GB2028756A

GB2028756A - Shrink wrappings

Info

Publication number: GB2028756A
Application number: GB7834623A
Authority: GB
Original assignee: Bakelite Xylonite Ltd
Current assignee: BXL Plastics Ltd
Priority date: 1978-08-25
Filing date: 1978-08-25
Publication date: 1980-03-12

Abstract

A method of wrapping e.g. bottles or an article having a plurality of projections, comprises passing the necks 8 of at least some of the bottles or at least some of said projections through holes 3 provided in a first area of a heat- shrinkable blank 1, passing at least some of the aforementioned bottle necks or projections through holes 2 provided in a second area of the blank spaced from the first area, in such a manner as to encircle the bottles or article with the blank, and applying heat to shrink the blank taut around the bottles or article. <IMAGE>

Description

SPECIFICATION Shrink wrapping This invention relates to a method of wrapping articles, particularly, but not exclusively bottles or bottle-like articles, using a heat-shrinkable wrapper blank.

Heat-shrinkable films are widely used for packaging various articles such as bottles. Conventionaliy, such packaging is carried out by wrapping a sheet of a heat-shrinkable film around the articles, welding the two end portions of the sheet together, and applying heat to shrink the film taut around the articles.

The invention provides a method of wrapping a plurality of bottle-like articles which comprise passing the upper ends of at least some of the articles through holes provided in a first area of a heatshrinkable wrapping blank, and passing the upper ends of at least some of the aforesaid at least some articles through holes provided in a second area of the blank, in such a manner as to encircle a substantial part of the articles with the blank, and applying heat to shrink the film taut around the articles. The method of the invention is preferably carried out using a generally rectangular blank of a heat-shrinkable film, having a number of holes, for reception of the upper ends of the articles, in each end thereof.An end of the blank is slipped loosely over the upper ends of the articles, and the other end of the blank is passed around the bottom of the articles, before being slipped loosely over the upper ends of the articles. When subjected to heating, for example a conventional heat-shrinking tunnel, the film shrinks to form a tight pack, because of the opposing forces acting on the necks of the articles.

It is preferable that the articles be arranged in at least two rows, and that at least one of the said areas of the blank has the same number of holes as there are articles. The other of the said areas of the blank need have only a single row of holes, although it is preferred that this also has the same number of holes as there are articles wrapped, since this tends to lead to the maximum overlap of the two areas of the film during the heat-shrinking process. During the heat-shrinking process, overlapping areas of blanktend to become welded together, and this adds to the strength of the pack.

Although the blank may be formed by punching appropriate holes in a continuous sheet of a heatshrinkable film, it is possible to use a heat-shrinkable film having perforations for example regularly spaced holes over all its surface, or a heat-shrinkable net. Appropriate holes may be selected in the perforated film or net, for passing over the upper ends of the articles, or additional holes may be punched in the perforated film or net for this purpose, particularly if the perforations are small.

In a preferred embodiment of the invention, a blank may be supplied in a continuous reel, having holes provided along opposite edges thereof. Such a reel may advantageously be used in a continuous wrapping process, in which the articles to be wrapped are conveyed to a wrapping station substantially continuously, together with the blank from the reel.

At the wrapping station, the blank is fed around the underside of the articles, and the upper ends of the articles are passed through the holes in each side of the blank. The articles with the blank located thereon are then passed through a heat-shrink tunnel, to shrink the film taut, and provide a continuous wrapped pack of articles. The wrapped pack may be sub-divided to form smaller packs, and appropriate spaces may be left, or perforations provided in the blank, for example at every third article along the blank, to assist sub-division.

The heat-shrinkable blank for use in this invention may comprise any heat-shrinkable, plastics material, for example a heat-shrinkable film or net of low, medium or high density polyethylene, polyvinyl chloride, polypropylene, ethylene-vinyl acetate copoiymer, or polyvinylidene chloride. It is preferably of the kind having a shrinkage capacity of greater than 60% in a principal shrinkage direction. It preferably also has a shrinkage capacity of from 10 to 20% transverse to the principal shrinkage direction. Polyethylene films are particularly preferred for example polyethylene film of the type designated SBZ in PFMS 4/68 amended in August 1970 (issued by the Packaging Films Manufacturers Association).

The film is preferably of an extra low slip type designated "EL" to make stacking of packs formed from the material safer. The said two areas of the film are preferably spaced along the principal shrinkage direction of the film.

To facilitate handling of the resulting pack, the blank preferably includes means for forming a handle, for example one or more additional holes for forming a finger hole in the finished pack. Such finger holes are preferably positioned such that, in the finished pack, they will lie in the region of the upper ends of the articles, i.e. in the region where there is a double thickness of shrunk blank. The means for forming a handle may alternatively comprise an injection moulded handle, which may be attached to the remainder of the blank, by mechanical means, or by adhesion or heat-welding.

