Resealable flexible package

Abstract: A snap enclosure for a flexible package having opposite panels (26, 28) and side gussets (30) comprises interengaging elements (24A, 24B). One element (24A) defines a channel (60) below which is a flange (56) anchored by adhesive (64) to the outside of a panel. The other element (24A) has a tongue (48) received in the channel (60) with the panel (26, 28) and gussets (30) in between when the package is sealed. The tongue (48) is secured to the wall of the respective panel.

Description: This invention relates to flexible packages, and more particularly to flexible packages for holding products, such as foods, under vacuum therein, and which can be repeatedly re-opened and re-closed, while keeping the contents fresh. Flexible packages for holding particulate materials, e.g. ground or whole bean coffee, chemicals, etc., under vacuum therein are known from US-A-4,576,285, US-A-4,705,174, and USA-A-4,913,561. One common flexible package is the so-called "gusseted" package or bag. Typically such a package is formed from a web of flexible stock material, e.g. polyethylene, polyester, polypropylene, metal foil, and combinations thereof in single or multiple plies, into a tubular body, having a face panel, a back panel, and a pair of gusseted sides. Each gusseted side is formed by a pair of gusset sections and a central fold edge interposed between a pair of outer folded edges. The lower end of the bag can be permanently sealed, e.g. heat sealed, along a line extending across the width of the bag close to its bottom edge. The top of the bag is commonly sealed across the entire width of the bag to maintain the contents under vacuum until the bag is opened. For example, in one known package the top seal is made peelable by modifying the sealant layer with a peelable coating or incompatible additive. When the seal is peeled apart the unsealed portions form an open mouth through which the contents of the package may be removed. The package of US-A-4,705,174 includes a peel strip applied to the inner surface of the package below the top edges. The strip provides an air-tight interfacial seal which can be readily peeled apart to provide access to the interior of the package. It is also known to score the upper flap of the package by laser or mechanical means through a tear initiation resistant layer of the package structure so that the package can be opened by tearing away the scored area to form the package's mouth. US-A-5692837 discloses a gusseted flexible package having an integrated snap closure for resealing the package after it has been initially opened. The package is formed of a flexible material and includes a front panel, a rear panel, and a pair of opposed side gussets. The panels and gussets each include a top portion, which between them define the package's mouth. A peelable closure is present within the mouth and a snap closure is present above the peelable closure. The package is sealed under vacuum, with the peelable closure maintaining the vacuum within the package until it is peeled open. The snap closure comprises a pair of snap strip members which are secured to the front and rear panel and have end portions which extend through openings in the side gussets. The snap strip portions can be opened and re-closed after the peelable closure has been opened for access to the interior of the package. Non-gusseted flexible packages, such as stand-up pouches typically include so-called "zipper-type" closures known from US-A-5,059,036 and US-A-5,147,272. A stand-up, zipper-closure type pouch does not allow efficient use of case packing and retail shelf space, as does a gusseted package. The stand-up pouch cannot be stacked readily, if at all. WO92/16424 discloses a flexible package according to the preamble of claim 1. It is one object of the invention to provide a flexible package gusseted bag having a snap type closure which is efficient in use, and does not require openings in the gussets. It is also an object to provide a package which has an efficient snap closure and whose state can easily be determined visually. According to the invention in one aspect there is provided a flexible package holding contents under vacuum comprising a front panel connected to a rear panel, the panels having upper end portions which together form a mouth for access to the interior of the package, male and female inter-engaging closure means being present to seal the mouth airtight after it has been opened, the closure means each being present on the outer surface of one of the panels characterised in that the male engaging means includes one portion which is fixed to the corresponding panel and another portion movable relative to the fixed portion, the fixed portion and the movable portion being connected by a