WO2008155749A1

WO2008155749A1 - Laminate packaging opening device

Info

Publication number: WO2008155749A1
Application number: PCT/ID2008/000008
Authority: WO
Inventors: Austen James Kernohan; Romy Julias
Original assignee: Pt. Alcan Packaging Flexipack
Priority date: 2007-06-18
Filing date: 2008-06-17
Publication date: 2008-12-24

Abstract

A method for forming a partial perforation to provide an opening area for tearing or piercing by a straw on a laminate packaging comprising: directing a laser beam onto a top surface layer of the laminate; and moving the laser beam along the surface of the laminate, such that the top surface layer of the laminate is removed from an area of the packaging to form a partial perforation pattern that will facilitate tearing of the packaging or piercing by a straw, wherein after laser treatment an inner layer of the laminate is exposed and the presence of the inner layer of the laminate will prevent leakage from the packaging

Description

LAMINATE PACKAGING OPENING DEVICE

Technical Field This invention relates to forming partial perforations in an area of a laminate packaging, in particular beverage packaging, to facilitate piercing of the packaging.

Background Art

The use of flexible laminate packaging material is well known. In both food and non- food packaging it is often required to have an easy opening device such as a perforation line for easy tear purpose or a straw hole which a straw can be inserted. When the packaging material used is thin piercing or tearing of the packaging is relatively easy. However if thicker packaging material is used, tearing of the packaging by hand or piercing of the packaging with an instrument such as a straw, to provide an opening becomes more difficult. A number of ways have been suggested to provide an easy opening device in packaging material. These include mechanical perforation of the packaging material for easy tearing by making small holes along the tearing line by mechanical punching or piercing or punching out a portion of the material to form a hole and then adhering a barrier layer to the inner side of the packaging material, which can be pierced through with the straw.. These methods generally require a sealant layer to be over the straw opening area that has been formed to prevent leakage from the packaging and protect the contents from moisture and oxygen etc.

It is an object of the invention to provide a method for providing a flexible packaging material with an easy opening device, by forming an area in the packaging that can be easily torn or pierced, whilst still maintaining the inner barrier layers of the packaging material.

Disclosure of the Invention

A first aspect of the invention comprises a method for forming a partial perforation to provide an opening area for tearing or piercing by a straw on a laminate packaging comprising directing a laser beam onto the top surface layer of the laminate; and moving the laser beam along the surface of the laminate, such that the top surface layer of the laminate is removed from an area of the packaging to form a partial perforation pattern that will facilitate tearing of the packaging or piercing by a straw, wherein after the laser treatment an inner layer of the laminate is exposed and presence of the inner layer of laminate will prevent leakage from the packaging.

The laser beams moves in a predetermined path along the surface of the packaging to form the partial perforation in the laminate packaging in a pattern that facilitates piercing of the packaging by a straw or tearing of the packaging along a line. A portion of the top layer of the laminate material is removed but the remaining inner layers of the laminate packaging remain intact, this will provide a barrier to the outside for the contents of the package, so that leakage will not occur from the packaging and /or prevent exposure of the contents to oxygen or moisture. Preferably moving the laser comprises moving at least two mirrors to change the location of the laser on the laminate. The movement of the mirrors moves the laser beam across the surface of the packaging and therefore determines the pattern of the partial perforations. Preferably a first mirror determines the Y-position of the laser on the laminate and a second mirror determines the X-position of the laser on the laminate. The first mirror preferably rotates about an axis perpendicular to the axis of rotation of the second mirror.

The preferred pattern to facilitate piercing of the packaging by a straw an X surrounded by a circle.

Preferably the laminate comprises a multilayer laminate having a structure comprising a polyethylene terephthalate (PET), a metal foil, and polyethylene layers. Preferably the laser beams removes the PET layer of the laminate to expose a metal layer, such as aluminium.

The packaging can be for food or non-food applications however preferably the laminate packaging is a beverage package.

A second aspect of the invention is the laminate packaging made by the method described above.

A third aspect of the invention comprises a laminate beverage packaging comprising a partial perforation for facilitating tearing or piercing of a straw into the packaging wherein the partial perforation comprises a portion of the packaging wherein a top outer layer of the laminate has been removed by a laser beam such that an inner layer of the laminate is exposed to form a partial perforation.

Brief Description of the Drawings

Figure 1 shows a schematic cross section of a partial perforated laminate; Figure 2 shows a laser system that can be used to form the partial perforation; and Figure 3 shows one straw piercing pattern that can be formed on a laminate package.

Mode(s) for carrying out the invention

Figure 1 shows a schematic cross section of a partially perforated laminate. The laminate can comprise a structure comprising an outer layer 1, i.e. a polyester film such as polyethylene terephthalate, a barrier layer 2, such as a metal foil, and an inner layer 3, such as a polyethylene film. An area of the outer layer of the laminate is removed by the laser beam. This exposes the barrier layer of the laminate to the outside environment. Removing only one layer of the laminate weakens the laminate in this area, buts still maintains the barrier layers of the laminate. The outer layer is generally tougher to pierce than the inner layer and therefore removing this layer, makes the laminate easy to pierce. The weakened portion of the laminate is easier to pierce, than the laminate that has not been treated by the laser, as the straw will have fewer layers to go through. However this weakened area still provides a barrier to prevent leakage of the contents of the packaging, and as a barrier from moisture or oxygen, as the inner and lower layers of the laminate are intact as they do not get perforated by the laser. Typical beverage packaging is made from laminate material having the following structure from the outside to inside: polyethylene terephthalate (PET) film/printing ink/ coating adhesive/metal foil/coating adhesive/heat sealable plastic film. Such laminates are described in US5425583. However the outer may consist of a biaxial oriented polypropylene or orientated nylon film and the inner layer may consist of an extruded polypropylene or cast polypropylene film. The choice of material used to form the laminate for the packaging material will depend on the application of the packaging. The outer layer 1 of the laminate is removed to expose the metal foil barrier layer 2, such as aluminium. The use of aluminium allows for easy piercing of the packaging with a straw, while still preventing leakage from the packaging.

