CA2183720A1 - Hermetically sealed package with heat-sealable tear strip and method of manufacture - Google Patents
Hermetically sealed package with heat-sealable tear strip and method of manufactureInfo
- Publication number
- CA2183720A1 CA2183720A1 CA 2183720 CA2183720A CA2183720A1 CA 2183720 A1 CA2183720 A1 CA 2183720A1 CA 2183720 CA2183720 CA 2183720 CA 2183720 A CA2183720 A CA 2183720A CA 2183720 A1 CA2183720 A1 CA 2183720A1
- Authority
- CA
- Canada
- Prior art keywords
- package
- tear strip
- sealant layer
- layer
- wall
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 24
- 238000004519 manufacturing process Methods 0.000 title description 3
- 239000010410 layer Substances 0.000 claims abstract description 120
- 239000000565 sealant Substances 0.000 claims abstract description 91
- 239000012792 core layer Substances 0.000 claims abstract description 70
- 229920006280 packaging film Polymers 0.000 claims abstract description 42
- 239000012785 packaging film Substances 0.000 claims abstract description 42
- 238000009459 flexible packaging Methods 0.000 claims abstract description 14
- 238000007789 sealing Methods 0.000 claims abstract description 14
- 238000004806 packaging method and process Methods 0.000 claims description 35
- -1 polypropylene Polymers 0.000 claims description 19
- 229920000642 polymer Polymers 0.000 claims description 9
- 239000004698 Polyethylene Substances 0.000 claims description 8
- 239000004743 Polypropylene Substances 0.000 claims description 8
- 229920000573 polyethylene Polymers 0.000 claims description 8
- 229920001155 polypropylene Polymers 0.000 claims description 8
- 239000005020 polyethylene terephthalate Substances 0.000 claims description 5
- 229920000139 polyethylene terephthalate Polymers 0.000 claims description 5
- 239000005038 ethylene vinyl acetate Substances 0.000 claims description 4
- 229920001903 high density polyethylene Polymers 0.000 claims description 4
- 239000004700 high-density polyethylene Substances 0.000 claims description 4
- 229920001577 copolymer Polymers 0.000 claims description 3
- 238000010030 laminating Methods 0.000 claims description 2
- 229920001684 low density polyethylene Polymers 0.000 claims 3
- 239000004702 low-density polyethylene Substances 0.000 claims 3
- DQXBYHZEEUGOBF-UHFFFAOYSA-N but-3-enoic acid;ethene Chemical compound C=C.OC(=O)CC=C DQXBYHZEEUGOBF-UHFFFAOYSA-N 0.000 claims 2
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims 2
- 238000012856 packing Methods 0.000 claims 1
- 239000002344 surface layer Substances 0.000 claims 1
- 239000000725 suspension Substances 0.000 claims 1
- 239000005026 oriented polypropylene Substances 0.000 abstract description 4
- 239000000853 adhesive Substances 0.000 description 11
- 230000001070 adhesive effect Effects 0.000 description 11
- 238000001125 extrusion Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 4
- 235000013351 cheese Nutrition 0.000 description 3
- 235000013305 food Nutrition 0.000 description 3
- 229920010126 Linear Low Density Polyethylene (LLDPE) Polymers 0.000 description 2
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000007765 extrusion coating Methods 0.000 description 2
- 239000005022 packaging material Substances 0.000 description 2
- 238000003855 Adhesive Lamination Methods 0.000 description 1
- 239000011127 biaxially oriented polypropylene Substances 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 230000001055 chewing effect Effects 0.000 description 1
- 235000019504 cigarettes Nutrition 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 235000019692 hotdogs Nutrition 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 235000013372 meat Nutrition 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 239000005033 polyvinylidene chloride Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
Landscapes
- Packages (AREA)
Abstract
An easy open package adapted for hermetic sealing of its contents. The package includes a flexible packaging film forming a first package wall and a tear strip sealed to an inner surface of the first package wall. The tear strip includes a core layer formed of oriented polypropylene so as to provide sufficient tensile strength for tearing the package. The core layer includes first and second surfaces. An outer sealant layer is adhered to the first surface of the oriented core layer and is sealed to the inner surface of the first package wall. An inner sealant layer is adhered to the second surface of the oriented core layer. A second package wall is connected to the first package wall around its periphery to define a product receiving chamber between the first and second package walls. The second package wall is adapted to be sealed to the inner sealant layer of the tear strip in a heat seal zone so as to hermetically seal the tear strip between the first and second package walls. A lateral edge of the tear strip extends beyond the heat seal zone into the chamber to provide uniform and reliable opening of the package upon removal of the tear strip. An aperture extends through the package walls and the tear strip such that the tear strip reinforces the package walls to prevent tearing of the package walls that may otherwise be caused by support members inserted through the aperture.
Description
~ERMETICALLY SEALED PACKAGE WITH HEAT-SEALABLE TEAR STR~P
AND MET~IOD OF MANUFACTURE
Back~round of the Invention llle present invention is directed to herrnetically sealed packages and tear strips which are pa~icularly adapted for opening the package and methods of rnaking the package.
Nurnerous forms of tear strips have been provided to facilitate the opening of sealed packages E~carnpies which are probably familiar to rnany consumers include the tear strip used to open a package of cigarettes or a package of chewing gurn. Most tear strips of this type are sirnply positioned inside one portion of a package wall with an end extending outwardly to be grasped by the consurner. Once grasped and pulled, the tear strip opens an edge or end of the package either by unsealing it or by physically tearing through the package wall.
The present invention constitutes a specially constructed tear strip or tape and a package in which the tear strip extends along a portion theteof to facilitate easy opening of the package to provide access to the contents. Tear strips utilized in prior art constructions do not provide herrnetic seals with conventional rnaterials. That is because they are norrnally provided with a silicone based releæ coat on one surface thereof. The tear strip of the present invention is adapted to be sealed on both opposing sides thereof, and at each end of the tear s~ip, to the package film to thereby provide a herrnetically sealed package for containLng food products and other items.
Brief Description of the Drawin~es Figure 1 is a top plan view of a first embodiment of the heat-sealable tear tape.
Figure 2 is an enlarged partial cross-sectioral view of the tear tape taken along lines 2-2 of Flgure 1.
Figure 3 is a top plan view of a piece of packaging filrn with the tear tape heat sealed thereto.
Figure 4 is an enlarged partial cross-sectional view of the packaging film and tear tape taken along lines 44 of Figure 3.
Figure 5 is a side elevational view of a first embodiment of a package including a tear tape.
Figure 6 is a rear view of the first package embodiment taken along lines 6-6 of Figure 5.
Figure 7 is an end view of the first package embodiment taken along lines 7-7 of Figure 6.
Figure 8 is a cross-sectional view of the first package embodiment taken along lines 8-8 of Figure 6.
Fig,ure 9 is an enlarged cross-sectional view of a second embodiment of the tear tape.
Fig,ure 10 is an enlarged cross-sectional view of third embodirnent of the tear tape.
Figure 11 is a partial front elevational view of a second embodiment of a package including a tear tape.
Detailed Description of the Preferred Embodiments A herrnetically sealed package 10 is illustrated which comprises a sheet of packaging filrn 12 and a tear tape or strip 14 heat sealed to the packaging film 12. As best shown in Figures 1 and 3, the tear tape 14 is forrned as a thin and flat elongate strip extending between a first end or edge 16 and a second end or edge 18. As best shown in Figure 2, one embodiment of the tear tape 14 includes a first sealant layer 20 adhesively lan~inated to a first surface 21 of a core layer 22 by a layer of adhesive 24. A second sealant layer 26 is adhesively l~min~ted to a second opposing surface 27 of the core layer 22 by a layer of adhesive 28. Ille first and second sealant layers 20 and 26 are each forrned of a copolymer 218372~
of polyethylene containing 5% ethylene-vinyl acetate (EVA). Each sealant layer 20 and 26 is preferably approximately 1.5 mils thic~ The core layer 22 is fo~ned of tensilized rnachine oriented polypropylene (MOPP~ which is preferably approximately two rnils thic~ Various types of adhesives rnay be used for the adhesive layers 24 and 28, however, one preferred adhesive is "TYCEL" adhesive as sold by the Liofol Company.
~ e sealant layers 20 and 26 of the tear tape 14 can be rnanufactured as blown fikns on extruders. The first sealant layer 20 can be adhesively lamirLated to the core layer 22 on an adhesive lamirlator. l~e combination of the sealant layer 20 and core layer 22 can then be adhesively laminated to the second sealant layer 26. This tear tape base structure is initially about forty-one inches wide and rnay be trirnrned into two millimeter wide strips which forrn the individual tear tapes 14. Alternatively, the tear tapes 14 may be trirnmed into strips having larger widths as desired. The tear tapes 14 are rolled as a continuous length onto spools for future dispensing.
