GB2525741A

GB2525741A - Improvements in or relating to manufacture of packaging

Info

Publication number: GB2525741A
Application number: GB1504683.2A
Authority: GB
Inventors: Jamie Kearns
Original assignee: Coveris Flexibles UK Ltd
Current assignee: Coveris Flexibles UK Ltd
Priority date: 2014-03-20
Filing date: 2015-03-19
Publication date: 2015-11-04
Also published as: GB201504683D0; GB201405013D0

Abstract

A method of forming adhesive packaging is disclosed in which adhesive is applied to select portions of a first substrate, rather than all of the first substrate, in order to bond a second substrate, which may be of a different material, to the first substrate. The method includes the forming a web of laminated foldable substrate using a single automated apparatus which runs a continuous process using a continuous or reel-fed supply of substrate and of laminate film. Also disclosed is an alternate automated apparatus in which adhesive is applied in select portions to a packaging. Also disclosed is an alternate package, with adhesive applied to select portions. Typical non-adhesive treated portions of the first substrate are shown by the hatched areas in fig.4. Use of adhesive on select portions of the first substrate, as opposed to using adhesive across all of the substrate, may present a materials and cost saving advantage.

Description

Title: Improvements in or Relating to Manufacture of Packaging

Field of Invention

The present invention relates to a novel method of manufacturing packaging, and to novel apparatus for use in a method of manufacturing packaging.

Background of the Invention

It is conventional to manufacture articles of packaging using card, paperboard or other similar foldable materials. In particular, it is well-known to use card or paperboard to manufacture packaging for foodstuffs. Often articles of card or paperboard packaging are produced as flat blanks, which may be folded and/or glued to produce a partially assembled food container, desirably still in a substantially fiat or flattened form for ease of storage and transport. The partially assembled food container is then erected into a container, typically by a simple push-action, immediately prior to filling with a foodstuff.

Packaging made from card or paperboard is generally biodegradable and can be formed from recycled materials, and so is more environmentally friendly and sustainable than packaging made from synthetic plastics. However, card or paperboard packaging has undesirably high permeability. Accordingly, in order to prevent a packaged foodstuff from becoming dehydrated and/or to prevent the ingress of moisture into the package during storage and/or transit, it is commonplace to apply a thin film of moisture-resistant coating to at least one side of the packaging. Such as moisture-resistant coating may be formed from an oil-based synthetic plastics material, but it is preferred to use a biodegradable laminate film such as BOPP (biaxially oriented polypropylene) or PLA (polylactic acid) e.g. "Earthfirst"® film, available from Sidaplax (see US 7,615,183).

In the UK, a major market for laminate-coated packaging exists in relation to packaging of sandwiches. A typical sandwich carton, formed from a blank of laminated card or paperboard, is disclosed in GB 2,397,573. The assembled carton is of generally triangular-prism shape.

Recently, methods of making laminated card or paperboard packaging, using a continuous process run on automated apparatus have been adopted and are disclosed in, inter a/ia, W02008/025982, W02008/099195, and GB 2,481,681. Tn general terms, the method taught in the prior art involves the use of apparatus provided with a reel of card or paperboard substrate, and a reel of laminate film to be applied to a surface of the substrate. In a first step, an aperture is formed in the substrate, then the laminate film is applied to one side of the substrate using an adhesive, and the laminated substrate is folded and cut as desired, to produce a plurality of packaging blanks.

The present invention aims to provide an improved method of making laminated card or paperboard packaging.

Summary of the Invention

In a first aspect the invention provides a method of forming a web of laminated foldable substrate, typically card or paperboard, suitable for making articles of packaging for a foodstuff the method comprising the use of automated apparatus to perform the steps of: (a) optionally passing a web of foldable substrate through a first die station at which one or more cuts may be introduced into the substrate; (b) applying, to at least one side of the substrate, on selected portions only, an adhesive; (c) applying a laminate film to the adhesive-treated side of the substrate to form a laminated substrate; (d) optionally forming folds or creases in the laminated substrate; and (e) optionally cuffing the laminated substrate to form a plurality of blanks, Steps (b) and (c), and preferably also each of steps (a), (d) and (e) of the method of the first aspect defined above, are performed using a single automated apparatus which runs a continuous process using a continuous or reel-fed supply of substrate and of laminate film, as opposed to a discontinuous process using a batch-fed supply of materials.

The card or paperboard substrate typically has a density in the range 80-250 grams per square metre ("gsm"), preferably in the range 125-200gsm. The card or paperboard is advantageously formed from recycled material, optionally coated or treated to confer particular desirable characteristics.

The laminate film applied to the card or paperboard is preferably a transparent film, typically formed from a plastics film, such as PLA, BOPP or the like. Desirably the film is heat sealable and may be provided with a coating, if necessary, to confer suitable heat-sealing capability. Suitable film is available commercially e.g. from Sidaplax and Innovia Films Limited (Wigton, Cumbria), such as Innovia 25mc RKplus, Heat-sealable coatings are well-known to those skilled in the art. Heat-sealing is effected by bringing two portions of the packaging into juxtaposition, at least one of which (preferably both) has/have a heat-sealable coating. Heat is then applied to one or both of the juxtaposed portions, so as to bring about a sufficient temperature, for a sufficient duration, to cause at least partial melting of the heat-sealable coating.

Typical conditions are exposure to a temperature of 180°C with 1-2 seconds dwell time.

In known methods of manufacture, as exemplified by the disclosures in W02008/025982, W02008/099 195 and GB 2,481,681, in order to adhere a laminate film to a web of paperboard or card substrate, a suitable adhesive is applied to the entire surface of the substrate (that is, the entire surface of the substrate that remains after possible prior removal of portions to create windows etc.). Conventional wisdom is that application of adhesive to the entire surface of the substrate is desirable to ensure good bonding of the laminate to the substrate and, moreover, is technically simple to accomplish.

The present inventor has realised that it is possible to obtain good bonding of the laminate film to the card or paperboard substrate even if adhesive is applied only to selected portions thereof This reduces the amount of adhesive required. For the avoidance of doubt, the term "selected portions" as used herein does not encompass selection of the entire surface of the substrate, such that at least part of the surface of the substrate on the adhesive-treated side is left with no adhesive applied.

