SE1550147A1 - Labeled container - Google Patents

Abstract

A labeled container and a method of producing a labeled container are presented. The method of producing the labeled container comprises: arranging a sleeve of stretchable paper material within a mold and establish a clearance between the sleeve and the mold; and blow molding a plastic preform within the mold to form the container such that the expansion of the preform stretches the sleeve at least partly around the circumference of the container.(Fig id)

Description

LABELED CONTAINER TECHNICAL FIELD The present disclosure generally relates to a labeled container and to amethod of producing a labeled container. In particular, a blow moldedcontainer with a stretchable paper sleeve and a method of producing the labeled container with blow molding are described.

BACKGROUND US 2002166833 A1 discloses a process for making a labeled plastic containerusing a stretch blow molding process wherein a polymer label sleeve ispositioned over at least a portion of the exterior surface of a preform toproduce a sleeved preform and the sleeved preform is stretch blow molded to produce a labeled container having a snug-fit label.

With the labeling process of US 2002166833 A1, it is difficult to correctlyposition the label sleeve on the preform and the label sleeve is subjected to arather high stretch. The high stretch required of the label sleeve practicallylimits the material selection to plastics and it is difficult to make the distorted printing on the preform to correctly expand into the desired printing.

Although US 2002166833 A1 suggests that the label sleeve diameter can bemade significantly larger than the diameter of the preform in order toimprove print quality, the label sleeve does not give sufficient support to thecontainer. Consequently, a high amount of plastic is required in the containerresulting in a large total weight and an increased environmental burden.

Additionally, the thermal isolation provided by the label sleeve is low.

SUMMARY Accordingly, there is a need for improvements related to labeled containersand their production. In particular, there is a need for a labeled containerwith a fast and reliable production, high freedom of design, high rigidity, lowweight, low environmental load, high user friendliness and a wide range of printing possibilities.

A method of producing a labeled container is provided, wherein the methodcomprises arranging a sleeve of stretchable paper material within a mold,establish a clearance between the sleeve and the mold, and blow molding aplastic preform within the mold to form the container such that theexpansion of the preform stretches the sleeve at least partly around the circumference of the container.

The container may for example be a bottle, such as bottles for beverages, oliveoils, ketchup and liquid detergents. Alternatively, the container may be a jar,such as jars for pharma, foods and cosmetics or a yoghurt cup. The containermay have a neck smaller than its body. Alternatively, the container may havea “wide mouth”. The width of the “wide mout ” may substantially correspondto the width of the body. The container may be any type of package. Onesuitable material for the container is PET. Thus, a typical example of container is a PET-bottle.

The neck or mouth of the container may have a screw thread for attaching a cap. This screw thread may be provided already on the preform.

The exterior profile of the container may include one or more inclinedportions and/ or bulges. For example, the exterior profile of the containermay be wave formed. Alternatively, or in addition, the container may becylindrical, conical, pyramidal or spherical. The cross section of the containermay for example be circular, triangular, square or polygonal. The weight of the container may be 3-80 grams, such as 5-20 grams, for example 8 grams.

The rigidity of the sleeve enables the thickness of the container (i.e., thecontainer without the sleeve) to be reduced. Thus, the amount of plastic (i.e.,non-renewable material) in the container may be reduced without reducingthe overall stability of the labeled container. One type of stability may be thegrip stiffness. Since the density of the sleeve is typically lower than thedensity of plastics such as PET, also the overall weight of the labeled container could possibly be reduced.

As a further consequence of reducing the amount of plastic, the cooling timeafter the injection molding of the preform and after the blow molding of thecontainer is shortened. The cooling times are the most time consuming stepin many blow molding processes. Thus, also the production costs are reduced in this manner.

The container may shrink somewhat When cooling after the blow molding.Due to the elasticity of the paper material in the sleeve, the sleeve springsback and follows the shrinkage of the container during cooling and stays fully attached to the container.

The stretchability of the paper may be at least 5 % in both the machinedirection (MD) and the cross direction (CD). For example, it may be at least 6or 7 % in both directions. In one embodiment, it is at least 7 % CD and at least14 % in the MD. An example of a stretchable paper suitable for being usedwith the present disclosure is FibreForm® marketed by BillerudKorsnäs AB.The stretchability may for example be measured according to standard ISO1924-3. The grammage of the paper may for example be 50-500 g / m2, suchas 80-150 g/ m2.

When the sleeve is attached to the container, the container is regarded as asleeved or labeled container. The sleeve may be a paper sheet composed of asingle layer. However, it may also be a laminate composed of a plurality ofpaper layers, such as two, three or four layers. The paper sheet may thus be a paperboard sheet or a cardboard sheet.

The paper sheet of the sleeve may also be coated with one or more coatinglayers having one or more barrier properties, for example a plastic coatingagainst moisture. Alternatively or as a complement, a film having one ormore barrier properties may be glued to the paper sheet to form a barrier layer.

The sleeve may have a substantially cylindrical or substantially conicalappearance. It may be provided as a banderole or label tube around the container. One or more sleeves may be provided around the container. In case several sleeves are used, the stretch in these sleeves may differ, forexample due to attachment on container regions of different diameter.