living hinge which allows the movable portion to pivot with respect to the fixed portion during engagement/disengagement respectively of the closure, wherein when the closure means are not engaged the movable portion is remote from the respective panel and when the closure means are engaged the movable portion is adjacent to that panel. In one specific embodiment the movable portion of the male inter-engaging means comprises two flanges, one located at each side of the fixed portion, each having a return bend so that the free ends of the flanges contact the panel when the closure means are not engaged. In another specific embodiment the male member comprises one portion anchored to the wall panel, from which extends a wall incorporating at least one bend the free end portion of the wall contacting the panel at a location remote from the anchored portion. The male and female closure means are each elongate strips preferably having a length essentially the same as the width of the respective panel and located at substantially the same vertical distance from the open mouth of the package. The male and female closure means are adapted to interengage as a snap closure. While the invention may be applied to any package, good advantage is seen in one having side gussets portions which are also received in the closure means when these are engaged. In order that this invention may be well understood it will now be described by way of illustration with reference to the accompanying diagrammatic drawings in which:- Figure 1 is an isometric view of a flexible gusseted package before opening; Figure 2 is an enlarged isometric view taken from one side of the package of Figure 1 after it has been initially opened; Figure 3 is an enlarged isometric view as Figure 2, taken from the opposite side of the package; Figure 4 is an enlarged sectional view taken along line 4-4 on Figure 1; Figure 5 is a sectional view as Figure 4, showing the package in the process of being re-closed; Figure 6 is an isometric view of a separate closure for use on a known flexible gusseted package; Figure 7 is an isometric view of one embodiment of a flexible gusseted package of this invention before opening; Figure 8 is an enlarged isometric view taken from one side of the package of Figure 7 after it has been initially opened; Figure 9 is an enlarged sectional view taken along line 9-9 on Figure 7; Figure 10 is a view, as Figure 9, showing the package in the process of being re-closed; Figure 11 is a sectional view, like that of Figure 4 of another flexible gusseted package of the invention before opening; and Figure 12 is a sectional view as Figure 5, showing the package of Figure 11 in the process of being re-closed. The embodiments of Figures 1 to 6 are not the subject of the claims of this application, but are presented as background art. The same reference numerals are used to describe the different embodiments where convenient. A flexible package 20 shown in Figures 1 to 5, comprises a gusseted bag 22 having resealable closure 24. The bag 20 is arranged to hold any material, e.g. coffee beans, ground coffee, chemicals, and the like for dispensing therefrom. The package 22 comprises a front wall or panel 26, a rear wall or panel 28, gusseted sides 30 and 32, a top end portion 34, and a bottom end portion 36. The top end portion 34 of the package has a top marginal edge 38. The bottom end portion 36 has a bottom marginal edge (not shown). The front panel 26, rear panel 28, and the two gusseted sides 30 and 32 are all integral portions of a single sheet or web of the flexible material, or single or multiple ply or layers, which has been folded and seamed to form a tubular body. One particularly useful flexible material for the package 22 is a laminated web of flexible packaging material commercially available from Fres-Co System USA, Inc. of Telford PA 18969-1033, USA. That material comprises a 48 gauge polyester layer, ink, an adhesive layer, a 28 gauge aluminium foil layer, another adhesive layer, a 60 gauge nylon layer, another adhesive layer, and a 300 gauge easy open sealant layer. When a web of such material is formed into the tubular body for the package the polyester layer is the outer surface of the package, and the easy-open sealant layer is the inner surface of the package. The closure 24 is located in the top end portion 34 of the package. The details of the closure 24 will be described later. The package 20 is hermetically sealed along a transverse seal line 40, after it has been filled and vacuumised. The seal line 40 may be permanent or openable (e.g. peelable) and may be formed in any conventional manner. If the seal line is peelable it may be located at any location either above, below or aligned with the closure 24 and the package can be readily