The smaller the area of the "selected portions", the less adhesive is required, and hence the greater the economy of material, but against this must be set the conflicting requirement to apply adhesive over a sufficiently large area to ensure that the laminate film is securely adhered to the substrate. A typical percentage area to which adhesive is applied in the method of the invention is in the range 30 to 90%, preferably 35 to 85, more preferably 40 to 80% (that is, the % area of one side of the substrate which is present in the finished blank). The selected portions of the substrate to which adhesive is to be applied preferably include substantially all those parts of the substrate which form edges of the packaging blank when the blank is separated from the web of substrate. Desirably a "margin" or border of adhesive is applied, such that the laminate film is adhered to the substrate at the edges of the blank at the periphery and inwards therefrom. Advantageously the margin or border has a width in the range 5- 20mm, more preferably 7-15mm. Securing the film to the substrate in a margin or border of this size around the edges of the blank is found sufficient to provide a sufficiently robust adhesion between the film and the substrate to prevent the ingress of air and/or moisture between the substrate and the film, which might otherwise cause the film to peel away from the board.

Typically the selected portions of the substrate to which adhesive is applied will all lie on one side of the substrate, preferably that side which forms the inner side of the finished article of packaging, Desirably there will be at least two or more, separate, selected portions. Advantageously a substantially continuous margin around the periphery of the blank (in order to form a good edge seal with the laminate film) will be one of the selected portions, and there are one, two or more further selected portions on the main body of the blank to which adhesive is applied. Tt will be apparent to those skilled in the art that the number of portions to which adhesive is applied may be inversely related to the average area of those portions (i.e. one may use a large number of selected portions of relatively small area, or a smaller number of selected portions of larger average area, and obtain an equivalent result).

In conventional methods of manufacture, adhesive is applied to the entire surface of one side of the substrate, by applying adhesive to a roller, and contacting the adhesive-coated roller with the substrate. This is a simple and effective way of applying adhesive to the entire surface of the substrate, but is not suitable for use in the present invention.

In one embodiment, in a method in accordance with the present invention, adhesive is applied to selected portions of the surface on one side of the substrate by processing the substrate through a station comprising a spray head or, preferably, a plurality of spray heads, a spray of adhesive from the spray heads being controlled by a programmable control means, such that adhesive is deposited only on the desired selected portions of the substrate. The spray heads may spray adhesive directly onto the selected portions of the substrate or, in the alternative, may spray adhesive onto appropriate portions of a intermediate member, which intermediate member contacts the surface of the substrate, the movement of the substrate (as it advances through the apparatus), relative to the spray heads, or relative to the intermediate member, as the case may be, serving to distribute the adhesive in the desired pattern on the substrate.

In a preferred embodiment adhesive is supplied (by spray head or, more preferably, by any conventional means), from a reservoir, onto an intermediate member, the intermediate member having a profiled surface with relatively projecting parts, such that the projecting parts of the intermediate member contact the respective or corresponding selected portions of the substrate web. Adhesive on the raised parts of the profiled surface of the intermediate member is deposited onto those selected portions of the substrate, the movement of the substrate relative to the intermediate member causing the adhesive to be distributed in a desired pattern on the surface of the substrate. Preferably the intermediate member is free to rotate and conveniently takes the form of a roller or the like. In an alternative, and less preferred, embodiment adhesive is applied to the surface of the substrate in "negative" style, the profiled surface of the intermediate member contacting portions of the substrate surface which are to be shielded, whilst adhesive is applied (e.g. by spraying or inkjet printing or the like) to the exposed portions of the substrate surface. Accordingly, the portions of the substrate contacted by the profiled surface of the intermediate member may be the portions to which adhesive is to be applied (i.e. the "selected portions"), or may be the portions to which adhesive is not applied, depending on the details of the method employed.

In a preferred arrangement, the intermediate member comprises a rotating cylinder, conveniently with a removable sleeve. The cylinder and/or sleeve typically is formed of metal or ceramic but other durable materials will suffice, The cylinder or removable sleeve may be laser engraved or otherwise treated so as to obtain the desired profile. In this way, adhesive can be printed' onto the selected portions of the surface of the substrate in a manner similar to the use of an anilox roll in conventional printing. A doctor blade may be used to scrape excess adhesive off the anilox roll.

A suitable adhesive needs to be able to dry or cure quickly. In one embodiment, the adhesive is UV-curable.

Once the adhesive has been applied to the desired portions of the surface of one side of the substrate, the adhesive-treated surface is coated with the thin film of laminate material, This is typically accomplished by bringing a feed of adhesive-treated substrate together with a feed of laminate and pressing the two together by passage through a pair of rollers, in conventional manner, The adhesive is then dried or cured by e.g. heating and/or exposure to UV radiation at a curing station in the apparatus.

Adhesives suitable for use in the present invention are typically based on or comprise fast-curing UV-curable laminating adhesives, and typically have a viscosity in the range 30 to 60 poise (equivalent to 3-6 Pascal seconds). Commercially available adhesives suitable for practising the invention include Stehlin 4OUC 901916, Vision SNO 042 and Colergen 3401111, Laminate film could be applied to both surfaces of the substrate but at least one surface has adhesive applied to selected portions only of the surface, In preferred embodiments, adhesive is applied to selected portions only on that surface of the blank which will form the inside of the finished article of packaging. Optionally, adhesive maybe applied also to the opposite surface of the blank, which will form the outer side of the container when assembled. Adhesive applied to the outer side surface of the blank may be applied to selected portions of that surface or may be applied to the entire surface.

The article of packaging (or blank therefor) made by the method of the invention is preferably a container for a sandwich, especially a triangular-shaped sandwich or sandwiches, but other articles of packaging (or blanks therefor) can be made by the method, including for example salad boxes, baguette trays, ready meal sleeves, and any other food packaging of this sort. The laminated side of the substrate is usually, but not necessarily, that side of the substrate which is closest to the foodstuff in the finished packaged article, which may generally be thought of as the inside' of the finished article of packaging. In preferred embodiments, the article of packaging (or blank therefor) made by the method of the invention, will preferably comprise a lid, which forms an integral part of the article and is typically substantially continuous with the rest of the packaging article, along an edge thereof, which typically will include a fold or score line which acts as a hinge. Folding the lid about the fold or score line brings the lid to lie over the opening in the article of packaging, and heat sealing of the lid to flange portions around the periphery of the opening closes the lid, secures it in place, and forms a substantially hermetic seal around the packaged foodstuff, In preferred embodiments the blank will comprise an aperture in the substrate, which is overlaid by the transparent film, so as to form a window in the assembled packaging, through which window a prospective consumer can view the packaged foodstuff prior to purchase. The aperture is conveniently provided in the integral lid part of the blank. The window can be any shape e.g. circular or triangular, but will typically be generally rectangular (optionally with rounded corners). The window will, in some embodiments, preferably have a visible area of about 50-75cm2 on one surface which, for a sandwich carton, affords a reasonable view of the packaged sandwiches within the carton.

