WO2010136282A1

WO2010136282A1 - A method and apparatus for forming, filling and sealing pouches with a non-linear edge

Info

Publication number: WO2010136282A1
Application number: PCT/EP2010/055515
Authority: WO
Inventors: Gautam Debnath; Sanjay Ghoshal
Original assignee: Hindustan Unilever Ltd; Unilever NV
Current assignee: Hindustan Unilever Ltd; Unilever NV
Priority date: 2009-05-26
Filing date: 2010-04-26
Publication date: 2010-12-02
Anticipated expiration: 2011-11-26
Also published as: AR076788A1

Abstract

The invention relates to a method and apparatus for forming, filling and sealing pouches with a non-linear edge. The method comprises the steps of : (i) drawing a web of film (1) over a forming shoulder (4) to form a tube (8) having vertically overlapping edges (5,6); (ii) sealing said edges (5,6) with a vertical sealer (7) to define a vertical seal, while said tube (8) continuously moves along machine direction; (iii) effecting a horizontal seal across said tube at a predetermined location below said vertical sealer (7), to simultaneously define a non-linear top horizontal seal of a pouch (11) filled with a product, and a non-linear bottom horizontal seal of a pouch (12) to be filled with the product; and effecting a non-linear line of weakness between said top and bottom seals, to define said non-linear edge; and, (iv) filling said product within said pouch (11) to be filled.

Description

A METHOD AND APPARATUS FOR FORMING, FILLING AND SEALING POUCHES WITH A NON-LINEAR EDGE

The present invention relates to a method and apparatus for forming, filling and sealing pouches with a non-linear edge.

The invention has been developed primarily for use in the packaging of detergent powders and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Pouches, or bags made of plastic films are used for packing various products like creams, powders, liquids, tablets, noodles, granular detergents and pastes. Pouches enable packing and selling of these products in small, as well as large quantities; typically in the range of 200 g to 10 kg. Generally, pouches are manufactured/filled in two ways. One way is to fill a material in "pre-formed pouches", which are formed at one station and filled and sealed on another station. The second way is to use automatic Form-Fill-Seal (FFS) machines which enable forming, filling and sealing in a systematic, on-line operation starting from a web of monolayer film or a laminated film.

Pouches can be manufactured from a single web of a film or a laminate (a laminate has two or more layers of films which are bonded to each other); or by using two webs of film, or two laminates. Three-side-seal pouches are made by using a single web of film; whereas four-side-seal pouches are made by using two webs of film.

In addition to performing the primary function of packaging; pouches are almost always used to convey product information, and serve as effective tools for branding. Logos, brand-names, holograms, and decorative artwork related to the product, by which the package stands-out on the shelf and readily catches the eye of a prospective buyer, are generally printed on pouches.

Contoured pouches, i.e. pouches that have attractive shapes are also known in the art. A popular product that is sold in such attractive profiled or contoured pouches is MARS®, a well-known confectionery brand.

Brand Development teams have constantly been looking for pouches with which they can convey interesting shapes or patterns that form part of the brand mnemonics. Such pouches are very likely to beat other pouches on the shelf, by way of their differentiated looks.

WO 06/018140 A1 (Unilever PIc) describes a multi-track FFS process, in which one or more edges of the sachets have non-linear profile over at least 10% of the length of the edge, in which after sealing the two webs to each other, the unwanted areas are punched out from the sealed edges of the sachets to define the non-linear edges. A drawback of this method is that it generates a relatively high amount of scrap. Such a process has relatively high environmental-impact.

Profiled pouches that are made without generation of scrap material have been described in WO 01/23271 A2 and WO/2004/106182 A1 (both by CRYOVAC INC). The described pouches have zigzag or S-shaped lateral edges. The pouches are formed on a pouch former, which also forms (seals) the zigzag lateral edges along the cross-direction of the film movement (i.e. in a direction perpendicular to the direction of movennent of the film which is known as the machine direction). In both the above cases, the end sealing component is configured to provide a pouch with a lateral edge having a concave portion and a convex portion, in a zigzag or non-linear sealing surface. The apparatus also includes a separate cutting component for cutting the lateral edges between subsequent pouches.

Whilst the benefit of the above applications is that the processes do not result in any scrap material between contiguous pouches; one of the limitations is that the zigzag or S-shaped profiles are sealed and cut in separate operations, with separate tools. A further limitation is that even for a minor increase in height of the pouch, the dimensions of the pouch-former would need to be modified, and at the same time, the entire tooling pertaining to the top and bottom seals of the zigzag or S-shaped profile, as well as the cutting blade would need to be changed; thereby making the process relatively less amenable for any changes in pouch dimensions.