opened by merely grasping the top edges of the front and rear panels and pulling them apart to cause the peelable seal line to open, thereby forming a mouth for access to the interior of the package. If the seal line is permanent it should be located above the closure 24 with some space between it and the closure so that the package can be severed along a line between the seal line and the closure to thereby form the mouth. In either case, the seal line 40 extends across the width of the package 22 and seals the inner surfaces of the abutting front and rear panels to each other between the inner fold lines 30A and 32A of the gussets 30 and 32, respectively, while sealing the outer marginal portions of the front panel 26 to the portions of the gusseted sides contiguous therewith, while also sealing the outer marginal portions of the rear panel 28 to the portions of the gusseted sides contiguous therewith, as is conventional. Thus the seal line 40 serves to isolate the contents of the package from the ambient atmosphere once it is sealed. If the seal line 40 is peelable, it may be formed by the appropriate heat sealing of the abutting easy-open sealant layer portions forming the inner surface of the package 22. The peelable seal line 40 can be formed in any other manner, e.g. the use of peelable sealing strips. When the package 22 is filled, vaccumised, and sealed its contents, e.g. whole coffee beans (not shown), will be kept from the ambient air by the seal line 40. The closure 24 is also preferably closed, i.e. the strips 24A and 24B are interengaged. The top portion 34 of the package may be folded down to form a flap (not shown). The flap may, if desired, be held in place by adhesive tape (not shown) or some other adhesive means, so that the package is "brick-like" in shape to facilitate stacking or storage. If the package has a peelable seal line 40, the portions of the front and rear panels of the package contiguous with the top marginal edges 38 of the package are grasped and pulled apart to open the mouth. This action peels open the seal line 40, while also disconnecting or separating the two strips (to be described later) making up the closure 24 to open the mouth of the package. The contents of the package can then be removed through the mouth. If the package includes a non-openable seal line 40, e.g. a permanent heat seal, then the package can be severed below the heat seal line and above the closure 24. The newly formed top edge of the front and rear panels of the package which were formed by the severing action can then be grasped and pulled apart to separate and disconnect the two strips 24A and 24B to open the mouth of the package. The closure 24 is a part of the package (as in the embodiment of Figures 1 to 5) or the use of a separate closure 100 (as in the embodiment of Figure 6) with a conventional package enable the mouth of the package to be resealed. The closure 24 of Figures 1 to 5 comprises the pair of interengageable strips 24A and 24B. Each strip is an elongate member formed of a plastic material, e.g. high or low density polyethylene or polypropylene or other material selected to be slightly flexible to enable it to be bent out of its original shape by the application of force thereto, but which will return to its original shape after removal of that force. Each strip is anchored, e.g. welded or permanently adhered to the outer surface of the top portion of one of the panels 26 and 28 of the package 22 and across the full width of panel only and at substantially the same height. The strip 24A, best shown in Figures 4 and 5, is generally U shaped in section and includes an elongated planar upper flange section 42, an elongated planar lower flange section 44 and an intermediate section 46. The strip section includes a generally planar base wall 48 and a bridging section comprising a pair of sidewalls 50 and 52 which are inclined to merge with the upper and lower flanges 42 and 44 respectively. The planar wall 48 of the tongue shaped strip 24A is secured (at 54, Figure 5) along to the outer surface of the front panel 26 e.g. by a hot melt adhesive, any other type of adhesive, a weld joint or the like. The strip 24B, best shown in Figures 4 and 5, is generally channel shaped and includes an elongated planar lower flange section 56 and a generally C-shaped upper section 58 defining a groove or recess 60 therein. The free edge of the upper section 56 is in the form of a curved lip 62, but could be in the form of a rounded bead. The lower marginal portion, i.e. the flange section 56 is anchored at 64 along the outer surface of the rear panel 28, e.g. by a hot melt adhesive, any other type of adhesive, a weld joint or the like, whereas the upper marginal portion 62 is not. The strips are shaped so that the strip 24B