In preferred embodiments, the aperture provided in the integral hinged lid does not extend right to an edge of the lid. Thus, there is preferably (but not necessarily) a border of substrate in the lid "framing" the aperture. Preferably the frame is asymmetric, being wider on the outer side than on the inner side (adjacent the "hinge"). The width of the frame along the inner side of the frame around the aperture is preferably at least 7mm wide, more preferably at least 8mm wide, and most preferably 9-11mm wide. The frame on this inner (hinge) side of the lid serves both to provide increased rigidity to the assembled article of packaging (reducing the likelihood of the side bowing in) and also to obscure the edges of the folded sides of carton when assembled, which would otherwise be visible through the window if the aperture in the lid extended right to the hinged edge of the lid.

Whilst it is entirely conventional to print information onto the side of the substrate which will form the outer surface of the packaging when in use (e.g. to display product information), a particular feature of the method of the present invention is the appreciation by the Applicant that, in preferred embodiments, it is also possible to print infonriation on the side of the substrate, which will fonn the inner surface of the packaging when in use and which may, in particular, become visible to a consumer when the packaging is opened.

The printed matter may be of any sort whatsoever, but in particular may preferably include information about the packaged foodstuff (e.g. nutritional information additional to that displayed on the outside of the packaging, or information about the source of one or more of the ingredients), promotional or marketing information (about the packaged foodstuff and/or the retailer) and the like.

It will be apparent to those skilled in the art that any print, ink or the like, to be applied to the side of the substrate which is to be laminated, must be applied prior to the application of the laminate film. The ink may typically be applied to the "inner" side of the substrate in substantially any conventional manner (e.g. substantially in the same way in which ink is applied to the "outer" side of the substrate), typically by conventional printing processes well known to those skilled in the art. The print or ink may be applied to those parts of the substrate which are not treated with adhesive, and the print or ink may be applied before or after the application of adhesive (preferably before), but certainly before lamination.

Accordingly, the method of the present invention may result in an article of packaging, or a blank therefor, in which there is printed matter on both the inner and outer surfaces. The printing may use ink, dye or any suitable coloured substance, usually applied in liquid form to the substrate. Suitable inks and dyes will be apparent to those skilled in the art. Preferably the printed matter comprises legible text.

Accordingly, in preferred embodiments of the method of the first aspect of the invention, the method may involve applying print or ink to the side of the substrate which forms the inner surface of the packaging, prior to lamination of that side.

Generally the application of adhesive to the entire surface of the substrate on the side to be laminated would deter the person skilled in the art from applying print or ink to the inner surface, but since the present invention leaves portions of the surface free from adhesive, it may be especially desirable to apply print or ink to the non-adhesive coated portions of the substrate. The printed information or the like is protected against contact with the packaged foodstuff by the intervening laminate film.

In another embodiment information is formed or applied to that side of the substrate which will form the inner surface of the packaging by incorporating a dye, ink or suitable coloured substance into the adhesive formulation applied to the substrate. In such embodiments, the "selected portions" of the substrate to which the adhesive is applied can include areas to form a pattern, or, more preferably, text, which is visible to a consumer typically only after the packaging has been opened. In this way, the adhesive can perform both a structural role, securing laminate film to the substrate, and an informational role.

In a second aspect of the invention provides automated apparatus for manufacturing a laminated web of substrate, typically of card or paperboard, suitable for use in making an article of packaging, the apparatus comprising: (a) means for accepting a feed of substrate; (b) means for accepting a feed of laminate film to be applied to one side of the substrate; (c) optionally, a first die station at which one or more cuts may be introduced into the substrate; (d) an adhesive application station, at which adhesive is applied to selected portions only of the surface of at least one side of the substrate; and (e) a laminating station, at which laminate film is adhered to the adhesive-treated side of the substrate, to form a laminated substrate; and (f) optionally, a further die station to form folds or creases in the laminated substrate and/or cut blanks from the web of substrate.

It will be appreciated that the adhesive application station must precede the laminating station, or else a single station of the apparatus performs both the adhesive applying and laminating steps, in that sequence. The first die station will preferably precede the adhesive application station, but this is not essential. A second or third die station may be located before or, more preferably, after the adhesive application and laminating stations. Also, as implied above, a single station may perform two or more processes, either substantially simultaneously or sequentially.

The first die station is optional but preferred. Typically the first die station is at a point in the apparatus upstream of the adhesive application and laminating stations.

The first die station may introduce one or more lines of cut into the substrate. These may be lines of partial cut, in which only some of the thickness of the substrate is cut e.g. introduce lines of perthration in the substrate, In particular, the first die station may introduce one or more lines of total cut so as to define an aperture or window in the substrate. This aperture or window is subsequently covered by the laminate ifim, creating a film-covered window, through which a packaged foodstuff may be viewed by a prospective customer, Advantageously the aperture or window is created in a portion of the blank which forms a lid in the finished article of packaging. Lines of cut can be introduced into the substrate at the one or more various die stations by essentially conventional means, as described below.

II

The apparatus may preferably comprise additional stations. For example, a second, third or frirther die station may be provided, at which additional creases, folds, cuts, partial cuts or score lines may be introduced into the substrate or laminated substrate.

The apparatus may comprise a curing station at which the adhesive is cured. The curing station may comprise a heater (e.g. an infra-red heater), ultra-violet lamps, or both, The apparatus may, preferably, additionally comprise a station at which the laminated, creased substrate is cut into separate blanks. Desirably this occurs at or near the downstream end of the apparatus, preferably as a final step in the process performed by the apparatus.

The apparatus is preferably adapted and configured to perform the method of the first aspect of the invention. Features of the method of the first aspect which are described as preferred, advantageous etc, and are typically respected in the apparatus of this second aspect.

