AU767648B2 - Plastic sheet material useful for packaging and packaging made from such sheet material and related methods - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

AMENDED

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: AEP INDUSTRIES (NZ) LIMITED and 4US~TRIA PLANT AND TECI''ITTCTT LIMITEDP Lawrence Joseph Olsen and Andr6 Kramer A J PARK SON, Level 11, 60 Marcus Clarke Street, Canberra ACT 2601 Plastic Sheet Material Useful for Packaging and Packaging Made From Such Sheet Material and Related Methods The following statement is a full description of this invention, including the best method of performing it known to me/us The present invention relates to plastic sheet material useful for packaging and packaging made from such sheet material and related methods.

In particular although not solely the present invention relates to the manufacture of a sheet material and packages formed from such a sheet material which incorporates a recloseable seal.

The use of recloseable seals of an interlocking kind has recently seen many alternative shapes and configurations of packages being formed. Such recloseable seals are typically referred to as a rib and groove type but are also commonly referred to as recloseable zippers.

Recent developments have seen zipper seals being manufactured in advance of being incorporated in a recloseable package. Such recloseable zippers normally consists of two strips often referred to as profile strips having interlockable components which form the recloseable seal thereof. The zipper seals are normally co-extrude and can later be attached to film material. Manufacturers of plastic film are known to provide film material which incorporates a zipper seal and provided this to customers as a roll of material which customers can then run through form, fill and seal machines to produce filled and sealed packages. Such is for example detailed in US Patent 55823933 where there is described the use of a zipper closure located on part of a film of the package away from an edge thereof. The disadvantage of a packaged formed in this nature is that it is difficult to remove the entire contents from the pack through the opening formed by the zipper.

S. The object of the present invention is to provide plastic sheet material useful for packaging and packaging made from such sheet material and related methods to at least provide the public with a useful choice.

Accordingly in a first aspect the present invention consists in a bag which in a lie flat condition comprises; two overlying plies of plastic film material defining a receptacle region there between bounded by a sealed bottom and two sealed sides and a mouth region defined between said plies at a top of said bag, a recloseable zipper means consisting of a first and second profile strip, each strip including a complimentary elongate recloseable seal means of an interlocking kind, said first profile strip including at least one integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means -3said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means said zipper means extending substantially from side to side of said bag adjacent said mouth region, wherein a) said first profile strip is heat sealed to the inwardly facing surface of a first of said two overlying plies along the flange thereof positioned receptacle region side of said bag, and b) said second profile strip is heat sealed to the inwardly facing surface of a second of said two overlying plies along a flange thereof, such that said elongate recloseable seal means of said first and second profile strips can be interlocked with each other and are positioned in respect of said two overlying plies to define an openable mouth region at said top of said bag, and wherein the first and second profile strips are sealed to each other only at regions of their distal ends immediately inwardly of each of said side of said bag, and wherein a heat sealed patch connecting together the overlying plies of material including the said flange of said first profile strip positioned receptacle side of said bag and said two overlying plies of plastic film material defining said receptacle is provided at a region immediately inwardly of said sides of said bag.

Preferably said two overlying plies are formed from one sheet of plastic film material with longitudinally extending edges, wherein said edges have been brought together in an overlapping relationship and heat sealed together to extend mouth region to bottom of said bag.

Preferably said first profile strip has said two elongate flanges each extending on one side of said elongate recloseable seal means, each flange of said first profile strip heat sealed there along to said first of said overlying plies.

Preferably said second profile strip has only one said elongate flange on one side only of said elongate recloseable seal means and which is heat sealed there along to said second of said overlying plies.

30 Preferably said bag in its lie flat condition, is substantially rectangular is plan "shape, wherein the two side regions are of longer length than said mouth region and bottom.

Preferably said bag has a tamper evident region of said overlying plies is provided adjacent to said recloseable zipper means wherein said overlying plies are heat sealed together along a closure seal extending across said mouth region to close -4said mouth region, but severably openeable along a line of perforations intermediate said recloseable zipper means and said closure seal to allow access to be gained to said receptacle via the mouth region.

