JPH0360728B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for wrapping and applying thin plastic labels to containers in continuous motion in an upright position during a labeling operation.

BACKGROUND OF THE INVENTION Labels are applied around a container by moving the container at intervals and tangentially engaging a drum carrying the individual labels held to the surface of the drum by a vacuum. It is publicly known. A drum carrying the labels rotates around its axis, glue or a recently developed solvent for plastic labels is applied to selected areas within the labels, and the labels on the drum are attached to the containers. do.
The container continues to rotate around the drum so that the label wraps around the container. The length of the label is slightly longer than the circumference of the container, so that the trailing edge of the label overlaps its leading edge, or the portion of the label that was first adhered to the container. This trailing edge is overlapped forming a seam (so-called seam) with the leading edge to form a label that wraps around the container with a completely vertical seam. This known device was well suited for applying non-thermosensitive labels.

Problem to be Solved by the Invention In the case of the above-mentioned labels, where the label material was made of less heat-sensitive plastic or paper laminates, hot-melt adhesives could be used. However, most commercially available hot melt adhesives have melting points above 149°C (300°C), so it is not appropriate to use such adhesives when the label is made of thin heat-sensitive plastic. Not. Hot melt causes deformation of the label,
Alternatively, the original condition of the label may actually be damaged, resulting in an incomplete labeled product.

It is important that the labeling device is free from getting stuck in the body and that the speed of movement of the containers through the gap is even and fast. Obviously, when using glues that take a very long time to harden, the device must be operated at relatively slow speeds. For this reason, hot melt adhesives that harden rapidly have been used only if they are compatible with the label. Another disadvantage of using hot melt glue is the high cost of heating the glue and the sometimes cumbersome operation of applying the glue to the label.

In view of the incompatibility of hot melt glue with thin plastic labels, the use of solvents has been considered. A solvent-based labeling method is disclosed in U.S. Patent Application No. 555,758, filed Nov. 28, 1983, and involves applying a thin plastic label around a container, such as a plastic bottle. , which completely surrounds and pastes. This solvent-based application method allows labels to be attached to fairly thin sheets of plastic or thin film laminates.
foam laminate) and is the preferred method in situations where the label is to be adhered to an oriented plastic container. It is convenient to apply a label to an oriented plastic container in such a manner that the label can be readily peeled off the container when the container is to be reused. If the label is adhered to the container by applying small dots of solvent to the leading edge of the label and then applying solvent to the overlapping part of the label or along the entire (vertical) line of the trailing edge, If so, you will be able to easily remove the label. In this case, the label adheres tightly to itself, but lightly adheres to the container. Therefore, the label can be removed without much effort or expense.

OBJECTS OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a method for applying relatively thin plastic labels to containers, such as glass containers, using labels coated with heat-activated glue. It is said that To this end, in the method of the invention, the label is conveyed to the outer surface of the vacuum drum in a relationship that is slightly longer than the circumference of the bottle and coincides with the tangential direction of the circumference with respect to the bottle or container. Just before the label reaches the point where it is tangential to the container, heat is applied to the adhesive and at the point where the label is tangential to the container it sticks to the surface of the container and is completely removed from the surface of the drum. Leave. A heat-activated polymeric cross-linked adhesive is also carried to the trailing edge of the label and bonded to the leading edge by overlapping it.

The heat-activated glue hardens quickly, creating a very tight seam, and subsequent heating of the resulting sleeve-like label causes the sleeve to contract and form a snug fit on the container, leaving the label intact. It is designed so that its original shape will not be deformed. The polymers of the adhesive are thermally crosslinked so that the label forms a seam that resists the tension applied during heat shrinkage.

Furthermore, another object of the invention is to use plastic labels pre-applied with adhesive for labeling beer containers before filling with beer, in which case the cross-linked adhesive can withstand sterilization temperatures.

Other objects of the invention will become apparent from the following description of some embodiments of the invention, taken in conjunction with the accompanying drawings.

