EP0928273B1

EP0928273B1 - Label, tape and bundle of containers assembled by such a tape

Info

Publication number: EP0928273B1
Application number: EP97936877A
Authority: EP
Original assignee: Beleggingsmaatschappij Doorgang BV
Current assignee: Beleggingsmaatschappij Doorgang BV
Priority date: 1996-08-21
Filing date: 1997-08-19
Publication date: 2001-04-25
Anticipated expiration: 2017-08-19
Also published as: NL1003841C2; EP0928273A1; AU3953697A; ATE200769T1; DE69704665D1; DE69704665T2; WO1998007635A1

Abstract

The invention concerns a label to be applied on a container which label comprises a polymeric substrate at one side printed and at the other side to be applied onto the container coated with an adhesive for which label the adhesive is a pressure sensitive adhesive which label is to be obtained from a roll. The invention also relates to a tape to be used to assemble two or more containers, which tape is printed in the same way as the label above-mentioned. By using the tape, an assembly of two or more containers can be obtained which containers can be joined by using the tape. The invention also concerns a process for the production of the label and tape and a method to apply the label or tape on a container.

Description

The invention relates to a label to be applied onto a container, said label comprises a polymeric substrate at one side printed and at the other side to be applied onto the container, coated with a pressure sensitive adhesive, wherein said label is to be obtained from a roll. The invention further relates to a tape to be used to assemble two or more containers and to an assembly of two or more containers joined by an envelope. The invention also relates to a method for producing such an adhesive tape or label.

European patent application 0 673 839 relates to a method and an apparatus for handling linerless label material wherein the tape of a roll per se is conventional and comprises a substrate, such as plastic or paper, with a pressure sensitive adhesive side or face, and a release material coated face which will not stick to the pressure sensitive adhesive on said face.

U.S. patent 5.375.752 relates to an apparatus for facilitating tear off of linerless labels from a web of linerless labels, the label web having a pressure sensitive adhesive face and a non-adhesive face.

International patent application WO 96/15907 relates to a linerless label printing apparatus, wherein a strip of linerless label material having an adhesive side and a non-adhesive side is dispensed from a roll of material and is advanced through a label of strip guide.

According to US-A-4,544,194 containers such as bottles, cans and other vessels, in particular filled with a liquid, preferably a beverage, had been marketed as a pack of several containers, for example a pack of six cans, bundled by means of a foil of a reinforced polymer. A drawback of such a pack was that as soon as one of the cans is removed from the pack, the connection between the cans was lost and the remaining pack only consists of five separate cans in an envelope, whereby the cans can freely move with respect to each other, so that the envelope has lost its function. These problems have been solved according to said US patent by using a carrier together with a band and a web such that an assembly of at least two bottles can be packed together. However, such a carrier configuration will cost a hugh amount of polymers and produces a hugh amount of waste and the problem at least partly remains when one bottle is removed from the package so that the remaining pack of bottles can really move with respect to each other. A comparable solution has been disclosed in DE 296 03 563 Ul according to which several containers and boxes have been brought together by using a collecting element (14), a top element (16) and a band (18).

According to DE 295 12 594 U1 several boxes have been brought together by using a tape, which tape has been produced on basis of a paper or polymer comprising material. If one uses a tape on basis of a substrate of polymer, then a backing material is used from which the label or tape can be released. This system in which a label has been used removed from a backing material causes a hugh amount of waste especially the backing material for which usually paper has been used coated with silicon.

In practice one also uses wraparound labels, having no pressure sensitive adhesive coating which labels are supplied as printed reels, and applied with special machines, where the individual label is cut away from the reel, and applied onto the container or where the machine itself has previously applied a wax-like material (hot-melt) on the entire area of contact with the item to be labelled, or, more recently, on longitudinal or transversal strips.

A drawback of these wraparound labels is that the hot-melt coating has to be applied with machines, although inherently fast (30,000 - 40,000 bottles/minute on standard 1.5 litre soft drink PET bottles), using a hot-melt coating station. This station causes significant safety and contamination problems, because the heated unit poses significant hazards for machine operators and maintenance personnel and the possibility of leakages and sprays of the melted waxy material contained in the applicator unit poses contamination problems unacceptable for modern food industry standards.

