EP1449776B1

EP1449776B1 - Method for manufacturing a strip of film packages

Info

Publication number: EP1449776B1
Application number: EP04250730A
Authority: EP
Inventors: David J Matthews
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2003-02-19
Filing date: 2004-02-11
Publication date: 2008-08-06
Anticipated expiration: 2024-02-11
Also published as: EP1449776A3; DE602004015519D1; EP1449776A2; US20040159075A1

Description

The present invention relates to a method for manufacturing reclosable plastic packages of the variety in which consumer products are packaged for retail sale. More particularly, the present invention relates to a method for manufacturing strips of packages wherein individual packages making up the strip are separable from one another by perforations therebetween.
US5085031 discloses a method of forming a series of plastic pouches having a reclosable fastener for holding foodstuffs, according to the preamble of claim 1.
The present invention relates to improvements in the package-making art and may be practiced in the manufacture of thermoplastic bags and packages of the kind that may be used for various consumer products, but which are particularly useful for food products which must be kept in moisture- and air-tight packages, free from leakage until initially opened for access to the product contents. The prior art is fairly well developed, but nevertheless has aspects worthy of development and improvement.
In the present case, package strips made on horizontal form-fill-and seal (HFFS) machines or on flow-wrap machines are well known in the art. There has long been an interest in producing strips of individual packages, wherein each individual package has a reclosable plastic zipper. The present invention provides for this need.
Accordingly, the present invention comprises a method for manufacturing package strips having a preselected number of individual packages of a consumer product, each of said individual packages having a reclosable plastic zipper, said method comprising the steps of:

a) providing a top sheet of polymeric film material (16)and a bottom sheet of polymeric film material;
b) providing a supply of reclosable zipper strip;
c) attaching preselected lengths of said reclosable zipper strip, one for each individual package being manufactured, transversely upon one of said top and bottom sheets at package-length intervals thereon;
d) depositing a consumer product to be packaged on said bottom sheet at package-length intervals thereon;
e) covering said consumer product with said top sheet;
f) sealing said top sheet to said bottom sheet so as to enclose said consumer product between said top and bottom sheets;
g) attaching said preselected lengths of said reclosable zipper strip to the other of said top and bottom sheets;
h) making a cross seal on a side of said consumer product opposite to said preselected length of reclosable zipper strip to form said individual packages thereof; and
i) cutting between adjacent individual packages at preselected intervals to obtain said package strips having a preselected number of individual packages,
characterised by:
j) making perforations between each adjacent individual packages to enable said individual packages to be separated from one another.

Optionally, a peel seal between flange portions of the reclosable zipper strip may be formed and activated.
Particular embodiments will now be described with reference to the accompanying drawings; in which:-

Figure 1 is a schematic view of an apparatus for manufacturing package strips whose individual packages have transverse zippers;
Figure 2 is a cross-sectional view of a zipper-application station for the apparatus shown in Figure 1;
Figure 2A is a cross-sectional view of an alternate zipper-application station for zippers having sliders;
Figure 3 is a perspective view of a sheet of polymeric film material passing over a folding board in the apparatus shown in Figure 1;
Figure 3A is an enlarged view of the indicated portion of Figure 3;
Figure 4 is a schematic cross-sectional view of the cross-sealing, perforating and cutting stations of the apparatus shown in Figure 1;
Figure 4A is a schematic cross-sectional view, analogous to that of Figure 4, for the case where the zippers have sliders;
Figure 5 is a schematic cross-sectional view of the same stations as are shown in Figure 4 where the zipper has a peel seal;
Figures 5A and 5B are enlarged views of the indicated portions of Figure 5;
Figure 6 is a schematic view of another apparatus for manufacturing package strips whose individual packages have transverse zippers; and
Figure 7 is a schematic view of still another apparatus for manufacturing package strips whose individual packages have transverse zippers.