Structure of the Invention The present invention provides for a label having an adhesive applied at its leading and trailing edges, transported around the circumference of a drum to a position where the container is brought into contact with the adhesive on the label; The label and container are then rotated around the circumference of the drum, wrapping the label completely around the container until the trailing edge of the label is over the leading edge, creating a closed seam. A method of applying an enclosing label to a container, wherein the label used is a thin heat-shrinkable plastic label, at least two areas of adhesive are pre-applied to the label before the label is applied to the transport drum, and the label is Nodal agents are heat-activated, cross-linked polymers that bind when the label is first engaged to a container.
applying heat to the adhesive on the leading edge; and applying heat to the adhesive on the trailing edge just before the trailing edge is superimposed on the leading edge. It is about the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With particular reference to FIG. 1, which is a partial plan view of the labeling section of the apparatus used in a first embodiment of the invention, in the labeling section a label support drum 10 is shown. is supported for rotation about a vertical axis 11 by an arm 12 which supports a central hub 13 for the drum. Hub 13 includes an internal vacuum manifold (not shown) in which vacuum line 14 is engaged. hub 1
It should be understood that 3 does not rotate and the arm 12 is connected to a fixed support 15. A detailed and complete description of drum 10 is not deemed necessary. The drum 10 is of a conventional type with vacuum channels extending radially outwardly from the manifolds in the hub to the drum surface opening to the surface of the drum. The leading edges of the drums are fed one after the other and held on the surface of the drum. Additionally, a continuous vertical vacuum opening is positioned below the trailing edge of the label to allow the label to slide around the container as the drum rotates and the container rotates along the surface of the drum. Guarantees even rotation. In the method of the present invention, the labels may be supplied in the form of a web 16 from a roll (not shown), as shown in FIG. That is, the labels are fed in the form of an endless web 16 of labels to which adhesive has previously been applied in the adhesive area by a printing operation. The term "printing" as used herein means the operation of depositing adhesive on a label by a technique similar to printing technology, which operating situation is already known. As shown in Figure 1,
When the web 16 enters from the right side in the figure, it engages a pair of nip rollers 17, 18, and then, after passing approximately 1/2 of the circumference of the roll 18,
The web engages a feed roller 19 which feeds the web into the area of a web slicer 20. The web slicer 20 cuts the web at precise locations along its length, defining a length of web that becomes a label. The leading edge of the label is guided into engagement with the periphery of the drum 10 by guides 21 before being cut from the web. When the web engages the drum,
The drum's vacuum port holds the web to the drum, and rotation of the drum pulls the web through the knives 22, 23 of the rotary slicer 20. The blade 22 is in a reciprocating gripper, while the blade 23 is carried by the rotating gripper so that the two blades engage the web precisely at a given time, positioning the web in the correct label position. Cut to length. Note that the leading edge of the web has adhesive in at least two vertically spaced areas 45 on the outer surface facing away from the drum, as shown in FIG. Similarly, near the trailing edge of the label, adhesive 45 is applied over the entire height or transverse line by a printing operation using a die.

The adhesive used is a water-born adhesive that can be printed and is characterized by being heat-sealable. Examples of specific adhesives include crosslinkable thermosetting adhesives such as carboxylated ethylene vinyl acetate. The adhesive is heat-activated and cross-linked at approximately 99°C (210°) and, upon curing, has a softening point of over 149°C (300°). The curing time of the adhesive is less than 1 minute, and when cured, it can withstand the sterilization temperatures at which beer containers are processed after being filled. The heat activation temperature of the adhesive is only 99°C (210°C
〓), so the label never reaches its deformation temperature. On the other hand, at least 177℃ (350℃) to melt
In the case of application of conventional hot melt adhesives requiring temperatures of 〓), there was a risk that the label would reach its deformation temperature. Also, until now, it was thought that only labels coated with hot melt adhesives could withstand sterilization temperatures.