Preferably said heat sealed patch extends, in a mouth region to bottom direction, from the elongate recloseable seal means of said first profile strip to the receptacle region side edge of the flange of said first profile strip positioned receptacle region side of said bag.

Preferably said heat sealed patch extends in a mouth region to bottom direction, only between the elongate recloseable seal means of said first profile strip to the receptacle region side edge of the flange of said first profile strip positioned receptacle region side of said bag.

In a further aspect the present invention consists in a sheet for making a bag as hereinbefore described comprising, a longitudinal panel of plastic film material having two parallel sides, a plurality of a recloseable zipper means of a length less that half the width (side-to-side) of said longitudinal panel and consisting of a first and second profile strip, each profile strip comprising of elongate recloseable seal means of a kind to interlock with a complementary elongate recloseable seal meansof the other of said profile strips, said first profile strips including two integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means •said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means :the plurality of recloseable zipper means (wherein said profile strips thereof are interlocked with each other) secured, and at regular bag length intervals substantially transverse to the general longitudinal direction of, to one face of said panel by heat seal engagement of a flange of said first profile strips to said plastic film intermediate of said sides of said panel, and wherein each distal end of said first and second profile strip are heat sealed o.o 30 together.

a further aspect the present invention consists in a method of making recloseable bags comprising: a) taking a plurality of elongate recloseable zipper means consisting of a first and second profile strip each strip including a complementary elongate recloseable seal means of an interlocking kind, said first profile strip including two integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means wherein said first and second profile strips are in interlocking engagement with each other and of substantially identical length b) connecting said plurality of recloseable zipper means to a longitudinal panel of plastic film material having two parallel sides and being of a width greater than twice the length of said recloseable zipper means, by heat sealing at least one flange of one of said profile strips to one side of said panel at bag length intervals inwardly from said sides of said film and transverse to the longitudinal direction thereof, c) bringing together said parallel edges of said panel to form a tube having a top edge and bottom edge and heat sealing said parallel edges of said panel to enclose said recloseable fasteners inside of said then formed tube, d) heat sealing along said bottom edge of said tubeto enclose said tube at its bottom, e) heat sealing a flange of the other of said profile strips to the profile strip heat sealed in step to the overlying portion of said film extending from its said edges to the distal ends of said recloseable zip fastener, f) heat sealing to connect together overlying plies of material including the flange of said first profile strip positioned bottom edge side of said tube and said panel 0 0 S•defining said tube, said heat sealing of step provided at a region immediately •go• inwardly of the distal ends of said recloseable zipper means, g) cutting said tube a bag length from the bottom edge to form a top edge mouth region of a discrete bag.

Preferably the said method further includes heat sealing said tube a said bag length from said bottom edge to form a sealed top edge of said bag.

Preferably the said method further includes perforating across the substantial 30 width of said top edge between the zipper means and sealed top edge to provide a severable means of accessing said mouth region of said bag.

Preferably the said method further includes intermediate of steps d) and e) the filling of the lower most potion of said tube with a food or other material to a level not above the lower most zip fastener.

In a further aspect the present invention consists in a bag which in a lie flat condition comprises; two overlying plies of plastic film material defining a receptacle region there between bounded by a sealed bottom and two sealed sides and a mouth region defined between said plies at a top of said bag, a recloseable zipper means consisting of a first and second profile strip, each strip including a complementary elongate recloseable seal means of an interlocking kind, said first profile strip including at least one integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means said zipper means extending substantially from side to side of said bag adjacent said mouth region, wherein a) said first profile strip is heat sealed to the inwardly facing surface of a first of said two overlying plies along the flange thereof positioned receptacle region side of said bag, and b) said second profile strip is heat sealed to the inwardly facing surface of a second of said two overlying plies along a flange thereof, o. such that said elongate recloseable seal means of said first and second profile strips can be interlocked with each other and are positioned in respect of said two overlying plies to define an openable mouth region at said top of said bag, and wherein the first and second profile strips are sealed to each other only at regions of their distal ends immediately inwardly of each of said side of said bag, and wherein the overlying portions of said flange of said first profile strip positioned receptacle side of said bag and said two overlying plies of plastic film material defining said receptacle are connected together by heat sealing provided at a region immediately inwardly of said sides of said bag.