can be snap received with the channel section of the strip 24A with portions of the panels 26, 28 trapped in between. The material forming the strips is selected to be sufficiently elastic and/or flexible to enable the tongue like portion 46 of the strip 24A to snap-fit into the channel 60 of the strip 24B, and to be locked therein against accidental disconnection, yet which will enable the tongue to exit that recess when the strips are pulled apart. To close the package the strips 24A and 24B are squeezed together to cause the tongue-like male element to snap into the channel 60 carrying with it contiguous portions of the front panel 26 and side gussets 30 and 32. During this action portions of the front panel 26 and contiguous side gussets bend around the top surface 48 and sidewalls 50 and 52 of the tongue 46 to be carried into engagement with opposed portions of the rear panel 28 and contiguous side gussets 30 and 32. These engaging panel and gusset portions are forced into the channel 60. Because the strip 24A is secured to the rear panel 28 only along its lower marginal flange section 56, the portion of the rear panel and contiguous side gussets immediately above the securement point 64 can move, e.g. pivot relative to the free edge 62 of the strip 24B to be received in the mouth 60, as shown in Figure 4. The strips 24A and 24B are substantially rigid so that when they are snapped together as just described, the confronting portions of the tongue and groove serve to sandwich the front panel 26, rear panel 28, and side-gussets 30 and 32 tightly therebetween, thereby producing a substantially air-tight seal. The longitudinal marginal portions extending from the flanged portions tend to reinforce the strips and keep them linear to further ensure that the mouth of the package is sealed closed when the strips are snap connected to each other. The package can be readily opened merely by snapping apart (disconnecting) the two strips 24A and 24B. The user of the package readily grasps any portion of the front panel of the package contiguous with its top edge between the thumb and forefinger of one hand, and any portion of the rear panel of the package contiguous with its top edge between the thumb and forefinger of the other hand to pull the panels apart and to separate the strips. The user can directly grasp one of the strips between the thumb and forefinger of one hand and the other strip between the thumb and forefinger of the other hand to pull the strips apart. In either case this action unsnaps the closure, i.e. causes the tongue of strip 24A to snap out of the mouth of strip 24B, thereby freeing the panels and providing access to the interior of the package through its mouth. The closure 100 of Figure 6 is a separate device to be mounted or releasably secured to a package 102 after it has been opened to reseal it. The closure 100 is identical to the closure 20. Thus closure 100 includes a male strip 100A which is identical to strip 24A and a female strip 100B which is identical to strip 24B. In use the male strip 100A is brought into engagement with the outer surface of the front panel or rear panel of the bag 102. The female strip 100B is brought into engagement with the outer surface of the other panel 26 so that its groove 60 is aligned with the tongue 46 of the strip 100A. The two strips 100A and 100B are then pressed together to cause the tongue of strip 100A to enter into the groove of strip 100B carrying with it the contiguous portions of the rear panel 28, front panel 26 and interposed side gussets 32 and 30 in the same manner as described above. The package 200 of Figures 7 to 10 includes a gusseted bag 22 identical to the bag of the package 20, and a closure 202. The closure 202 comprises a naked strip 202A and female strip 202B. The strip 202B of package 200 is similar to the groove strip 24B but has an upper flange as the free end of the upper C-shaped section (as will be described later). The strip 202A of the package 200 is also similar to the strip 24A, except that upper and lower flanges are initially curved and arranged to be flattened when the two strips of the closure 202 are secured together to provide a visual indication of that fact (as will also be described later). As shown best in Figures 9 and 10 the strip 202A is an elongated member which includes an elongated arcuate upper flange section 204, an upper hinge section 206, an elongated arcuate lower flange section 208, a lower hinge section 210, and a central projecting tongue section 212. The tongue section 212 has planar top wall 48 and inclined sidewalls 50 and 52 which merge with the upper and lower hinge curved sections 206 and 210, respectively. Section 206 and 210 is generally semi-circular in cross section. The planar wall 48 of the tongue shaped