According to another known system one uses pre-cut self-adhesive labels. These labels are supplied as pressure sensitive adhesive facestock material, generally printed on the outside, and laminated to a silicone-coated release liner or "backing" material (usually paper). Such labels are pre-cut in their final shape, and they are removed from the release liner and applied onto the surface of the items to be labelled. A drawback of these labels is that the material is a thick laminate and the release material is discarded after application. This gives a waste of material, and causes recyclability/recoverability problems. That system is intrinsically slow and is reasonably suited for medicine droppers, small bottles, or small-size items. The full coverage of adhesive poses problems when applying labels on big items; these problems are typically wrinkles, entrapment of bubbles of air between the label and the item to be labelled.

These problems have been solved now by a label according to the invention and this label comprises a polymeric substrate at one side printed and at the other side to be applied on the container, coated with a pressure sensitive adhesive, wherein said label is to be obtained from a roll, characterized in that the substrate is of a bi-oriented polypropylene and that the adhesive is a water-soluble pressure sensitive adhesive based on an acrylic polymer.

On basis of the same system a label has been developed which is printed such that it can be used as a tape to assemble two or more containers. With such a tape it is possible to assemble two or more containers in such a way that the printed area on the tape has the function of the printed text on a label while at the other side the tape can be used to assemble two or more containers.

The label material is a plastic film such as a bi-oriented polypropylene that has been surface printed or reverse printed, then coated with a pressure sensitive coating, applied by conventional methods such as hot-melt coating, solvent coating, or aqueous emulsion coating.

This coating can be applied with full coverage of the label surface or only in selected areas (patterned coating).

The adhesive formulation can be a "permanent" one, to be used on bottles or items where the label cannot be removed, due to safety or security reasons (medicine, etc.). Otherwise, the formulation can be "removable", to be used on bottles or items where the label must be easily removed, for recycle/recovery purposes.

The printed/coated adhesive material is wound on itself without the need of a release layer.

The outside of the plastic material has peculiar characteristics that renders unwinding very easy without possibility of removal of the adhesive layer from the surface it was applied upon. Because of this characteristic the material can also be used as a tape to assemble containers such as bottles according to the invention which self-adhesive tape is provided around a part of the circumference and over a part of the height of each container forming part of the assembly. Such an unprinted adhesive tape can be provided over the labels of the containers in such a manner that the label remains clearly legible. It also is possible that the tape is printed and can be used as a label.

According to a preferred embodiment the assembly consists of three or more bottles filled with a beverage, in particular a soft drink, which bottles are made of polyethylene terephthalate.

The use of an adhesive tape for joining packaging units made of for example cardboard into one unit is known per se from WO 94/00362. Said patent application does not provide any information with regard to a specific adhesive tape to be used with containers as aimed at by the present invention, nor is the tape used according to the said publication provided with a handle.

The invention will be explained in more detail in the following description, wherein reference is made to the accompanying drawing, in which:

Figure 1 shows an assembly according to the invention, in which three bottles are joined in the form of a triangle; and

Figure 2 shows a comparable assembly, in which the three bottles are placed in side-by-side relationship, however.

Figures 1 and 2 show the bottles indicated by numerals 1-3 joined into an assembly by means of adhesive tape 4. A handle 5 is incorporated in said adhesive tape, which handle 5 is made of a material different from that of tape 4. In particular it is possible to produce handle 5 of a material which functions as a substrate for the adhesive tape. The labels on the bottles may remain visible in at least two manners, by making the adhesive tape transparent or by printing the adhesive tape in such a manner that the printed tape coincides with the text present on the labels of the bottles. In that case the text on the adhesive tape must to that end be adapted to the text and the illustration of the labels of the bottles or containers and be provided round the containers with precision.

The material of the adhesive tape, that is the substrate and the adhesive, must be adapted to the material of which the bottles or containers are made. The adhesive tape must be self-adhesive, which means that when one bottle is removed from the assembly, the adhesive tape can be readily opened by means of a strip provided thereon without damaging the labels on the bottles, the bottle to be used can be removed from the assembly, after which the adhesive tape can be provided around the remaining bottles again. Although the assembly shown in the drawing is limited to three bottles, it will be apparent that such an assembly may also consist of two, four or more bottles.

Experiments have shown that when the containers are made of polyethylene terephthalate (PET), it is to be preferred to make the tape of a substrate consisting of a film of bi-oriented polypropylene, to which an adhesive on the basis of an aqueous composition of an acryl polymer has been applied.