The tear tape 14 rnay alternatively be forrned by extrusion larrunating the first sealant layer 20 to the first surface 21 of the core layer 22 by means of a polymer l~min~ting layer in the same position as the layer 24 and extrusion l~min~ting the second sealant layer 26 to the second surface 27 of the core layer 22, using, as an example, polyethylene laminate layers and prir,ners which are well-known in the art as necessary to bond the layers.
The tear tape 14 rnay also be forrned by e~ctrusion coating the first sealant layer 20 to the first surface 21 of the core layer 22 and extrusion coating the second sealant layer 26 to the second surface 27 of the core layer 22, with any primers that may be required as are well-known in the art. The tear tape 14 rnay also be forrned as a co-extrusion of all three layers 20, 22 and 26 on a cast or blown extruder.
21~3720 A combination of the above techniques may also be used to forrn the tear tape 14, such as a combination of co-extrusion of the first sealant layer 20 to the first surface 21 of the core layer 22 and adhesive l~min~tion of the second sealant layer 26 to the second surface 27 of the core layer 22.
The tear tape 14 as shown in Figure 2 includes first and second sealant layers 20 and 26 which are formed from the same rnaterials. The sealant layers 20 and 26, however, rnay be formed from different rnaterials if desired to construct a tape 14 that provides different sealing characteristics with each sealant layer 20 and 26. Each of the sealant laye~.~ 20 and 26, and the core layer 22, are forrned with at least one layer of rnaterial, but may be forrned with two or more layers of materials if desired.
Each of the sealant layers 20 and 26 may be formed as thin as 0.1 mil for use in a co-extrusion with the core layer 22 or as thin as 0.5 rnil when intended for larrLination to the core layer 22. The rnaxirnum thickness of each of the layers 20 and 26 is approximately 4 mils.
The rnaterials which forrn the sealant layers 20 and 26 must be sealable to the film 12, preferably by heat sealing, but pressure sensitive adhesive sealing techniques may also be used.
The rnaterial which forrns the core layer 22 is preferably polypropylene uniaxially or biaxially oriented for tensile strength. The core layer 22 preferably has a thichless of approximately one to approximately five rnils depending on the strength of the packaging film 12. The core layer 22 rnay be formed from polypropylene, polyethylene terephthalate (PET) (polyester), high density polyethylene (HDPE) and other polymers that may be oriented and which possess sufficient tensile strength to ~ear the packaging film 12.
As best shown in Figure 4, the packaging fikn 12 includes an inner layer 40 of approximately 1.5 rnil thick ethylene-vinyl acetate (EVA) film. llle packaging fikn 12 also 2183~20 includes a layer 42 of fifty gauge coextruded biaxially onented polypropylene, a layer 44 of polyvinylidene chloride (PVDC), and a layer 46 of 0.5 rnil thick polyethylene lan~inate (PEL~.
A layer 48 of ink or other printing indicia rnay be applied to the layer 46. An outer layer 50 of thirty-five gauge PET is applied to the layer 48. One preferred packaging filrn 12 is a protective packaging filrn sold as CURPOLENE~ 600XLT packaging film in Grades 7008 and 7008-I by Curwood, Inc., the applicant herein. The CURPOLENE~) packaging filrn is described in U.S. Patent No. 4,421,823, which is incorporated herein by reference.
As best shown in Figure 3, the packaging filrn 12 includes a left linear edge 54 and a right linear edge 56 which is spaced apart and parallel to the left edge 54. The packaging filrn 12 also includes a top edge 58 and a bottom edge 60.
The packaging fiLrn 12 preferably should have at least one layer of oriented fikn.
Materials over ten or twelve rnils thick are probably not candidates for use as the packaging filrn 12 since they n~y not be readily tom. However, a weak n~terial such as polyethylene rnay work in such thicknesses. Heat-sealable coated paper may also be used as the packaging material 12. The two most important characteristics of the packaging film 12 are that the film be tearable and sealable.
The packaging filrn 12, as shown in Figure 3, with the tear tape 14 sealed thereto, is forrned by placing a spool of the tear tape 14 on an unwind stand for dispensing of the tape 14 to a guide roller. The tear tape 14 is pinched between the packaging filrn 12 and a heated roller or heated seal bar to heat seal the tape 14 to the packaging film 12 in a selected position before the packaging filrn 12 is forrned into the package 10. Other suitable methods Icnown in the art may be used to attach the tear tape 14 to the film 12. The tear tape 14 may be heat sealed along its entire length to the packaging filrn 12, rnay be heat sealed orlly at the fLrst and second ends or edges 16 and 18 to the packaging filrn 12, or may be heat sealed to 21837~0 the packaging film 12 at both ends or edges 16 and 18 and at one or more locations therebetween. The tear tape 14 rnay be applied to the packaging filrn 12 just prior to the forming of the package 10, or the packaging filrn 12 and tear tape 14 rnay be wound into a roll for later use in forrming the packages 10. A roll of the combination of the packaging fikn 12 and tear tape 14 presents a problem of lumpiness due to the additional thickness of the tear tape 14 across only a small portion of the width of the packaging film 12.
The hermetically sealed package 10, as shown in Figures 5-8, is formed by feeding the packaging fikn 12 with the tear tape 14 sealed thereto through various types of packaging rnachinery which are well known in the art. Suitable packaging machinery includes horizontal forrn fill seal (Hl;FS) equipment such as manufactured by Hayssen Manufacturing Company.
Such packaging machinery is known as ~Rrs~ in the packaging industry. Vertical forrn fill seal (VFFS) equipment rnay also be used, as well as gas flush and vacuum types of packaging rnachinery.
As best shown in Figures 5-8, the package 10 extends longitudinally between a fust end 64 and a second end 66. The package 10 includes a fin seal 68 which is formed in a manner well known to one of ordinary skill in the art by overlapping an interior surface portion of the packaging film 12 at the left edge 54 with an interior surface portion of the packaging film 12 at the right edge 56, with the edges 54 and 56 positioned adjacent to one another, and heat-sealing the overlapping portions together with a heat-seal 70 which extends between an edge 71 and an edge 73 which is spaced apart from the edges 54 and 56 of the packaging film 12. The heat seal 70 and the fin seal 68 extend the length of package 10 between the first end 64 and the second end 66 and between the top edge 58 and bottom edge 60 of the packaging film 12. The packaging film 12 at each end of the fin seal 68 is heat-sealed from the edge 71 to the edges 54 and 56 of the packaging film 12. In one embodirnent 2 1 ~20 of the package 10, the tear tape 14 extends between the fir~t end 64 and the second 66 of the package 10 with the first end 16 of the tear tape 14 being located at the first end 64 of the package 10 and the second end 18 of the tear tape 14 being located at the second end 66 of the package 10.
nle top edge 58 of the packaging filrn 12 is heat sealed to itself at the first end 64 of the package 10 by a heat seal 72 which extends transversely across the width of the first end 64 between a left edge 74 and a right edge 76 of the first end 64. The heat seal 72 includes an outer lateral edge 77 and a spaced apart and generally parallel inner lateral edge 78. The heat seal 72 extends longitu-lin~lly between its lateral edges 77 and 78. The sealant layers 20 and 26 at the first end 16 of the tear tape 14 are sealed to and between the overlying plies of the packaging film 12 at the top edge 58 by the heat seal 72. The first end 16 of the tear tape 14 is thereby hermetically sealed between the overlying plies of the packaging film 12 at the first end 64 of the package 10.
~ e bottom edge 60 of the packaging film 12 is heat sealed to itself by a heat seal 80 which extends between a left edge 82 and right edge 84 of the second end 66. The heat seal 80 includes an outer lateral edge 85 and a spaced apart and generally parallel inner lateral edge 87. The heat seal 80 e~ctends longitudinally between its lateral edges 85 and 87. The sealant layers 20 and 26 at the second end 18 of the tear tape 14 are heat sealed to and between the overlying plies of the packaging fikn 12 at the bottom edge 60 by the heat seal 80. The second end 18 of the tear tape 14 is thereby hermetically sealed between the overlying plies of the packaging filrn 12 at the second end 66 of the package 10. The heat seals 70, 72 and 80 form a hermetically sealed charnber 86 within the package 10 which is adapted to contain various iterns such as food products or the like. The package disclosed herein is particularly suited for cont~ining and displaying bricks of cheese and is rendered 21~3720 easily openable by incorporation of the tear strip 14.
A notch or slit 90, best shown in Figure 6, is formed in the first end 64 of the package 10 adjacent to the first end 16 of the tear tape 14. A notch or slit 92 is formed in the second end 66 of the package 10 adjacent to the second end 18 of the tear tape 14. The slits 90 and 92 facilitate the initiation of the tearing of the tear tape 14 away from the package 10. ln order to preserve the integrity of the herrnetically sealed package it is irnportant that the notches do not extend into the product receiving charnber past the inner end of the seal zone.