Further, the present inventors have found that some non-linear profiles, e.g. steep angular curves or intricate patterns, are relatively difficult to effect and cut-along at the same time, as the tooling will become complex.

Thus there is a need in the art for a method for making pouches with a non-linear edge, which overcomes some or all of the above drawbacks and limitations of the prior art. Particularly, there is a need in the art for a method and apparatus for making pouches with a non-linear edge which has relatively higher adaptability towards changes in pouch dimensions, and has relatively lower complexity involved in the tooling.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art. - A -

It is an object of the present invention to provide a method for making pouches with a non-linear edge with relatively higher adaptability towards changes in pouch dimensions.

It is an object of the present invention to provide an apparatus for making pouches with a non-linear edge which involves relatively lower complexity of tooling.

Other objects of the present invention will become apparent to those skilled in the art by reference to the specification.

The present inventors have provided a solution to the above problems with a view to meet the above objects.

According to a first aspect, the present invention provides a method of forming, filling and sealing pouches with a non-linear edge, comprising the steps of:

(i) drawing a web of film over a forming shoulder to form a tube having vertically overlapping edges;

(ii) sealing the edges with a vertical sealer to define a vertical seal, while the tube continuously moves along machine direction;

(iii) effecting a horizontal seal across the tube at a predetermined location below the vertical sealer, to simultaneously define a non-linear top horizontal seal of a pouch filled with a product, and a non-linear bottom horizontal seal of a pouch to be filled with the product; and effecting a non-linear line of weakness between the top and bottom seals, to define the non-linear edge; and,

(iv) filling the product within the pouch to be filled. In a second aspect, the present invention provides an apparatus for use in a method according to the first aspect, the apparatus comprising:

(i) a forming shoulder for assembling a pouch from a web of film; (ii) a vertical sealer for sealing the vertically overlapping edges;

(iii) a means for continuous movement of the tube along machine direction;

(iv) a pair of horizontal sealing jaws located below the vertical sealer, each jaw having non-linear top and bottom raised projections, and a means for effecting a line of weakness, located there-between; and, (v) a filling means for filling the pouch with a product.

In a third aspect, the present invention provides a pouch with a non-linear edge, obtainable by a method according to the first aspect.

The term "comprising" is meant not to be limiting to any subsequently stated elements but rather to encompass non-specified elements of major or minor functional importance. In other words the listed steps, elements or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material ought to be understood as modified by the word "about".

It should be noted that in specifying any range of concentration or amount, any particular upper concentration can be associated with any particular lower concentration or amount.

Turning now to the preferred aspects of the method, it is preferred that the lateral web-wander of the web of film is not greater than 5 mm. Wander in the range of 0.5 to 5 mm is acceptable. This to ensure proper alignment of the web of film during its movement, so that the vertically overlapping edges are neither under- lapped, nor do the overlapping edges overshoot each other. This might affect the profile of the non-linear edge.

It is preferred that the web of film has artwork on it. When printed with artwork, any web-wander beyond the above preferred range is undesirable, because, if it wanders more than the above range, the artwork may not come in registration or alignment with the vertical seal, and more specifically, the non-linear top and bottom horizontal seals may not be in registration with the artwork and brand mnemonics.

Further, it is preferred that the continuous movement along the machine direction is synchronised with respect to the artwork on the web of film. If this does not happen, then each pull may result in un-equal pull-lengths, in which case, on some occasions, each resultant pouch length may not have the entire artwork on it. This may be done by use of servo-motor controlled mechanism. This may also be done by using sealing jaws that are capable of sealing and pulling in a cyclical manner.

It is preferred that the horizontal seal is also synchronised with the artwork. If this is not done, the non-linear seal might come into the artwork area. To minimise this, it is further preferred that a clearance is provided between the non-linear seal and the artwork on the pouches.

Although the pouches may be formed without side gussets, it is preferred that the method includes a step of forming side gussets on the pouches. These may be formed by use of gusset pins disposed on either side of the vertical sealer. In this case, the gussets are aligned with respect to the non-linear edge. The alignment of gussets and non-linear seal is preferred, as the gussets, if not aligned, can enter the artwork area and disturb the non-linear profile as well. It is preferred that the gussets exactly overlap, but the overlaps could extend beyond a distance in the range of 0.5 to 1 mm.

It is preferred that the pressure of sealing is in the range of 3 to 5 bar, so that the pouch seals remain intact, in particular, the non-linear seals. Excess pressure will generally damage the web, while lower pressures will not produce coherent seals. It is further preferred that distribution of seal pressure should be uniform across every unit length of the non-linear seal. That is to say, every unit length of the seal should experience uniform pressure. If the pressure is differential, it might result in rupture at weak points.