As shown in FIG. 1, a label 41 carried by drum 10 on a rubber layer or facing 10a engages a container C and, just before being picked up by the container, the adhesive on the leading edge of the label 45 is activated by passing in front of a source of hot air, indicated generally at 24. The hot air source 24 is generally in the form of a hollow rectangular box 25 , which box is formed with an opening 26 provided in the side 27 facing the drum 10 . Conduit 28 communicates with the interior of box 25;
It is coupled to a hot air source (not shown). According to the above, at the same time as the label is conveyed by the drum, the area of adhesive is placed in the opening 26 of the box or manifold 25.
It can be seen that the hot air is blown towards the adhesive. The size of the aperture 26 is selected taking into account the speed of drum movement and the temperature of the hot air so that the adhesive is sufficiently activated as it passes in front of the aperture 26. 99℃ (210〓)
Immediately after heating to the activation temperature of , the adhesive on the label engages the side of the incoming container C and the container is held against the surface of the drum by the curved guide 29, rotate along the surface,
At the same time the label is rolled onto the container. The trailing edge of the label, on which adhesive is applied to the full height line, is likewise activated by the hot air from chamber 25, and is superimposed on the leading edge. Since the container is confined between the drum surface and the container guide bar 29, the overlap area is a vertical seam that spans the entire height of the label. The container and the seamed label are then moved by a curved exit bar 42 to the conveyor 30 through a heat shrink zone 31 between a pair of infrared heaters 32 to the right as shown in FIG. be led upwards.

As can be easily seen from Figures 1 and 2, the containers enter the labeling area from the left on a moving conveyor and are fed normally to the right, after which they rotate in the direction of the arrow. Pocket 3 of rotating star wheel 34
3. The container is guided during its movement until it engages the label, i.e. by a bar 29 on one side of its path of travel and by a pair of vertically spaced guide rails 35 on the other side. You will be guided there. Guide rail 35
is configured to guide the container in a curved path having the same center of curvature as the axis of the star wheel, so that the container engages asymptotically in the adhesive area of the leading edge of the label. The guide bar 29 is generally parallel to the guide rail 35 over its initial length. However, once the container is engaged with the label, the bar 29 changes its curvature so that the container follows a path parallel to the circumference of the drum. In this way, the guide bar 29 draws a curve coaxial with the rotational axis of the drum 10. Of course, the star wheel pushes the container along the circumference of the drum, and as the container leaves the star wheel it is kept in engagement with the drum by the bar 29 so that the container still follows the surface of the drum. It rotates.

FIG. 3 is a diagram showing a second embodiment of the present invention. Elements similar to those shown in FIG. 1 are designated with the same reference numerals. In this implementation, the preheating furnace 36 is located on a conveyor 37 on which the containers are located and successively moved towards the star wheel 34 . The reciprocating gate 38 is positioned to engage and positively restrain the containers, moving the containers one at a time onto the star wheel as the pockets move onto the conveyor. In this example, the container is
Preheated to a temperature above 99°C (210°C), the heat of the container activates the adhesive carried by the label and causes cross-linking. The container has sufficient heat,
As a result, the trailing edge of the label, which is coated with adhesive over the entire label height, is also thermally activated, creating a seam that extends the full vertical length of the overlap.

Since the bottle is preheated and the heat is used to activate the adhesive, the step of activating the adhesive with "hot air" is omitted. Label 46 is pre-cut;
The adhesive is already applied and stored in a magazine 48, in which a pair of feed rolls 39, 40 are driven in synchronization with the drive of the drum and the drive of a star wheel (not shown). The labels are successively fed around the vacuum drum 10.