The package 10 is selectively opened by grasping either the first end 16 or the second end 18 of the tear tape 14 and by pulling the tear tape 14 away from the remainder of the package 10. The slit 90 or 92 initiates a tearing of the packaging film 12 which is continued by the tear tape 14. As the first end 16 or second end 18 of the tear tape 14 is pulled away from the package 10, the packaging film 12 is tom along the length of the tear tape 14 to the opposite end of the package 10. An opening is thereby provided in the package 10, by the removal of the tear tape 10, which extends the length of the package 10 between the first end 64 and the second end 66 to facilitate the easy removal of the product contained therein.
An altemative embodiment of the package of the present invention includes a tear tape 14' having a first end 16' and a second end 18' as shown in Figures S and 6. The tear strip 14' is constructed in the sarne manner and with the sarne materials as the tear strip 14. The first end 16' of the tear tape 14' is located at the first end 64 of the package 10 and is sealed thereto with the heat seal 72 just as is the first end 16 of the tear tape 14. The outer sealant layer of the tear strip 14' is adhered to a first wall portion of the packaging filrn 12 and the inner sealant layer is adhered to a second wall portion of the packaging film 12 by the heat seal 72 at the first end 64 of the package 10. The second end 18' of the tear tape 14' is located between the first end 64 and the second end 66 of the package 10. The second end 2 t~720 18' of the tear tape 14' is localed at a distance of less than one-half of the longitudinal length of the package 10 from the first end 64 of the package 10 and preferably less ~n one-third of the length of the package 10 from the first end 64. The outer sealant layer of the tear strip 14' is adhered to the packaging filrn 12 at the second end 18' of the tear strip 14'. The inner sealant layer of the tear strip 14' at the second end 18' of the tear strip 14' is unattached to the packaging filrn-12. The tear tape 14' is preferably heat sealed to the packaging film 12 along its entire length, but may be heat sealed only at the first and second ends 16' and 18' to the packaging film 12, or may be heat sealed at the ends 16' and 18' and at one or more locations therebetween.
When the tear strip 14' is removed from the package 10 by pulling the first end 16' from the remainder of the package 10, the package film 12 is tom along the length of the tear strip 14' to the second end 18'. An opening in the upper portion of the package 10 is thereby provided while the packaging filrn 12 in the rem~ining lower portion of the package 10 rernains intact. The opening would be located in the upper left-hand comer of the package 10, as the package 10 is shown in Figure 6. The opening created by the removal of the tear tape 14' provides a pouring spout for dispensing the product contained in the package.
It is possible to substitute a pressure sensitive adhesive for a heat sealant in rnany situations. If the adhesive was coated to the surface 27 of the core layer 22 of the tear strip 14 it could replace the other layers 26 and 28 and forrn a tight seal between the packaging film 12 and the tear strip 14.
It is easiest to apply the tear tape 14 to the packaging film 12 by most rnachines if it is done in the direction the machine moves the film (the machine direction). However, it is possible for one skilled in the art to conceive that it might be necessary and it is certainly possible to apply the tape across the direction of film flow in order to acnieve a desired 21~372Q
package cor~lguration. Since most packaging machines move in an intermittent or inde~ed ~ashion there is opportunity when the film is not moving to apply the tape with a properly designed mechanism using adhesive or heat sealing techniques.
A second embodiment of the tear tape of the present invention is shown in cross-section in Figure 9 and is identified with the reference numeral 100. The tear tape 100 includes a first core layer 102 having an irmer surface 104 and an outer surface 106. The tear tape 100 also includes a second core layer 108 having an inner surface 110 and an outer surface 112. The inner surface 104 of the first core layer 102 is adhesively laminated to the inner surface 110 of the second core layer 108 by a layer of adhesive 114. A first sealant layer 116 is adhered to the outer surface 106 of the first core layer 102. A second sealant layer 118 is adhered to the outer surface 112 of the second core layer 108. The sealant layers 116 and 118 may be respectively attached to the core layers 102 and 108 by co-extrusion, e~ctrusion coating, extrusion larninating, adhesive l~min~tion, or a combination of these techniques.
The core layers 102 and 108 are each formed of tensilized rnachine oriented polypropylene (MOPP) or biaxially oriented polypropylene (BOPP). Each core layer 102 and 108 is preferably approximately 0.85 mils thick. The first and second sealant layers 116 and 118 are each formed of linear low density polyethylene (LLDPE). Each sealant layer 116 and 118 is preferably appro~imately 0.10 mils thic~ The adhesive layer 114 has a thickness of approximately 0.10 rnils such that the tear tape 100 has a total thickness of appro~irnately two mils. The tear tape 100 is thus substantially thinner than the tear tape 14 which is appro~imately five mils thic~ The first and second sealant layers 116 and 118 rnay be respectively forrned from different rnaterials if desired to provide different sealing characteristics ~,vith each s-ealant layer 116 and 118. The tear tape 100 may be used in ~18~720 connection with the package 10 in the same rnanner as the tear tape 14.
Another embodiment of the tear tape of the present invention is shown in cross-section in Figure 10 and is designated with the reference numeral 120. The tear tape 120 includes a core layer 122 having a first surface 124 and a second surface 126. A first sealant layer 128 is adhered to the first surface 124 of the core layer 122. A second sealant layer 130 is adhered to the second surfaoe 126 of the core layer 122. The sealant layers 128 and 130 may be adhered to the core layer 122 by co-extrusion, extrusion coating, extrusion laminating, adhesive lamination, or a combination of these techniques.
The core layer 122 is forrned of ten~ ed oriented polypropylene. The core layer 122 is preferably approximately 1.80 rnils thic~ l~e first and second sealant layers 128 and 130 are each formed of linear low density polyethylene (LLDPE). Each sealant layer 128 and 130 is preferably approxirnately 0.10 rnils thick The total thickness of the tear tape 120 is approximately two mils. The sealant layers 128 and 130 rnay be respectively formed from different rnaterials if desired to provide different sealing characteristics with each sealant layer 128 and 130. The tear tape 120 rnay be used with the package 10 in the same rnanner as the tear tape 14.
The tear tapes 100 and 120 provide several advantages over the tear tape 14. ~e tear tapes 100 and 120 are less costly to produce than the tear tape 14 as less rnaterial is u~ed to rn~nufacture the tear tapes 100 and 120 and as the rnanufacturing process for making the tear tapes 100 and 120 is simpler and involves less operations than the process for mal~ng the tear tape 14. The tear tapes 100 and 120 are thinner than the tear tape 14 such that the tear tapes 100 and 120 enable a better seal to be forrned with the package walls. ~e thinner tear tapes 100 and 120 also enable more lineal footage of the tear tape material to be wound onto a spool, and also enable rnore lineal footage of paclcage rnaterial cont~ining the tear tape to be ~1~372~
wound onto a spool.
One preferred embodiment of the package of the present invention is a back or fin seal type of package commonly seen on blocks of natu~al cheese such as the package 10. There is ano~her large group of packages rnade from two webs that are sealed on all four sides.
Typically these packages have a vacuum formed tray covered with a nonformed film and heat sealed around the edges of the tray. Such packages are seen in luncheon meat and hot dog packaging as well as in connection wi~h many other items. These can be referred to as four side seal types of packages. The tear tape 14, 100 or 120 could also be applied from one edge to another through one of the sides of such a package. This could be done on nearly any of the sides depending mostly on the machine used to package and on the opening desired.
Another family of package types is referred to as side sealed pouches which are seen in packages of shredded cheese, liquids and other similar products. These packages are characteristically formed by folding a packaging film over on itself and heat sealing the edges.
llle bottom is sometimes sealed and other times left unsealed. A gusset can be inserted in the bottom if desired. However the package is rnade, it is possible to run the heat-sealable tear tape 14, 100 or 120 through the top of the package in the gene~al area of the top seal to provide an opening feature if combined with notches or nicks in the side seals.
Figure 11 shows a top portion of a package 140 having a first package wall 142 overlying a second package wall 144. Each package wall 142 and 144 is formed from a flexible packaging film such as CURPOLENE~ packaging material sold by Curwood, Inc., the applicant herein, as previously described. The package 140 includes a top latelal edge 146, a first longitudinal side edge 14~, and a second longitudinal side edge 150 s~aced apart from and extending generally pa~llel to the first longitudinal edge 148. The first and second 21837~,,0 package walls 142 and 144 are sealed ~o one another along the si~e edges 148 and 150 and along a bottom edge (not shown~. The package walls 142 and 144 forrn a product receiving charn~er 152 therebetween. A tear strip 154 having a first lateral edge 156 and a spaced apart and generally parallel second lateral edge 158 is located between the first and second package walls 142 and 144 adjacen~ the top edge 146 of the package 140. The tear strip 154 e~tends from the first side edge 148 to the second side edge 150 of the package 140. The tear strip 154 is constructed in the same manner and with the same rnaterials as any of the tear strips 14, 100 or 120.