In another aspect the invention provides an apparatus for use in a method of the first aspect, comprising:

(i) a forming shoulder for assembling a pouch from a web of film;

(ii) a vertical sealer for sealing the vertically overlapping edges;

(iii) a means for continuous movement of the tube along machine direction;

(iv) a pair of horizontal sealing jaws located below said vertical sealer, each jaw having non-linear top and bottom raised projections, and a means for effecting a line of weakness located there-between; and,

(v) a filling means for filling the pouch with a product.

The raised projections are shaped so as to provide the top and bottom seals.

The preferred means for continuous movement of the tube along machine direction is a servo-motor. These motors have the ability to start and stop at predetermined intervals, with precision. The preferred means for effecting the line of weakness is a pressure activated knife. This is located within a groove between the top and bottom raised projections. The lines of weakness could be in the form of slits, cuts or perforations.

The raised projections in sealing jaw are non-linear in shape, as they have to effect the non-linear seals. It is preferred that heating elements are present in the raised projections, preferably linearly distributed. Further preferably, the ΔT (i.e. temperature difference) between any two given points in each of said raised projections is not more than 5 °C. It is also possible to have the jaws designed in the non-linear shape.

It is preferred that the non-linear sealing and cutting actions of the sealing jaws, and the continuous movement along machine direction are independent of each other. This gives flexibility in terms of the aspect ratio of the pouches that can be manufactured, i.e. effective pouch height to pouch width in this process. In the prior art that has been cited, they are fixed for all seals.

It is preferred that the non-linear raised projections are centred on the sealing jaws, so that the non-linear profiled of the seals appear in the centre of the pouches. In this way, the same pair of jaws may handle wide range of pouch widths with minimum change in tooling.

Pouches may be manufactured from a variety of materials. It is particularly advantageous, however, that they be constructed from relatively thin, strong and flexible material such as Polyethyleneterepthalate (PET), which is polyester; biaxially oriented nylon (BON), linear low density polyethylene (LLDPE), commonly abbreviated as PET/BON/LLDPE film. For example, the following combinations, some with multiple layers or ply of the same material, may be used for making the pouches. It is preferred that 2-ply laminates are used, but, if desired, 3-ply laminates can also be used, although these laminates are less preferred because of their cost.

Polyester/adhesive (or Extrusion PoIy)/ Linear Low Density P. E film (2-ply)

Polyester/adhesive (or Extrusion PoIy)/ Polyester/ adhesive (or Extrusion)/ Linear Low Density P. E. film (3-ply)

Polyester/adhesive (or Extrusion poly)/ Aluminium foil/adhesive (or Extrusion poly)/LLDPE (3-ply)

Polyester/adhesive/Metallised Polyester/adhesive/LLDPE (3-ply)

Polyester/adhesive/Nylon/adhesive/LLDPE (3-ply)

Polyester/adhesive/Nylon/adhesive/Aluminium foil /adhesive/LLDPE

Nylon/adhesive/LLDPE (2-ply)

Nylon/adhesive/Metallised Polyester/adhesive/LLDPE (3-ply)

Nylon/adhesive/ Aluminium Foil/adhesive/LLDPE (3-ply)

Nylon/adhesive/Nylon/adhesive/LLDPE (3-ply)

Nylon/adhesive/Nylon/adhesive/Aluminium Foil/ LLDPE (3-ply)

Other materials such as Polypropylene may also be used in place of the above or in combination with the other materials. Material thickness may also vary. For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following description of preferred embodiments.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying figures in which:

figure-1 is an isometric view of an apparatus according to the invention;

figure-2 is an enlarged view of a portion of figure-1 showing the sealing jaws and pouches;

figure-3 is an isometric view of the sealing jaws of figure-1 ; and,

figure-4 is an isometric view of a pouch made on the apparatus of figure-1.

In the detailed description of the accompanying figures, like numerals have been used to indicate like features in all figures.

Figure-1 is an isometric view of an apparatus for use in a method of forming, filling and sealing pouches with a non-linear edge according to the invention. The apparatus is constructed in the form of an enclosed frame on which all parts for the forming, filling, and sealing of the pouches are mounted.

In this figure, a continuous web of film 1 is un-wound from a roll (not shown) and is drawn over conveying Aluminium rollers 2 and 3. It then reaches a forming shoulder 4 on which the sheet of film 1 is folded over itself so that the opposite vertical edges 5 and 6 are juxtaposed to form a common overlapping edge. A vertical sealer 7 then seals the overlapping edges to each other to form a tube 8. Pulling means (not shown) for continuous movement then continuously pull the tube 8 along machine direction, (shown by a solid arrow) as set on a stroke length lever (not shown). The tube is then sealed in the horizontal direction by a pair of horizontal sealing jaws 9 and 10 at a predetermined location below the vertical sealer 7. Each horizontal sealing jaw has two raised projections which are shaped to provide the non-linear top and bottom seals (these features can be seen clearly in figure-3). The horizontal sealing jaws simultaneously define the non-linear top horizontal seal of a pouch 11 filled with a product. (In continuum can be seen pouch 11 a which is also filled with the product); and the non-linear bottom horizontal seal of a pouch 12 to be filled with the product. In the pouch to be filled 12, a product is continuously fed through filling port 13. The open end of the tube is then sealed with the horizontal sealing jaws, at a pre-determined location, which corresponds to a distance of one pouch length. The cycle is repeated to form plurality of pouches.