Alternatively, the sleeve may enclose substantially the entire container.

The sleeve may fully encircle the container around its central axis. In thiscase, two ends of the stretchable paper material may be glued together, orotherwise attached, to form the sleeve. Alternatively, the sleeve may onlypartially encircle the container by having a circumferential extension of atleast 2oo°. The sleeve may be printed either before or after the blow molding process.

According to one variant, the sleeve is only partly constituted by stretchablepaper material along a central axis of the container, or along thecircumference of the container. For example, the sleeve may be constitutedby two portions of stretchable paper material and an intermediate non-stretchable material in an alternating manner along the central axis of thecontainer. Such sleeve may be used together with a corresponding mold thatprevents the intermediate non-stretchable material from being broken duringthe blow molding. For example, the mold may in this case have anappearance similar to an hourglass where the waist of the hourglass preventstensioning of the non-stretchable material of the sleeve during the blow molding.

Furthermore, such intermediate non-stretchable material may be providedwith additional properties, such as a further reduced weight and/ or a higher rigidity compared to the stretchable paper material of the sleeve.

However, in case the entire sleeve is constituted by a stretchable papermaterial, only one or some regions of the sleeve, as seen along the central axisof the container, may be stretched during the blow molding. For example, incase a container with a wave profile is blow molded, the sleeve is stretched inregions adjacent the peaks of the wave profile and is not stretched, or stretched less, in regions adjacent the valleys of the wave profile.

When the sleeve is arranged within the mold, the clearance between thesleeve and the mold constitutes a space allowing the sleeve to be stretchedoutwards, away from the center of the container. For example, the clearanceis a radial clearance. The size of the clearance largely depends on the final dimensions of the container. For example, the clearance may be 1-30 mm.

The sleeve may be arranged in the center of the mold, e.g. concentricallyarranged. Alternatively, the sleeve may be laterally offset within the mold. Itis possible to arrange the sleeve in contact with the mold prior to moldingand also to carry out the blow molding with the sleeve in this position. Thus,the clearance does not have to be provided around the entire circumference of the sleeve. More than one clearance may also be provided.

By stretching the sleeve around the container, the sleeve is attached to thecontainer. Thus, no gluing is required between the sleeve and the container.The stretchability of the sleeve also allows it to follow any shape of thecontainer. Thus, in contrast to a non-stretchable paper sleeve, the sleeve ofstretchable paper material does not need a smooth area for attachment to the container.

The sleeve of stretchable paper material also smoothes out thin regions of theblow molded container in contact with the sleeve. Thereby, the sleeveprevents thin regions of the container to get a wobbly surface by the blow molding.

The material of the preform may be selected in dependence of the blowmolding process and the desired characteristics of the container. The preformmay be an injection molded or extrusion molded plastic tube, e.g. of polymermaterial. Any preform mentioned in US 2002166833 A1 may be used. Thepreform may be produced separately from (e.g. by a different company), or inimmediate connection with (e.g. in the same production line or with the same machine), the blow molding process.

The preform may be heat conditioned prior to the blow molding. For example, the preform may be heated to a temperature of 100-120 °C. The heat conditioning may also be a cooling of the preform, for example when thepreform has a high temperature (such as 300 °C) from an injection molding process.

According to one variant, the heat conditioning is varied at different portionsof the preform to influence the stretch properties of the final container. Forexample, the lower part of the preform may be controlled to have a higher temperature than the upper part of the preform.

Thus, both the heating of the preform and the interior shape of the mold may be varied to obtain a particular shape of the container.

The mold may be openable and closable. This may be realized by hingedattachments between two or more mold parts. According to one realization,the mold is constituted by a left part, a right part and a bottom part. The leftpart and the right part may be hingedly attached. The bottom part may behinged to one of the left part and the right part. Alternatively, the bottom partmay be raised or lowered independently of the remaining parts. In this case,the left part and the right part may enclose the bottom part. The mold maycontain any combination of reliefs, embossings and patterns for shaping the sleeve and/ or the container.

The blow molding may be carried out by blowing air of sufficient pressureinto the preheated preform. The mold cools the container when this (or thesleeve) contacts the mold during the blow molding. This cooling effect may beaccomplished by a using a mold material with high thermal conductivity and/ or with a cooling arrangement.

Prior to starting the blow molding, the sleeve may be fixed relative to thepreform and/ or the mold. This may be realized by indexing arrangements onthe preform and/ or on the mold. As an example, the label is fixed with an indexing arrangement at a bottom part of the mold.

The indexing arrangement may be movable, i.e. retractable away from the mold. This movement may be synchronized with the blow molding process in order to maintain the sleeve in its proper position as long as possible while atthe same time avoiding interference between the expanding preform and the indexing arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS Further details, advantages and aspects of the present disclosure will becomeapparent from the following embodiments taken in conjunction with the drawings, wherein: Figs. 1a-1e illustrate a method of producing a labeled container in theform of a bottle; Fig. 2 shows a labeled container in the form of a yoghurt cup; Fig. 3 shows a labeled container in the form of a bottle with twosleeves provided around the bottle; and Fig. 4 shows a labeled container with a wave formed exteriorprofile.

