GB2378934A

GB2378934A - Packaging material incorporating a resealable strip

Info

Publication number: GB2378934A
Application number: GB0120706A
Authority: GB
Inventors: Ian William Mcdonald
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-08-24
Filing date: 2001-08-24
Publication date: 2003-02-26
Also published as: GB0120706D0

Abstract

A packaging material web 1 comprises a web with a continuous slit or line of weakness 2 running longitudinally, over which is applied a flexible sealing strip 3. The flexible sealing strip is fixed to the web by adhesive 4, and may have a portion 5 not adhered to the web, to act as a gripping means. Once formed into a package, the slit 2 can form an aperture openable resealably by the strip 3. The web 1 may be formed from a single sheet of material and provided with a slit 2, or from two sheets of material joined at their respective edges by the strip 3. The web can be a polymeric film, paper, or a metal foil. A method of producing said packaging material and apparatus for producing said packaging material are also claimed.

Description

Packaging Materials and Their Production This invention concerns packaging materials which can be used to make packages which can be repeatedly opened and reclosed, packages made from such packaging materials, and apparatus for use in their production.

Many food and non-food items are packaged in flexible packaging materials, for example paper, films and foils. Such packaging materials are relatively inexpensive, and they are in general effective and therefore attractive as packaging materials.

Although for many items the packaging materials used to transport them are used only once and then discarded after opening, it would be advantageous for some items to be able to open and close the packaging a number times, for example where it is desired to return at least some of the contents to the packaging after the package has been opened.

There have been a number of proposals hitherto for recloseable packaging materials, especially where it is desired to keep the contents of the packages in a sealed-in environment, for example to prevent moisture loss from a packaged product.

Although many attempts have been made to produce packaging materials which can be repeatedly opened and closed, their use on standard packaging machines generally requires the machines to be modified considerably and/or they require the use of relatively complex packaging materials compared with, for example, simple polymeric films.

Examples of such packaging materials include pre-formed

semi-rigid polymeric container bodies with hinged lids which L clip into locking engagement with the container bodies, flexible polymeric bags with"tongue and groove"closures, and flexible polymeric bags with removable adhesive labels over an aperture in the bags.

These various prior art proposals suffer from a variety of disadvantages, poor seal integrity prior to first opening of the packages being a common problem. For example, the lids of pre-formed semi-rigid polymeric containers usually form poor seals with the container bodies and are therefore only suitable for non-perishable items or perishable items which have short shelf lives such as sandwiches."Tongue and groove"closures generally produce better seals after re-closing but they are not sufficiently good for many packaging situations and they are expensive to produce. Finally, although the seal integrity of bags sealed using replaceable adhesive labels is generally good, such packages tend to suffer from the disadvantage that the aperture for gaining access to the contents of the bags is either relatively small, and so restricts the size of the packaged items, which can be removed through the aperture, or if of larger size it can be difficult to replace accurately over the aperture in the bag.

According to the present invention there is provided packaging material for producing a succession of repeatedly openable and closeable packages in a packaging machine, the material comprising a flexible sealing strip adhered over a substantially continuous slit or a line of weakness in a flexible packaging web or over an edge portion of the said packaging web and an edge portion of a further flexible packaging web.

The invention further provides packages consisting of a packaged article and a packaging material according to the present invention which enables the packages to be repeatedly opened and reclosed.

The present invention still further provides a method of manufacturing a packaging material for producing a succession of openable and recloseable packages, the method comprising supplying at least one flexible packaging web and a flexible sealing strip to an applicator station where the sealing strip is placed over a slit or line of weakness in the packaging web or over an edge portion of the said packaging web and over an edge portion of a further flexible packaging web, and adhering the sealing strip to the web or webs to produce an openable and recloseable seal between the web or webs and the sealing strip.

The present invention yet further provides apparatus for manufacturing a packaging material for producing a succession of openable and recloseable packages, the apparatus comprising first feed means for feeding a flexible packaging web, second feed means for feeding a flexible sealing strip, and an applicator station for receiving the flexible web from the first feed means and the flexible sealing from the second feed means and adhering the flexible sealing strip to the said flexible packaging web over a slit or line of weakening in the packaging web or over an edge portion of the said flexible packaging web and over an edge portion of a further flexible packaging web supplied from an optional third feed means.