30 This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or o..

-6collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The invention consists in the foregoing and also envisages constructions of which the following gives examples.

One preferred form of the present invention will now be described with reference to the accompanying drawings in which; Figure 1 is a perspective view of one preferred form of the bag of the present invention, Figure 2 is a perspective view of a part of a sheet material for the forming of a preferred form of a bag of the present invention, Figure 3 is a sectional view through section CC of figure 2 and figure 9, ""Figure 4 is a more detailed view of a portion of the view as shown in figure 2, Figure 5 is a sectional view through section AA of figure 1, Figure 6 is a sectional view through the sheet material of the present invention intermediate of one of the preferred steps of forming the package of the present **invention, Figure 7 is a sectional view through the sheet material of the present invention intermediate of one of the preferred steps of forming the package of the present invention, Figure 8 is a sectional view through section BB of figure 1, Figure 9 is an end view of the preferred form of the sheet material as shown in S-figure 2, Figure 10 is a view of the top region of a package of the present invention wherein a tamper evident region has been provided, Figure 11 is an end view as shown in directions EE of figure 12 of a sealing/cutting/perforating station of the preferred form of the present invention, Figure 12 is a sectional view through section DD of figure 11, Figure 13 is a sectional view through section DD of figure 11 wherein a tube of the sheet material for forming the bag of the preferred form of the present invention is in between, Figure 14 is a perspective view of an example of the form, fill and seal operation for the forming of packages from the sheet material of the preferred form of the present invention, -7- Figure 17-22 illustrate in cross section more preferred configurations of heat sealing jaws, Figure 23 is a schematic of the way in which the jaws are displaced, Figure 24 is a sectional view through section XX of Figure 25 and, Figure 25 is a side view of a belt drive arrangement for the forming tube.

With reference to figure 1 which illustrates the preferred form of the package of the present invention there is illustrated a packaged which has been formed from a sheet material preferably as shown in figure 2. The package 1 is preferably formed from overlying sheets of plastics material, whether such plastics material is of a single layer material or whether it is co-extruded and/or of different material such as LDPE or HDPE/ LLDPE or blend or the like. The bag preferably has side regions 2 and a bottom region 3. In the preferred form the overlying sheets of material are provided from a single flat sheet inwardly folded to bring the sides of the sheet together. With *ooo 1 reference to figure 2 the sides 4 are able to be brought together by folding them along 15 lines to define the edge regions 2 and with reference to figure 1 the sides 4 end up S. overlapping and inwardly from the edge regions 2. In the preferred form the folds defining the edge regions 2 of the package are substantially symmetrical across the width of the sheet material however the present invention is certainly not limited to the 22. overlapping sides 4 of the package to be substantially centrally between the edge regions 2.

The bag of the present invention as shown in the preferred form in figure 1 also has a top region 5 which defines a mouth to provide access to the interior of the bag.

The mouth region functions to allow material to be inserted and taken from the package. Across substantially the entire mouth region of the bag there is provided a recloseable zipper means 6. The recloseable zipper means is of a kind consisting of a first and second profile strip 7, 8 (reference to figure 5) having elongate recloseable seal means 9 and flange portions 10, 11, 12 on at least one side of the elongate recloseable seal means. The flange portions provide the regions which allow for the sealing of the recloseable zipper means to for example a plastic film or sheet. With reference to figure 2 the present invention includes the provision of a sheet material capable of being formed into discrete packages as shown in figure 1. The sheet material is preferably of an elongate nature having longitudinal edges 4 wherein between and transverse to the longitudinal direction the recloseable zipper means are provided at bag length intervals. With reference to figure 6 the sides 4 of the sheet material as shown in figure 2 are able to be brought together and sealed longitudinally -8to form a tube. In order for the recloseable zipper means not to be folded the width (side to side) of the sheet material figure 2 is at least twice the length of the recloseable zipper means located thereon. This will allow the side 4 to be brought together in a partially overlapping condition and allow for a sealing be achieved there between. As shown in figure 7 the sealing is of an overlapping kind wherein the opposing faces of the sheet material are broad in contact however alternatively the overlapping may be such as to bring together the same major surfaces of the sheet material for sealing. In the preferred form such sealing is by a heat sealing however alternative forms such as adhesive sealing may also be employed.

