the flexible product and not the paperboard container. The package construction contains a plastic film on its outer surfaces which is shrunk wrapped thereover and is fused thereto, thereby providing weather resistant protection for the contents thereof.
4 Claim, 1 Drawing Figure P'A'TENTEnJunzo m2 3,670,880
INVENTORS E. RICHARD BURLESON CARL HOWARD DAVIS ATTORNEY PACKAGE FOR FLEXIBLE PRODUCTS Heretofore, flexible products have been packaged in ordinary paperboard cartons. By flexible products" it is intended to mean granular-type material packaged in paper or cloth sacks and the like. The carton is disposed on a wooden pallet and the completed package is stacked four or five pallets high. Because of the weight of the pallets and package at the top of the stack and the inherent poor load resistance of paperboard containers, the packages at the bottom of the stack buckled, causing the remainder of the packages to tumble and break.
One solution to this problem has been to construct the cartons out of wood. This would provide the required strength for stacking numerous packages. However, economy always being a factor, the cost of the wooden cartons was prohibitive.
Accordingly, it is an object of the present invention to provide a weather resistant, puncture resistant paperboard package for packaging flexible products.
It is another object of the invention to provide a paperboard package that will not buckle and collapse when stacked one on top of the other.
Other objects, uses and advantages of this invention will become apparent from a reading of the following description which proceeds with reference to the accompanying drawing, forming a part thereof, and wherein the single FIGURE is a perspective view of the improved package construction of this invention.
Broadly, the container of the present invention consists of two separate parts. Each part is constructed of multi-wall corrugated board. The board is preferably coated inside and out with a fusible and weather resistant material. In the bottom tray is stacked the required amount of flexible products. The top corrugated cover is slipped over the material and telescoped over the outside of the bottom tray. A shroud of shrink film plastic is disposed over the outside of the entire package and is fused to the coating.
Referring now to the drawing, the improved package construction of this invention is generally indicated by the reference numeral 10. On top of a pallet 12 is disposed a receptacle 14 which may be permanently secured to the pallet with staples. The receptacle contains a substantially flat botmm 15 and upwardly extending peripheral sidewalls 16. The flexible products 18, which in this case are paper containers filled with powdered material, are vertically stacked on the receptacles within and extending above the top edge of the sidewalls.
A closure which contains a substantially flat top 21 and downwardly extending peripheral sidewalls 22 is disposed on the products 18. The top 21 of the closure rests on the flexible products, and the sidewalls 22 of the closure overlap a portion of the sidewalls 16 of the receptacle 14.
The receptacle and closure which are fabricated from multilayer corrugated board contain a fusible and weather resistant coating on the inner and outer surfaces thereof. Preferably, the fusible coating is composed of a mixture of paraffin wax and polyethylene in an approximate ratio of 50:50. Generally, paraffin waxes are produced from paraffin distillates and have melting points which range from about 120 to 150 F. The polyethylene additive should have a melting point in the range from about 150 to 200 F., preferably closer to 150" F. Another suitable composition consists of paraffin wax, microcrystalline wax and a copolymer of ethylene-vinyl acetate. The copolymer should have a molecular weight in the range from about 1,000 to 10,000. The base paraflin wax and the microcrystalline waxes may be of the type described in U.S. Pat. No. 3,098,598 issued July 23, 1963. The ethylenevinyl acetate copolymer may be one such as described in U.S. Pat. No. 3,093,623 issued June ll, i963. The wax mixture may be applied to the surfaces of the paperboard receptacle and closure by spraying, brushing or any other method known to those skilled in the art.
The top 21 and sidewalls 22 of the closure 20 and the sidewalls 16 of the receptacle 14 is then draped with a heat shrinkable plastic film having a thickness of about 8 mils, and
the package is disposed in a heat shrink oven which is maintained at a temperature sufficient to shrink the film over the containers and also to fuse it to the coating on the external surfaces of the container.
The films used in the present invention are nonnally composed of a thermoplastic resinuous material which has been oriented at least in one direction by stretching during its process of manufacture to render it shrinkable by heat. A cast or extruded film can be stretched to align the molecules into a more orderly pattern, giving the film increased strength and toughness, as well as shrinkability. In some cases, the film may be biaxially oriented to provide equal shrink in both the longitudinal and transverse dimensions of the film. The orientation also serves to increase the resistance to cold cracking of the film, so that it retains its flexibility at low temperatures.
One of the particularly preferred materials for use in this invention is a biaxially oriented polyvinyl chloride film. This material will shrink a maximum of about 60 percent at 325 F. With a source of hot air as the heating medium, the film is normally heated to 300 to 310 F. with a residence time of about 2 to 5 seconds.
While polyvinyl chloride is the preferred material, other heat shrinkable polymers can also be employed, such as,
oriented polyvinylidene polymers, vinyl-vinylidene copolymers, rubber hydrochloride, polyethylene, polypropylene and polyethylene terephthalate.
EXAMPLE A receptacle and closure as described above, was coated on the internal and external surfaces with a 50-50 blend of paraffin wax and polyehtylene. The receptacle was stapled to a wooden pallet. Both the receptacle and the closure were subjected to sub-zero temperatures to determine the effect. The bags of granular material were then stacked on the receptacle within the sidewalls to the desired height. The closure was then disposed above the packaged articles with the flat top surface resting thereon. The sidewalls telescoped over the sidewalls of the receptacle to a distance of about one-half the length of the receptacle sidewalls. The container was then draped on the top surface and all side surfaces with a polyvinyl chloride shroud which extended to the bottom of the pallet. The package was then placed in a shrink wrap oven maintained at a temperature of about 450 F.
After removal, the bond between the shroud and the coating was examined and found to be excellent. The container was found to be water resistant and when subjected to subzero temperatures, it was practically unaltered. The package was subjected to 12,000 pounds of pressure on the top and did not buckle.
Having thus described the invention in detail and with sufficient particularity as to enable those skilled in the art to practice it, what we desire to have protected by Letters Patent is set forth in the following claims.
1. A paperboard package capable of being vertically stacked one upon another, comprising a receptacle including a substantially flat bottom and upwardly extending peripheral sidewalls, flexible products vertically disposed on said receptacle within and extending above the top edge of said sidewalls, a closure including a substantially flat top and downwardly extending peripheral sidewalls, the top of the closure resting on the flexible products, at least the outer surfaces of said receptacle and closure having a fusible and weather resistant coating thereon, the sidewalls of the closure overlapping only a portion of the sidewalls of the receptacle and a heat shrunk synthetic film sealed to the coating on at least the outer surfaces of the top and sidewalls.
2. Package of claim 1, which contains an inflexible pallet thereunder.
3. Package of claim 1, in which the coating is a mixture of paraffin wax and polyethylene.
4. Package of claim 1, in which the film is polyvinyl chloride.
'4: a t a a