The method for producing the adhesive tape according to the invention is characterized in that said substrate of a bi-oriented polypropylene is in the form of a film and that said adhesive is a water soluble pressure sensitive adhesive based on an acrylic polymer and applied thereto by means of a smooth roller, which rotates in the same direction as the direction of movement of the film, that the adhesive is applied by having said roller rotate in a vessel filled with an aqueous emulsion of adhesive, that excess adhesive is removed, so that a layer of adhesive having a thickness of 15-50 g/m² remains after drying, with the solid matter content of said layer being 30-70 % by weight. Preferably the amount of adhesive is 20-40 g/m². If a print is provided on the adhesive tape, the substrate is first provided with said print, after which said layer of adhesive is applied to said print, so that the text or the illustration is screened by the substrate on the outside.

Furthermore it is to be preferred to provide a bar code during printing, so that the price of the assembly can be read at a cash-desk. In order to prevent errors by reading a bar code it may be preferred to make it impossible to decode the bar code provided on the separate containers, possibly by means of the print present on the adhesive tape. With the term "to decode" is meant that the bar code can be read out.

The invention will be explained in more detail below by means of the following examples.

Example 1

In order to produce a printed adhesive tape a 40 µm thick tensilized film of bi-oriented polypropylene was provided with a print by means of a flexography press, using a polyamide-based ink. Said ink is commercially available from Sun Chemical under the designation PM 214. An adhesive was applied to the printed side of said printed film by means of a roll coater. Said roll coater rotated through a bath filled with an adhesive consisting of an aqueous dispersion of modified acryl polymer, which is commercially available from Rohm & Haas under the designation PS 6120. The adhesive was applied to the film by having the roll coater rotate in the vessel, with the film being moved over the roll coater in the same direction as the direction of rotation of said roll coater. The excess amount of adhesive was removed from the film by means of a Mayer bar, resulting in an amount of 15 g/m² of adhesive on the film after drying. The adhesive tape thus obtained was cut to a width of 10 cm and affixed to PET bottles provided with polyethylene labels, which were provided with a print on the outside. The adhesive tape could be affixed to said labels in a self-adhesive manner and be removed therefrom, which operation could be carried out repeatedly without the label on the bottle being damaged.

For comparison an adhesive tape was produced in a conventional manner by means of a 40 µm thick PVC film, whereby a conventional natural rubber adhesive in a solvent was applied. Said adhesive tape was also cut to a width of 10 cm and affixed to the PET bottles as described above.

When using the adhesive tape used by way of comparison it became apparent that said comparative tape was difficult to remove from the roll on which the tape has been wound and that the packaging speed obtained when using said comparative tape was low, namely 30 two-bottle assemblies per minute. Removal of the adhesive tape from the bottles immediately resulted in damage to the printed surface of the labels, in some cases even in the label being pulled from the bottle.

When on the other hand the adhesive tape according to the invention was used, it became apparent that said adhesive tape could be readily removed from the roll on which the adhesive tape was present and that said adhesive tape could be readily placed on the winding machine. Packaging appeared to be possible at a production speed of 65 assemblies per minute with smooth and jamming-free operation. On removing a bottle from the assembly it appeared to be readily possible to remove the adhesive tape from the bottles without damaging the polyethylene labels, although the adhesive power of the tape ensured a stable assembly without bottles unintentionally becoming detached from the assembly.

Example 2

The method according to example 1 was repeated, whereby the same substrate was used, which substrate was in this case printed with an acryl polymer-based aqueous dispersion of an ink composition marketed by Sun Chemical under the designation Idromono. An adhesive with a base of modified acryl polymer in the form of an aqueous dispersion, which was marketed by Icap under the designation 2459/P, was applied to the printed surface. Said adhesive was applied to the film in an amount of 18 g/m². This adhesive tape was used to form an assembly consisting of three bottles as shown in Figure 2. The bottles, which were made of PET, were provided with paper labels affixed to the bottles by means of a conventional adhesive. For comparison the adhesive tape mentioned in Example 1 was used.

From the experiments that were carried out it became apparent that the speed of forming the assemblies when using the adhesive tape used for comparison was less than 25 assemblies per minute. Removal of the adhesive tape resulted in the paper labels, at least the print present thereon, being damaged and in some cases even in the paper label being pulled from the bottle.