The recloseable zip elements are applied to the sheet material of a kind shown in figure 2 by sealing along the at least one flange of one of the profile strips. With reference to figure 3 it can be seen how one profile strip has been heat sealed to the sheet material at only one flange thereof. Should the profile strip have two flanges (and 1this is shown in figure 3) the other flange may or may not necessarily be also heat 15 sealed to the sheet material. It is preferably not sealed to the sheet and hence only one seal along substantially the entire length of the flange of a first profile strip 7 is provided.

Securing of the recloseable zipper means to the sheet material may also include the sealing of the distal ends thereof to the sheet material. With reference to figure 4 sealing of the distal ends is at least at the elongate recloseable seal mean 13 and may also be across part of the at least one flange of each of the first and second profile strips. Such end sealing ensures that both profile strips are secured together. Such securing is obviously however very undesirable across the length of the profile strips as hence no access would be able to be obtained to the package of the present invention. Therefore in one preferred form the first profile strip 7 has a flange extending from one side of the elongate recloseable seal means where the second profile strip does not have such a flange or perhaps does not have such a flange extending to the same extent as the first profile strip. A single bar heat seal for example may then provide a sealing of the recloseable zipper means to the sheet material without also joining the two profile strips together across the same distance. With reference to Figure 15 the sealing of the profiles strips 7, 8 may be that on both flanges 11, 12, 38, there is a sealing thereof to the respective and adjacent films.

Alternatively and as shown in Figure 16 (which also includes a mouth edge seal to provide complete air tightness to the pack) the inward most flanges of the profile strips may be sealed to the adjacent files of the bag. In another of the preferred forms the first seal of the first profile strip 14 (as in figures 3 and 4, is on that flange of the first profile strip further most away from the mouth region to be formed from the sheet material.

The sides 2 of the sheet material are brought together in a direction to enclose the recloseable zipper means within the tube. With reference to figure 7 there is shown the preferred recloseable zipper means 6.

In sealing the other (second) profile strip, 8 to the then overlying portions of the sheet material a seal is applied to the at least one flange of the second profile strip 8.

With reference to figure 5 or 16 the second profile strip preferably has only one flange and hence only one seal of the elongate recloseable seal means of that strip is provided.

The sealing of both profile strips to the sheet material is preferably achieved by a heat seal which extends between the distal ends of the strips.

o*oo It can hence be seen with reference to figure 1 that the recloseable zipper means provides a first strip to one side of the mouth region of the package and another strip 15 to the other side of the mouth region of the package. The elongate recloseable seal means are then hence positioned across the mouth region to allow interlocking thereof to provide a substantially secure seal.

The package of figure 1 is preferably also provided with a tab heat seal to seal S the overlying plies of material immediately below and inwardly from the elongate recloseable seal means. With reference to figure 10 such plies include the flange of the first strip, one side of the sheet to form the walls of the package and the other side of the sheet to form the wall of the package. These tabs 15 are preferably provided in this region to ensure that the contents of the package does not get trapped immediately below the distal ends of the strips. These tabs are preferably formed by heat sealing all of the plies of the material in this region so that they become secured together and to eliminate any space or void which may exist there.