A first sealant layer of the tear strip 154 is initially sealed to the inner surface of the first package wall 142 such that the top of the package 140 is open to allow the insertion of food or o~her products into the product receiving charnber 152. Thereafter a second sealant layer of the tear strip 154 is heat sealed to the inner surface of the second package wall 144 within a heat seal zone 160 such that the tear strip 154 is hermetically sealed to the first and second package walls 142 and 144. The heat seal zone 160 extends between the longitudinal side edges 148 and 150 of the package 140 and between a first lateral edge 162 of the heat seal zone 160, which is shown as being cc~extensive with the first lateral edge 156 of the tear strip 154 in Fig~re 11, and a second lateral edge 164 of the heat seal zone 160 which is spaced part and generally parallel to the first lateral edge 162.
As shown in Figure 11, the first lateral edge 156 of the tear strip 154 is coextensive with the first lateral edge 162 of the heat seal zone 160. The second lateral edge 158 of the tear strip 154 extends beyond the second lateral edge 164 of the heat seal zone 160 such that the second lateral edge 158 of the tear strip 154 is positioned within the product receiving chamber 152. The tear strip 154 includes a projecting portion lS9 which extends between the late~l edge 164 of the heat se~l zone 160 and the lateral edge 158 of the tear sIrip 154 which is located in the product receiving chamber 152. As shown in Figure 11, the tear strip 154 has a width be~ween the lateral edges 156 and 158 which is greater than the width of the heat seal zone 160 between the lateral edges 162 and 164. Alternatively, the first lateral edge 156 of the tear strip 154 may be positioned beyond the lateral edge 162 of the heat seal zone 160, or it may be positioned within the heat seal zone 160 between the first and second lateral edges 162 and 164 of the heat seal zone 160.
Wllen the tear strip 150 is tom away from the package 140 the extension or projection of the projecting portion 159 and second lateral edge 158 of the tear strip 154 beyond the second lateral edge 164 of the heat seal zone 160 into the chamber 152 enables the tear strip 150 to easily and consistently remove the entire heat seal zone 160 from the remainder of the package 140 to fully open the package 140 between the side edges 148 and 150 and expose the contents of the product receiving chamber 152. This effectively eliminates the p~ssibility of removing the tear strip while allowing the product receiving chamber to remain sealed and inaccessible as sometimes happens in prior art packages.
The package 140 may include a zipper 168, comprising respective gripping strips attached to the interior surface of each package wall 142 and 144, that is selectively openable and reclosable. The zipper 168 is located within the charnber 152 of the package 140 and is spaced below the second lateral edge 158 of the tear strip 154. The zipper 168 enables the chamber 152 to be selectively closed after the tear strip 154 has been tom away from the package 140 to open a passage to the chamber 152.
The package 140 also rnay include an a~.lure 172 which extends through the fLrst package wall 142, the tear strip 154, and the second package wall 144 within the heat seal zone 160. Ihe tear strip 154 reinforces the ape~ e around the aperture 172 to prevent tearing of the aperture 172 by hooks, rods or other support members which are inserted 2~_83q20 through the aperture 172 to suppon the package 140 for display.
Various features of the invention have been particularly shown and described in connection with the illustrated embodiments of the invention, however, it must be understood that these particular arrangements merely illustrate, and that the invention is to be given its fullest int~ eta~ion within the terms of the appended claims.
AND MET~IOD OF MANUFACTURE
Back~round of the Invention llle present invention is directed to herrnetically sealed packages and tear strips which are pa~icularly adapted for opening the package and methods of rnaking the package.
Nurnerous forms of tear strips have been provided to facilitate the opening of sealed packages E~carnpies which are probably familiar to rnany consumers include the tear strip used to open a package of cigarettes or a package of chewing gurn. Most tear strips of this type are sirnply positioned inside one portion of a package wall with an end extending outwardly to be grasped by the consurner. Once grasped and pulled, the tear strip opens an edge or end of the package either by unsealing it or by physically tearing through the package wall.
The present invention constitutes a specially constructed tear strip or tape and a package in which the tear strip extends along a portion theteof to facilitate easy opening of the package to provide access to the contents. Tear strips utilized in prior art constructions do not provide herrnetic seals with conventional rnaterials. That is because they are norrnally provided with a silicone based releæ coat on one surface thereof. The tear strip of the present invention is adapted to be sealed on both opposing sides thereof, and at each end of the tear s~ip, to the package film to thereby provide a herrnetically sealed package for containLng food products and other items.
Brief Description of the Drawin~es Figure 1 is a top plan view of a first embodiment of the heat-sealable tear tape.
Figure 2 is an enlarged partial cross-sectioral view of the tear tape taken along lines 2-2 of Flgure 1.
Figure 3 is a top plan view of a piece of packaging filrn with the tear tape heat sealed thereto.
Figure 4 is an enlarged partial cross-sectional view of the packaging film and tear tape taken along lines 44 of Figure 3.
Figure 5 is a side elevational view of a first embodiment of a package including a tear tape.
Figure 6 is a rear view of the first package embodiment taken along lines 6-6 of Figure 5.
Figure 7 is an end view of the first package embodiment taken along lines 7-7 of Figure 6.
Figure 8 is a cross-sectional view of the first package embodiment taken along lines 8-8 of Figure 6.
Fig,ure 9 is an enlarged cross-sectional view of a second embodiment of the tear tape.
Fig,ure 10 is an enlarged cross-sectional view of third embodirnent of the tear tape.
Figure 11 is a partial front elevational view of a second embodiment of a package including a tear tape.
Detailed Description of the Preferred Embodiments A herrnetically sealed package 10 is illustrated which comprises a sheet of packaging filrn 12 and a tear tape or strip 14 heat sealed to the packaging film 12. As best shown in Figures 1 and 3, the tear tape 14 is forrned as a thin and flat elongate strip extending between a first end or edge 16 and a second end or edge 18. As best shown in Figure 2, one embodiment of the tear tape 14 includes a first sealant layer 20 adhesively lan~inated to a first surface 21 of a core layer 22 by a layer of adhesive 24. A second sealant layer 26 is adhesively l~min~ted to a second opposing surface 27 of the core layer 22 by a layer of adhesive 28. Ille first and second sealant layers 20 and 26 are each forrned of a copolymer 218372~
of polyethylene containing 5% ethylene-vinyl acetate (EVA). Each sealant layer 20 and 26 is preferably approximately 1.5 mils thic~ The core layer 22 is fo~ned of tensilized rnachine oriented polypropylene (MOPP~ which is preferably approximately two rnils thic~ Various types of adhesives rnay be used for the adhesive layers 24 and 28, however, one preferred adhesive is "TYCEL" adhesive as sold by the Liofol Company.
~ e sealant layers 20 and 26 of the tear tape 14 can be rnanufactured as blown fikns on extruders. The first sealant layer 20 can be adhesively lamirLated to the core layer 22 on an adhesive lamirlator. l~e combination of the sealant layer 20 and core layer 22 can then be adhesively laminated to the second sealant layer 26. This tear tape base structure is initially about forty-one inches wide and rnay be trirnrned into two millimeter wide strips which forrn the individual tear tapes 14. Alternatively, the tear tapes 14 may be trirnmed into strips having larger widths as desired. The tear tapes 14 are rolled as a continuous length onto spools for future dispensing.
The tear tape 14 rnay alternatively be forrned by extrusion larrunating the first sealant layer 20 to the first surface 21 of the core layer 22 by means of a polymer l~min~ting layer in the same position as the layer 24 and extrusion l~min~ting the second sealant layer 26 to the second surface 27 of the core layer 22, using, as an example, polyethylene laminate layers and prir,ners which are well-known in the art as necessary to bond the layers.
The tear tape 14 rnay also be forrned by e~ctrusion coating the first sealant layer 20 to the first surface 21 of the core layer 22 and extrusion coating the second sealant layer 26 to the second surface 27 of the core layer 22, with any primers that may be required as are well-known in the art. The tear tape 14 rnay also be forrned as a co-extrusion of all three layers 20, 22 and 26 on a cast or blown extruder.
21~3720 A combination of the above techniques may also be used to forrn the tear tape 14, such as a combination of co-extrusion of the first sealant layer 20 to the first surface 21 of the core layer 22 and adhesive l~min~tion of the second sealant layer 26 to the second surface 27 of the core layer 22.