The present invention further provides packages comprising an article packaged using a packaging material according to the present invention.

Embodiments of packaging materials in accordance with the present invention, packages produced therefrom, and machinery for producing the packaging materials will now be described with reference to the accompanying diagrammatic drawings in which :- Figs. la-c show sections through a packaging film at various stages in the production of recloseable packages in accordance with the present invention; Fig. 2 shows a section through the recloseable seal of a second embodiment recloseable packages in accordance with the present invention; Fig. 3 shows a modification of the recloseable seal of the embodiment of Fig. 2; Fig. 4 shows a yet further modification of the embodiment of Fig. 2; Fig. 5 shows a schematic representation of a machine for producing packaging materials in accordance with the present invention; and Figs. 6a-d show packages recloseable packages in accordance with the present invention produced from packaging materials in accordance with the present invention.

Fig la shows a section through a conventional packaging film 1

which itself is preferably heat or pressure salable and may consist of one or more layers (not shown). Fig. Ib shows the film 1 after it has been slit along a line 2 perpendicular to the section shown in Fig. la.

Fig. lc shows a packaging material in accordance with the present invention which has been produced by adhering a length of flexible polymeric tape 3 over the slit 2, adhesion being provided by an adhesive layer 4 on the tape 3. The adhesive layer 4 does not cover the entire width of the under surface of the tape 3 and so the portion of the tape 3 without the adhesive layer 4 can serve as a pull tab 5. Alternatively, the non-adhesive region of the tape could be obtained by folding over an edge of the tape so that it partially adheres to itself along its length.

The adhesive used for the adhesive layer 4 is such that the tape 3 can be peeled from the film 1 by pulling the tab 5 and thereafter readhered to the film 1 by pressure, such adhesives being known in the adhesive tape art.

The film shown in Fig. lc can be used in a similar manner to that used for simple sheets of packaging film to produce packages, for example using a flow wrap packaging machine. The packages can then be opened by pulling the tab 5, the adhesive layer 4 initially lifting from the film 1 on one side of the slit until the slit 2 is reached, at which stage the contents of the package can be accessed through the slit 2. Thereafter, the package can be reclosed by pressing the adhesive layer 4 which has been peeled away from the film back onto its original surface, thereby forming a good seal.

An alternative form of recloseable packaging material in accordance with the present invention is shown in Fig. 2. As with the packaging material of Fig. lc, the film 1 has a slit 2 covered by a length of flexible polymeric tape 3 over the slit 2, adhesion being provided by an adhesive layer 4 on the tape 3.

However, the tape 3 has the adhesive layer 4 over its entire lower surface, and a tab-forming tape 6 is positioned between the adhesive layer 4 and the film 1, thereby enabling the tape 3 to be pulled away from the film 1 by pulling the tape 6.

As an alternative to the use of the tab-forming tape 6, the tape 3 can have the adhesive layer 4 all over its surface as shown in Fig. 2 but with areas of the adhesive layer de-activated in certain areas where adhesion or more particularly repeated adhesion and parting of the adhesive seal are not required. The effect can then be similar to that achieved with the packaging material shown in Fig. lc.

Other packaging materials in accordance with the present invention consisting of combinations of slit packaging film and adhesive tape are shown with reference to Figs. 3 and 4.

That shown in Fig. 3 consists of a film 1 with a slit 2 covered by an adhesive tape 3 having an adhesive layer 4 over its entire under surface. In addition to the use of the tab-forming tape 6, this embodiment also includes a removable or peelable strip 7 which may be partially or totally peelable from the adhesive layer 4.

That shown in Fig. 4 is similar to that shown in Fig. 3 in including a removable or peelable strip 7 but in this case the tab-forming tape 6 does not extend beyond the edge of the tape 3.

Once packages produced from packaging materials as shown in Figs. 3 and 4 have been peeled open and the removable or peelable strips 7 have been removed, the packages can be opened and reclosed repeatedly using the adhesive which previously held the strips 7 on to the tape 3 in addition to that which adhered the tape 3 to the film 1.

The tape 3 will usually be transparent when the packaging film 1 is transparent, but is can be in the form of a label. The label can, for example, include instructions as to how to open and close packages formed from these packaging materials.