Typically a die station used in the method and apparatus of the invention will comprise a pair of rollers, between which the web of substrate (or laminated web, as the case may be) is fed. Desirably one of the pair of rollers (the "die" roller) will have protruding portions which act to nip the web against the other roller (the "anvil" roller), which will desirably have a generally smooth surface, The die roller will preferably additionally comprise resilient portions, eg. resilient foam or rubber inserts, which are positioned so as to urge the blank away from the die roller. The waste of the web material is conveniently not acted on by such resilient portions and therefore tends to adhere slightly to the die roller, In this way, at a final die station, the finished blank can be readily separated from the rest of the web, In a preferred embodiment, at the final die station, the anvil roller is beneath the web and the die roller is above the web, such that the waste material tends to be separated in an relatively upward direction and the finished blanks tend to separate from the waste in a relatively generally downward direction. This is found to allow the apparatus to run at high speed whilst still allowing the finished blanks to separate from the waste substrate and stack readily with the assistance of gravity.

The means for accepting a feed of card or paperboard will conveniently comprise a spindle or roller for accepting a reel of card or paperboard, and a suitable drive means.

A similar arrangement may be provided for feeding the laminating film into the apparatus. Thus, the feed of card or paperboard, and the feed of laminating film, in the method/apparatus of the invention may conveniently be made substantially continuous.

The card or paperboard is typically provided on a large reel, as is the laminating film, (although the reel of laminating film is considerable smaller than the reel of board or card, as the film is much thinner). Desirably the apparatus is capable of accepting, simultaneously, two reels of board or card; one of the reels being in use and actively fed into the machine, the other being idle, such that, when the "in use" reel is exhausted or is approaching exhaustion, the machine can then start to be fed from the previously idle reel, whilst the exhausted reel is replaced. In this way, "down time" for the apparatus can be minimised, A similar dual reel system is conveniently also adopted for the laminating film supply. The joining of the new reel of board or card to the end of the previous reel is termed "splicing", as is the joining of the new reel of film to the end of the old reel of film.

Apparatus generally suitable for use in the invention is available from Gallus (Gallus Ferd, RUesch AG, 9W6 St. Gallen, Switzerland), but which lacks, inter cilia, an adhesive application station which applies adhesive to selected portions only of the substrate, The person skilled in the art can, with the benefit of the present disclosure, readily modify the commercially available apparatus to include an adhesive application station which applies adhesive to selected portions only of the substrate.

In a third aspect, the invention provides a flat blank for forming an article of packaging for a foodstuff the flat blank comprising: a foldable substrate, typically of board or card, being laminated on at least one surface thereof with a layer of laminate film; the blank having adhesive applied to selected portions only of the laminated side of the substrate, with the film adhered to the blank by adhesive at said selected portions only, Preferably the film is transparent. 1-,

Preferably the film comprises or is substantially formed from a biodegradable synthetic plastics film, such as PLA or BOPP as aforementioned. Preferably the film is heat-sealable.

The blank may conveniently be laminated on one side only. Generally, if only one side of the blank is laminated, then that laminated side will be that which forms the inner surface of the finished article of packaging (i.e. that side which is in contact with, or closer to, the packaged foodstuff).

In typical embodiments the blank will be adapted and configured to package triangular-cut sandwiches, and the blank may comprise a generally rectangular base wall and generally rectangular back wall joined along a fold line, with two substantially triangular side walls, or components that fold or assemble to form substantially triangular side walls, and an integral lid attached via a hinge or fold line to at least one wall of the blank, The lid may advantageously comprise a laminate film-covered window through which the packaged foodstuff may be viewed by a prospective consumer.

The blank may also comprise other "film-only" portions, from which the substrate has been removed, In one embodiment, one or both side walls of the assembled packaging will comprise folded, overlapping portions. Desirably at least a part of the folded or overlapping portion will be formed of a "film-only" portion. The "film-only" portion, lacking the substrate, is thinner and more flexible than those parts of the blank where substrate is present, and can therefore be folded far more readily.

In a particular embodiment, the blank comprises two adjacent portions, at least one of which has a "film-only" part, The two adjacent portions are joined along a fold line.

Preferably the "film-only" part extends along the junction of the two adjacent fold lines (i.e. such that the fold occurs substantially in, or adjacent to, the "film-only" part, which is most flexible). Advantageously, the "film-only" part extends along the majority (ic. over 50%) of the length of the fold between the adjacent portions, preferably over 60%, more preferably over at least 70%, and most preferably over at least 80% of the length of the fold. It is however preferred to retain at least some substrate present along the fold, in order to give some structural strength and some "permanence" to the fold, since the film alone is too flexible and will unfold or uncrease too readily. Advantageously, the retained substrate is provided at an end region of the fold, desirably at the end region which is at the outer edge of the blank.

The ease with which the substrate portion can be folded can be increased by providing a cut (partially or completely through the thickness of the substrate) along a fraction of the length of the fold.

The blank of the third aspect of the invention is conveniently made by the method of the first aspect as defined and detailed above. The Nank is conveniently manufactured using the automated apparatus of the second aspect.

In a preferred embodiment, the blank of the invention is for a sandwich carton, with a "handedness" which facilitates manipulation of the blank (either in its completely flat form, or in a glued, arid partially folded flat form). In particular, the blank preferably possesses a handedness which, when the blank is in a fiat but glued and partially folded fonu, allows it to be fed into the hopper of an automated machine for packaging foodstuffs into the packaging and/or for dosing and sealing the lid of the packaging. Thus a preferred embodiment has an integral flap positioned between a base and a sidewall, on the same side of the base as an integral lid. A blank with opposite handedness (i.e. with the integral flap provided adjacent the other side wall) is within the scope of the invention, but is not preferred.

In a fourth aspect, the invention provides a method of packaging a foodstuff, the method comprising the steps of: assembling an article of packaging, including folding and gluing a laminated blank essentially as defined in the third aspect of the invention; inserting a foodstuff into the assembled article of packaging; and heat sealing a lid to one or more flange portions present on the packaging to seal the foodstuff within the packaging. Optionally the method may also comprise the step of flushing and/or fifing the package, with the foodstuff inside, with an inert gas (such as nitrogen) prior to heat-sealing the packaging. The lid is preferably an integral part of the blank, but may alternatively be provided as a separate component of the packaging.

Another advantage of the method of the present invention is that it allows the formation of cartons, containers and the like by the folding and gluing of blanks, in particular which could not be made using blanks in which a laminate film is adhered over the entire surface of the blank.