When on the contrary the adhesive tape according to the invention was used, the speed of forming the assemblies could be increased to more than 50 assemblies per minute, with a smooth and jamming-free operation. The adhesive tape could be readily removed from the roll in order to carry out the method for forming the assemblies. When a bottle had to be removed from an assembly the adhesive tape could be readily removed from a bottle without any damage to the label being noticeable thereby, after which the adhesive tape could be affixed round the remaining two bottles. This operation could be carried out repeatedly without any problems.

Example 3 3a (state of art)

A 500-cc glass jar for medicinal products was traditionally labelled with a conventional adhesive facestock material having the following structure:

white HDPE outside printed 50 µm + 80 g/m² Kraft paper (silicone coated) release liner.

The labels were pre-cut in the conventional way, and they almost covered the entire circumference of the jar, leaving a 5 mm area free from the square label.

3b (invention)

The 500-cc jar was labelled on a wraparound machine using an adhesive material being a solvent-based 15 g/m² permanent adhesive.

The substrate was a 60 µm white pigmented bi-oriented polypropylene film gravure-printed on the outside and coated with the adhesive on the inside.

The printed surface was overlacquered with a 2 g/m² transparent varnish, to guarantee an easy unwinding of the adhesive coated roll.

The length and width of the label were equivalent to those of example 3a, with no overlapping of the label sides.

The labelling system 3a, for comparison, was intrinsically slow, never exceeding 100 bottles/minute and more than 50 % of the weight of the adhesive facestock laminate was discarded. The release liner was a silicone-coated paper, impossible to recycle with conventional systems causing scrap paper/board. Jammings of the labelling machine were frequent, due to the high tack of the adhesive formulation and the large size of the label. Machine downtime was significant and this forced to slow down the labelling operation to 60 bottles/minute.

The labelling process 3b according to the invention, was practically free from jamming. No scraps of the labelling material were produced, and the wraparound machine operated at speeds consistently in excess of 10,000 bottles/hour.

Example 4 4a (prior art)

A standard 1,5 litre straight-wall injection-blow moulded PET soft drink bottle was labelled on a wraparound machine with a 37 µm outside printed white cavitated bi-oriented polypropylene film. This reel-fed labelling machine operated with the conventional hot-melt applicator, applying 1.0 cm wide vertical strips of hot-melt (perpendicular to the web direction of motion or "longitudinal" direction). The machine overlapped the label, so as it was glued to the bottle or on itself on a vertical strip, leaving the label free to adjust to the expansion of the bottle generated by the pressure of the carbonated drink after filing.

4b (according to the invention)

With the existing machine setup, the hot-melt applicator was removed from the labelling machine, and the machine was run with a labelling material suitable for the process according to the invention.

This material was a 35 µm transparent bi-oriented polypropylene film, reverse printed by rotogravure and coated with a patterned coating of removable acrylic-based aqueous emulsion adhesive (15 g/m² on the coated areas),

The coating pattern was a transversal stripe, perpendicular to the web direction of motion, 1 cm wide, in register with the cut position of the label.

On the labelling line, half of this adhesive area glued on the bottle, and half on it glued on itself after overlapping of the two label sides, leaving the bottle free to expand as in the previous reference example.

The results were that according to example 4a the contamination from sprays of hot-melt was a major drawback. Some sprays contaminated the empty bottles to be labelled, increasing the amount of scrapped bottles in the subsequent automated bottle inspection process. In some cases, the hot-melt applicator lost its register control, the hot-melt was applied in the wrong area of the label, generating scraps and machine downtime. During the operation on the jammed machine, the risk of severe burns and injuries was high, due to the necessity to remove crap label materials clinging to the hot glue applicator surfaces.

The same machine, operating in accordance to the process described in this invention, (4b) reached a 40.000 bottles/hour speed, without machine downtime, no jammings, and a much cleaner operation. Moreover, some energy saving were the result of the fact that the hot-melt applicator unit was switched off. Start-up of the machine was much quicker due to the fact that there was no need to warm up the hot-melt applicator. The labels were easily removed from the used bottles to be recycled via a simple mechanical process, without the need of costly processes that foresee the use of steam or solvents.

Example 5 5a (prior art)

A 5 litre injection blow moulded container, made of HDPE, was labelled with a conventional adhesive label being a calendered coated paper (120 g/m²) + 80 g/m² silicone coated release paper.

