SE1550147A1

SE1550147A1 - Labeled container

Info

Publication number: SE1550147A1
Application number: SE1550147A
Authority: SE
Inventors: Hein Van Den Reek
Original assignee: Billerudkorsnaes Ab
Priority date: 2015-02-10
Filing date: 2015-02-10
Publication date: 2015-02-10
Also published as: WO2016130071A1

Description

1O 15 20 25 A method of producing a labeled container is provided, wherein the method comprises arranging a sleeve of stretchable paper material within a mold, 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.

The container may for example be a bottle, such as bottles for beverages, olive oils, ketchup and liquid detergents.A1ternatively, the container may be a jar, such as jars for pharma, foods and cosmetics or a yoghurt cup. The container may have a neck smaller than its body. Alternatively, the container may have a "wide mouth". The width of the "wide mouth" may substantially correspond to the width of the body. The container may be any type of package. One suitable 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 inclined portions and/ or bulges. For example, the exterior profile of the container may be wave formed. Alternatively, or in addition, the container may be cylindrical, conical, pyramidal or spherical. The cross section of the container may 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., the container without the sleeve) to be reduced. Thus, the amount of plastic (i.e., non-renewable material) in the container may be reduced without reducing the overall stability of the labeled container. One type of stability may be the grip stiffness. Since the density of the sleeve is typically lower than the density of plastics such as PET, also the overall weight of the labeled container could possibly be reduced. 10 15 20 25 30 As a further consequence of reducing the amount of plastic, the cooling time after the injection molding of the preform and after the blow molding of the container is shortened. The cooling times are the most time consuming step in 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 springs back 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 machine direction (MD) and the cross direction (CD). For example, it may be at least 6 or 7 % in both directions. In one embodiment, it is at least 7 % CD and at least 14 % in the MD. An example of a stretchable paper suitable for being used with the present disclosure is FibreForm® marketed by BillerudKorsnäs AB.

The stretchability may for example be measured according to standard ISO 1924-3. The grammage of the paper may for example be 50-500 g /m2, such as 80-150 g/ m2.

When the sleeve is attached to the container, the container is regarded as a sleeved or labeled container. The sleeve may be a paper sheet composed of a single layer. However, it may also be a laminate composed of a plurality of paper 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 coating layers having one or more barrier properties, for example a plastic coating against moisture. Alternatively or as a complement, a ﬁlm having one or more barrier properties may be glued to the paper sheet to form a barrier layer.

The sleeve may have a substantially cylindrical or substantially conical appearance. It may be provided as a banderole or label tube around the container. One or more sleeves may be provided around the container. In 10 15 20 25 case several sleeves are used, the stretch in these sleeves may differ, for example 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 this case, two ends of the stretchable paper material may be glued together, or otherwise attached, to form the sleeve. Alternatively, the sleeve may only partially encircle the container by having a circumferential extension of at least 2o0°. The sleeve may be printed either before or after the blow molding process.

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

Furthermore, such intermediate non-stretchable material may be provided with 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 paper material, only one or some regions of the sleeve, as seen along the central axis of the container, may be stretched during the blow molding. For example, in case a container with a wave profile is blow molded, the sleeve is stretched in regions adjacent the peaks of the wave profile and is not stretched, or stretched less, in regions adjacent the valleys of the wave profile. 1O 15 20 25 30 When the sleeve is arranged within the mold, the clearance between the sleeve and the mold constitutes a space allowing the sleeve to be stretched outwards, away from the center of the container. For example, the clearance is 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. concentrically arranged. Alternatively, the sleeve may be laterally offset within the mold. It is possible to arrange the sleeve in contact with the mold prior to molding and 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 the container. Thus, no gluing is required between the sleeve and the container.

