CA1287309C - Easy-open film package - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An easy-open mechanism for packaging includes spaced punctures aligned intermediate the lateral edges of a thermoplastic film, and pressure sensitive labels applied to the punctures, and including header tabs at one end of the labels to permit easy-opening of the package by propagating the tear initiated at the puncture along the length of the package.

Description

~2~373(:~

EASY-OPEN FILM PACKAGE

BACKGROUND OF THE INVENTION

The present invention relates to the packaging of products, espe--cially food products, and more particularly packaging of food products on trays or other carrying means.

Food products such as smoked and processed meats, and fresh red meat are commonly centrally processed in bulk packages or, in the case of fresh red meat, in sub-primal form. After shipment to the retailer, these food products must then be divided and repackaged in smaller retail portions for the consumer.

Typically, this repackaging is done on a foam tray and overwrapped with polyvinyl chloride (PVC) film. This overwrapping step is usually accomplished by hand or by automatic overwrapping machines at the retail outlet.

PVC-overwrapped retail packages typically have a very short shelf life of about two to three days.

Alternatively, retail portions of products such as food products, and in particular smoked and processed meats, fresh red meat, and pork may be processed at a central processing plant utili~ing oxygen impermeable flexible film and gas flushing with mixtures of for example carbon dioxide and nitrogen, and carbon dioxide and oxygen to provide a tight fitting film which will retain the freshness of the product over a longer period, such as ' ' ' ~' ', . , ' :

,~, ' ' , .:

14 to 21 days for fresh red meats and up to 60 days in the case of smoked and processed meats.
Whatever the packaging system or the particular film used, the consumer bears the inconvenience of needing a knife or a similar sharp object to initiate a tear in an overwrapped retail meat portion. In the case of modified atmosphere packages or controlled atmosphere packages, making use of gas flushing of mixtures of gases such as those described above, a very tight package fit around the product may be obtained. Thls is advantageous ~rom the point of view oE consumer appeal, and lack of ballooning of these film about the product. However, the tight package, especially one having longitudinal and -transverse seals~
may be difficult to open without the knife or sharp object to initiate the tear.
It is therefore an object of the present invention to provide a method of producing an easy-open package in which a tear may be conveniently initiated in the package wi-thout the need for a knife or other sharp instruments.
It is also an object of the present invention to provide an easy-open package having a tear initiation feature which does not require the use oE a sharp instrument, and does not compromise the integrity of the paclcage with respect to product shelf life.
SUMMARY OF THE INVEWTION
In one aspect the present invention provides a method oE
producing an easy-open paclcage for containing a product comprising: (a) puncturing an elongate thermoplastics film intermediate longitudinal edges thereof; ~b) covering the puncture ,, ..~ .
s~

37~
6~536-597 with a pressure sensitive label having a nonstick portion at one end thereof; (c) forming the film around the product to form an elongate tube; (d) longitudinally sealing the formed film; (e) transversely sealing the formed film; and (f) severing the formed -film adjacent to the transverse seals to provide an elongate package containing the product, said package having sides such that when the label is pulled back along -the length o~ the film the film is torn open along a line substantially parallel -to and intermediate the sides of the elongate package.
In another aspect the present invention provides an easy-open package comprising: (a) a food product; (b) a thermoplastic ~ilm formed around the product, the ~ormed film having a longitudinal seal along one edge, and transverse seals at each end of the package to form a hermetically sealed package;
(c) a puncture intermediate the lateral edges of the film; and (d) a pressure sensitive label covering the puncture, and having a non-stick portion at one end thereof.
BRIEF DESCRIPTION OF THE_DRAWINGS
Further details are given below with reference to the drawings wherein:
Figure 1 is a partially schematic view o~ a thermoplastic film depicting the inventive easy-open mechanism;
and Figure 2 is a schematic plan view of a packaged product in accordance with the present invention.
DESCRIPTION OE' THE PREFERRED EMBODIMENT
ReEerring to the drawings, in Figure l, a thermoplastic , ~
~---.: :
~ .