The tear tape 14 as shown in Figure 2 includes first and second sealant layers 20 and 26 which are formed from the same rnaterials. The sealant layers 20 and 26, however, rnay be formed from different rnaterials if desired to construct a tape 14 that provides different sealing characteristics with each sealant layer 20 and 26. Each of the sealant laye~.~ 20 and 26, and the core layer 22, are forrned with at least one layer of rnaterial, but may be forrned with two or more layers of materials if desired.
Each of the sealant layers 20 and 26 may be formed as thin as 0.1 mil for use in a co-extrusion with the core layer 22 or as thin as 0.5 rnil when intended for larrLination to the core layer 22. The rnaxirnum thickness of each of the layers 20 and 26 is approximately 4 mils.
The rnaterials which forrn the sealant layers 20 and 26 must be sealable to the film 12, preferably by heat sealing, but pressure sensitive adhesive sealing techniques may also be used.
The rnaterial which forrns the core layer 22 is preferably polypropylene uniaxially or biaxially oriented for tensile strength. The core layer 22 preferably has a thichless of approximately one to approximately five rnils depending on the strength of the packaging film 12. The core layer 22 rnay be formed from polypropylene, polyethylene terephthalate (PET) (polyester), high density polyethylene (HDPE) and other polymers that may be oriented and which possess sufficient tensile strength to ~ear the packaging film 12.
As best shown in Figure 4, the packaging fikn 12 includes an inner layer 40 of approximately 1.5 rnil thick ethylene-vinyl acetate (EVA) film. llle packaging fikn 12 also 2183~20 includes a layer 42 of fifty gauge coextruded biaxially onented polypropylene, a layer 44 of polyvinylidene chloride (PVDC), and a layer 46 of 0.5 rnil thick polyethylene lan~inate (PEL~.
A layer 48 of ink or other printing indicia rnay be applied to the layer 46. An outer layer 50 of thirty-five gauge PET is applied to the layer 48. One preferred packaging filrn 12 is a protective packaging filrn sold as CURPOLENE~ 600XLT packaging film in Grades 7008 and 7008-I by Curwood, Inc., the applicant herein. The CURPOLENE~) packaging filrn is described in U.S. Patent No. 4,421,823, which is incorporated herein by reference.
As best shown in Figure 3, the packaging filrn 12 includes a left linear edge 54 and a right linear edge 56 which is spaced apart and parallel to the left edge 54. The packaging filrn 12 also includes a top edge 58 and a bottom edge 60.
The packaging fiLrn 12 preferably should have at least one layer of oriented fikn.
Materials over ten or twelve rnils thick are probably not candidates for use as the packaging filrn 12 since they n~y not be readily tom. However, a weak n~terial such as polyethylene rnay work in such thicknesses. Heat-sealable coated paper may also be used as the packaging material 12. The two most important characteristics of the packaging film 12 are that the film be tearable and sealable.
The packaging filrn 12, as shown in Figure 3, with the tear tape 14 sealed thereto, is forrned by placing a spool of the tear tape 14 on an unwind stand for dispensing of the tape 14 to a guide roller. The tear tape 14 is pinched between the packaging filrn 12 and a heated roller or heated seal bar to heat seal the tape 14 to the packaging film 12 in a selected position before the packaging filrn 12 is forrned into the package 10. Other suitable methods Icnown in the art may be used to attach the tear tape 14 to the film 12. The tear tape 14 may be heat sealed along its entire length to the packaging filrn 12, rnay be heat sealed orlly at the fLrst and second ends or edges 16 and 18 to the packaging filrn 12, or may be heat sealed to 21837~0 the packaging film 12 at both ends or edges 16 and 18 and at one or more locations therebetween. The tear tape 14 rnay be applied to the packaging filrn 12 just prior to the forming of the package 10, or the packaging filrn 12 and tear tape 14 rnay be wound into a roll for later use in forrming the packages 10. A roll of the combination of the packaging fikn 12 and tear tape 14 presents a problem of lumpiness due to the additional thickness of the tear tape 14 across only a small portion of the width of the packaging film 12.
The hermetically sealed package 10, as shown in Figures 5-8, is formed by feeding the packaging fikn 12 with the tear tape 14 sealed thereto through various types of packaging rnachinery which are well known in the art. Suitable packaging machinery includes horizontal forrn fill seal (Hl;FS) equipment such as manufactured by Hayssen Manufacturing Company.
Such packaging machinery is known as ~Rrs~ in the packaging industry. Vertical forrn fill seal (VFFS) equipment rnay also be used, as well as gas flush and vacuum types of packaging rnachinery.
As best shown in Figures 5-8, the package 10 extends longitudinally between a fust end 64 and a second end 66. The package 10 includes a fin seal 68 which is formed in a manner well known to one of ordinary skill in the art by overlapping an interior surface portion of the packaging film 12 at the left edge 54 with an interior surface portion of the packaging film 12 at the right edge 56, with the edges 54 and 56 positioned adjacent to one another, and heat-sealing the overlapping portions together with a heat-seal 70 which extends between an edge 71 and an edge 73 which is spaced apart from the edges 54 and 56 of the packaging film 12. The heat seal 70 and the fin seal 68 extend the length of package 10 between the first end 64 and the second end 66 and between the top edge 58 and bottom edge 60 of the packaging film 12. The packaging film 12 at each end of the fin seal 68 is heat-sealed from the edge 71 to the edges 54 and 56 of the packaging film 12. In one embodirnent 2 1 ~20 of the package 10, the tear tape 14 extends between the fir~t end 64 and the second 66 of the package 10 with the first end 16 of the tear tape 14 being located at the first end 64 of the package 10 and the second end 18 of the tear tape 14 being located at the second end 66 of the package 10.
nle top edge 58 of the packaging filrn 12 is heat sealed to itself at the first end 64 of the package 10 by a heat seal 72 which extends transversely across the width of the first end 64 between a left edge 74 and a right edge 76 of the first end 64. The heat seal 72 includes an outer lateral edge 77 and a spaced apart and generally parallel inner lateral edge 78. The heat seal 72 extends longitu-lin~lly between its lateral edges 77 and 78. The sealant layers 20 and 26 at the first end 16 of the tear tape 14 are sealed to and between the overlying plies of the packaging film 12 at the top edge 58 by the heat seal 72. The first end 16 of the tear tape 14 is thereby hermetically sealed between the overlying plies of the packaging film 12 at the first end 64 of the package 10.
~ e bottom edge 60 of the packaging film 12 is heat sealed to itself by a heat seal 80 which extends between a left edge 82 and right edge 84 of the second end 66. The heat seal 80 includes an outer lateral edge 85 and a spaced apart and generally parallel inner lateral edge 87. The heat seal 80 e~ctends longitudinally between its lateral edges 85 and 87. The sealant layers 20 and 26 at the second end 18 of the tear tape 14 are heat sealed to and between the overlying plies of the packaging fikn 12 at the bottom edge 60 by the heat seal 80. The second end 18 of the tear tape 14 is thereby hermetically sealed between the overlying plies of the packaging filrn 12 at the second end 66 of the package 10. The heat seals 70, 72 and 80 form a hermetically sealed charnber 86 within the package 10 which is adapted to contain various iterns such as food products or the like. The package disclosed herein is particularly suited for cont~ining and displaying bricks of cheese and is rendered 21~3720 easily openable by incorporation of the tear strip 14.
A notch or slit 90, best shown in Figure 6, is formed in the first end 64 of the package 10 adjacent to the first end 16 of the tear tape 14. A notch or slit 92 is formed in the second end 66 of the package 10 adjacent to the second end 18 of the tear tape 14. The slits 90 and 92 facilitate the initiation of the tearing of the tear tape 14 away from the package 10. ln order to preserve the integrity of the herrnetically sealed package it is irnportant that the notches do not extend into the product receiving charnber past the inner end of the seal zone.
The package 10 is selectively opened by grasping either the first end 16 or the second end 18 of the tear tape 14 and by pulling the tear tape 14 away from the remainder of the package 10. The slit 90 or 92 initiates a tearing of the packaging film 12 which is continued by the tear tape 14. As the first end 16 or second end 18 of the tear tape 14 is pulled away from the package 10, the packaging film 12 is tom along the length of the tear tape 14 to the opposite end of the package 10. An opening is thereby provided in the package 10, by the removal of the tear tape 10, which extends the length of the package 10 between the first end 64 and the second end 66 to facilitate the easy removal of the product contained therein.
