US 3502486 A
Description (OCR text may contain errors)
B. R. LUNDQUIST RECLOSABLE PACKAGE FOR FOOD PRODUCTS Filed Sept. 30, 1966 a d n 5 V 2 n WU w j J C a 1% F/ 125: H a/W f 0 9w .4 2 a March 24, 1970 I N VEN TOR. BUR TON R. LUNDQUIST BY f 7 A TTORNE Y United States Patent Ofice Patented Mar. 24, 1970 3,502,486 RECLOSABLE PACKAGE FOR FOOD PRODUCTS Burton R. Lundquist, Highland Park, Ill., assignor to Swift & Company, Chicago, Ill., a corporation of Delaware Filed Sept. 30, 1966, Ser. No. 583,344
Int. Cl. B65b 25/06 US. Cl. 99-171 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to the packaging of products which are subject to undesirable deterioration; and more particularly relates to an improved reclosable package for food products.
In the packaging art many advances have been made in recent years in methods of packaging products subject to deterioration or spoilage upon contact with the atmosphere. Vacuumizing, inert gas backfilling, and in-package oxygen removal are now standard techniques in the preservation of packaged food products such as luncheon meats, cheese, bacon and other perishable comestibles. Inexpensive packages have been designed for use in such methods. The packages previously formed using these techniques have been designed primarily to lengthen the storage life and shelf life of the packaged food product; these packages after being opened by the consumer are not easily reclosable.
Many food products are sold to consumers in packages which contain more product than may be used at one time. Most manufacturers presently package perishable food products in flexible film pouches. Opening such a package involves tearing off one end of the package which is followed by removal of a portion of the product. With most flexible film packages it is diflicult or impossible, even with careful manipulation of the film, to completely reclose the package. In many situations the film does not tear in a straight line making it absolutely impossible to reclose the package. Unless the package is reclosed, the product desiccates, loses flavor and is subject to odor pickup during further storage.
It is therefore an object of the invention to provide reclosable packages adapted to aid in preserving a deteriora'ble product after opening of the package.
Another object of the invention is to provide a vacuum or gas-filled food package for long shelf-life which is easily reclosable for subsequent protection of unused product.
A further object of the invention is to provide a package wherein the resiliency of the materials of construction of the package tends to eliminate manipulation of the package for reclosing.
Additional objects will be readily apparent to those skilled in the art from the following description of the invention.
In general, the present invention contemplates enclosing a product subject to deterioration within a reclosable package formed by a resilient blister and a rigid backing member. A biasing member precludes complete separation of the package by interconnecting the blister and the backing member. The resiliency of the blister tends to reclose the package. Preferably the biasing member is provided with a hinged flap which positively urges the blister and backing material into a reclosed position.
In the drawings:
FIGURE 1 is a top view of a package embodying the invention;
FIGURE 2 is a section through the package of FIG- URE 1 taken along line 2-2.
More specifically, the inventive package illustrated in FIGURES 1 and 2 of the drawings includes a relatively rigid backing member 10. Preferably the backing member 10 is oxygen and moisture impermeable and may be composed of paperboard, pressed fiber, plastic, cardboard or the like. The backing member may be made of a material inherently impermeable to oxygen and moisture or may include a film laminate such as disclosed in US. Patent No. 2,621,129. A resilient (semi-rigid) blister generally 12 is preferably formed to conform generally to the shape of a food product 16 which is enclosed between the blister 12 and the backing member 10. The blister is also usually preferred to be moisture and oxygen impermeable.
The blister 12 may be of the form of a tray including a bottom wall 18 and side walls 20, and terminates in a peripheral sealing flange 22. The blister must be made of a resilient material selected 'by type and thickness to "be capable of resisting deformation and returning to approximately its original position and shape upon deformation. Preferably the blister is transparent to attractively display the product. Suitable blister materials include (but are not limited to) plasticized and unplasticized polyvinyl chloride, cellulose acetate, and styrene; and where the package is to be oxygen impermeable the latter two materials should be coated with an oxygen barrier such as polyvinylidene chloride (Saran).
The thickness of the blister material may vary from 7.5 to 20 mils. The preferred blister material is 10 mils unplasticized polyvinyl chloride.
The backing member 10 is secured and sealed to a minor portion 24 of the sealing flange 22 adjacent a biasing member generally 30 and is releasably sealed to a major portion 26 of the flange 22. In the drawings which illustrate packages having rectangular sealing flanges, it is convenient to secure a side of the flange adjacent to the biasing member 30 to the backing member and releasably seal the other three sides of the flange.
Securing of the minor portion 24 of the flange 22 to the backing member 10 may be accomplished by any permanent joint. Preferably the portion 24 is extended between the biasing member 30 and the backing member 10, and the three parts fused together by heat sealing. However, any convenient mechanical fastening, such as stapling, riveting, and sewing or adhesive bond would be suitable.