The film 1 can be made from a variety of polymeric materials, for example homo-and copolymers of polyolefins, e. g. derived

from ethylene, propylene and/or butylen-1, polyamides, e. g. nylons, or poly vinyl acetate. The films can be mono-webs or multi-layered film structures, and they can be cast or oriented.

As will be appreciated, the packaging film can be formed from a variety of polymeric materials, for example polyolefins, e. g. containing units derived from one or more of ethylene, propylene and butylen-1, polyamides, e. g. nylons, and polyesters, e. g. polyvinyl acetate. Furthermore, the film can be replaced by paper or a metal foil, e. g. aluminum foil.

The adhesive tape can also be made from a variety of materials and it too can be formed from a polymeric material, paper or a foil.

It is particularly convenient for the adhesive tape to be adhered over a substantially continuous slit in the packaging web. However, it will be appreciated that a line of weakness in the web could be used to facilitate access to the contents of a package after the sealing tape has been removed sufficiently to obtain access thereto. A particular advantage of packages in accordance with the present invention having the tape adhered over a line of weakness rather than over a slit in the packaging web is that prior to its first opening the seal itself will in general provide a better barrier than if the tape were sealed over a slit in the packaging web. Furthermore, the use of a line of weakness rather than a slit in the packaging web can provide evidence of tampering with the packages.

Slits in the packaging web can be obtained by known methods, for example using a blade or the like. However, the present invention also encompasses the use of two adjacent webs of material brought into substantially abutting arrangement with each other. In this latter case the two adjacent webs can be made from the same or different materials.

Lines of weakening can also be created using known methods, for example by perforation using a laser, wires or pins, if

necessary with heating, or by selective thinning, for example using embossing blades or discs, or a laser.

The slits or lines of weakness are preferably continuous along the packaging materials substantially in the line of the machine direction of the packaging machine which is supplied with the packaging material in accordance with the present invention. In the case of polymeric films, paper and foils this direction will in general be their machine direction.

The packaging film in accordance with the present invention

shown in Fig. 2 can be produced using the machine shown in Fig.

S.

The machine shown schematically in Fig. 5 has a first roll 20, from which polymeric packaging film 21 is drawn, a second roll 22 from which a tab-forming polymeric film 23 is drawn, and a third roll 24 for an adhesive coated film 25 is drawn. The three films 21, 23 and 25 pass around a guide roll 26, and they are adhered together by a pair of nip rolls 27. The nip rolls 27 can serve to draw the films 21,23 and 25 from the rolls 20, 22 and 24 respectively, but when the machine shown in Fig. 5 is used to feed a packaging machine directly, the packaging machine will usually be used to pull the various components of the packaging material through the rolls 27.

A slitting blade or knife 28 between the roll 20 and the guide roll 26 serves to slit the film 21 as it is pulled off the roll 20, and the tab-forming film 23 and the adhesive coated film 25 are positioned relative to the slit formed in the film 21 by the blade or knife 28 to produce a packaging material according to the present invention as shown in Fig. 2.

The composite film structure leaving the nip rolls 27 can then be fed to a conventional flow wrap or other type of packaging machine.

The composite film structures shown in Figs 3 and 4 can be produced using a machine similar to that shown in Fig. 5, for example by the inclusion of a slitting blade or knife to slit the tab-forming film 23 along its length in a similar manner to that in which the slitting blade or knife 28 slits the film 21.

Alternatively separate rolls of tab-forming film could be used by suitably positioning them relative to each other and to the slit which is formed in the film 21.

Various types of packages in accordance with the present invention which have been produced from packaging materials in accordance with the present invention are shown in Figs. 6a-d.

Fig. 6a shows a vertical section through thermoformed container 30 having a heat sealed lid 31 formed from a packaging film according to the present invention. The container 30, which can be of any desired shape when viewed from above, for example substantially circular, oval, square or rectangular, has the slit 2 in the film 1 and the associated tape 3 extending across the full width of the container. Pulling the tab 5 upwardly parts the adhesive layer 4 from the film 1, and since the slit 2 and the tape 3 extend across the full width of the container 30, the result is that the contents of the container 30 are much more accessible than, for example, in the case of prior art packages having an adhesive patch over an aperture in the container.

Fig. 6b and 6c show two substantially similar packages in accordance with the present invention, both having been formed by heat sealing a packaging material in accordance with the present invention to itself to form a fin-sealed package. The difference between the two packages is in the positions of the seals 32 and 33 relative to the tape 3.