An altemative embodiment of the package of the present invention includes a tear tape 14' having a first end 16' and a second end 18' as shown in Figures S and 6. The tear strip 14' is constructed in the sarne manner and with the sarne materials as the tear strip 14. The first end 16' of the tear tape 14' is located at the first end 64 of the package 10 and is sealed thereto with the heat seal 72 just as is the first end 16 of the tear tape 14. The outer sealant layer of the tear strip 14' is adhered to a first wall portion of the packaging filrn 12 and the inner sealant layer is adhered to a second wall portion of the packaging film 12 by the heat seal 72 at the first end 64 of the package 10. The second end 18' of the tear tape 14' is located between the first end 64 and the second end 66 of the package 10. The second end 2 t~720 18' of the tear tape 14' is localed at a distance of less than one-half of the longitudinal length of the package 10 from the first end 64 of the package 10 and preferably less ~n one-third of the length of the package 10 from the first end 64. The outer sealant layer of the tear strip 14' is adhered to the packaging filrn 12 at the second end 18' of the tear strip 14'. The inner sealant layer of the tear strip 14' at the second end 18' of the tear strip 14' is unattached to the packaging filrn-12. The tear tape 14' is preferably heat sealed to the packaging film 12 along its entire length, but may be heat sealed only at the first and second ends 16' and 18' to the packaging film 12, or may be heat sealed at the ends 16' and 18' and at one or more locations therebetween.
When the tear strip 14' is removed from the package 10 by pulling the first end 16' from the remainder of the package 10, the package film 12 is tom along the length of the tear strip 14' to the second end 18'. An opening in the upper portion of the package 10 is thereby provided while the packaging filrn 12 in the rem~ining lower portion of the package 10 rernains intact. The opening would be located in the upper left-hand comer of the package 10, as the package 10 is shown in Figure 6. The opening created by the removal of the tear tape 14' provides a pouring spout for dispensing the product contained in the package.
It is possible to substitute a pressure sensitive adhesive for a heat sealant in rnany situations. If the adhesive was coated to the surface 27 of the core layer 22 of the tear strip 14 it could replace the other layers 26 and 28 and forrn a tight seal between the packaging film 12 and the tear strip 14.
It is easiest to apply the tear tape 14 to the packaging film 12 by most rnachines if it is done in the direction the machine moves the film (the machine direction). However, it is possible for one skilled in the art to conceive that it might be necessary and it is certainly possible to apply the tape across the direction of film flow in order to acnieve a desired 21~372Q
package cor~lguration. Since most packaging machines move in an intermittent or inde~ed ~ashion there is opportunity when the film is not moving to apply the tape with a properly designed mechanism using adhesive or heat sealing techniques.
A second embodiment of the tear tape of the present invention is shown in cross-section in Figure 9 and is identified with the reference numeral 100. The tear tape 100 includes a first core layer 102 having an irmer surface 104 and an outer surface 106. The tear tape 100 also includes a second core layer 108 having an inner surface 110 and an outer surface 112. The inner surface 104 of the first core layer 102 is adhesively laminated to the inner surface 110 of the second core layer 108 by a layer of adhesive 114. A first sealant layer 116 is adhered to the outer surface 106 of the first core layer 102. A second sealant layer 118 is adhered to the outer surface 112 of the second core layer 108. The sealant layers 116 and 118 may be respectively attached to the core layers 102 and 108 by co-extrusion, e~ctrusion coating, extrusion larninating, adhesive l~min~tion, or a combination of these techniques.
The core layers 102 and 108 are each formed of tensilized rnachine oriented polypropylene (MOPP) or biaxially oriented polypropylene (BOPP). Each core layer 102 and 108 is preferably approximately 0.85 mils thick. The first and second sealant layers 116 and 118 are each formed of linear low density polyethylene (LLDPE). Each sealant layer 116 and 118 is preferably appro~imately 0.10 mils thic~ The adhesive layer 114 has a thickness of approximately 0.10 rnils such that the tear tape 100 has a total thickness of appro~irnately two mils. The tear tape 100 is thus substantially thinner than the tear tape 14 which is appro~imately five mils thic~ The first and second sealant layers 116 and 118 rnay be respectively forrned from different rnaterials if desired to provide different sealing characteristics ~,vith each s-ealant layer 116 and 118. The tear tape 100 may be used in ~18~720 connection with the package 10 in the same rnanner as the tear tape 14.
Another embodiment of the tear tape of the present invention is shown in cross-section in Figure 10 and is designated with the reference numeral 120. The tear tape 120 includes a core layer 122 having a first surface 124 and a second surface 126. A first sealant layer 128 is adhered to the first surface 124 of the core layer 122. A second sealant layer 130 is adhered to the second surfaoe 126 of the core layer 122. The sealant layers 128 and 130 may be adhered to the core layer 122 by co-extrusion, extrusion coating, extrusion laminating, adhesive lamination, or a combination of these techniques.
The core layer 122 is forrned of ten~ ed oriented polypropylene. The core layer 122 is preferably approximately 1.80 rnils thic~ l~e first and second sealant layers 128 and 130 are each formed of linear low density polyethylene (LLDPE). Each sealant layer 128 and 130 is preferably approxirnately 0.10 rnils thick The total thickness of the tear tape 120 is approximately two mils. The sealant layers 128 and 130 rnay be respectively formed from different rnaterials if desired to provide different sealing characteristics with each sealant layer 128 and 130. The tear tape 120 rnay be used with the package 10 in the same rnanner as the tear tape 14.
The tear tapes 100 and 120 provide several advantages over the tear tape 14. ~e tear tapes 100 and 120 are less costly to produce than the tear tape 14 as less rnaterial is u~ed to rn~nufacture the tear tapes 100 and 120 and as the rnanufacturing process for making the tear tapes 100 and 120 is simpler and involves less operations than the process for mal~ng the tear tape 14. The tear tapes 100 and 120 are thinner than the tear tape 14 such that the tear tapes 100 and 120 enable a better seal to be forrned with the package walls. ~e thinner tear tapes 100 and 120 also enable more lineal footage of the tear tape material to be wound onto a spool, and also enable rnore lineal footage of paclcage rnaterial cont~ining the tear tape to be ~1~372~
wound onto a spool.
One preferred embodiment of the package of the present invention is a back or fin seal type of package commonly seen on blocks of natu~al cheese such as the package 10. There is ano~her large group of packages rnade from two webs that are sealed on all four sides.
Typically these packages have a vacuum formed tray covered with a nonformed film and heat sealed around the edges of the tray. Such packages are seen in luncheon meat and hot dog packaging as well as in connection wi~h many other items. These can be referred to as four side seal types of packages. The tear tape 14, 100 or 120 could also be applied from one edge to another through one of the sides of such a package. This could be done on nearly any of the sides depending mostly on the machine used to package and on the opening desired.
Another family of package types is referred to as side sealed pouches which are seen in packages of shredded cheese, liquids and other similar products. These packages are characteristically formed by folding a packaging film over on itself and heat sealing the edges.
llle bottom is sometimes sealed and other times left unsealed. A gusset can be inserted in the bottom if desired. However the package is rnade, it is possible to run the heat-sealable tear tape 14, 100 or 120 through the top of the package in the gene~al area of the top seal to provide an opening feature if combined with notches or nicks in the side seals.
Figure 11 shows a top portion of a package 140 having a first package wall 142 overlying a second package wall 144. Each package wall 142 and 144 is formed from a flexible packaging film such as CURPOLENE~ packaging material sold by Curwood, Inc., the applicant herein, as previously described. The package 140 includes a top latelal edge 146, a first longitudinal side edge 14~, and a second longitudinal side edge 150 s~aced apart from and extending generally pa~llel to the first longitudinal edge 148. The first and second 21837~,,0 package walls 142 and 144 are sealed ~o one another along the si~e edges 148 and 150 and along a bottom edge (not shown~. The package walls 142 and 144 forrn a product receiving charn~er 152 therebetween. A tear strip 154 having a first lateral edge 156 and a spaced apart and generally parallel second lateral edge 158 is located between the first and second package walls 142 and 144 adjacen~ the top edge 146 of the package 140. The tear strip 154 e~tends from the first side edge 148 to the second side edge 150 of the package 140. The tear strip 154 is constructed in the same manner and with the same rnaterials as any of the tear strips 14, 100 or 120.
A first sealant layer of the tear strip 154 is initially sealed to the inner surface of the first package wall 142 such that the top of the package 140 is open to allow the insertion of food or o~her products into the product receiving charnber 152. Thereafter a second sealant layer of the tear strip 154 is heat sealed to the inner surface of the second package wall 144 within a heat seal zone 160 such that the tear strip 154 is hermetically sealed to the first and second package walls 142 and 144. The heat seal zone 160 extends between the longitudinal side edges 148 and 150 of the package 140 and between a first lateral edge 162 of the heat seal zone 160, which is shown as being cc~extensive with the first lateral edge 156 of the tear strip 154 in Fig~re 11, and a second lateral edge 164 of the heat seal zone 160 which is spaced part and generally parallel to the first lateral edge 162.