By way of explanation, in the preferred embodiments of the method of this invention, a plurality of flat blanks of creased card or paperboard substrate, laminated on at least one side with a film of plastics matetial, is typically produced by a continuous process on an automated apparatus using reels of input substrate and laminating film, rather than a discontinuous process performed on sheet-fed apparatus. The resulting flat blanks are then preferably fed through a folding carton gluing machine which folds desired parts of the blank along the preformed crease lines, and applies glue to selected parts of the blank so that portions of the blank are glued to each other, to form a partially assembled carton or container. Folding carton gluing machines are commercially available from, for example, Heidelberg, Bobst, Jagenburg and the like, all well-known to those skilled in the art. The partially assembled, folded and glued cartons or containers are usually then supplied in that form to the business which packages the foodstuff the partially assembled cartons or containers being erected into their fully assembled form by the foodstuff packager, usually immediately prior to filling the carton or container with the relevant foodstuff. In particular, it may be desired to fold a first part of the blank (such as a corner tab or the like) onto a second part of the blank, and to secure the two parts by means of a "cold glue". Cold glues typically used in this connection may include those available from Henkel; such as Henkel 7362.

The strength of the resulting bond between the two parts of the blank may be compromised if one or both of the two parts is covered with adhesive and/or a laminate film: a stronger bond is formed between two "virgin" parts of the blank without any intervening adhesive or plastics film laminate.

Accordingly, the method of the present invention provides the ability to avoid the deposition or application of adhesive to a part of the blank which is subsequently to be glued to another part of the blank, thereby facilitating the formation of a stronger bond. In particular, for example, it may be desired to fold a part of a blank, especially at a corner or vertex thereof in such a way that an "inner" surface of the blank overlaps or overlies an "outer" surface of the blank and to the overlapping parts are to be glued together. II' the inner surface of the blank has a plastics laminate film coating, it may be desired to avoid applying adhesive to the part of the inner surface that is to be folded, such that there is no adhesive coating where the glue is to be applied.

Moreover, by not applying adhesive over the entire surface of the blank, it is possible to create blanks having a laminate film coating over substantially an entire surface of the blank but in which there are locations (with no adhesive) in which the laminate film overlies the substrate of the blank but is not, in the overlying film region, adhered or secured to the substrate. Desirably such areas of overlying, but unsecured, film are provided at corners or vertices of the blank, or other locations, where it is desired to create foldable tabs, flaps or the like which are to be glued to other parts of the blank.

If the film was secured to the substrate, the act of folding the blank (especially, folding the inner surface outwards i.e. forming a "reverse crease") would strain the film and possibly rupture or tear it, and/or the film coating would tend to interfere with or inhibit the folding. However because, in the method of the invention, the film is not secured to the underlying film in the relevant location, the film is free to float', allowing the fold to be formed without straining or tearing the film, and without interfering with or inhibiting the formation of the fold, but the presence of the film allows the formation of a liquid-tight seal e.g. at the junction of the flaps or the corner of the container.

Therefore, in a preferred embodiment of the method of the first aspect of the invention, one or more of the portions of the substrate which are not selected to have adhesive applied (on the laminated side of the substrate, if the substrate is laminated only one one side) will be at least a part of a flap or tab which part, in the partially assembled carton or container, is folded over and glued to another part of the blank, especially a flap or tab which is folded outwards ("reverse creased"). These parts of the tabs or flaps will thus have laminate film overlying them, but the film will not be secured to the underlying substrate in those particular locations. Such flaps or tabs are typically located at the corners of a tray-like carton, and/or the vertices of a more complex shaped container, or on at least some of the tabs of a blank for a "crash lock bottom" carton.

The invention also provides a corresponding blank, a corresponding partially assembled carton or container, and a method of making a partially assembled carton or container.

In particular, the invention provides, in a further aspect, a method of making a partially assembled, folded and glued carton, container or other article of packaging for a foodstufl the method comprising the steps of: a) supplying a folding carton gluing machine with a plurality of creased blanks, each blank have a substrate of card or paperboard laminated on at least one side with a laminate film, the film substantially overlying the entire surface of said at least one side of the substrate, but being adhered thereto by the application of adhesive to selected portions only of the side of the substrate which is laminated, such that each blank comprises at least one area of substrate having overlying but unsecured film; b) folding the blanks and applying glue using the folding carton gluing machine so as to form a plurality of partially assembled, folded and glued, cartons, containers or other articles of packaging for a foodstuff.

Typically the blank is folded by the folding carton gluing machine along at least one pre-formed crease line which is formed in the blank during the preceding method of forming the blank as aforesaid in the method of the first aspect of the invention.

Advantageously the said at least one area of substrate having overlying but unsecured film will be a part of a tab or flap and, typically, present at a corner or vertex of the partially assembled, glued and folded carton or container As an example, the blank may be used to fonn a partially assembled folded and glued laminated carton or container having a "crash lock bottom". The "crash lock bottom" construction is well known to those skilled in the art and, in simple terms, allows a partially assembled folded and glued carton to be provided in a substantially flattened form but, when opposite sides of the carton are pushed inwards the carton is self-erecting and the bottom parts of the container interlock, such that the carton is ready for use without any further gluing required. The present invention allows the formation of partially assembled folded and glued cartons or containers, having a substantially wholly laminated (inner) surface, and having tabs which co-operate to form a crash lock bottom, by automated processes, in a manner which could not hitherto be performed.

For the avoidance of doubt, it is hereby expressly stated that the features described herein as "preferred", "desirable", "convenient", "advantageous" or the like may be present in the invention in isolation, or in any combination with any other features so described, unless the context dictates otherwise. Additionally, all preferred features of each of the aspects of the invention apply to all the other aspects of the invention imitatEs inutandEs, unless the context dictates otherwise.

The various aspects of the invention will now be described by way of illustrative embodiment and with reference to the accompanying drawings, in which: Figure 1 is a plan view of one embodiment of a flat laminated blank in accordance with the invention; Figure 2 shows the blank of Figure 1 in partially assembled form, folded and glued; Figure 3 is a schematic illustration of automated apparatus generally suitable for performing the method of the first aspect of the invention; Figure 4 is a plan view of the embodiment of the blank depicted in Figure 1, during an early stage in the manufacture thereot and indicates those selected portions of the substrate to which adhesive is applied (no shading), and those which are left untreated with adhesive (shaded); Figure 5 is a schematic illustration of an one embodiment of an adhesive application station, for applying adhesive to selected portions of one side of a web of substrate, during a method of manufacture in accordance with the first aspect of the invention; Figure 6 is a plan view of a one embodiment of a flat blank in accordance with the invention, which can be assemNed into a crash lock bottom carton; and Figures 7 and 8 are plan views of flat blanks in accordance with the invention which can be assembled into a "four corner" and "six corner" carton respectively.

