EP0945360A1

EP0945360A1 - Bag

Info

Publication number: EP0945360A1
Application number: EP99302330A
Authority: EP
Inventors: John Reginald Gregory
Original assignee: Welton Packaging Ltd
Current assignee: Rexam FW Ltd
Priority date: 1998-03-25
Filing date: 1999-03-25
Publication date: 1999-09-29

Abstract

A double-layer paper bag has a permanently-closed top fill opening (10) and a dispensing opening (26) formed in a side gusset wall (6) of the bag. A cover layer (18) is secured over the opening (26), and is peeled away before use. After use the opening (26) can be reclosed by folding together the gusset walls (6) and holding it in that folded condition by means of a releasable adhesive securement. In one version the cover layer (18) is used as a strap for this purpose, having an adhesive end which is wrapped around and stuck to the outer bag wall. Additionally or alternatively, an adhesive region (24) surrounding the dispensing opening (26) sticks releasably to itself when the gusset wall (6) is folded together.

Description

This invention relates to bags suitable for holding and dispensing consumer products which are flowable, being either liquid or particulate e.g. powders, granules, tablets, biscuits and the like.
A variety of consumer products of this general type are marketed in robust paper or laminated paper bags designed to hold the product securely and stably even after the bag has been opened, especially if the product is one likely to be consumed gradually. A typical bag for this purpose, exemplified by the so-called "self-opening-satchel" type, is a single, double or multi-layer bag, usually of paper, with opposed side walls linked across one or both ends of the bag by gusset walls, a top fill opening which can be closed or sealed after filling e.g. by hot-melt or cold lacquer adhesive, stitching or other conventional means, and preferably a flat base e.g. provided by a base gusset region. These bags are popular because their sturdy material and gusseted form helps to keep them open on filling lines.
However with these and bags of other types there is a general problem relating to re-closure after the bag has been opened, particularly in the case where the product is one which is consumed gradually. Generally speaking the more secure and permanent the closure of the top fill opening (note that herein the expression "top" may also be taken to mean "end" except where the context requires otherwise) the more difficult it is to re-close the bag conveniently and effectively after opening. Either the bag remains open, which may lead to gradual deterioration of the contents, or the user must resort to some other means such as folding over the top (not very effective) or a discrete clip (more effective, but inconvenient) to re-close the bag.
What we now propose is a bag which in addition to a top fill opening with a closure has a dispensing opening through the side wall. A cover layer is releasably secured over the opening preferably by at least a region of peelable adhesive provided on the side wall adjacent the dispensing opening.
Some aspects of the invention are set out in the claims.
The side wall of the bag preferably has at least one gusset region extending up the bag. In one independent aspect, and preferably in other aspects, the dispensing opening is provided in this gusset region.
One basic principle here is that for dispensing the product it is not necessary to disrupt the top closure. Instead, the cover layer is peeled away to open the dispensing opening and desired quantities of product can be dispensed through the dispensing opening. In one aspect, having an adhesion region adjacent the dispensing opening enables it to be re-closed. For example, the cover layer may be stuck back over the dispensing opening. Or, adjacent regions of the bag side wall may be stuck together using the adhesion region, to cover or close the dispensing opening. In the preferred embodiment where the dispensing opening is provided in a gusset wall as mentioned above, it may be re-closable by sticking together opposing faces of the gusset wall in a re-entrant fold of the bag side wall. Another possibility is that a top portion of the bag may be rolled or folded down and stuck over the dispensing opening.
The cover layer is preferably a removable part of an outer layer integral with the bag. The cover layer may be defined by a pre-formed line of weakness in the outer layer which forms an outline of the cover layer so that the cover layer can reliably be torn away with the proper outline to uncover the dispensing opening, while its construction integral with the bag wall lends integrity to the initial closed state.
The cover layer may be connected to or include a tab or tab portion which is more easily grasped than the remainder of the cover layer, e.g. by being pre-cut to a greater extent from a surrounding outer layer region, and/or not being adhered to the underlying wall region, and/or projecting from the surrounding bag wall.
An outer layer of which the cover layer forms a removable part may extend over part or all of the bag. In a preferred embodiment the outer layer is an outer layer of a two-layer or multi-layer bag and extends all over the bag surface.
The cover layer may have the form of a patch or elongate strip localised around the dispensing opening. The cover layer preferably has a nexus or join to the bag (e.g. to a surrounding outer layer with which it is integral), so that it remains attached to the bag after being pulled clear of the dispensing opening. This keeps the cover layer available, either for re-closing the dispensing opening or for use as a securing strap as will be described later.
In the preferred case where the bag is used upright, so that the "top fill opening" is indeed at the top, the dispensing opening is effectively in the side and will preferably be positioned adjacent or above a product fill level for the bag. (Note that the bag filled with product is an independent aspect of the present invention.) Typically therefore the dispensing opening will be in the upper half of the bag. A preferred form for the dispensing opening is an elongate slot or slit, since this is more effectively re-closed than a wide open area. The dispensing opening may initially be provided by a pre-formed line of weakness in the bag wall, either as an line segment creating a slit-form dispensing opening or as a closed loop creating an open area, mouth or slot. It is particularly preferred to have a horizontally-elongate opening (e.g. slit or slot) disposed on the bag wall so as to gape open for pouring of the bag contents. This is particularly effective if the opening is formed in a gusset region, extending across the inward fold line. Generally this gaping is assisted by the outward pressure of the bag's contents below the opening, forming a kind of spout, while restraint of the wall structure above the opening tends to prevent that part of the wall bulging out as well.