Turning now to these figures, Figure 1 is a schematic view of an apparatus for practicing the method for manufacturing the package strips of the present invention. Apparatus 10 comprises a drive roller 12 and a companion roller 14 forming a nip therewith for supplying a sheet 16 of polymeric film material in package-length increments from a supply roll 18 thereof. The sheet 16 proceeds to zipper-application station 20 which applies lengths of reclosable zipper strip 22 transversely onto sheet 16 at package-length intervals from a supply not shown.
Figure 2 is a cross-sectional view of zipper-application station 20. The station 20 comprises a zipper guide 24 which pivots counterclockwise around hinge 26, when urged to do so by spring 28, to release a length of reclosable zipper strip 22 which has been attached to sheet 16. It will be appreciated by those of ordinary skill in the art that zipper guide 24 is but an example of those known in the art and useful for the practice of the present invention. The station 20 also comprises a first seal bar 30 and a second seal bar 32, one on each side of the sheet 16, for attaching the length of reclosable zipper strip 22 thereto.
Reclosable zipper strip 22 includes a male interlocking profile 34 and a female interlocking profile 36. The former includes a male interlocking member 38, perhaps having an arrowhead-shaped cross section as shown in Figure 2, and a flange 40 integrally formed therewith. The latter includes a female interlocking member 42, perhaps comprising two inwardly curving members having barbed edges and defining a channel as shown in Figure 2, into which male interlocking member 38 snappingly engages, and a flange 44. The mutually facing surfaces of flanges 40,44 may have ridges 48 to facilitate gripping when a package having reclosable zipper strip 22 is being opened. It should be understood that reclosable zipper strip 22 is an example of the strips that may be used in practicing the present invention, and that the present invention is not to be construed to be limited to such a specific zipper design.
First seal bar 30 and second seal bar 32 seal the length of reclosable zipper strip 22 to film 16, and optionally form a peel seal between the two flanges 40,44.
Specifically, the upper portion 50 of first seal bar 30 is rubber, while the upper portion 52 of second seal bar 32 is heated so that, when the first and second seal bars 30,32 clamp together, flange 44 is sealed to sheet 16 without being sealed to flange 40 as well. The first and second seal bars 30,32 may also have lower portions 54,56, respectively, which activate an optional peel seal 58 between flanges 40,44. Peel seal 58, alternatively, may be formed during the manufacture of the reclosable zipper strip 22.
Figure 2A is a cross-sectional view of an alternate zipper application station 20' for use where the reclosable zipper strip 22' has a slider 49. Elements appearing in both Figures 2 and 2A have the reference numbers used in Figure 2, and the descriptions thereof given above are equally applicable for them in Figure 2A. Reclosable zipper strip 22' in Figure 2A has a slider 49, which separates the male and female interlocking profiles 34,36 from one another when moved in one direction along zipper strip 22', and joins them together when moved in the other direction. Zipper guide 25 is modified, relative to zipper guide 24 in Figure 2, to accommodate slider 49.
Referring back to Figure 1, individual lengths 60 of reclosable zipper strip 22 are attached transversely to film 16 at package-length intervals. The individual lengths 60 extend for approximately one half of the width of the sheet 16, and, in the schematic view of Figure 1, are attached adjacent to one of the two lateral edges of the sheet 16. Proceeding along in the direction of travel of sheet 16 from zipper-application station 20, sheet 16 passes through a dancer 62 which accumulates sheet 16 so that its incremental motion past zipper-application station 20 is converted to a continuous motion.
Sheet 16 continues from dancer 62 to folding board 64. Figure 3 is an enlarged view of folding board 64 and of sheet 16 passing thereover, and Figure 3A is a further enlarged view of the indicated portion of Figure 3. Folding board 64 extends for half the width of the sheet 16, namely the half having the individual lengths 60 of reclosable zipper strip 22, or of reclosable zipper strip 22' having slider 49, attached thereto, and changes the direction of travel of the sheet 16 by 90g. As a consequence, the half of the sheet 16 not supported by the folding board 64 becomes slack, enabling it to be folded over the half having the individual lengths 60 of reclosable zipper strip 22. The consumer product 63 being individually packaged is deposited on the sheet 16 in the amounts intended for each individual package between each individual length 60 of reclosable zipper strip 22 on or adjacent to folding board 64, such as at point 65, so that the sheet 16 is folded over the consumer product 63. It should be noted that the sheet 16 could alternatively be folded by other methods known to those of ordinary skill in the art and not requiring a 90° change in direction of travel to accomplish the folding.