Detailed Description of Embodiments

Example 1

Referring to Figure 1, the invention provides in one aspect a flat blank for an article of packaging for a foodstuff. In the embodiment depicted in Figure 1, the blank is for a sandwich carton, for packaging two triangular-cut sandwiches. When folded together the blank forms a triangular prism-shaped carton.

The blank is formed primarily from a substrate of paperboard or card. A typical quality of board is in the range 80-250 grams per square metre (gsm). Any suitable board may be used. The substrate is laminated on one surface with a thin film of a transparent synthetic plastics material. In the embodiment depicted the film comprises biaxially oriented polypropylene and has a heat-sealable coating.

The blank has several fold lines and several cut lines, which define various features of the blank. In particular, the blank has a base 2 and a back 4, joined along fold line 6; a side wall 8 with an integral flap 10, formed from two integral flap portions 12a and 12b; and a second side wall formed from side wall components 14a, 14b, which, in the assembled carton, overlap each other to form a substantially continuous triangular-shaped wall. The blank also comprises an integral lid 16, attached to side wafl 8 along fold line 18. The lid 16 has a generally rectangular aperture formed therein, which is covered by the transparent laminate film to provide a window 20. The window 20 allows a prospective consumer to view the sandwiches within the carton when assembled.

The aperture provided in the integral hinged lid does not extend right to an edge of the lid 16. There is a border of substrate in the lid "framing" the aperture. The frame is asymmetric, being wider on the outer side than on the inner side (adjacent the "hinge") with side wall 8. The width of the frame along the inner side of the frame around the aperture is 9-11mm wide, The frame on this inner (hinge) side of the lid serves both to provide increased rigidity to the assembled article of packaging (reducing the likelihood of the side bowing in) and also to obscure the edges of the folded integral flap portions]2a, l2b of the carton when assembled, which would otherwise be visible through the window if the aperture in the lid extended right to the hinged edge of the lid.

To assemble the blank, the side wall 8 and side wall components Na, b, (together with the associated flaps, lid etc.) are folded upwards through about 900 about the respective fold lines 22 and 24, The blank is then folded through about 90° along fold line 6.

In so doing, side wall component 14b comes to overlap the tab 26 at the end of side wall component 14a; and integral flap portions 12a and 12b are brought together, folding inwardly about fold line 28, It will be noted that the board is cut away at parts of the blank which form part of the sides of the carton when it is assembled, Thus, there are portions 30 and 32 where there is laminate film, but no board, These portions, lacking board substrate, are very thin and flexible. As a result they greatly facilitate the folding of the blank into the assembled carton. There is another advantage accming from the use of a "film-only" portion at 30, When the integral flap is formed by folding along fold line 28, there are two thicknesses of board (provided by flap portions]2a and 12b respectively), The inventors have found that, if the integral flap is formed entirely from laminated board it is resistant to folding, and tends to bulge outwards, projecting into that part of the interior of the carton which is visible through window 20, which looks untidy and is undesirable, Another feature which facilitates folding of the flap portions 2aI12b, and which lessens the tendency of the folded flap to bulge outwards, is that the strip of board 34 joining flap portions 12a and 12b is very narrow, about 7 or 8 mm long. Moreover there is a notch' or partial cut in this strip of board, so that only about I or 2 mm is completely intact.

At the outer edges of base 2 and back 4 are "flange" portions 40. Similar flange portions 40 are formed at the outer edge of side wall components t4a and t4b. The flange portions are defined by discontinuous lines of cut through the board. The discontinuous cut lines comprise cuts 7 mm long, with intervening 1 mm portions of uncut board. These flange portions are "reverse" creased during manufacture of the blank and are heat sealed to the lid when the carton is fully assembled.

Example 2

Figure 2 shows the blank of Figure 1 in a glued and partially folded form. In the partially folded carton, flap portion 12b is glued to flap portion 12a, and overlapping tab 26 of side wall component 14a is glued to side wall component Nb; and the blank is folded about central fold line 6.

The blank has a "handedness" which facilitates manipulation of the blank (either in its completely flat form, or in a glued, and partially folded flat format). In particular the blank preferably possesses a handedness which, when the blank is in a flat but glued and partially folded form, allows it to be fed into the hopper of an automated machine for packaging foodstuffs into the packaging and/or for closing and sealing the lid of the packaging. Thus a preferred embodiment has an integral flap positioned between a base and a side wall, on the same side of the base as an integral lid.

Example 3

Apparatus generally suitable for performing the method of the invention, once subjected to certain necessary modifications, is commercially available from e.g. Gallus-Stanz-und Druckmaschinen GmbH, Figure 3 is a schematic representation of the automated apparatus of the invention performing the method of the invention, A large reel of board 100 is fed into the machine through a pair of guide rollers 102, and passes through an initial cleaning station 104, at which, inter a/ia, suction is applied to the web to remove dust and lint. The web then passes through a plurality of (typically seven) printing stations 106, at one or more of which a particular print colour is applied to one side of the board to build up the desired graphics images and/or text.

The web then passes a series of infra-red heaters 108 to assist in drying the printed surface.

Next the web passes to a first die station t 10. At die station t tO the web passes between a pair of rollers 112. These have cutting surfaces which are shaped so as to form the discontinuous hinge lines of cut which partially define the flange portions 40 in the blank, cut out the board from the portion of the blank which forms window 20 in the lid, to cut out the board from the "film-only" portions 30 and 32 of the blank, and also to introduce the kiss cut in the narrow strip of card at 34.

The waste portions cut out from the web are extracted into a waste pipe.

At the next stage, laminating station 114, an adhesive is applied, to selected portions only, of the inner surface of the Nank (as described in greater detail b&ow) and a layer of film, supplied from reel 116, is applied to the glued inner surface to form a continuous coating on the inside of the blank, This is cured by exposure to ultra-violet radiation of the order of a few seconds.

The laminated web is then fed to a second die station 118. At this station, the parts of the blank which correspond flange portions 40 are creased outwards (i.e. reverse creased), along the hinge lines.