Although substantially all of the blank will normally be of heat-shrinkable material, part of the blank, for example the base portion in which the articles will sit in the finished wrapping may be of a non heat-shrinkable material, for example cardboard, and a heat-shrinkable material, such as polyethylene, is then bonded to the cardboard by some suitable means, to form a heat shrinkable blank.

After heat-shrinkage, the part of the blank which passes around the base of the articles forms a tray-like structure, which inhibits the lateral movement of the articles in the pack. The formation of an upturn in the blank around the base of the articles may be assisted by suitably placed jets of air during shrinkage, in a manner known per se. Other means for inhibiting lateral movement, for example a cardboard tray or yoke as conventionally used in shrink-wrapping, may also be used. The method of the invention is particularly suited to the wrapping of bottles, but it should be appreciated that it may be used for wrapping any articles having a similar shape, i.e. having a relatively narrow neck at their upper ends, so that the articles cannot slip through the holes and out of the finished pack.

Because there is no need to weld the two areas of the blank together before heat-shrinking, substantial economies in machine time can be achieved. Thus, although bottle-filling lines normally run at several hundred bottles per minute, conventional shrink tunnels run at speeds up to 45 bottles per minute. By providing a shrink-tunnel of sufficient length and heating capacity, the method of the invention may be used to wrap bottles or bottle-like articles directly as they leave the bottle-filling line, since the need for an intermediate rate influencing welding step is obviated.

In the pack provided by the method of the invention, the necks of the bottles protrude, and can be used to affix a handle or advertising labels and the like to the bottles.

It should be appreciated that the method of the invention is applicable not only to the wrapping of a plurality of bottle-like articles, but also to the wrapping of a single article having a plurality of projections, when it is desired to wrap only the body of the article, and not the projections. The manner in which the invention may be adapted to such a situation will be readily apparent to one skilled in the art, and the method generally comprises passing at least some of the projections through holes provided in a first area of a heat-shrinkable wrapping blank, passing at least some of the aforesaid at least some projections through holes provided in a second area of the blank, in such a manner as to encircle with the blank the part of the article to be wrapped, and applying heat to shrink the blank as before.One or mare articles having a plurality of projections may be wrapped in this way.

A number of preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which Figure I represents a blank suitable for use in the method of the present invention.

Figure 2 is an end view of an array of six bottles at an intermediate stage in the wrapping process, using the blank of Figure 1 (i.e. before heat shrinkage), Figure 3 is a side view of the pack formed after the blank Figure 2 has been heat shrunk Figure 4 is a section on A - A of the pack of Figure 3, Figure 5 is a top view of the pack of Figure 3, and Figure 6 is a continuous blank for use in the method of the invention.

Referring now to Figure 1, a rectangular blank 1 is provided with six holes 2 for the reception of the upper ends of six bottles. The holes 2 are arranged in a 3 x 2 array adjacent an end of the blank 1. Six holes 3 are provided in a second area of the blank adjacent the other end thereof, in a similar array. The blank is also provided with additional holes 4 and 5, to provide finger holes in the pack.

Figure 2 is on a slightly different scale from Figure 1, and shows how the blank of Figure 1 may be used to wrap a plurality of bottles 6. The bottles 6 are arranged in a 3 x 3 array, and have tops 8 of a size that pass easily through the holes 2 and 3. The holes 3 are passed over the tops 8 of the bottles, and the blank is passed around and below the bottles, before the holes 2 are passed over the top 8 of the bottles.

The film is then shrunk by a conventional heatshrinking technique to tauten it around the bottles.

The resulting pack is shown in side elevation and plan view respectively in Figures 3 and 5. Figure 4 shows a section on A - A of Figure 3. The shrunk film holds the bottles in a rigid pack, and the two areas of the film in which the holes 2 and 3 are provided may become welded together during the heat shrinking process to form a region of film of double thickness 7. The sets of holes 4 and 5 align in this region, to form reinforced finger holes, for lifting the pack.

Figure 6 shows a blank suitable for use in the method of the invention, which may be supplied in reel form. Alternatively, a reel of non-perforated film may be punched with the appropriate holes to form such a blank, as it leaves the reel. The blank of Figure 6 may either be cut up before use to form a plurality of smaller blanks, similar to the blank shown in Figure 1, or alternatively may be fed to a wrapping station together with bottles in 3 x 2 arrays, which are wrapped at the wrapping station to form a continuous pack of spaced 3 x 2 arrays of bottles.

These may subsequently be cut up to form separate smaller packs, each containing six bottles. Perforations may be provided between each set of 12 holes in the blank of Figure 6, to assist division. In an alternative embodiment, a blank similar to that of Figure 6 has holes continuously spaced at regular intervals along its two opposite edges. This is used in a similar manner to the blank of Figure 6, but forms a continuous pack in which all the bottles are equally spaced. The pack is then divided to form a plurality of small packs of any convenient size.

The following is an Example of a method of wrapping bottles according to the invention.