In the preferred form the steps of sealing both the upper flange of the first profile strip and the upper flange of the second profile strip (flanges 11, 12) is preferably achieved simultaneously by the use of a heat sealing bars. The profile strips which allow for such heat sealing to occur between the flanges and the sheet material but not between the flanges of each of the strips themselves is of a kind as described in US Patent 5238306 its contents by way of reference hereby disclosed. The flanges where heat sealing of the two strips occur simultaneously onto the separate sheets of material are provided with the profiled ribs 40 facing each other. Another form of this method can be provided where one side of a heat seal bar is heated whereas the other bar on the other side of the bag is cooled.

With reference to figure 10 the packaging of the present invention may also be provided with a tamper evident region 16 which is either an extension of the sheet of material of the present invention or may alternatively be an additional strip which is attached to the sheet material at the mouth region. The tamper evident region preferably is provided in the form of seal 17 of the strip and immediately below that seal and between the seal and the recloseable zipper means a region of perforation 18 which allows for severable access to the recloseable zipper means and hence the mouth region of the package to be obtained.

As the package of the present invention is preferably manufactured from a sheet material having a plurality of recloseable zipper means and preferably as part of a form, fill and sealing machine it is suggested that the station at which the closing of the lower most bag from the elongate sheet of material simultaneously separates this lower most "15 bag therefrom to form a discrete bag as well as forming the bottom seal of the next .*lower most bag. With reference to figure 13 it can be seen that the lower most bag 19 with its bottom seal 20 in place in the preferred form prior to the top region of the bag being sealed the interior of the bag is filled with substance such as a food product or the like. The sealing jaw arrangement 21 preferably consists of pairs of opposed pressure applying means 22, 23 between which the plies of material forming the package of the present invention are positioned at their appropriate positions. Pairs of jaws are preferably of a heat sealing kind wherein preferably one of each pair is heated.

In one preferred form both of the pairs are heated and with the selection of the correct material for the plies of material of the bag heat sealing appropriate regions is able to be achieved. In an alternative form of the present invention the first of the pairs 23 of the jaw arrangement 21 may be heated and at least one of the complementary of each pair may be cooled. This may be desirable where full through seal of all of the plies at that point is not desirable. Cooling will hence allow for at least some control in respect of which plies of material are sealed together and which are not. With reference to figure 13 there is preferably provided first pair of sealing jaws 24 which provide the bottom seal of the subsequent bag to be filled and sealed. A preferred second pair of jaws 25 provide the preferred seal of the lower most bag along line 17 as shown in figure Jaws 26 seal those portions of the sheet material folded over and onto the other side of the recloseable zipper means as well as that portion (if any) of the zipper means -11which was already attached to the sheet material on the other side of the elongate recloseable seal means. With the use of a recloseable zipper means of a kind that is described in US5238306 and with the appropriate dwell times of the heat pressure applying operation (including the appropriate temperatures) the application of heat and pressure by the sealing means 26 will ensure there is separation between the overlying flanges of both strips of said zipper and that the only significant sealing which occurs is between the flanges of each strip and the opposed sheets of plastics film material.

Sealing means 24, 25 and 26 apply a heat seal substantially across the entire mouth region of said bag.

Sealing means 27 are to provide the sealing of webs of material at points 15 as substantially shown in figure 10. These sealing means do not extend across the entire width of the package and with reference to figure 11 it can be seen that these are Ssubstantially spaced apart to provide the preferred of sealing as shown in figure There is also preferably provided a perforation means 28 and a cutting means 29.

These are preferably located to provide the preferred perforation as shown in figure as well as the separation of the discrete lower most package from the sheet material.

S"With reference to Figure 17-22 more alternative and more preferred forms of the sealing jaws to be incorporated in the present invention are shown. In these figures the sealing jaws illustrated are each of substantially a unitary body or a body which will move in unison.

The sealing jaws illustrated have a design which is compact in its height and allows the features of sealing and separating to be provided more proximate to each other. Such proximate location of these features 41, 42 and 43 has the benefit of reducing the amount of bag length that is required to seal the profile strips and separate a bag from the continuous feed tube, hence reducing material costs.