strip 202A is anchored along to the outer surface of the front panel 26. The strip 202B includes an elongated planar lower flange section 56 and a generally C-shaped upper section 58 defining a groove or recess 60 therein. The free edge of the upper section 56 is in the form of a planar upper flange 214 terminating in a curved lip 216. The lip may be in the form of a rounded bead. The lower flange section 56 is anchored along to the outer surface of the rear panel 28. To reseal package 200 the strips 202A and 202B are squeezed together to cause the tongue to snap into the channel carrying with it contiguous portions of the front panel 26 and side gussets 30 and 32. During this action the hinge sections flatten out, i.e. pivot outward, so that the upper and lower flange portions 204 and 208, respectively, assume a planar configuration to abut the outer surface of the contiguous portions of the front panel 26. At the same time portions of the front panel 26 and contiguous side gussets bend around the top surface 48 and undercut sidewalls 50 and 52 of the tongue 212 of the strip 202A to be carried into engagement with opposed portions of the rear panel 28 and side gussets 30 and 32. These engaging panel and gusset portions are forced into the groove or recess 60 in the strip 202B. Because the groove strip 202B is secured to the rear panel 28 only along its lower flange section 56, the portion of the rear panel and contiguous gussets immediately above the securement point 64 can move or slide with respect to the upper flange 214 and its curved free edge 216 of the strip 202B to be received in the groove 60 as shown in Fig. 9. When the tongue 212 is fully within the groove the upper and lower flanges 204 and 208 will be planar as shown in Figure 9. The confronting portions of the tongue and groove serve to sandwich the front panel 26, rear panel 28, and side-gussets 30 and 32 tightly therebetween, thereby producing a substantially air-tight seal. The upstanding and now planar upper flange 204 of the tongue strip 202A and the confronting upstanding flange 216 or the female strip 202B sandwich portions of the top portion 34 of the bag 22 between them and thus ensure that the top portion 34 of the bag 22 extends upward generally parallel to the front and rear panels of the package. The female strip 202B may be constructed like the C-shaped section of the groove strip 24B. In such an embodiment the top portion 34 of the bag 22 may not be oriented so that it is parallel to the front and rear panels of the bag when the closure is in place since the upper flange 204 of the tongue strip 202A will tend to assume its natural arcuate shape, thus bending the top portion of the bag 22 away from it. The flange portions tend to reinforce the strips and keep them linear to further ensure that the mouth of the package is sealed closed when the strips are snap connected to each other. When the package 200 has been resealed the tongue of the strip 202A is fully seated within the groove 60 of the strip 202B so that an air-tight seal is produced, this fact will be readily apparent to anyone seeing the package since the flanges 204 and 208 of the tongue strip 202A will have assumed a planar configuration. Accordingly, the package 200 provides a visual indication of a good, air-tight reseal. Of course, closure 202 may be a separate item attached to a separate bag. The flexible gusseted package 300 in Figures 11 and 12 has a closure 302 which includes a male strip 302A and a female strip 302B. The male strip 302A is similar to strip 24A, except for the inclusion of additional means to enable it to be more securely affixed to its associated bag panel so it cannot accidentally become disconnected. The female strip 302B is identical to the female strip 24B of closure 24 and the gusseted bag 22 is identical to the package 20. Thus the male strip 302A has a lower flange section 304 for mounting the strip onto its associated panel. The lower flange section 304 comprises a living hinge 306 of reduced wall thickness to enable it to bend freely, an inverted projecting tongue portion 308, and a mounting flange 310. The inverted tongue portion 308 has a generally planar wall 48 and a pair of sidewalls 50 and 52 which merge with the upper and lower flanges 42 and 310, respectively, except that it faces in the opposite direction therefrom. The lower mounting flange 310 is used to anchor the male strip 302A to the panel 26. The flange 310 is similar to the flange 44 of the strip 24A, except that it is of greater height to provide greater contact area for the adhesive or the weldment. When the strip 302A is secured to the panel 26 and when the closure 300 is open, i.e. the tongue strip is not interlocked to the groove strip, the strip is in the orientation as shown in