~ ~s73n9 64536-597 film 10 useful in connection with the present invention is schematically illustrated. The film is generally stored in roIl form 12 to permit convenient transport of the film, and permit the film to be fed into for example a form fill seal machine, ~uch as a horizontal form fill seal machine well known in the art.
Thermoplastic film 10 is preferably of the type, when used in connection with packaging food products, having an oxygen impermeable layer to provide extended shelE life for the product.
Frequently such oxygen barrier films are of multi-layer construction.
Thermoplastic film 10 is also preferably a shrinkable film, i.e., has been orien-ted to create shrinkage of the film about a product upon immersion in hot water or exposure to hot air. The benefits of shrinkable film are well known.

3a ~;.i,, ' ' 12(3~ )9 In accordance with the invention, punctures 14 are introduced to the film at spaced intervals along its length. This may be accomplished during manufacture of the film, or just prior to use of the film in connection with the packaging of a product. Punctures 14 may be created by any suitable means? as long as a tear, puncture, or notch is created at spaced intervals along the film. Preferably, punctures 14 are Inade inter-mediate the lateral edges of film 10, run parallel to the lateral edges in a linear fashion, and are spaced at intervals to permit at least one puncture to be present on each packaging unit. Spacing of punctures 14 from the trailing or leading adjacent puncture can, therefore, be adJusted to accommodate the type of product to be packaged. As will be discussed below, a longitudinal seal is preferably used to seal the fil~n as it is formed in for example in a horizontally form fill seal machine. It i.s desirable that the punctures 14 do not coincide with the longitudinal seal area of a finished package, and that the punctures 14 be located in a substantially central position along the top of the package, above the product, to facilitate ease of opening of the package and to display the easy-open mechanism to the consumer.

Likewise, transverse seals are preferably used to seal the film at the terminal edges of each package. It is desireable that punctures 14 do not coincide with these transverse seals on the finished package.

When packaging food products especially, it is usually necessary to hermetically seal the package, and to ensure the integrity of the package with respect to its oxygen impermeability. It is also important to avoid contamination of the food product, which would be possible without means for covering the punctures 14 during the packaging operation.

To accomplish this, a pressure sensitive label 16 is placed over each puncture 14, preferably before a product is introduced into the package. The pressure sensitive label has a very sticky portion for fixing directly over the puncture 14, and also includes a header tab 18 which projects from a trailing end of the label 16. This header tab 18 also has a non-stick portion which will project from the label 16, and permit an initiation point when the package is to be opened.

~ ~r3~303 In operation, the pressure sensitive label 16 is grasped at header tab 18 and pulled back in the direction of directional arrow A shown in Figure 2. As the pressure sensitive label 16 is pulled back along the length of the film i.e. towards transverse seal 28 of Figure 2, film 10 is torn open along a line substantially parallel to and intermediate the lateral edges of the package. Product 22 can thereafter easily be removed from the package without the need for a sharp implement to create a puncture or tear in the film.

Optionally, a guide tape 20 aligned with the punctures 14 may be installed on the interior side of the film prior to packaging. The guide tape may be for example of a thermoplastic material, and brightly colored to facilitate the consumer use of the easy-open mechanism. Preferably the tape has a narrow lateral width, and is disposed intermediate and parallel to the lateral edges of the film. Such guide tapes are well-known in the art in connection with other packaging systems. The purpose of the guide tape is to direct the consumer's attention to the easy-open mechanism, and to facilitate propagation of the initiated opening down the entire length of the package. However, the guide tape is not necessary for this function, and use of the pressure sensitive label 16 with the header tab 18, in connection with puncture 14 present on each package, will provide pro-pagation of the tear down the package in alignment with puncture 14, and substantially parallel to the lateral edge of the package in normal- use.

Referring to Fig. 2, the thermoplastic film 10, equipped with punctures 14 at intervals along its length, pressure sensitive labels 16 covering each puncture 14, and optionally guide tape 20 is formed around a product 22, especially a food product in for example a hori~ontal form fill seal operation. A longitudinal seal 24 is made along one edge of the formed film and a first transverse seal 26 and second transverse seal 28 are made to preferably hermetically seal the package.

A carrying means (not shown), such as a tray, may optionally be used to carry product 22.