After the reverse creases have been introduced into the laminated web, the laminated web then advances to a third die station 20. This station introduces all the inward creases or folds of the inner (laminated) surface of the blank, and cuts out the finished flat blank 122 from the laminated web. The fiat blanks are then usually fed into a further (conventional) machine for gluing and folding, to make a partially folded blank, which can be supplied to commercial food packagers for final assembly of the carton or container, insertion of the foodstuff, and heat-sealing of the carton, fin Li The appearance of the blank is conventional, and looks essentially indistinguishable to that disclosed in, for example, GB 2,481,681. However, in the prior art blank, an adhesive is applied to the entire inner surface of the paperboard substrate during its manufacture, such that the laminate film is adhered to the entire inner surface of the substrate.

Example 4

In the method/apparatus/blank of the present invention, adhesive is applied instead only to selected portions of the inner surface of the substrate, as illustrated in Figure 4.

Referring to Figure 4, there is shown an outline of a blank to be made by the method of the invention, at a stage where the blank is still contained within a web of card or paperboard substrate, after passage through a first die station, but prior to contacting with laminating film. At the first die station, a generafly rectangular aperture 16' is cut in the lid portion 16 and a portion of the web 10' is removed from the flap 10.

Accordingly there is no substrate in those portions when the web is advanced to a gluing station.

In accordance with the method of the invention, at the gluing station adhesive is applied only to selected portions of one side of the substrate. The parts of the substrate to which no adhesive is applied are indicated in Figure 4 by the line hatching. It will be noted that adhesive is applied, /nter al/a, to those portions of the substrate which will form the periphery of the blank when it is cut out from the rest of the web of substrate, and (although Figure 4 is not drawn accurately to scale) to a width of about 10mm inwards from each outer edge. Applying adhesive only to the selected portions of the substrate makes a considerable reduction in the amount of adhesive required to laminate a film to the substrate.

Example S

Figure 5 is a more detailed view of one embodiment of an adhesive application station for use in the method/apparatus of the invention, The adhesive application station includes several rotating rollers, the direction of rotation being indicated by directional anows adjacent the rollers, A reservoir 200 contains a supply of adhesive 202. A reservoir roller 204 rotates about its axis, picking up adhesive from the reservoir and transferring it to a first intermediate member, roller 206. Excess adhesive is removed from the roller 206 by doctor blade 208. As the first roller 206 rotates it in turn transfers adhesive to second intermediate member, roller 2 tO, which has a profiled surface, with raised parts. The adhesive is transferred from first intermediate member 206 only onto the raised parts of the second intermediate member 210. The web of substrate 212 advances, in the direction indicated by the arrow 214, between the second intermediate member, roller 2t0, and a nip roller 2t6.

The raised parts of the roller 210 apply adhesive only to selected portions of one side of the web of substrate. Once the adhesive 202 has been applied to the selected portions of the substrate 212, the adhesive-treated side is immediately contacted with laminate film before the adhesive is cured to secure the film to the substrate.

In an alternative arrangement, the reservoir roller 204, reservoir 200, first intermediate member roller 206 and doctor blade 209 are replaced by a single component known as a "chambered doctor blade". This arrangement reduces the number of components and is generally therefore to be preferred.

Example 6

Figure 6 shows the shape of a blank for a "crash lock bottom" carton made by the method of the invention. The carton is laminated on the side which forms the inner surface of the finished article of packaging. The laminating film is a conventional transparent film made of biodegradable plastics material such as poly lactic acid (PLA), and has a heat-sealable coating. The film is indicated by the margin tOO around the card substrate 102. In practice, the edge of the film 100 would, in most parts, be flush wish the edge of the substrate 102.

The side of the substrate which is laminated has adhesive applied to selected portions only, leaving some parts of that side of the substrate untreated with adhesive. Two particular parts of the substrate which are NOT coated with adhesive are the tabs 104 and 106, Accordingly, the laminate film overlies those tabs 104, 106, but is not secured to them.

Once the laminated blank has been cut out from the web of laminated substrate, it is fed into a folding carton gluing machine, of conventional construction and operation.

Amongst other foftis made in the blank, the tabs 104 and 106 are folded backwards at a 45° angle along a fold line indicated by the dotted lines 108 and 110 respectively.

Such a backward fold would impose a strain on the laminating film if the film were secured to the tabs 104, 106 by adhesive, such that the film would tend to resist the introduction of the fold or, if the fold were successfully introduced, it would almost certainly tear the laminate film, probably in the general vicinity of the regions indicated by arrows 112 and 114.

However, because in the blank of the invention, the film is not secured to the tabs 104 and 106 (because there is no adhesive applied to the substrate there), the film is free to "float" and the tabs 104 and 106 can be successfully folded back ("reverse creased").

In addition, because the integrity of the film is not compromised it can contribute to the making of a water-tight seal at the crash lock bottom of the assembled container.

Such advantages have not previously been available in the context of a laminated blank having lamination on the inner surface of the blank.

In addition, as explained in the Summary of the Invention, the blank may optionally have ink or print applied on its inner surface, either to areas of the substrate which have not had adhesive applied thereto; or to areas in which adhesive is applied, in this instance the print or ink being incorporated into the adhesive formulation.

Example 7

The foregoing advantages of the invention described in the preceding example are not confined to blanks for crash lock bottom packaging. Rather, similar advantages apply to any laminated blank, laminated in its inner surface, and which, during processing into a folded and glued partially assembled article of packaging, has one or more tabs or flaps which are folded outwards ("reverse creased").

Figures 7 and 8 illustrate two further embodiments of laminated blanks in accordance with, and made by the methods of the invention. Figure 7 shows a laminated blank for making a "four corner tray", and Figure 8 shows a laminated blank for making a "six corner tray". As with the embodiment illustrated in Figure 6, each laminated blank is laminated on the surface which forms the inner side (i.e. nearer to the packaged foodstuff) in the finished article of packaging, the laminating material comprising a transparent synthetic biodegradable plastics material with a heat-sealable coating. The laminating film is adhered to the substrate by an adhesive, which is applied to the substrate in selected portions only. Amongst those portions to of the substrate to which adhesive is not applied are included the tabs 120, 122, 124 and t26 in Figure 7, and tabs 130-140 in FigureS. These are tabs which, during folding of the blanks on a folding carton gluing machine, in the manufacture of folded and glued, partially assembled articles of packaging, are reverse creased. As explained previously, such a reverse crease would tend to tear the laminate film if the film were secured by adhesive tothe tabs. Since the film overlies the tabs 120-126 and 130-140, but is not secured thereto, the tabs can be folded outwards, at an angle of 45° along the fold indicated by the respective dotted lines, with the film free to "float", and subsequently contribute to the formation of a liquid tight seal at the vertices of the finished article of packaging.