The labels were pre-cut in the conventional way and the labelling machine placed them in a circumferential recessed area on the side of the container. The size of the label was 400 mm x 150 mm.

5b (according to the invention)

The same 5 litre HDPE container was labelled on a labelling machine (produced by Gandini S.p.A. of Italy, owner of the trademark Twin Pack) with an adhesive material being a hot-melt pressure sensitive adhesive. The substrate of the label was a 50 µm white pigmented bi-oriented polypropylene film gravure-printed on the outside surface, coated on the inside surface with 20 g/m² hot-melt pressure sensitive adhesive. The outside of the adhesive material was overlacquered with a proper release coating in order to guarantee the correct and even unwinding of the reel-fed adhesive label.

The label was cut and applied by the labelling machine on the same recessed area of the container.

Due to the large size of the label in example 5a, the number of misplaced label was relatively high. Intrinsically, the labelling process was slow, never exceeding 30 labels per minute. Disposal of the discarded release paper was a further problem; overall, label scraps and release paper weight was higher than the one of the labels successfully applied.

Conversely the labelling technique described in example 5b allowed a jamming-free operation at speeds of 50-60 labels per minute.

Claims

Label to be applied onto a container, said label comprises a polymeric substrate at one side printed and at the other side to be applied onto the container, coated with a pressure sensitive adhesive, wherein said label is to be obtained from a roll, characterized in that the substrate is of a bi-oriented polypropylene and that the adhesive is a water-soluble pressure sensitive adhesive based on an acrylic polymer.
Label according to claim 1 characterized in that said label is printed such that it can be used as a tape to assemble two or more containers.
Assembly of two or more containers joined by an envelope, characterized in that the envelope consists of a tape according to claim 2.
Assembly according to claim 3, characterized in that the tape comprises a handle provided in or on said tape.
Assembly according to claim 3, characterized in that the tape is self-adhesive and can be re-used after being provided and removed.
Assembly of two or more containers according to claims 3-5, characterized in that said tape is provided around a part of the circumference and over part of the height of each container forming a part of the assembly.
Assembly according to claims 3-6, characterized in that said tape is transparent over a substantial portion of its surface area.
Assembly according to claims 3-7, characterized in that said assembly consists of two or more bottles preferably made of polyethylene terephthalate.
Label or tape according to claims 1-2, characterized in that said tape is self-adhesive and can be re-used after being provided and removed.
Label or tape according to claims 1-2, characterized in that said adhesive is an aqueous modified acryl polymer.
Label or tape according to claims 1-2 and 9, characterized in that the amount of the adhesive is 15-50 g/m² after drying the adhesive to a solid matter content of 30-70 % by weight.
Label or tape according to claims 1-2 and 9-11, characterized in that the thickness of the film is 8-100 µm.
Label or tape according to claim 12, characterized in that the thickness of the film is 20-60 µm.
Label or tape according to claims 1-2 and 9-13, characterized in that a bar code is provided on said label or tape, and that decoding of the bar code on the individual containers can be made impossible by means of a print present on said adhesive tape.
Tape according to claims 2 and 9-14, characterized in that said tape is provided with a strip for opening the tape.
A process for wraparound application of a label or a tape according to claim 1 or according to claim 2 on a container, characterized in that the label or the tape is supplied in rolls, the individual label or tape is cut by the labelling machine and applied onto the container(s) to be labelled or taped.
A process according to claim 16, characterized in that a bottle is used in the container.
A process for producing an adhesive tape obviously intended for a label according to claim 1 or for a tape according to claim 2 by applying a layer of an adhesive on a substrate, characterized in that said substrate is of a bi-oriented polypropylene and in the form of a film and that said adhesive is a water soluble pressure sensitive adhesive based on an acrylic polymer and applied thereto by means of a smooth roller, which rotates in the same direction as the direction of movement of the film, that the adhesive is applied by having said roller rotate in a vessel filled with an aqueous emulsion of adhesive, that excess adhesive is removed, so that a layer of adhesive having a thickness of 15-50 g/m² remains afer drying, with the solid matter content of said layer being 30-70 % by weight.
A process according to claim 18, characterized in that the amount of adhesive is 20-40 g/m².
A process according to claims 16-19, characterized in that first a print is provided on said substrate, after which said layer of adhesive is applied to said printed substrate.
A method according to claims 16-20, characterized in that said adhesive tape or label is wound on a roll.