The major portion of the flange 22 is releasably sealed to the backing member by a temporary joint that can be broken by a consumer without difficulty. It is possible to provide for easy opening of the package by using semicompatible agents affixed to the flange and the backing board. When in compressive contact the sealing agents provide a hermetic seal but do not fuse together. Good results are obtainable with a variety of sealing agent pairs, such as rubber hydrochloride (Pliofilm) and polyethylene where one material is applied to the backing board and the others applied to the blister. The thickness of the coating of sealing agent varies with the size and weight of the packages. Where a hermetic seal is desired, the entire peripheral flange 22 must be sealed to the backing board 10 in this portion. A preferred hermetic seal is obtained by coating both surfaces to be joined with polyethylene wherein one coating is adhered to its surface by a pressure sensitive adhesive. Thereafter the coated blister and backing board are joined by heat fusing the polyethylene surfaces together. Later the package can be opened by pulling the parts away, causing the adhesive secured polyethylene to delaminate in the fused area and expose the pressure sensitive adhesive. An additional advantage of this seal is that the exposed adhesive will rejoin when the package is reclosed.
Preferably the biasing member generally 30 includes a margin 32, extending parallel to the backing member away from the food product and engaging minor secured portion 24 of the flange 22, and a coextensive flap 34 which is folded back towards the product so as to press against the wall 20 of blister 12. The biasing member generally 30 may be an integral fold of the backing member 10, as shown in the figures, or it may simply be attached thereto.
In the use of the illustrated packages, the user lifts the edge of the blister 12 at the end of the package opposite the biasing member 30. The blister will peel back along the three edges of the blister comprising the major portion 26 of the flange 22, but cannot be separated from the fourth edge, the minor portion 24. In this respect the minor portion 24 in conjunction with the biasing member 30 acts as a biased hinge for the package. After the seal is broken along the three edges the blister may be folder back and a portion of the product removed. Reclosure of the package is facilitated by the return action of the biasing member acting in conjunction with the resiliency of the blister. In the reclosed position the package protects the product from odor pickup and dessication.
Packages embodying the invention may be produced on commercially available equipment which is presently used to produce all-film packages. The resilient plastic blister 12 may be thermoformed on a packaging machine or preformed blisters placed into the cavities of a packaging machine. The product 16 is placed into the blister and backing member is placed over the product. The described package may be sealed in a variety of Ways depending on whether on not it is to be evacuated. If a long shelf life such as is given by vacuumizing or inert gas backfilling is desired, one portion of the seal is left open and the package is evacuated and backfilled with a gas which has a non-deleterious effect on the product. The amount of gas backfill should be suflicient to prevent distortion of the package.
It should be further understood that the present invention although especially suitable for packaging food products is not restricted to packaging any particular type of product or a product having a particular form. Also, the product within the package may be arranged in any desired manner. For example, when a sliced product is being packaged, the slices may be superimposed one directly over the other, or the slices may be arranged in a single thickness or in slightly overlapping arrangement. Also the package may be made in a variety of shapes.
1. A reclosable package which comprises in combination with a food product:
a resilient blister partially enclosing said product, said blister made of a material capable of returning to approximately its original position upon deformation and having a thickness of greater than about 7.5 mils, and said blister terminating in a peripheral sealing flange;
a relatively rigid backing member releasably sealed to a major portion of the peripheral flange of said blister and permanently secured to a minor portion of said blister and permanently secured to a minor portion of said blister flange to completely enclose said product between said backing member and said blister; and a biasing member opposite said backing member across said minor portion of said flange and permanently secured to said minor portion of said blister flange so that said minor portion is permanently sealed between said backing member and said biasing member whereby pressure is applied against said blister to urge same into engagement with said backing member whenever said blister is raised from its normal position of contact with said backing memher. 2. The package of claim 1 wherein said blister and said backing member are moisture and oxygen impermeable.
3. The package of claim 2 wherein the atmosphere of the package is a non-deleterious gas.
4. The package of claim 1 wherein said biasing member terminates in a hinged flap portion which applies pressure against said blister whereby said blister is urged towards engagement with said backing member.
5. The package of claim 4 wherein the food product is a sliced food product; the blister is formed in a rectangular tray-like shape including a bottom wall and side walls, and said hinged flap contacts the side wall of said blister adjacent said minor portion of said flange.
6. The package of claim 1 wherein the major portion of said peripheral flange is' sealed to said backing material by an interface of two semi-compatible sealing agents, one of said agents originally applied on the backing material and the other on the flange of the blister.
7. The package of claim 6 wherein the sealing agent on the blister is rubber hydrochloride and the sealing agent on the backing material is polyethylene.
8. The package of claim 6 wherein said biasing member terminates in a hinged flap portion which applies pressure on said blister whereby said blister is urged towards said backing member.
9. The package of claim 1 wherein the blister is formed in a shape conforming to the food product from a material selected from the group consisting of unplasticized polyvinyl chloride, plasticized polyvinyl chloride, cellulose acetate, and styrene, the thickness of said material varying from 7.5 to 20 mils.
10. The package of claim 9 wherein the Peripheral sealing flange is rectangular, and the secured minor portion is one side of the flange.
References Cited UNITED STATES PATENTS 5/1958 Reuman 99-l71 9/1967 Nugarus 99l74 X US. Cl. X.R.