Claims

Claims A method of forming a web of laminated foldable substrate, suitable for making articles of packaging for a foodstuff, the method comprising the use of automated apparatus to perform the steps of (a) optionally passing a web of substrate through a first die station at which one or more cuts may be introduced into the substrate; (b) applying, to at least one side of the substrate, on selected portions only, an adhesive; (c) applying a laminate film to the adhesive-treated side of the substrate to form a laminated substrate; (d) optionally forming folds or creases in the laminated substrate; and (e) optionally cutting the laminated substrate to form a plurality of blanks, wherein steps (b) and (c) at least are performed using a single automated apparatus which mns a continuous process using a continuous or reel-fed supply of substrate and of laminate film.
2. A method according to claim 1, wherein adhesive is applied to the selected portions only, by means of a roller or other member.
3, A method according to claim 2, wherein the roller or other member has a profile with projecting parts, and the projecting parts contact the corresponding selected portions of the substrate web.
4. A method according to any one of the preceding claims, wherein the selected portions comprise substantially all those parts of the substrate which form the edges of a packaging blank when the blank is removed from the rest of the web of substrate.
5. A method according to claim 4, wherein the selected portions include a margin, with a width in the range 5-20mm, inwards from the edges of the blank.
6. A method according to claim 5, wherein the width of the margin is in the range 7-15mm.
7, A method according to any one of the preceding claims further comprising the step of cutting the laminated substrate to form a plurality of blanks.
8. A method according to claim 7, further comprising the step of feeding the plurality of blanks into automated apparatus that folds and glues the blanks to produce a plurality of folded and glued, partially assembled, articles of packaging for a foodstuff
9. A method according to any one of the preceding claims, wherein performance of the method produces a blank for an article of packaging for a sandwich.
10. A method according to any one of the preceding claims, wherein the film is adapted to be heat-sealed so as to close the article of packaging once a foodstuff has been inserted into the packaging.
11. A method according to any one of the preceding claims, wherein ink or print forming legible text is applied to the substrate on the side which forms the inner side of the packaging, the ink or print being applied to the substrate in one or more portions which are not coated with adhesive prior or subsequent to said application of the ink of print.
12. A method according to claim II, wherein the ink or print is applied to the inner side of the substrate, prior to the step of application of adhesive, and wherein the ink or print is applied to one or more portions of the substrate to which no adhesive is applied.
13. A method according to any one of claims 1-10, wherein the adhesive comprises a print or ink, and is applied to one or more portions on the inner side of the substrate so as to form legible text or a meaningful message which is visible when the article of packaging formed from the blank is opened.
14. A method according to any one of the preceding claims, wherein adhesive is not applied to at least one tab or flap, which tab or flap, during subsequent folding of the blank to form a partially-assembled carton, is folded outwards or reverse creased.
15. Automated apparatus for manufacturing a laminated web of foldable substrate, suitable for use in making an article of packaging, the apparatus comprising: (a) means for accepting a feed of substrate; (b) means for accepting a feed of laminate film to be applied to one side of the substrate; (c) optionally a first die station at which one or more cuts may be introduced into the substrate; (d) an adhesive application station, at which adhesive is applied only to selected portions of the surface of at east one side of the substrate; and (e) a laminating station, at which laminate film is adhered to the adhesive-treated side of the substrate.
16. Apparatus according to claim 15, comprising a roller or other member having a profile with projecting parts, which projecting parts come into contact with corresponding selected portions of the substrate web.
17. Apparatus according to claim 16, wherein the projecting portions include parts which apply adhesive in the shape of one or more letters.
18. Apparatus according to any one of claims 15-17, comprising a reservoir of adhesive containing a dye or ink which renders the adhesive visible on a white or pale-coloured substrate.
19. Apparatus according to any one of claims 15-18 further comprising one or more of the following: a curing station comprising a liv lamp and/or an infra red heater to cure an adhesive applied to the substrate; and one or more die stations to introduce cuts, folds or creases in the laminated substrate and/or to cut out flat blanks from the laminated substrate.
20. A laminated flat blank for forming an article of packaging for a foodstuff, the flat blank comprising a foldable substrate, being laminated on an inner surface thereof with a layer of film; the blank having adhesive applied only to selected portions of the inner side of the substrate, with the film adhered to the blank by adhesive only at said selected portions.
21. A laminated flat blank according to claim 20, the blank being adapted and configured to form a triangular prism shaped carton for packaging a sandwich, the blank comprising a base wall and a back wall joined along a fold line; two side walls or components which co-operate in the assembled item of packaging to form two side walls; and an integral lid attached to a wall of the blank.
22. A laminated flat blank according to claim 20 or 21 and made by the method of any one of claims 1-14.
23. A method of forming a plurality of flat laminated blanks, the method being in accordance with the any one of claims 1-Pt, and further comprising the step of cutting the laminated substrate web to form a plurality of blanks.
24. A method of forming a plurality of folded and glued, partially-assembled, articles of packaging for a foodstuff, the method comprising the step of forming a plurality of flat laminated blanks in accordance with claim 23; folding the blanks along performed crease lines; and applying glue to at least one part of the blanks.
25. A method according to claim 24, wherein the folding and gluing is effected by feeding the laminated blanks into a conventional folding carton gluing apparatus.II26. A method of forming a web of laminated substrate substantially as hereinbefore described.27. A laminated flat blank substantially as hereinbefore described and with reference to the accompanying drawings.28. A method of forming a plurality of laminated flat blanks substantially as hereinbefore described.29. A method of packaging a foodstuff, the method comprising the step of forming a laminated flat blank in accordance with any one of claims 1-14; folding and gluing the flat blank to forming a folded and glued partially-assembled article of packaging; erecting the partially-assembled article of packaging and inserting a foodstuff into the erected article of packaging; and closing the article of packaging by heat-sealing a lid thereto, wherein the lid may be an integral part of the laminated flat blank or may be a separate component.