Longitudinal seal 24 is depicted in Figure 2 to further clarify the position of the longitudinal seal in relation to the package as a whole. In fact, in the case of a food product substantially filling the interior of the package~ or in case of an optional carrying means carrying the food :., ~ ~3~7~09 product, such a seal may not be vislble except perhaps at its interface with transverse seals 26 and 28, when viewed in plan view.

Referring to FIG 2, a transverse seal 30 is depicted as a trailing edge of a previously formed package. Each package may be separated from the adjacent package by severing along a line intermediate transverse seals 28 and 30.

Several handmade pouches were notched with an inverted V shaped puncture at the top of each package. The notches were covered with a very sticky pressure sensitive label with a non-stlck header tab. The pouches were then filled with product, gas flushed with 20% carbon dioxide and 80%
nitrogen gas, and hermetically sealed. After sealing, residual oxygen was measured. The results are summari~ed in Table 1.

Table 1 Initial Residual Residual Oxygen Easy-Open Sample Oxygen (%) After l ~our (%) Performance 1 0.32 0.34 Good 2 0.53 0.53 Good 3 0.48 0.49 Good 4 0.64 0.68 Good Packages were pumped and determined to be totally hermetic.

373~g Samples 1 through 4 above were made using an oxygen barrier shrink film in which the longitudinal and transverse seals were hermetically sealed. The results indicate that the oxygen barrier characteristics of the film were essentially maintained after one hour after packaging. This indicates that the pressure sensitive labels 16 were effective in preventing any substantial leakage through the punctures 14. At the same time, the easy-open mechanism proved to be good in each sample. Thus, the use of the pressure sensitive label 16 with the header tab permitted propagation of the tear initiated at the puncture 14 along the length of the package without difficulty. The pressure sensitive label did not separate from the film during the opening of the package by the easy-open mechanism.

Although the punctures utili~ed in the sample packages described above were of an inverted V configuration, any suitable configuration which permits a notching or tearing of the film at spaced intervals is suitable 3 provided it permits propagation of a tear along the length of the film when the header tab of the pressure sensitive label is forced back along the package.

Various changes and modifications may be made to the invention as described above without departing from the spirit and scope of the claims below.

Claims (12)

1. A method of producing an easy-open package for containing a product comprising:
(a) puncturing an elongate thermoplastics film intermediate longitudinal edges thereof;
(b) covering the puncture with a pressure sensitive label having a nonstick portion at one end thereof;
(c) forming the film around the product to form an elongate tube;
(d) longitudinally sealing the formed film;
(e) transversely sealing the formed film; and (f) severing the formed film adjacent to the transverse seals to provide an elongate package containing the product, said package having sides such that when the label is pulled back along the length of the film the film is torn open along a line substantially parallel to and intermediate the sides of the elongate package.

2. The method according to claim 1 further comprising the step of affixing a narrow guide tape to the film prior to puncturing said film, said tape disposed intermediate and parallel to the lateral edges of the film, on the interior side of the film, and in communication with the puncture.

3. The method according to claim 1 further comprising the step of gas flushing the tube.

4. The method according to claim 1 further comprising the step of shrinking the formed film after transversely sealing the formed film.

5. The method according to claim 1 further comprising the step of placing the product on a carrying means prior to forming the film around the product to form a tube.

6. The method according to any one of claims 1 to 5 wherein the film is punctured in the form of an inverted V.

7. The method according to any one of claims 1 to 5 wherein the film is longitudinally and transversely hermetically sealed.

8. An easy-open package comprising:
(a) a food product;
(b) a thermoplastic film formed around the product, the formed film having a longitudinal seal along one edge, and transverse seals at each end of the package to form a hermetically sealed package;
(c) a puncture intermediate the lateral edges of the film;
and (d) a pressure sensitive label covering the puncture, and having a non-stick portion at one end thereof.

9. The package according to claim 8 further comprising a carrying means for carrying the product.

10. The package according to claim 8 further comprising a gaseous mixture within the package, said mixture comprising a blend of carbon dioxide with nitrogen gas or oxygen.

11. The package according to claim 8, 9 or 10 further comprising a narrow guide tape affixed to the interior side of the film, intermediate and parallel to the lateral edges of the film, and in communication with the puncture.

12. The package according to claim 8, 9 or 10 wherein the puncture is in the form of an inverted V.