As shown in Figure 11, the first lateral edge 156 of the tear strip 154 is coextensive with the first lateral edge 162 of the heat seal zone 160. The second lateral edge 158 of the tear strip 154 extends beyond the second lateral edge 164 of the heat seal zone 160 such that the second lateral edge 158 of the tear strip 154 is positioned within the product receiving chamber 152. The tear strip 154 includes a projecting portion lS9 which extends between the late~l edge 164 of the heat se~l zone 160 and the lateral edge 158 of the tear sIrip 154 which is located in the product receiving chamber 152. As shown in Figure 11, the tear strip 154 has a width be~ween the lateral edges 156 and 158 which is greater than the width of the heat seal zone 160 between the lateral edges 162 and 164. Alternatively, the first lateral edge 156 of the tear strip 154 may be positioned beyond the lateral edge 162 of the heat seal zone 160, or it may be positioned within the heat seal zone 160 between the first and second lateral edges 162 and 164 of the heat seal zone 160.
Wllen the tear strip 150 is tom away from the package 140 the extension or projection of the projecting portion 159 and second lateral edge 158 of the tear strip 154 beyond the second lateral edge 164 of the heat seal zone 160 into the chamber 152 enables the tear strip 150 to easily and consistently remove the entire heat seal zone 160 from the remainder of the package 140 to fully open the package 140 between the side edges 148 and 150 and expose the contents of the product receiving chamber 152. This effectively eliminates the p~ssibility of removing the tear strip while allowing the product receiving chamber to remain sealed and inaccessible as sometimes happens in prior art packages.
The package 140 may include a zipper 168, comprising respective gripping strips attached to the interior surface of each package wall 142 and 144, that is selectively openable and reclosable. The zipper 168 is located within the charnber 152 of the package 140 and is spaced below the second lateral edge 158 of the tear strip 154. The zipper 168 enables the chamber 152 to be selectively closed after the tear strip 154 has been tom away from the package 140 to open a passage to the chamber 152.
The package 140 also rnay include an a~.lure 172 which extends through the fLrst package wall 142, the tear strip 154, and the second package wall 144 within the heat seal zone 160. Ihe tear strip 154 reinforces the ape~ e around the aperture 172 to prevent tearing of the aperture 172 by hooks, rods or other support members which are inserted 2~_83q20 through the aperture 172 to suppon the package 140 for display.
Various features of the invention have been particularly shown and described in connection with the illustrated embodiments of the invention, however, it must be understood that these particular arrangements merely illustrate, and that the invention is to be given its fullest int~ eta~ion within the terms of the appended claims.
Claims (36)
1. A tear strip adapted for use in forming a hermetically sealed package having first and second package walls, said tear strip formed of at least a three layer laminate including:
a core layer formed of oriented polymeric film so as to provide sufficient tensile strength for tearing the package, said core layer including first and second surfaces;
an outer sealant layer adhered to said first surface of said oriented core layer, said outer sealant layer adapted to be adhered to the first package wall; and an inner sealant layer adhered to said second surface of said core layer, said inner sealant layer adapted to be adhered to the second package wall;
wherein said tear strip is constructed such that said core layer provides tensile strength for tearing and said sealant layers provide sealability whereby when said tear strip is sandwiched between and sealed to the first and second package walls, a hermetically sealed package is formed with an integrally sealed tear strip.
a core layer formed of oriented polymeric film so as to provide sufficient tensile strength for tearing the package, said core layer including first and second surfaces;
an outer sealant layer adhered to said first surface of said oriented core layer, said outer sealant layer adapted to be adhered to the first package wall; and an inner sealant layer adhered to said second surface of said core layer, said inner sealant layer adapted to be adhered to the second package wall;
wherein said tear strip is constructed such that said core layer provides tensile strength for tearing and said sealant layers provide sealability whereby when said tear strip is sandwiched between and sealed to the first and second package walls, a hermetically sealed package is formed with an integrally sealed tear strip.
2. The tear strip of claim 1 wherein said core layer includes a first layer of oriented polymeric film and a second layer of oriented polymeric film adhered to said first layer of oriented polymeric film.
3. The tear strip of claim 1 wherein said oriented polymeric film of said core layer is formed of polypropylene.
4. The tear strip of claim 1 wherein said oriented polymeric film of said core layer is a polymer selected from the group consisting of polypropylene, polyethylene terephthalate, and high density polyethylene.
5. The tear strip of claim 1 wherein said inner sealant layer is formed of polyethylene.
6. The tear strip of claim 1 wherein said inner sealant layer is formed of low density polyethylene.
7. The tear strip of claim 1 wherein said inner sealant layer is formed of a copolymer of polyethylene containing ethylene-vinyl acetate.
8. The tear strip of claim 1 including a polymer laminating layer positioned between said core layer and said inner sealant layer.
9. The tear strip of claim 1 wherein said core layer comprises one or more layers of polypropylene having a total thickness of approximately 1.8 mils.
10. The tear strip of claim 1 wherein said inner and outer sealant layers each respectively comprise one or more layers of low density polyethylene, each sealant layer having a respective total thickness of approximately 0.10 mils.
11. An easy open package adapted for hermetic sealing of its contents including:
a flexible packaging film forming a first package wall;
a tear strip sealed to said first package wall along an inner surface thereof, said tear strip including a core layer formed of oriented polymer so as to provide sufficient tensile strength for tearing the package, said core layer including first and second surfaces, an outer sealant layer adhered to said first surface of said oriented core layer, said outer sealant layer sealed to said first package wall, and an inner sealant layer adhered to said second surface of said oriented core layer, a second package wall connected to said first package wall around its periphery so as to define a product receiving chamber between said first and second package walls, said second package wall adapted to be sealed to said inner sealant layer of said tear strip so as to hermetically seal said tear strip between said first and second package walls.
a flexible packaging film forming a first package wall;
a tear strip sealed to said first package wall along an inner surface thereof, said tear strip including a core layer formed of oriented polymer so as to provide sufficient tensile strength for tearing the package, said core layer including first and second surfaces, an outer sealant layer adhered to said first surface of said oriented core layer, said outer sealant layer sealed to said first package wall, and an inner sealant layer adhered to said second surface of said oriented core layer, a second package wall connected to said first package wall around its periphery so as to define a product receiving chamber between said first and second package walls, said second package wall adapted to be sealed to said inner sealant layer of said tear strip so as to hermetically seal said tear strip between said first and second package walls.
12. An easy open package as in claim 11 in which said product receiving chamber is hermetically sealed around its entire periphery.
13. An easy open package as in claim 12 in which said tear strip, upon removal, exposes the contents of said product receiving chamber for removal thereof.
14. An easy open package as in claim 11 including a seal zone formed along a portion of said first and second package walls, said seal zone sealing said first package wall, said second package wall and said tear strip together.
15. An easy open package as in claim 14 in which said tear strip has a width dimension which exceeds the width dimension of said seal zone.
16. An easy open package as in claim 14 including an aperture formed in said seal zone extending through said tear strip and said first and second package walls, said aperture adapted to facilitate suspension of said package for display, said tear strip providing additional support to resist tearing of said package around said aperture.
17. An easy open package as in claim 14 in which said tear strip is positioned relative to said seal zone such that said tear strip includes a lateral edge which extends beyond a lateral edge of said seal zone into said product receiving chamber.
18. An easy open package adapted for hermetic sealing of its contents including:
a flexible packaging film forming a package wall, said packaging film having a first longitudinal edge and a second longitudinal edge, said first and second longitudinal edges being sealed to one another thereby forming a product receiving chamber between a first wall portion and an opposing wall portion of said package wall, said package wall including a first lateral edge and a spaced apart second lateral edge, said first and second wall portions being sealed to one another along said first lateral edge and adapted to be sealed to one another along said second lateral edge; and a tear strip having a first end and second end, said tear strip extending longitudinally from said seal at said first lateral edge of said package wall to said seal at said second lateral edge of said package wall, said first end of said tear strip being hermetically sealed between said first and second wall portions at said first lateral edge of said package wall and said second end of said tear strip adapted to be hermetically sealed between said first and second wall portions at said second lateral edge of said package wall, said tear strip including a core layer formed of oriented polymer so as to provide sufficient tensile strength for tearing the package, said core layer including first and second surfaces, an outer sealant layer adhered to said first surface of said oriented core layer, said outer sealant layer sealed to said first wall portion of said package wall, and an inner sealant layer adhered to said second surface of said oriented core layer, said inner sealant layer adapted to be adhered to said second wall portion of said outer sealant layer of said package wall.
a flexible packaging film forming a package wall, said packaging film having a first longitudinal edge and a second longitudinal edge, said first and second longitudinal edges being sealed to one another thereby forming a product receiving chamber between a first wall portion and an opposing wall portion of said package wall, said package wall including a first lateral edge and a spaced apart second lateral edge, said first and second wall portions being sealed to one another along said first lateral edge and adapted to be sealed to one another along said second lateral edge; and a tear strip having a first end and second end, said tear strip extending longitudinally from said seal at said first lateral edge of said package wall to said seal at said second lateral edge of said package wall, said first end of said tear strip being hermetically sealed between said first and second wall portions at said first lateral edge of said package wall and said second end of said tear strip adapted to be hermetically sealed between said first and second wall portions at said second lateral edge of said package wall, said tear strip including a core layer formed of oriented polymer so as to provide sufficient tensile strength for tearing the package, said core layer including first and second surfaces, an outer sealant layer adhered to said first surface of said oriented core layer, said outer sealant layer sealed to said first wall portion of said package wall, and an inner sealant layer adhered to said second surface of said oriented core layer, said inner sealant layer adapted to be adhered to said second wall portion of said outer sealant layer of said package wall.