The shape and size of the adhesive region adjacent the dispensing opening are selected in accordance with the location on the bag, the strength of the adhesive used, the size and shape of the cover layer and whether or not the adhesive region is to be used for re-closure. Preferably the adhesive region will include adhesive areas at least on two opposed sides of the dispensing opening, and most preferably extends right around the dispensing opening immediately adjacent thereto.
The top or end closure of the bag, generally exploited for filling the bag in production, is typically constituted by the free edges of the bag layer(s) which have been closed after filling, e.g. by a heat seal, adhesive seal, stitching or otherwise.
According to an independent aspect of the invention, there is provided a bag comprising opposed side walls linked across at least one end of the bag by a gusset wall with an opening in the gusset wall, and a top closure, the opening being initially closed but capable of being opened such that, when product is contained in the bag, the pressure of the product causes the gusset wall below the opening to fold outwards relative to the gusset wall above the opening, which is restrained inwardly by the proximity of the top closure, such that the outwardly folded gusset wall defines a spout for dispensing the product.
It may be desirable to provide a reinforcing layer on the outer layer of the bag, at least in the region of the wall opening and cover layer. We envisage above that the outer layer is provided as an outer bag. The reinforcing layer can be provided as a strip or patch localised around the region of the dispensing opening and cover layer. Provision of reinforcement in this area can provide various advantages. Where the cover layer is a part of a more extensive outer layer, e.g. a bag, and is torn out from it along a predefined line of weakness such as a line of perforations, reinforcement can give a more definite tearing action. Where the cover layer has a nexus to the adjacent outer layer so that when pulled away it remains connected to the bag, the reinforcement strengthens the resulting projecting tab. Furthermore the reinforcing layer can be of a material which releases more easily from the adhesive around the dispensing opening than the basis material of the outer layer/outer bag, improving convenience of use in this respect also.
Desirably the reinforcing layer is a polymeric layer secured over the inward surface of the outer layer e.g. by adhesive. A layer of polyethylene is found to be very suitable, and can give good release from an outwardly-directed adhesive region surrounding the dispensing opening.
A further development proposed herein, independently of or in combination with the above, relates particularly to embodiments in which the cover layer has a nexus to an adjacent region of outer layer, or some other non-releasing connection to the bag wall, so that it remains attached to the bag wall after being peeled away from the region around the dispensing opening. The resulting projecting strip of cover layer is arranged to one side of the dispensing opening such that, when the bag wall opening has been re-closed, in particular by folding, and optionally with sticking together using its adjacent adhesive region, the strip which was previously the cover layer can be wrapped across the resulting fold and secured to the bag surface beyond the re-closed dispensing opening by adhesive engagement with the bag wall.
Adhesive engagement of the strip may conveniently be arranged by an adhesive region thereon, e.g. a localised patch, sufficiently far from its nexus with the bag wall to bridge the re-closed opening. The adhesive region may be spaced from the nexus with the bag wall.
When the inwardly-directed face of the cover layer has a release surface for easy release from the adhesive which initially underlies it, measures may be needed to provide an adhesive region securely on its surface. One way is by leaving part of the inner surface of this layer (e.g. a projecting tab which serves as a gripping location for the initial removal of the cover layer) free of easy-release finish. Or, a region susceptible of holding an adhesive suitable for the re-closure function can be provided by a localised treatment of the release surface to improve its adhesivity. Such treatments are well known, e.g. corona or plasma treatment. The adhesion may be applied e.g. as liquid or on a tape carrier.
Accordingly, an independent aspect of the present invention is a bag having a dispensing opening through the side wall for dispensing bag contents, and a cover layer releasably secured e.g. adhered over said dispensing opening, whereby after peeling away the cover layer the dispensing opening can be re-closed by folding together or rolling up the relevant region of the bag wall, optionally with adhesion of the bag wall to itself if an adhesive region has been provided thereon, the cover layer having a nexus to the bag wall to one side of the opening so that after peeling from over the dispensing opening it remains attached to the bag wall as a securing strip, and furthermore is adhesively securable to the bag wall on the other side of the dispensing opening so as to maintain the folded or rolled condition of said bag wall region adjacent the opening.
Optional and preferred features in this aspect are available as set out previously and subsequently.
By way of example, embodiments of the invention will now be described with reference to the accompanying drawings in which:
Fig 1 shows a perspective view of a bag before opening;
Fig 2 shows a perspective view of the same bag after opening;
Fig 3 is a perspective view of a bag as in Figs 1, 2, showing reinforcing modifications;
Fig 4 is a schematic vertical cross-section up the centre of the gusset wall of Fig 3 at V-V;
Fig 5 is a perspective view of a bag with a cover strip modified to provide a securing strap, and
Fig 6 shows a further version using a securing strap.
A bag 2 comprises two opposed side walls 4, two opposed re-entrant gusset walls 6 at the ends of the bag linking the side walls 4, a gusset base 8 and a top closure 10, formed by sealing the tops of the side walls 4 together. The bag 2 has an outer layer 12 which has an inner layer 14 within it, the two layers being bonded together with adhesive. Each layer is itself a bag, the inner bag being completely enclosed by the outer bag.
Both bags are of paper and this is generally preferred; paper laminated with polymeric film is also highly suitable for one or both layers.