A blank measuring 14 inches by 31 inches was cut from SBZ polyethylene film, 100 microns thick. The long direction of the blank corresponded with the machine direction (and hence the direction of maximum shrink capability) of the film.

Six holes, each about 13/8 in diameter were punched in each end of the blank in two rows of three positioned centrally between the edges and with centres spaced approximately 11/4" and 33/4" respectively from the end of the blank, the distance between centres being approximately 21/2".

The blank was used to wrap a close assembly of six bottles arranged in two rows of three, each bottle having a capacity of approximately 500 ml, a base diameter of approximately 2t/2" and a top diameter of approximately 1t/4".

The assembly of bottles was then placed transversely and centrally on the blank, the end portions of which were brought, in turn, up each side of the assembly and passed over the bottle tops so that the top and neck of each bottle protruded through the holes provided and so that the ends of the blank overlapped in the region of the necks of the six bottles. The pack thus assembled was then passed through a shrink tunnel type 30/15 ST supplied by engineering Developments (Farnborough) Limited set at 1 90 C air temperature with a belt speed of 9.76 feet per minute to form a tight heatshrunk pack.

Claims

1. A method of wrapping a plurality of bottle-like articles, which comprises passing the upper ends of at least some of the articles through holes provided in a first area of a heat-shrinkable wrapping blank, passing the upper ends of at least some of the aforesaid at least some articles through holes provided in a second area of the blank, in such a manner as to encirle a substantial part of the articles with the blank, and applying heat to shrink the blank taut around the articles.

2. A method as claimed in claim 1 wherein the blank is generally rectangular.

3. A method as claimed in claim 2 wherein the said first and second areas are adjacent opposite ends of the blank.

4. A method as claimed in any one of the preceding claims, wherein the blank comprises a sheet of an otherwise generally continuous heatshrinkable film, having the said holes provided therein.

5. A method as claimed in claim 4, wherein the number of the said holes in at least one of the first and second areas of the blank corresponds to the number of articles wrapped.

6. A method as claimed in claim 5, wherein the number of the said holes in both the first and second areas of the blank corresponds to the number of articles wrapped.

7. A method as claimed in any one of claims 1 to 3, wherein the blank comprises a heat-shrinkable film having regular perforations, or a heat-shrinkable net.

8. A method as claimed in any one of the preceding claims, wherein the articles wrapped are arranged in two adjacent rows.

9. A method as claimed in claim 8, wherein the articles wrapped are arranged in two adjacent rows of three.

10. A method as claimed in any one of claims 1 to 9 wherein the blank is supplied as a continuous reel, having the said holes provided along opposite edges thereof.

11. A method as claimed in claim 10, wherein the articles are supplied to a wrapping station substantially continuously, and wrapped to form a substantially continuous pack, which is divided into smaller packs after the blank has been heat-shrunk.

12. A method as claimed in any one of the preceding claims wherein the heat-shrinkable blank, comprises a heat-shrinkable material which is polypropylene, polyvinyl-chloride, polyvinylidene chloride or ethylene-vinyl acetate copolymer.

13. A method as claimed in any one of claims 1 to 12 wherein the heat-shrinkable blank comprises a heat-shrinkable material which is polyethylene.

14. A method as claimed in any one of the preceding claims wherein the blank has a shrinkage capacity of greater than 60% in a principal shrinkage direction.

15. A method as claimed in claim 14 wherein the blank has a shrinkage capacity of from 10 to 20% transverse to the principal shrinkage direction.

16. A method as claimed in claim 14 or claim 15 wherein the said two areas are spaced along the principal shrinkage direction.

17. A method as claimed in any one of the preceding claims, wherein the blank includes means for forming a handle.

18. A method as claimed in claim 17, wherein the means includes a hole for forming a finger hole in the finished pack.

19. A method as claimed in claim 17, wherein the means includes an injection moulded handle.

20. A method as claimed in any one of the preceding claims, wherein the articles wrapped are bottles.

21. A method of wrapping a plurality of bottlelike articles substantially as hereinbefore described with reference to the accompanying drawings.

22. A pack comprising a plurality of bottle-like articles when wrapped by a method as claimed in any one of the preceding claims.

23. A process for wrapping an article having a plurality of projections, which process comprises passing at least some of the projections through holes provided in a first area of a heat-shrinkable wrapping blank, passing at least some of the aforesaid at least some projections through holes provided in a second area of the blank in such a manner as to encircle with the blank the part of the article to be wrapped, and applying heat to shrink the blank.

New claims or amendments to claims filed on 1 sot October 1979.

New claims:

2. A method according to claim 1 wherein any welding together of the said areas in regions where they are necessarily caused to overlap in carrying out the method is produced during the heat shrinking process.

25. A method according to claim 24 wherein any welding together of the said areas in regions where they are necessarily caused to overlap in carrying out the the method is produced during the heat shrinking process.

Claims 2 to 23 have been renumbered and the appendancies of claims 2,3,6,7,9.10,11,13,15,16,18 and 19 have been corrected or changed.