With reference to Figure 17 which has sealing points which provide a single line seal, there is provided an upper seal line providing means 41 which seals the bottom of the next in line bag. The seal line providing means 42 provides the mouth seal 17 whereas the single line seal providing means 43 provides the seal of the flange or flanges of the profile strip on one side of the complementary profile ribs 9. Such may be on the outward or inward flange of the profile strips 7, 8.

Between the single line seal providing means (and not shown) can be the separation and/or perforation means.

-12- Between 41 and 42, there is preferably provided a separation means which is preferably a knife edge. This knife edge may act from one side of the sealing jaws into the other side.

Likewise between 42 and 43, a perforation means such as a perforating knife may be provided to provide the perforations 18 as shown in Figure A scrollable member 45 extends across the sealing surfaces of at least one of the sealing jaws.

Heating of the sealing jaws may be provided through a heating conduit 54 which may be provided by way of a heating element.

Figure 18 illustrates twin line seals to achieve the sealing as that described of the sealing jaws of Figure 17.

With reference to Figures 19-22, the lower seals 43 are preferably provided to S extend from each of the unitary members of the sealing jaws but are separated by a means to provide insulation 44. With reference to Figure 21, with the provision of such 15 insulation providing means 44, the lower seals can have a separately controlled temperature provision which may be provided through a conduit 46. Such temperature S"provision may be a heating element or may alternatively be a cooling element. Indeed one of the sealing jaws one side) may be heated whilst the other side is cooled.

S"With separate heat control over the lower seals of the sealing jaws, a significant degree of control over the speed of the sealing steps can be achieved. Dependent on choice of material, increased or reduced temperatures may be necessary at the lower seals as compared to the upper seals. With the ability to vary the temperature of the lower seals compared to the upper seals, an increased production rate is expected.

The insulation providing means 44 may for example be a rubber spacer. The use of a rubber spacer also allows for the displacement of the lower sealing jaws to be varied from the remainder of the seal providing means of the sealing jaws. This can be important where materials of different or varied thickness are incorporated in the pack of the present invention.

With reference to Figure 17-22, those part halves of the sealing jaws which provide the substantially "U-shaped" recess is preferably provided with a silicone insert against which the opposite and complementary portions of the sealing jaws can press.

An example where the two sealing jaws 22-23 are moved in an engaged condition is shown in Figure 23.

13- One of the parts of the sealing jaw, and for example shown in Figure 23, the sealing jaw 23 is displaceable relative to the other part 22. The displacement is preferably provided by an over-centre toggle providing arrangement which is preferably linkages 52-53 which at one end are secured to the seal bar 23 and at the other two a stationary point of the apparatus. With the application of a force to one or both of the link arms 52-53, a displacement of the sealing jaw 23 to and from the sealing jaw 22 can be achieved. A stop 55 may be provided where the appropriate and sufficient degree of over-centre of the linkages is achieved. The over-centre nature allows for a significant of pressure between the jaws to be achieved at a minimal demand of force required to be applied to the linkages.

As the present invention includes the method of forming the bag which utilises a reclose and is preferably achieved on a vertical form, fill and seal machine, as for S example shown in Figure 14, there are issues which need to be addressed in respect of a suitable adaptation of standard form, fill and seal machines where no transverse 15 reclose is provided to the film.

It will be appreciated and with reference to Figure 14, that when the reclose is advanced over the folding shoulder and down the filling tube 48 that the total material thickness at points where the reclose has been preapplied to the sheet of film, will be "thicker. As standard form, fill and seal machines incorporate a feed belt 49 which locates against the film advancing down the feed tube 48 which drives the tube of material downwardly by pressing it against the feed tube 48.

Prior art machine have provided for the increase in thickness of the materials at points where the reclose is applied, by providing a recess in the feed tube 48. However such recess is normally required to extend across the semi circle (in cross section) of the feed tube down which the reclose advance. Such can include expensive machining to remove the material from the feed tube, which is normally an extruded or rolled sheet metal material. With reference to Figure 24, an alternative arrangement is shown wherein a recess is provided in the feed belt 48 wherein such recess 50 is of a shape to accommodate the increase thickness as provided by the reclose elements.