Two parallel series of perforations 16 in the outer layer 12 of the re-entrant gusset wall 6 define an essentially rectangular removable strip 18. The strip 18 is oriented across the gusset wall 6, from one side wall 4 to the other, below the top closure 10 and above the final level of the product 28. The perforations 16 are arranged transversely such that the strip 18 can be separated from the outer layer 12 of the gusset wall 6 and remain connected to the outer layer 12 of the side wall 4 after separation. Heavy perforations 20 in the outer layer 12 of the side wall 4 define a tab 22 which is continuous with the strip 18 in the gusset wall 6. The strip 18 is bonded to the inner layer 14 with a peeling adhesive layer 24 which also has cohesive (re-sealing) properties. These properties are routine modifications of a base PVA adhesive. The strip 18 covers a slit 26 in the inner layer 14 running horizontally across the re-entrant gusset wall 6.
The bag 2 is filled with product, e.g. granular pet food or washing powder, through its open top mouth. After filling, the top closure 10 is formed by bringing the upper ends of the side walls 4 together, thereby closing the mouth of the bag 2, and bonding them together to seal the closure. The top closure 10 can be sealed in any conventional manner, for example heat sealing. The bag is filled such that the final level of product in the sealed bag is below the strip 18 in the gusset wall 6.
To open the bag 2 after filling and closure, the tab 22 is separated from the inner layer 14 and the surrounding outer layer 12 by tearing the heavy perforations 16. These heavy perforations 16 create a weak connection between the tab 22 and the outer layer 12 that allows the tab portion 22 to be separated more easily. Using the tab 22 as a grip, the strip 18 is peeled away from the adhesive coating 24 covering the inner layer 14. This peeling away of the strip 18 tears through the perforations 8 separating the strip 18 from the surrounding outer layer 12. The strip 18 is detached from the gusset wall 6, but remains attached to the side wall 4 which does not have perforations.
On removing the strip 18, the inner layer 14 containing the slit 26 is exposed. The product in the bag 2 exerts outward pressure on the side walls 4 and the gusset walls 6. When the slit 26 is exposed by the removal of the strip 18, the gusset wall 6 beneath the slit 26 is no longer constrained by the top closure and folds outwards as a result of this pressure. The gusset wall 6 above the slit 26 remains held in a re-entrant configuration by the close proximity of the top closure 10. The difference in the folding of the gusset wall 6 above and below the slit 26 forces the edges of the slit 26 apart such that the lower edge forms a spout 30. Inclination of the bag 2 allows product to be controllably poured through this spout 30.
To reseal the bag 2, the opposing sides of the gusset wall 6 are brought together. The adhesive layer 24 on the exposed inner layer 14 of the gusset wall 6 self-adheres to bond the opposing sides of the gusset wall 6 in the region of the exposed inner layer 14, sealing the opening. The bag 2 can be reopened by pulling apart the opposing sides of the gusset wall 6, such that the sides of the exposed inner layer 14 adhered together by the adhesive layer 24 are separated. The slit 26 is thereby re-exposed. The opposing pressures on the gusset wall 6 then cause the edges of the slit 26 to separate to reform the opening and the lower edge to reform the spout 30.
Referring next to Fig 3, the bag shown corresponds to that shown in Fig 1 and the same reference numbers are used. Fig 3 shows additionally the disposition of a polyethylene reinforcing patch 120, which in the region of the re-sealable closure is laminated over the interior surface of the outer paper layer 12 of the double bag. The reinforcing patch 120 extends to just beyond the outline of the cover layer 18, defined by the perforations 16. Since the layer 120 is on the inside Fig 3 shows its location only schematically. Fig 6 provides a sectional view indicating how the polyethylene layer 120 is laminated to the inner face of the outer paper layer 12 by a suitable adhesive 121. The line of perforation 16 is formed through both the outer layer 12 and its reinforcing layer 120, so that the cover layer in the form of the strip 18 is easily torn out from both of these layers simultaneously; the double-layer strip 18 then remains intact and joined to the bag outer wall 12 at one end, at one side of the gusset end wall 6. The reinforcement patch 120 continues through this join or nexus of the strip 18 with the side wall, so that the strip 18 is not torn off.
As seen in Fig 6, the polyethylene reinforcement patch 120 provides a face which is presented to the peelable adhesive 24 on the inner layer 14, for easy release of the cover strip 18 from the adhesive 24.
For economy it is preferred that the reinforcement layer be localised where it is needed. The broken lines in Fig 3 indicate the outline of a larger reinforcing strip 120' in an alternative embodiment. Here the reinforcing strip 120' extends the full height of the gusset wall, down to the floor, and up into the top closure 10 of the bag. This provides additional strength if needed and enables manufacture by feeding a continuous PE strip into the process.
Fig 4 illustrates a further variant. As in the previous embodiment, the free end of the cover layer 18 folds initially around onto the opposite side wall of the bag as a tab 22 which is easily gripped for additional removal of the cover strip 18. In this variant a spot 181 of peelable hot-melt adhesive is applied to the inner surface of the tab 22. After use of the gusset spout opening 26, and re-closure of this opening by folding together the opposed re-entrant walls of the gusset and the surrounding adhesive regions, security is achieved by wrapping the strip 18 round onto the opposite side wall of the bag (to the position indicated by broken line 18') and pressing the adhesive spot onto the side wall (position 181'). Because the adhesive 181 is peelable, the bag can be re-opened and re-closed repeatedly.
In this embodiment an ordinary peelable adhesive (e.g. PVA) may be used around the opening; it need not be modified to be re-sealable because the strip holds the fold shut. The use of adhesive 24 is nevertheless significant because it strengthens the un-opened bag in the region of the opening 26.
In to facilitate initial peeling the inner surface of the cover layer strip 18 has an easy-release finish, or is a polymeric reinforcing layer as described previously. To enable the adhesive spot 181 to be securely applied the inside surface of the tab region 22 of the strip 18 is given a corona treatment to increase its surface energy.
Fig 5 shows a variant in which the features are generally as in Fig 4, including the polyethylene reinforcing patch 120. For adhesive securement to the outer face of the bag after wrapping over the folded gusset 6, the cover layer strip 18 incorporates a patch of adhesive tape 181, whose rear surface is permanently bonded to the underlying polyethylene layer and whose front surface carried a releasable adhesive covered by a releasable cover layer. The latter protects the adhesive capability of the adhesive patch 181 until it is needed. The tape-form adhesive 181 is easily introduced into the bag manufacturing process.