19. The easy open package of claim 18 wherein said tear strip is sealed to said package wall along the entire length of said tear strip.
20. A method of forming a tear strip adapted for use in forming a hermetically sealed package having first and second package walls, said method including the steps of:
providing a core layer formed of oriented polymeric film adapted to provide sufficient tensile strength for tearing the package, said core layer having first and second surfaces;
adhering a first sealant layer to said first surface of said core layer, said first sealant layer adapted to be adhered to the first package wall; and adhering a second sealant layer to said second surface of said core layer, said second sealant layer adapted to be adhered to the second package wall;
wherein said tear strip is constructed such that said core layer provides tensile strength for tearing and said sealant layers provide sealability whereby when said tear strip is sandwiched between and sealed to the first and second package walls, a hermetically sealed package is formed with an integrally sealed tear strip.
providing a core layer formed of oriented polymeric film adapted to provide sufficient tensile strength for tearing the package, said core layer having first and second surfaces;
adhering a first sealant layer to said first surface of said core layer, said first sealant layer adapted to be adhered to the first package wall; and adhering a second sealant layer to said second surface of said core layer, said second sealant layer adapted to be adhered to the second package wall;
wherein said tear strip is constructed such that said core layer provides tensile strength for tearing and said sealant layers provide sealability whereby when said tear strip is sandwiched between and sealed to the first and second package walls, a hermetically sealed package is formed with an integrally sealed tear strip.
21. The method of claim 20 including the step of forming said core layer by adhering a first layer of oriented polymeric film to a second layer of oriented polymeric film.
22. The method of claim 20 wherein said oriented polymeric film of said core layer is formed of polypropylene.
23. The method of claim 20 wherein said oriented polymeric film of said core layer is a polymer selected from the group consisting of polypropylene, polyethylene terephthalate, and high density polyethylene.
24. The method of claim 20 wherein said first sealant layer is formed of polyethylene.
25. The method of claim 20 wherein said first sealant layer is formed of low density polyethylene.
26. The method of claim 20 wherein said first sealant layer is formed of a copolymer of polyethylene containing ethylene-vinyl acetate.
27. A method of forming an easy open package adapted for hermetic sealing of its contents, said method including the steps of:
providing a tear strip having a first end and a second end and a first lateral edge and a second lateral edge, said tear strip including a core layer formed of oriented polymer so as to provide sufficient tensile strength for tearing the package, said core layer having first and second surfaces, a first sealant layer adhered to said first surface of said core layer and a second sealant layer adhered to said second surface of said core layer, providing a first package wall and an overlying second package wall;
adhering a portion of said first sealant layer at said first end of said tear strip to said first package wall;
adhering a portion of said first sealant layer at said second end of said tear strip to said first package wall;
adhering a portion of said second sealant layer at said first end of said tear strip to said second package wall such that said first end of said tear strip is hermetically sealed between said first and second package walls; and adhering a portion of said second sealant layer at said second end of said tear strip to said second package wall such that said second end of said tear strip is hermetically sealed between said first and second package walls.
providing a tear strip having a first end and a second end and a first lateral edge and a second lateral edge, said tear strip including a core layer formed of oriented polymer so as to provide sufficient tensile strength for tearing the package, said core layer having first and second surfaces, a first sealant layer adhered to said first surface of said core layer and a second sealant layer adhered to said second surface of said core layer, providing a first package wall and an overlying second package wall;
adhering a portion of said first sealant layer at said first end of said tear strip to said first package wall;
adhering a portion of said first sealant layer at said second end of said tear strip to said first package wall;
adhering a portion of said second sealant layer at said first end of said tear strip to said second package wall such that said first end of said tear strip is hermetically sealed between said first and second package walls; and adhering a portion of said second sealant layer at said second end of said tear strip to said second package wall such that said second end of said tear strip is hermetically sealed between said first and second package walls.
28. The method of claim 27 including the step of adhering said first sealant layer of said tear strip to said first package wall between said first and second ends of said tear strip along the entire length of said tear strip.
29. The method of claim 28 including the step of adhering said second sealant layer of said tear strip to said second package wall between said first and second ends of said tear strip along the entire length of said tear strip.
30. The method of claim 27 including the step of adhering said first sealant layer to said first package wall across the width of said tear strip from said first lateral edge of said tear strip to said second lateral edge of said tear strip, and adhering said second sealant layer of said tear strip to said second package wall across the width of said tear strip from said first lateral edge of said tear strip to said second lateral edge of said tear strip.
31. The method of claim 27 including the step of adhering said first sealant layer of said tear strip to said first package wall and adhering said second sealant layer of said tear strip to said second package wall in a heat seal zone having a lateral edge spaced apart from said second lateral edge of said tear strip.
32. An easy open package adapted for hermetic sealing of its contents including:
a flexible packaging film having a first end and a spaced apart second end, said packaging film forming a first wall portion and a second wall portion, said first and second wall portions defining a product receiving chamber therebetween;
a tear strip having a first end and a second end, a core layer of oriented polymer having a first surface and a second surface, a first sealant layer adhered to said first surface of said core layer and a second sealant layer adhered to said second surface layer of said core layer, said first sealant layer being adhered to said first wall portion at said first end of said packaging film and said second sealant layer adapted to be adhered to said second wall portion at said first end of said packing film such that said first end of said tear strip is adapted to be hermetically sealed between said first and second wall portions at said first end of said flexible packaging, said second end of said tear strip being adhered to said flexible packaging at a location positioned between said first end and said second end of said packaging film.
a flexible packaging film having a first end and a spaced apart second end, said packaging film forming a first wall portion and a second wall portion, said first and second wall portions defining a product receiving chamber therebetween;
a tear strip having a first end and a second end, a core layer of oriented polymer having a first surface and a second surface, a first sealant layer adhered to said first surface of said core layer and a second sealant layer adhered to said second surface layer of said core layer, said first sealant layer being adhered to said first wall portion at said first end of said packaging film and said second sealant layer adapted to be adhered to said second wall portion at said first end of said packing film such that said first end of said tear strip is adapted to be hermetically sealed between said first and second wall portions at said first end of said flexible packaging, said second end of said tear strip being adhered to said flexible packaging at a location positioned between said first end and said second end of said packaging film.
33. The easy open package of claim 32 wherein said first sealant layer of said tear strip is continuously adhered to said flexible packaging film along the length of said tear strip between said first and second ends of said tear strip.
34. The easy open package of claim 33 wherein said second sealant layer at said second end of said tear strip is unattached to said flexible packaging film.
35. The easy open packaging of claim 32 wherein said second end of said tear strip is located at a distance from said first end of said flexible packaging film that is less than one-half of the length of said easy open package between said first end and said second end of said flexible packaging film.
36. The easy open package of claim 32 wherein said second end of said tear strip terminates at a point located between said first end of said flexible packaging film and the middle of the length of said flexible package film between said first and second ends of said flexible package film, such that when said tear strip is removed from said flexible packaging film a pour opening is formed in said flexible packaging film.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US269095P | 1995-08-23 | 1995-08-23 | |
| US60/002,690 | 1995-08-23 | ||
| US69335896A | 1996-08-06 | 1996-08-06 | |
| US08/693,358 | 1996-08-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2183720A1 true CA2183720A1 (en) | 1997-02-24 |
Family
ID=26670737
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2183720 Abandoned CA2183720A1 (en) | 1995-08-23 | 1996-08-20 | Hermetically sealed package with heat-sealable tear strip and method of manufacture |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2183720A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6316036B1 (en) | 1997-12-10 | 2001-11-13 | Pechiney Emballage Flexible Europe | Tear tape for plastic packaging |
-
1996
- 1996-08-20 CA CA 2183720 patent/CA2183720A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6316036B1 (en) | 1997-12-10 | 2001-11-13 | Pechiney Emballage Flexible Europe | Tear tape for plastic packaging |
| US6416841B1 (en) | 1997-12-10 | 2002-07-09 | Pechiney Emballage Flexible Europe | Tear tape for plastic packaging |
Also Published As
| Publication number | Publication date |
|---|---|
| MX9603529A (en) | 1998-05-31 |
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| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |
Effective date: 19990820 |