The stretchability of the sleeve also allows it to follow any shape of the container. Thus, in contrast to a non-stretchable paper sleeve, the sleeve of stretchable 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 the blow molded container in contact with the sleeve. Thereby, the sleeve prevents 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 blow molding process and the desired characteristics of the container. The preform may be an injection molded or extrusion molded plastic tube, e.g. of polymer material. Any preform mentioned in US 2002166833 A1 may be used. The preform may be produced separately from (e.g. by a different company), or in immediate 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 10 15 20 25 heat conditioning may also be a cooling of the preform, for example when the preform has a high temperature (such as 300 °C) from an injection molding process.

According to one variant, the heat conditioning is varied at different portions of the preform to inﬂuence the stretch properties of the final container. For example, 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 hinged attachments 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 left part and the right part may be hingedly attached. The bottom part may be hinged to one of the left part and the right part. Alternatively, the bottom part may 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 may contain 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 pressure into the preheated preform. The mold cools the container when this (or the sleeve) contacts the mold during the blow molding. This cooling effect may be accomplished 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 the preform and/ or the mold. This may be realized by indexing arrangements on the 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 1O 15 20 25 order to maintain the sleeve in its proper position as long as possible while at the 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 become apparent from the following embodiments taken in conjunction with the drawings, wherein: Figs. 1a-1e illustrate a method of producing a labeled container in the form 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 two sleeves provided around the bottle; and Fig. 4 shows a labeled container with a wave formed exterior profile.

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 a bottle. Fig. 1a shows the mold with substantially smooth interior surfaces.

Although the mold is illustrated as being rigid, it may be openable and closable in various ways. For example, the mold may be constituted by a left part, a right part and a bottom part, as described above. In the illustrated closed 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 substantially concentrically within the mold. In this embodiment, the sleeve is a substantially cylindrical tube. A radial clearance is established between the sleeve and the mold around the entire circumference of the sleeve. Upon 10 15 20 25 30 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, the heated preform is blown against the interior of the mold. When the expanding preform contacts the interior of the sleeve, also the sleeve starts to stretch radially outwards towards the interior of the mold along the clearance between 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 the circumference of the bottle to form a labeled bottle. Due to this stretch, the sleeve stays attached to the bottle. The stretched sleeve adds rigidity to the bottle. 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 may shrink somewhat during cooling. Due to the elasticity of the paper material in sleeve, the sleeve stays firmly attached to the bottle when shrinking. The bottle may then be further processed as desired. For example, the sleeve may be printed (if not previously done), the bottle may be filled and a cap may be attached. 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 one type of a so-called "wide mout " container. Both the yoghurt cup and the sleeve have a substantially conical appearance. The conical sleeve may be formed from a sleeve with substantially cylindrical appearance prior to the blow molding. In this case, after the blow molding, the stretch of the paper material in the sleeve varies substantially linearly along the longitudinal direction of the yoghurt cup. Thus, the stretch is highest at the largest diameter of the sleeve. 1O 15 20 25 As an alternative, the sleeve may be conical already prior to the blow molding. 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 separate sleeves of stretchable paper material stretched around the circumference of the bottle. Here, the two sleeves are separated along the longitudinal axis of the bottle. The two sleeves of stretchable paper material in Fig. 3 may be interconnected 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 formed exterior profile along the longitudinal axis of the bottle. A sleeve of stretchable paper material is provided around the circumference of the bottle.

Due to the larger diameter of the peaks of the wave profile, the sleeve is stretched more at these regions. Thus, the stretch in these regions makes the sleeve staying on the bottle and the entire sleeve adds rigidity to the bottle. In the valleys of the wave profile, the sleeve is not stretched. However, as mentioned 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 exemplary embodiments, it will be appreciated that the present invention is not limited to what has been described above. It will, for example, be appreciated that the dimensions of the parts may be varied as needed. Accordingly, it is intended that the present invention be limited only by the scope of the claims appended hereto.

Claims

1O 15 20 25 10 CLAIMS

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 container such 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 the stretchable 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 of FibreForm®.

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 the plastic preform contains threads that are substantially undeformed during the blow molding.

6. The method according to any of the preceding claims, wherein only one or 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 the sleeve 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.