Figure 2 shows one embodiment of the laser system that can be used for forming a partial perforation on a laminate packaging. The system comprises a laser device 4 that emits a laser beam 5. The laser beam is directed by series of mirrors 6, 7 through a lens 8 onto the outer surface of the packaging 9. Each of the mirrors is rotatable around an axis and is driven by a motor 10, 11, such as a galvanometer motor. The first mirror 6 is rotated around a first axis by a first motor 10, to control the position of the laser beam on the packaging in the Y-direction and the second mirror 7 is rotated about an axis perpendicular to the first axis, by a second motor 11, to control the position of the laser beam 5 on the packaging 9 in the X-direction. The size of the lens 8 defines the working area that the laser can operate and focuses the laser beam 5 to the outer surface of the packaging 9.

The laser system is programmed to produce a desired pattern on the packaging, and only perforate the outer layer of the laminate and not perforate the barrier or inner layers. The position of the laser beam on the packaging is determined by the position of the mirrors. Rotating the mirrors moves the laser beam along the packaging material to form the desired perforation pattern in the outer layer of the laminate. The rotation of the mirrors determines the pattern of the partial perforation on the packaging surface, as the rotation of the mirrors controls the path the laser beam takes, and therefore what part of the outer layer of the laminate is removed. The start of the movement of the laser beam is triggered by a print mark on the laminate web. The laser beam starts in one position on the laminate and the mirrors are rotated to track the laser beam in a particular pattern, as programmed by the system. The path the laser beam follows, along the packaging results in cuts through the outer surface of the laminate which exposes the aluminium barrier layer. The laser will also cut through the printing ink layer and the first adhesive layer that are between the outer surface PET film layer and the aluminium barrier layer. By not cutting through the barrier and inner layers of the laminate material, a further step of adding a barrier material to seal the hole formed, if the laminate is fully perforated is not needed. As shown in Figure 3 a preferred pattern for scribing into the laminate, for providing an inlet for a straw in the packaging consists of two intersecting lines, such as an X, surrounded by a circle. However other patterns that facilitate piercing by a straw can also be formed, such as concentric circles or three lines surrounded by a circle. To provide opening device for easy tearing of a packaging material, a series of horizontal perforation lines can be formed. Once the pattern has been scribed into the laminate surface the laser beam can be switched off and the mirrors returned to their original starting position, ready to repeat the tracking process on the next packaging unit that is directed towards the laser beam working area.

The packaging is preferably moved along a conveyor system towards the laser system where the perforations in the laminate are made. To obtain a good perforation through the top layer of the on the laminate packaging material, the laminate web should stay in the laser focus. Controlling the laminate web tension is also important to ensure a good cross web cutting of the laminate. The required tension will vary depending on the application.

The removal of the top PET layer from the packaging exposes the aluminium layer which provides a marking on the packaging for indicating where the consumer should insert the straw. The beverage packaging can be any type of laminate beverage packaging such as a pouch or bag-shaped container.

Although the invention is particularly described with regards to forming partial perforation in packaging material for insertion of straws in beverage packages, the method can also be used to form partial perforation in other food and non-food packaging to provide easy opening devices on these packaging, whilst still prevent leakage of the contents from the packaging. The pattern of partial perforations that is formed into the packaging material will depend on the use and contents of the packaging..

Claims

1. A method for forming a partial perforation to provide a opening area for tearing or piercing by a straw on a laminate packaging comprising: directing a laser beam onto a top surface layer of the laminate; and moving the laser beam along the surface of the laminate, such that the top surface layer of the laminate is removed from an area of the packaging to form a partial perforation pattern that will facilitates tearing of the packaging or piercing by a straw; wherein after laser treatment an inner layer of the laminate is exposed and the presence of the inner layer of the laminate will prevent leakage from the packaging.

2. A method according to claim 1 wherein moving the laser comprises rotating at least two mirrors to change the location of the laser on the laminate surface.

3. A method according to claim 2 wherein a first mirror determines the Y-position of the laser beam on the laminate and a second mirror determines the X-position of the laser beam on the laminate.

4. A method according to claim 3 wherein the first mirror rotates about an axis perpendicular to the axis of rotation of the second mirror.

5. A method according to any of claims 1 -4 wherein the piercing area is an X surrounded by a circle.

6. A method according to any one of claims 1-5 wherein the laminate is multilayered laminate comprising a PET layer, a metal foil layer, and a polyethylene layer.

7. A method according to claim 6 wherein the laser beam removes the PET layer from the laminate to expose the metal foil layer.

8. A method according to any one of claims 1-7 when the laminate packaging is a beverage packaging bag.

9. Laminate packaging made by the method according to any one of claims 1-8.

10. Laminate beverage packaging comprising a partial perforation for facilitating tearing or piercing of a straw into the packaging wherein the partial perforation comprises a portion of the packaging wherein a top outer layer of the laminate has been removed by a laser beam such that an inner layer of the laminate is exposed to form a partial perforation.