Figure 3A provides a perspective view of the end of an individual length 60 of reclosable zipper strip 22 as attached to sheet 16. As illustrated, individual length 60 extends for approximately one half of the width of the sheet 16, and does not quite extend to the lateral edge 66 of the sheet 16. The optional slider 49 is also shown in Figure 3A.
Returning again to Figure 1, as the sheet 16 is being folded longitudinally by folding board 64, lateral edge 68 is brought over and on top of lateral edge 66. Heated drive rolls 70, somewhat downstream from folding board 64, carry out two functions. Firstly, they drive sheet 16 at a constant rate, pulling it over the folding board 64 so that it may be folded as required. Secondly, heated drive rolls 70 seal the folded sheet 16 along lateral edges 66,68 and optionally along crease 72.
Downstream from heated drive rolls 70 are three additional stations for completing the manufacture of the package strips. Referring to Figure 4, seal station 74 seals flange 40 of reclosable zipper strip 22 to the half of sheet 16 which has been folded over by folding board 64.
Seal station 74 comprises a heated seal bar 76 and an unheated seal bar 78. Both bars 76,78 rotate as indicated by the curved arrow adjacent thereto, bar 76 rotating in a counterclockwise sense and bar 78 rotating in a clockwise sense. Each makes one half of a complete rotation in the time required for one of the individual packages to pass thereby, it being recalled that the sheet 16 is moved at a constant rate by heated drive rolls 70, and does not come to a stop at seal station 74 or at the other two stations whose function is to be discussed below. The rotation is synchronized such that the bars 76,78 are oriented vertically, as shown in Figure 4, as the reclosable zipper strip 22 arrives so that the intended sealing can occur.
It is to be noted that unheated seal bar 78 has silicone-rubber pads 80 at each end to apply pressure, but not heat, to flange 44 while heated seal bar 76 seals sheet 16 to flange 40. This is intended to prevent flanges 40,44 from being sealed to one another.
One package length downstream is another station, which seals the bottom of each individual package and provides perforations to enable the individual packages to be separated from one another. Specifically, seal/perforation station 82 comprises a first and a second heated seal bar 84,86, the former including a perforator 88. Both bars 84,86 rotate as indicated by the curved arrows adjacent thereto, bar 84 rotating in a counterclockwise sense and bar 86 rotating in a clockwise sense. Each makes one half of a complete rotation in the time required for one of the individual packages to pass thereby, as was the case with bars 76,78. Again, the rotation is synchronized such that the bars 84,86 are oriented vertically, as shown in Figure 4, as the reclosable zipper strip 22 arrives so that the intended sealing and perforating can occur. Seal bars 84,86 provide a bottom seal 90 for each individual package, and perforator 88 provides perforations so that each individual package can be separated from the next.
A further package length downstream is yet another station which cuts the 5 package strips being manufactured to a desired length comprising some preselected number of individual packages. The preselected number may be any number, including one. As such, cutting station 92 comprises first and second bars 94,96, the former including a cutting knife 98. Both bars 94,96 rotate as indicated by the curved arrows adjacent thereto, bar 94 rotating in a counterclockwise sense and bar 96 rotating in a clockwise sense. Each makes one half of a complete rotation in the time required for the preselected number of individual packages desired for the strip to pass thereby, at which time cutting knife 98 cuts the strip 100 from the rest of the individual packages, each containing consumer product 63, being manufactured.
Figure 4A is a schematic cross-sectional view, analogous to that of Figure 4, for the case where the reclosable zipper strips 22' have sliders 49. When comparing Figures 4 and 4A with one another, it will be noted that the consumer product 63 being packaged is downstream of the reclosable zipper strip 22' for a given package in Figure 4A, while it was upstream of the reclosable zipper strip 22 in Figure 4. The significance of this difference between Figures 4 and 4a will become apparent in the discussion to follow.
As in Figure 4, seal station 74 comprises heated seal bar 76 and unheated seal bar 78. Seal station 74 functions in the same manner as described above to seal sheet 16 to flange 40 without sealing flanges 40,44 to each other.