With reference to Figure 24 which is a cross sectional view through section XX of Figure 25, it can be seen how the feed belt 49 has a recess provided on that side of the semi-circle of the feed tube 48 down which the reclose elements travel.

With reference to Figure 23 a wear strip backing plate 52 may be provided on an outwardly facing surface of the feed tube 48 to improve the wear characteristics and -14also reduce friction between the film material and the regions against which the film material is pressed whilst it is being advanced by the feed belt 49.

The wear strip backing plates may also be provided with a complementary recess for allowing the advancement of the reclose carrying film regions to pass there through.

Provided as backing to the feed belts 49, there is a backing timing belt 51, as it can be appreciated that timing in respect of the features providing the forming of the bag is important as these do need to remain synchronised.

o• *o* •got *ooo

Claims (14)

1. A bag which in a lie flat condition comprises; two overlying plies of plastic film material defining a receptacle region there between bounded by a sealed bottom and two sealed sides and a mouth region defined between said plies at a top of said bag, a recloseable zipper means consisting of a first and second profile strip, each strip including a complementary elongate recloseable seal means of an interlocking kind, said first profile strip including at least one integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means said zipper means extending substantially from side to side of said bag adjacent said mouth region, wherein a) said first profile strip is heat sealed to the inwardly facing surface of a first of said two overlying plies along the flange thereof positioned receptacle region side of said bag, and b) said second profile strip is heat sealed to the inwardly facing surface of a second of said two overlying plies along a flange thereof, such that said elongate recloseable seal means of said first and second profile S strips can be interlocked with each other and are positioned in respect of said two S.overlying plies to define an openable mouth region at said top of said bag, and ,wherein the first and second profile strips are sealed to each other only at regions of their distal ends immediately inwardly of each of said side of said bag, and wherein a heat sealed patch connecting together the overlying plies of material including the said flange of said first profile strip positioned receptacle side of said bag and said two overlying plies of plastic film material defining said receptacle is provided at a region immediately inwardly of said sides of said bag. 30

2. A bag as claimed in claim 1 wherein said two overlying plies are formed from one sheet of plastic film material with longitudinally extending edges, wherein said edges have been brought together in an overlapping relationship and heat sealed S.together to extend mouth region to bottom of said bag... together to extend mouth region to bottom of said bag. -16-

3. A bag as claimed in claims 1 or 2 wherein said first profile strip has said two elongate flanges each extending on one side of said elongate recloseable seal means, each flange of said first profile strip heat sealed there along to said first of said overlying plies.

4. A bag as claimed in any one of claims 1 to 3 wherein said second profile strip has only one said elongate flange on one side only of said elongate recloseable seal means and which is heat sealed there along to said second of said overlying plies.

A bag as claimed in any one of claims 1 to 4 wherein said bag in its lie flat condition, is substantially rectangular is plan shape, wherein the two side regions are of longer length than said mouth region and bottom.

6. A bag as claimed in any one of claims 1 to 5 wherein a tamper evident region of said overlying plies is provided adjacent to said recloseable zipper means wherein said overlying plies are heat sealed together along a closure seal extending across said mouth region to close said mouth region, but severably openeable along a line of perforations intermediate said recloseable zipper means and said closure seal to allow access to be gained to said receptacle via the mouth region.

7. A bag as claimed in any one of claims 1 to 6 wherein said heat sealed patch extends, in a mouth region to bottom direction, from the elongate recloseable seal means of said first profile strip to the receptacle region side edge of the flange of said first profile strip positioned receptacle region side of said bag.

8. A bag as claimed in any one of claims 1 to 7 wherein said heat sealed patch extends in a mouth region to bottom direction, only between the elongate recloseable seal means of said first profile strip to the receptacle region side edge of the flange of said first profile strip positioned receptacle region side of said bag.