Effects of the Invention The foregoing description relates to two embodiments that involve feeding a label pre-applied with adhesive to a vacuum drum, in which the container is fed to the adhesive area of the label; Here, the leading edge of the label is first applied to the container, and then the container is turned on a drum to wrap the label around the container, the heat-activated adhesive on the label being applied to the preheated bottle or It is clear that thermal activation can also be achieved by means other than hot air mechanisms. For example, the adhesive can be activated by exposure to an infrared heater shortly before the label engages the bottle.
Alternatively, preheating the bottle and providing additional heating of the adhesive area of the glue or adhesive on the label could ensure that the label adheres to the perimeter of the container. Note that this label is a thin plastic that will deform if too much heat is applied, such as when applied with hot melt adhesive. The adhesive is applied so that the labeled container can be passed through a heat shrink oven (i.e., an oven to shrink the label around the container).
It must harden quickly and the labeled container, such as a beer bottle, must be able to withstand the sterilization temperatures of the filled contents (eg beer).

Although some embodiments of the present invention are described in detail in this specification, it will be apparent to those skilled in the art that the present invention can be implemented in various embodiments within the technical scope of the claims. It is possible to implement it.

[Brief explanation of drawings]

FIG. 1 is a plan view of the main parts of an apparatus used in a first embodiment of the present invention. FIG. 2 is an enlarged perspective view of the area where the label is applied to the container of FIG. 1; FIG. 3 is a plan view of the main parts of the apparatus used in the second embodiment of the present invention. FIG. 4 is an enlarged perspective view of the portion indicated by arrow 4 in FIG. 1. Figure 5 is the second
FIG. 3 is a front perspective view of the air manifold shown in FIG. 10...Drum, 11...Vertical axis, 12...Arm, 13...Hub, 14...Vacuum pipe line, 15...
... Support, 16 ... Web, 17, 18 ... Nitz roller, 18 ... Roll, 19 ... Feed roll,
20...Web slicer, 21...Guide, 2
2, 23...knife, 24...hot air source, 25...
Box, 26... Opening, 27... Side, 28... Conduit, 29... Container guide bar, 30... Conveyor, 31... Heat shrink area, 32... Infrared heater, 33... Pocket, 34... Star car, 35...
...Guide rail, 36...Preheating furnace, 37...Conveyor, 38...Reciprocating gate, 39, 40...Feed roll, 48...Magazine.

Claims (1)

Claims: 1. A label is applied with adhesive at its leading and trailing edges and is transported around the circumference of the drum to a position where the container is brought into contact with the adhesive on the label; The label and container are then rotated around the circumference of the drum, wrapping the label completely around the container until the trailing edge of the label is over the leading edge, creating a closed seam. A method of applying an enclosing label to a container, wherein the label used is a thin heat-shrinkable plastic label, at least two areas of adhesive are pre-applied to the label before the label is applied to the transport drum, and the label is The adhesive is a heat-activated, cross-linked polymer that, when the label is first engaged to the container,
and applying heat to the adhesive on the trailing edge immediately before the trailing edge is superimposed on the leading edge. . 2. The method according to claim 1, wherein applying activation heat to the adhesive is performed by adding hot air to the adhesive. 3. The method according to claim 1, wherein the adhesive used is a printable aqueous adhesive. 4. A method according to claim 1, wherein the adhesive used is carboxylated ethylene vinyl acetate. 5. Claim 1, wherein the heat for activating the adhesive is supplied by preheating the container to a temperature above the activation temperature of the adhesive but below the temperature at which the label thermally deforms. Method described. 6. The method of claim 5, wherein the container is a glass container preheated to a temperature of about 121°C (250°C). 7 Activation to the adhesive by preheating the container to a temperature between 66°C (150〓) and 93°C (200〓) and blowing a stream of hot air onto the adhesive just before the container engages the label. 2. A method according to claim 1, wherein heat is supplied. 8. The method of claim 7, wherein the combination of preheating the container and blowing hot air onto the adhesive activates and crosslinks the polymer. 9. The method of claim 8, wherein the combined heating of the polymer is carried out to a temperature of about 99°C (210°C).