Downstream from seal station 74 in Figure 4A is seal/perforation station 82', which differs from seal/perforation station 82 in Figure 4. Seal/perforation station 82' seals the bottoms of the individual packages being manufactured, provides perforations to enable the individual packages to be separated from one another, and optionally activates a peel seal at the tops of the individual packages. Specifically, seal/perforation station 82' comprises first and second heated seal bars 84',86', the latter including a perforator 88'. As in seal/perforation station 82 in Figure 4, seal bars 84',86' rotate in the directions indicated, making one half of a complete revolution in the time required for one of the individual packages to pass by station 82'. The upstream portions of first and second seal bars 84',86' provide a bottom seal 90 for each individual package, perforator 88' provides perforations so that each individual package can be separated from that preceding it, and the downstream portions of the first and second seal bars 82',84', which do not meet one another as closely as the upstream portions which form bottom seal 90, may activate an optional peel seal 91 at the top of the preceding package. It should be understood that the perforations and optional peel seal 91 in an individual package give a consumer access to slider 49 so that the individual package may be opened by manipulation thereof.
Cutting station 92 is one package length downstream from sea]Iperforation station 82', and is as described above for Figure 4. Cutting knife 98 cuts the strip 100, seen in Figure 1, from the rest of the individual packages, each containing consumer product 63, being manufactured between bottom seal 90 and optional peel seal 91.
Figure 5 shows the same stations as are shown in Figure 4 for the case where flanges 40,44 of reclosable zipper strip 22 are joined to one another with peel seal 58. Figures 5A and SB are enlarged views of the indicated portions of Figure 5. In all other respects, a discussion of Figures 5, 5A and SB would be identical to that above for Figure 4 and, as such, it will not be repeated here. Further, reclosable zipper strip 22', having a peel seal 58 and a slider 49, could also be used in the manufacture of reclosable packages in the manner illustrated in Figure 4A.
Figure 6 is a schematic view of an apparatus slightly different from that shown in Figure 1 for practicing the method for manufacturing the package strips of the present invention. Apparatus 110 is substantially the same as apparatus 10. Accordingly, the preceding discussion applies to apparatus 110, and elements in Figure 6 to which the preceding discussion equally applies will be given the same drawing reference numbers as appear in Figure 1, except to the extent described below.
Referring to Figure 6, and comparing it to Figure 1, it will be immediately apparent that zipper-application station 20 still applies individual lengths 60 of reclosable zipper strip 22 to film 16 at package-length intervals, but that, instead of being applied adjacent to one of the two lateral edges 66,68 of the sheet 16, they are centered with respect to the lateral edges 66,68. Moreover, downstream from dancer 62, the lateral edges 66,68 are folded toward one another and sealed together with a fin seal 114 by heated drive rolls 112, which also drive the sheet 16 at a constant rate. In all other respects, apparatus 110 is the same as apparatus 10. That is to say, downstream from the heated drive rolls 112, the manufacture of package strip 100 is completed by seal station 74, seal/perforation station 82 and cutting station 92, as previously described.
Figure 7 is a schematic view of still another apparatus for practicing the method for manufacturing the package strips of the present invention. Apparatus 120 is much the same as apparatuses 10,110, and elements appearing in Figure 7 to which the preceding discussion equally applies will be given the same drawing reference numbers as are used in Figures 1 and 6, and will not be described again.
Referring, now, to Figure 7, apparatus 120 produces package strips using two supplies of plastic film material rather than one which must be folded over the consumer product being packaged. Specifically, apparatus 120 uses a top sheet 122 of polymeric film material dispensed from a supply roll 124 and a bottom sheet 126 of polymeric film material dispensed from a supply roll 128.
Turning first to the top sheet 122, this sheet may be fed or dispensed from supply roll 124 in package-length increments and lengths of reclosable zipper strips attached transversely thereto at some point, such as point 130, before dancer 62, which converts the incremental motion of the top sheet 122 to continuous motion driven by heated drive rolls 70. Length 132 of reclosable zipper strip, applied using a zipper-application station like that shown in Figures 1 and 6 but not included in Figure 7, extends for substantially the full width of top sheet 122 between its lateral edges 134,136.
Bottom sheet 126, fed from supply roll 128, proceeds at a constant rate to a point, such as point 138, where a consumer product 139 may be placed thereon at package-length intervals. Bottom sheet 126 has lateral edges 140,142 which are sealed to lateral edges 134,136, respectively, by heated drive rolls 70. Thereafter, the manufacture of package strip 100 is completed by seal station 74, seal/perforation station 82 and cutting station 92, as previously described.