Fig. 6d shows a yet further form of package in accordance with the present invention in which a packaging material 31 in accordance with the present invention has been heat sealed to

another web 34 to form a package with heats seals 35 along four edges (only two such seals being shown).

It will be appreciated that the adhesive used to adhere the sealing strip to the packaging web can be present on the sealing strip and/or on the packaging web prior to their being adhered together during manufacture, and indeed it could be applied in the apparatus used to manufacture packaging materials in accordance with the present invention.

It will also be appreciated that the flexible sealing strip can with advantage be adhered to the flexible packaging web or webs only in a central region of the former, thereby enabling the flexible sealing strip to be peeled from the flexible packaging web or webs from either side of the strip.

Although packaging materials in accordance with the present invention can be produced off-line, that is they can be produced in a separate converting operation following which they are wound up before being used in a packaging machine, it is particularly preferred to produce them in line with the packaging machine with which they are to be used. This has the advantage that problems in winding up the packaging materials due to their increased thickness resulting from the presence of the adhesive tape can be avoided.

Packaging materials in accordance with the present invention can be used with a wide variety of packaging machines, for example where the packaging material forms substantially the whole of the exterior of the package, e. g. with horizontal or vertical form-fill-seal machines, or where the packaging material of the present invention forms a lid of the resulting package. When used as a lidding material for a container, the adhesive used to adhere the material to container is itself preferably peelable and recloseable.

Preferred packages in accordance with the present invention are in the form of flow wrapped, pouch or sachet packages having

peelable end seals with a sealing strip in accordance with the present invention extending between the end seals. Such packages can then be opened using the sealing strip, following which the end seals can be peeled to facilitate access to the packaged product. Thereafter the packages can be reclosed around the packaged products by re-adhering the sealing strip to the packages, and the position at which this occurs on the packages can be varied, for example to compensate for partial removal of the contents of the packages. In a preferred embodiment of such packages the peelable end seals are themselves resealable, thereby improving the integrity of the package after it has been reclosed.

Packaging materials in accordance with the present invention can be used to package a variety of articles including foodstuffs, for example portions of cheese.

Claims

Clalms 1. A packaging material for producing a succession of repeatedly openable and closeable packages in a packaging machine, the material comprising a flexible sealing strip adhered over a substantially continuous slit or a line of weakness in a flexible packaging web or over an edge portion of the said packaging web and an edge portion of a further flexible packaging web.
2. A packaging material according to claim 1, wherein at least one edge portion of the sealing strip is not adhered to the flexible packaging web or webs.
3. A packaging material according to claim 1 or claim2 wherein the flexible packaging web or webs comprise a polymeric film, paper or a metal foil.
4. A packaging material according to any of the preceding claims, wherein the line or weakness has been produced using a scoring knife or blade, or using a laser.
5. A package comprising a packaged article and a packaging material according to any of the preceding claims which enables the package to be repeatedly opened and reclosed.
6. A method of manufacturing a packaging material for producing a succession of openable and recloseable packages, the method comprising supplying at least one flexible packaging web and a flexible sealing strip to an applicator station where the sealing strip is placed over a slit or line of weakness in the packaging web or over an edge portion of the said packaging web and over an edge portion of a further flexible packaging web, and adhering the sealing strip to the web or webs to produce an openable and recloseable seal between the web or webs and the sealing strip.

<Desc/Clms Page number 13>
7. Apparatus for manufacturing a packaging material for producing a succession of openable and recloseable packages, the apparatus comprising first feed means for feeding a flexible packaging web, second feed means for feeding a flexible sealing strip, and an applicator station for receiving the flexible web from the first feed means and the flexible sealing from the second feed means and adhering the flexible sealing strip to the said flexible packaging web over a slit or line of weakening in the packaging web or over an edge portion of the said flexible packaging web and over an edge portion of a further flexible packaging web supplied from an optional third feed means.
8. Apparatus according to claim 7, including means for slitting or forming a line of weakness in the flexible packaging web from the first feed means.
9. Apparatus according to claim 8, wherein the means for slitting or forming a line of weakness in the flexible packaging web comprises a cutting or scoring knife or blade, or a laser.
10. Apparatus according to any of claims 7 to 9, combined with a packaging machine for producing a succession of packages using the packaging material as it is produced thereby.