Figure 12. The interface of the flat top 48 and the sidewall 52 of the tongue section 46 of the strip 302A then abuts the outer surface of the panel 26. In order to close the package, i.e. cause the two closure strips to interlock, all that is required is to press on the tongue strip to bend and pivot it inward and thereby force the tongue section 46 to enter into the mouth 60 in the groove strip 302B to tightly interpose the bag walls therebetween, as described earlier. The living hinge 306 facilitates the bending and pivoting of the tongue section from the orientation shown in Figure 12 to the orientation shown in Figure 11. The package can be readily opened by merely snapping apart the two strips 302A and 302B of the closure 302. The user can directly grasp the upper edge portion 62 of the strip 302B between the thumb and forefinger of one hand and the upper edge portion 42 the tongue strip 302A between the thumb and forefinger of the other hand to pull the strips apart. Either action unsnaps the closure, i.e. causes the tongue of strip 302A to snap out of the channel of strip 302B, thereby freeing the panels and providing access to the interior of the package through its mouth. The invention is not limited to the embodiments shown. An adhesive coating or coextrusion may be utilised to secure each strip in place on its associated panel. The material forming the strips or only a portion of the strips may be selected so that it can be heat sealed or welded to the material making up the panels. The closure of this invention can be used on packages which do not include side gussets, such as pouches. Either or both of the strips making up the closure may include some surface texture, e.g. ridges, knurls, grooves, etc. to enhance friction when grasped between the fingers of the user of the package. If desired, a one-way venting valve (not shown) may be included in any suitable portion of the package to enable gases which may be produced by the material(s), e.g. coffee, contained within the sealed package to vent to the ambient air without air gaining ingress to the package's interior. The invention offers advantages over pouch-type packages including conventional zip-lock type or other internally-located closures. For example, the closure may be applied to the pouch, after the pouch has been filled and sealed. Moreover, the closure provides rigid support to maintain the shape and integrity. The external closures do not render the package on which they are used subject to contamination and, hence, ineffective as can happen with internally applied closures, such as a zip-lock type closures. The packages provide an efficient air tight seal, and the condition of the closure means is visible so that the user can know whether or not the closure means are engaged or disengaged.

Claims: A flexible package (200; 300) holding contents under vacuum comprising a front panel (26) connected to a rear panel (28), the panels having upper end portions which together form a mouth for access to the interior of the package, male and female inter-engaging closure means (202A, 202B; 302A, 302B) being present to seal the mouth airtight after it has been opened, the closure means each being present on the outer surface of one of the panels (26, 28), characterised in that the male engaging means (202A, 302A) includes one portion which is fixed to the corresponding panel (26) and another portion movable relative to the fixed portion, the fixed portion and the movable portion being connected by a living hinge (206, 210, 306) which allows the movable portion to pivot with respect to the fixed portion during engagement/disengagement respectively of the closure means (202A, 202B; 302A, 302B), wherein when the closure means (202A, 202B; 302A, 302B) are not engaged the movable portion is remote from the respective panel (26) and when the closure means are engaged the movable portion is adjacent to that panel (26). A package (200) according to Claim 1, wherein the movable portion of the male inter-engaging means comprises two flanges (204, 208), one located at each side of the fixed portion, each having a return bend (206, 210) so that the free ends of the flanges contact the panel (26) when the closure means are not engaged. A package (300) according to Claim 1, wherein the male member (302A) comprises one portion (310) anchored to the wall panel (26), and from which extends a wall incorporating at least one bend, the free end portion of the wall contacting the panel (26) at a location remote from the anchored portion (310).

Inventors: BEER JEFFREY SCOTT, GALOMB DAVID E, SUTO DAVID K, BEER, JEFFREY SCOTT, GALOMB, DAVID E., SUTO, DAVID K.
Applicants: FRES CO SYSTEM USA INC, FRES-CO SYSTEM USA, INC.
Application year: 2000
Main classification: B65D33
IPC codes: B65D33