DETAILED DESCRIPTION In the following, several embodiments of the labeled container and the method of producing the labeled container will be described.

Figs. 1a-1e show a method of producing a labeled container in the form of abottle. Fig. 1a shows the mold with substantially smooth interior surfaces.Although the mold is illustrated as being rigid, it may be openable andclosable in various ways. For example, the mold may be constituted by a leftpart, a right part and a bottom part, as described above. In the illustratedclosed condition, the mold has a threaded portion corresponding to the threads of the container to be formed.

Fig. 1b shows a sleeve of stretchable paper material arranged substantiallyconcentrically within the mold. In this embodiment, the sleeve is asubstantially cylindrical tube. A radial clearance is established between the sleeve and the mold around the entire circumference of the sleeve. Upon insertion of the sleeve into the mold, the mold may open and/ or the sleeve may be folded.

Fig. 1c shows a PET preform being inserted into the opening of the mold. The preform has a temperature of about 110 °C.

Fig. 1d shows the blow molding of the preform. With pressurized air, theheated preform is blown against the interior of the mold. When theexpanding preform contacts the interior of the sleeve, also the sleeve starts tostretch radially outwards towards the interior of the mold along the clearancebetween the sleeve and the mold. Upon contact with the mold interior, the blown container is cooled.

When the blow molding is completed, the sleeve is stretched around thecircumference of the bottle to form a labeled bottle. Due to this stretch, thesleeve stays attached to the bottle. The stretched sleeve adds rigidity to thebottle. Thereby, the overall thickness and weight of the bottle (i.e., the bottle without the sleeve) may be reduced.

Fig. 1e shows the bottle ejected from the mold to cool. The heated bottle mayshrink somewhat during cooling. Due to the elasticity of the paper material insleeve, the sleeve stays firmly attached to the bottle when shrinking. Thebottle may then be further processed as desired. For example, the sleeve maybe printed (if not previously done), the bottle may be filled and a cap may beattached. Any of these steps may be performed in the same production line or at a different location.

Fig. 2 shows a labeled container in the form of a yoghurt cup, which is onetype of a so-called “wide mouth” container. Both the yoghurt cup and thesleeve have a substantially conical appearance. The conical sleeve may beformed from a sleeve with substantially cylindrical appearance prior to theblow molding. In this case, after the blow molding, the stretch of the papermaterial in the sleeve varies substantially linearly along the longitudinaldirection of the yoghurt cup. Thus, the stretch is highest at the largest diameter of the sleeve.

As an alternative, the sleeve may be conical already prior to the blowmolding. In this case, the stretch of the sleeve may be substantially equal along the longitudinal direction of the yoghurt cup.

Fig. 3 shows a labeled container in the form of a bottle with two separatesleeves of stretchable paper material stretched around the circumference ofthe bottle. Here, the two sleeves are separated along the longitudinal axis ofthe bottle. The two sleeves of stretchable paper material in Fig. 3 may beinterconnected by a section of non-stretchable material. This section of non-stretchable material may have a wider diameter than the two sleeves of stretchable paper material prior to the blow molding.

Fig. 4 shows a labeled container in the form of a bottle with a wave formedexterior profile along the longitudinal axis of the bottle. A sleeve ofstretchable paper material is provided around the circumference of the bottle.Due to the larger diameter of the peaks of the wave profile, the sleeve isstretched more at these regions. Thus, the stretch in these regions makes thesleeve staying on the bottle and the entire sleeve adds rigidity to the bottle. Inthe valleys of the wave profile, the sleeve is not stretched. However, asmentioned above, a certain stretch may also be provided in the valleys of the wave profile.

While the present disclosure has been described with reference to exemplaryembodiments, it will be appreciated that the present invention is not limitedto what has been described above. It will, for example, be appreciated that thedimensions of the parts may be varied as needed. Accordingly, it is intendedthat the present invention be limited only by the scope of the claims appended hereto.

Claims (9)

1. Method of producing a labeled container, the method comprising: - arranging a sleeve of stretchable paper material within a mold and establish a clearance between the sleeve and the mold; and - blow molding a plastic preform within the mold to form the containersuch that the expansion of the preform stretches the sleeve at least partly around the circumference of the container.

2. The method according to claim 1, wherein the stretchability of thestretchable paper material is at least 5 % in the machine direction (MD) and at least 5 % in the cross direction (CD).

3. The method according to claim 1 or 2, wherein the sleeve is made ofFibreForm®.

4. The method according to any of the preceding claims, wherein the container and the sleeve have a conical appearance.

5. The method according to any of the preceding claims, wherein theplastic preform contains threads that are substantially undeformed during the blow molding.

6. The method according to any of the preceding claims, wherein only oneor more partial regions of the sleeve are stretched by the expansion of the preform.

7. The method according to any of the preceding claims, wherein thesleeve is only partly constituted by the stretchable paper material along the central axis of the container, or along the circumference of the container.

8. A container produced according to any of the preceding claims.

9. A blow molded container comprising a stretched sleeve of paper material.