Referring now to Figure-2 which shows an enlarged view of a portion of figure-1 , the tube is 8 (not seen) is sealed in the horizontal direction by a pair of horizontal sealing jaws 9 and 10. Each horizontal sealing jaw has two raised projections (can be seen clearly in figure-3) which are shaped to provide the non-linear top and bottom seals. The horizontal sealing jaws simultaneously define the non- linear top horizontal seal of a pouch 11 filled with a product (the seal cannot be seen in this view as it is blocked by the jaw 10), and the non-linear bottom horizontal seal 14 of the pouch 12 to be filled with the product. In continuum can be seen pouch 11 a which is also filled with the product. Perforations 15 defining the line of weakness are formed between the non-linear top horizontal seal and the bottom horizontal seal 14 for later severing the filled and sealed pouches to form individual pouches therefrom.

Referring now to figure-3 which is an isometric view of the sealing jaws of figure-1 , each jaw 9 and 10 has two raised projections 16 and 17 (common numerals for raised projections of both jaws), which are shaped to provide the non-linear top and bottom seals, with a groove 18 therebetween. A means for effecting a line of weakness (in the form of a knife) is present in the groove.

Turning now to figure-4, which is an isometric view of a pouch made on the apparatus of figure-1 , the pouch 11 has a top non-linear horizontal seal 19 and a bottom non-linear horizontal seal 14, and a vertical seal 20 running along the length of the pouch, including both the horizontal seals. The non-linear edges can be seen clearly.

It will be appreciated that the illustrated examples provide a method for making pouches with a non-linear edge with relatively higher adaptability towards changes in pouch dimensions and provides an apparatus for making pouches with a nonlinear edge which involves relatively lower complexity of tooling.

It should be understood that the specific forms of the invention herein illustrated and described are intended to be representative only as certain changes may be made therein without departing from the clear teachings of the disclosure.

Although the invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A method of forming, filling and sealing pouches with a non-linear edge, comprising the steps of:

(ii) sealing said edges with a vertical sealer to define a vertical seal, while said tube continuously moves along machine direction;

(iii) effecting a horizontal seal across said tube at a predetermined location below said vertical sealer, to simultaneously define a non-linear top horizontal seal of a pouch filled with a product, and a non-linear bottom horizontal seal of a pouch to be filled with the product; and effecting a non-linear line of weakness between said top and bottom seals, to define said non-linear edge; and,

(iv) filling said product within said pouch to be filled.

2. A method as claimed in claim 1 wherein lateral web-wander of said web of film is not greater than 5 mm.

3. A method as claimed in claim 1 or 2 wherein said web of film has artwork on it.

4. A method as claimed in claim 3 wherein said continuous movement along the machine direction is synchronised with respect to the artwork on said web of film.

5. A method as claimed in any one of the preceding claims wherein said horizontal seal is synchronised with said artwork.

6. A method as claimed in any one of the preceding claims comprising a step of forming side gussets on said pouches.

7. A method as claimed in claim 6 wherein said gussets are aligned with respect to said non-linear edge.

8. A method as claimed in any one of the preceding claims wherein pressure of sealing is in the range of 3 to 5 bar.

9. An apparatus for use in a method as claimed in claim 1 comprising:

(i) a forming shoulder for assembling a pouch from a web of film;

(ii) a vertical sealer for sealing the vertically overlapping edges;

(iii) a means for continuous movement of said tube along machine direction;

(iv) a pair of horizontal sealing jaws located below said vertical sealer, each jaw having non-linear top and bottom raised projections, and a means for effecting a line of weakness located there-between; and, (v) a filling means for filling the pouch with a product.

10. An apparatus as claimed in claim 9 wherein said means for continuous movement of said tube along machine direction is a servo-motor.

11. An apparatus as claimed in claim 9 or 10 wherein said means for effecting the line of weakness is a pressure activated knife.

12. An apparatus as claimed in any one of the preceding claims 9 to 11 wherein heating elements are present in said raised projections.

13. An apparatus as claimed in claim 12 wherein temperature difference between any two given points in each of said raised projection is not more than 5 °C.

14. A pouch with a non-linear edge obtainable by a method as claimed in claim-1.