9. A sheet for making a bag as claimed in any one of claims 1 to 8 comprising, a longitudinal panel of plastic film material having two parallel sides, a plurality of a recloseable zipper means of a length less that half the width (side-to-side) of said longitudinal panel and consisting of a first and second profile strip, each profile strip comprising of elongate recloseable seal means of a kind to 30 interlock with a complementary elongate recloseable seal meansof the other of said profile strips, said first profile strips including two integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means -17- said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means the plurality ofrecloseable zipper means (wherein said profile strips thereof are interlocked with each other) secured, and at regular bag length intervals substantially transverse to the general longitudinal direction of, to one face of said panel by heat seal engagement of a flange of said first profile strips to said plastic film intermediate of said sides of said panel, and wherein each distal end of said first and second profile strip are heat sealed together.

10. A method of making recloseable bags comprising: a) taking a plurality of elongate recloseable zipper means consisting of a first and second profile strip each strip including a complementary elongate recloseable seal means of an interlocking kind, said first profile strip including two integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means wherein said first and second profile strips are in interlocking engagement with each other and of substantially identical length b) connecting said plurality of recloseable zipper means to a longitudinal panel of plastic film material having two parallel sides and being of a width greater than twice the length of said recloseable zipper means, by heat sealing at least one flange of one of said profile strips to one side of said panel at bag length intervals S: inwardly from said sides of said film and transverse to the longitudinal direction thereof, c) bringing together said parallel edges of said panel to form a tube having a top edge and bottom edge and heat sealing said parallel edges of said panel to enclose said recloseable fasteners inside of said then formed tube, d) heat sealing along said bottom edge of said tubeto enclose said tube at its bottom, e) heat sealing a flange of the other of said profile strips to the profile strip heat sealed in step to the overlying portion of said film extending from its said edges to the distal ends of said recloseable zip fastener, -18- f) heat sealing to connect together overlying plies of material including the flange of said first profile strip positioned bottom edge side of said tube and said panel defining said tube, said heat sealing of step provided at a region immediately inwardly of the distal ends of said recloseable zipper means, g) cutting said tube a bag length from the bottom edge to form a top edge mouth region of a discrete bag.

11. A method as claimed in claim 10 wherein the method further includes heat sealing said tube a said bag length from said bottom edge to form a sealed top edge of said bag.

12. A method as claimed in claim 11 wherein the said method further includes perforating across the substantial width of said top edge between the zipper means and sealed top edge to provide a severable means of accessing said mouth region of said bag.

13. A method as claimed in any one of claims 10 to 12 wherein the said method further includes intermediate of steps d) and e) the filling of the lower most potion of said tube with a food or other material to a level not above the lower most zip fastener.

14. A bag which in a lie flat condition comprises; two overlying plies of plastic film material defining a receptacle region there between bounded by a sealed bottom and two sealed sides and a mouth region defined between said plies at a top of said bag, a recloseable zipper means consisting of a first and second profile strip, each strip including a complementary elongate recloseable seal means of an interlocking kind, S"said first profile strip including at least one integrally formed elongate flanges one provided extending adjacent each side of its elongate recloseable seal means said second profile strip including at least one integrally formed elongate flange extending adjacent of its elongate recloseable seal means said zipper means extending substantially from side to side of said bag adjacent said mouth region, 30 wherein a) said first profile strip is heat sealed to the inwardly facing surface ofa first of said two overlying plies along the flange thereof positioned receptacle region side of said bag, and I -19- b) said second profile strip is heat sealed to the inwardly facing surface of a second of said two overlying plies along a flange thereof, such that said elongate recloseable seal means of said first and second profile strips can be interlocked with each other and are positioned in respect of said two overlying plies to define an openable mouth region at said top of said bag, and wherein the first and second profile strips are sealed to each other only at regions of their distal ends immediately inwardly of each of said side of said bag, and wherein the overlying portions of said flange of said first profile strip positioned receptacle side of said bag and said two overlying plies of plastic film material defining said receptacle are connected together by heat sealing provided at a region immediately inwardly of said sides of said bag. oo0a g. oe