Claims

A bag having a closed base (8), a top closure (10), a dispensing opening (26) through the side wall of the bag and a cover layer (18) over the dispensing opening (26) which can be peeled away to expose the dispensing opening,
in which
the dispensing opening (26) is formed in a region (6) of the bag side wall pre-creased to form an inward fold which in its folded condition re-closes the dispensing opening (26) after peeling away the cover layer (18), and a releasable adhesive securement (24, 181) is provided to hold said region (6) releasably in the folded condition.
A bag according to claim 1 in which said region (6) is a side gusset wall region.
A bag according to claim 1 or claim 2 in which the dispensing opening (26) is an elongate slot or slit.
A bag according to any one of the preceding claims in which the cover layer (18) has a non-releasing nexus to the bag wall to one side of said region (6) and is releasably adhesively securable to the bag wall to the other side of the region (6) to act as a strap constituting a said releasable adhesive securement for holding said region (6) in the folded condition.
A bag according to claim 4 in which the inner surface of the cover layer (18) has a localised adhesive region (181) for said releasable adhesive securement to the bag wall.
A bag according to any one of the preceding claims in which the cover layer (18) is in the form of an elongate strip.
A bag according to any one of the preceding claims in which peelable adhesive (24) is provided around the dispensing opening (26), and the cover layer (18) is peelably adhered to said peelable adhesive region (24).
A bag according to claim 7 in which the peelable adhesive (24) is a re-sealing adhesive which, after removal of the cover layer (18), provides a said releasable adhesive securement for holding said folded condition of the bag side wall region (6).
A bag according to any one of the preceding claims in which the bag side wall comprises inner and outer layers (14,12), the dispensing opening (26) being defined through the inner layer (14) and the cover layer (18) being a separable region of the outer layer (12).
A bag according to claim 9 in which the outer layer (12) has a preformed line of weakness (16) providing the outline of the cover layer (18).