Claims

A method for manufacturing package strips having a preselected number of individual packages of a consumer product, each of said individual packages having a reclosable plastic zipper, said method comprising the steps of:
a) providing a top sheet of polymeric film material (16) and a bottom sheet of polymeric film material (16);

b) providing a supply of reclosable zipper strip (22);

c) attaching preselected lengths (60) of said reclosable zipper strip, one for each individual package being manufactured, transversely upon one of said top and bottom sheets at package-length intervals thereon;

d) depositing a consumer product (63) to be packaged on said bottom sheet at package-length intervals thereon;

e) covering said consumer product with said top sheet;

f) sealing said top sheet to said bottom sheet so as to enclose said consumer product between said top and bottom sheets;

g) attaching said preselected lengths of said reclosable zipper strip to the other of said top and bottom sheets;

h) making a cross seal (90) on a side of said consumer product opposite to said preselected length of reclosable zipper strip to form said individual packages thereof; and

i) cutting between adjacent individual packages at preselected intervals to obtain said package strips having a preselected number of individual packages,
characterised by:

j) making perforations between each adjacent individual packages to enable said individual packages to be separated from one another.
A method as claimed in claim 1 wherein step a) is performed by providing a sheet of polymeric film material(16) and by folding said sheet lengthwise along a single fold line over said consumer product (63) to form said top sheet and said bottom sheet.
A method as claimed in claim 2 wherein two lateral edges of said sheet (16) are sealed to one another to seal said top sheet over said consumer product (63).
A method as claimed in claim 1 wherein step a) is performed by providing a sheet of polymeric film material (16) and by folding said sheet lengthwise along two fold lines and bringing both lateral edges thereof toward one another over said consumer product to form said top sheet and said bottom sheet.
A method as claimed in claim 4 wherein said two lateral edges are sealed to one another with a fin seal (14) to seal said top sheet over said consumer product (63).
A method as claimed in claim 1 wherein step a) is performed by supplying said top sheet (122) separately from said bottom sheet (126).
A method as claimed in claim 1 further comprising the step of providing a peel seal (58) on said preselected lengths of reclosable zipper strip (60).
A method as claimed in claim 2 or 4 wherein said preselected lengths of said reclosable zipper strip (60) extend for substantially one half of the width of said sheet of polymeric film material (16).
A method as claimed in claim 6 wherein said preselected lengths of said reclosable zipper strip (60) extend for substantially the width of said bottom sheet of polymeric film material (16).
A method as claimed in claim 1 further comprising the step of providing said preselected lengths of said reclosable zipper strip (60) with sliders (49).
A method as claimed in claim 1 further comprising the step of providing a peel seal between said top sheet and said bottom sheet adjacent to said preselected lengths of reclosable zipper strip.
A method as claimed in claim 1 wherein step f) is performed by heated drive rolls.
A method as claimed in claim 1 wherein said preselected number of individual packages in said package strips is in a range from five to eight.