|Publication number||US20050008266 A1|
|Application number||US 10/838,121|
|Publication date||Jan 13, 2005|
|Filing date||May 3, 2004|
|Priority date||Jul 10, 2003|
|Publication number||10838121, 838121, US 2005/0008266 A1, US 2005/008266 A1, US 20050008266 A1, US 20050008266A1, US 2005008266 A1, US 2005008266A1, US-A1-20050008266, US-A1-2005008266, US2005/0008266A1, US2005/008266A1, US20050008266 A1, US20050008266A1, US2005008266 A1, US2005008266A1|
|Inventors||Gregory Crunkleton, Basil Linton, Eric Fenzl|
|Original Assignee||Crunkleton Gregory H., Linton Basil C., Fenzl Eric J.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (13), Referenced by (21), Classifications (18), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is a continuation-in-part of and claims priority from U.S. patent application Ser. No. 10/617,234 filed on Jul. 10, 2003 and entitled “Tamper-Evident Reclosable Bag Having Slider-Actuated String Zipper”.
This invention generally relates to reclosable bags and other packages having profiled (e.g., extruded) plastic zippers and tamper-evident features. In particular, the invention relates to reclosable bags and other packages having a tamper-evident feature on the product side of the zipper.
In the use of plastic bags, pouches and other packages, particularly for containing foodstuffs, it is important that the bag be hermetically sealed and tamper evident until the purchaser acquires the bag and its contents, takes them home, and opens the bag or package for the first time. It is then commercially attractive and useful for the consumer that the bag or package be reclosable so that its contents may be protected. Such bags provide the consumer with the ability to readily store, in a closed, if not sealed, package any unused portion of the packaged product even after the package is initially opened. Flexible plastic zippers have proven to be excellent for reclosable bags, because they may be manufactured with high-speed equipment and are reliable for repeated reuse.
Many reclosable bags comprise a receptacle having a mouth with a slider-actuated zipper installed therein for opening and closing the bag. As the slider is moved in an opening direction, the slider causes the zipper sections it passes over to open. Conversely, as the slider is moved in a closing direction, the slider causes the zipper sections it passes over to close. Typically, a zipper for a reclosable bag includes a pair of interlockable profiled closure strips that are joined at opposite ends of the bag mouth. The profiles of interlockable plastic zipper parts can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure elements, etc. Reclosable bags having slider-operated zippers are generally more desirable to consumers than bags having zippers without sliders because the slider eliminates the need for the consumer to align the interlockable zipper profiles before causing those profiles to engage.
Various additions to reclosable bags have been made to provide tamper-evident seals or indicators that will reveal when the bag has been opened or otherwise tampered with prior to purchase by the consumer. It is known to provide a reclosable package construction that is designed to undergo some permanent change in the package appearance when the package is opened for the first time. For example, it is known to provide a reclosable package with a tamper-evident, non-reclosable peel seal that gives a positive indication of having been broken when a package is first opened. It is also known to cover the zipper (with or without slider) under a shroud or inside an enclosed header on the top of the bag. Another type of tamper-evident feature is the provision of a membrane on the product side of the zipper that partitions the interior volume in an airtight manner.
There is a continuing need for new designs for reclosable bags with tamper-evident features for hermetic packages that can be manufactured at low cost.
The present invention is directed to reclosable bags and other packages that have a profiled plastic zipper and a tamper-evident feature on the product side of the zipper. The tamper-evident feature is a strip of double-sided adhesive tape adhered to opposing walls of the package and extending from one side seal to the other, thereby hermetically sealing and partitioning the portion of the package interior volume containing a perishable product. The invention is further directed to methods of manufacturing such packages.
One aspect of the invention is a reclosable package comprising: a receptacle having a mouth and an interior volume; a string zipper installed in the mouth; a slider mounted to the string zipper; and a tamper-evident feature that blocks access to at least a portion of the interior volume, wherein the tamper-evident feature comprises double-sided adhesive tape located within the interior volume and adhered to the receptacle, the adhesive tape comprising a substrate having respective continuous layers of adhesive material on both sides thereof.
Another aspect of the invention is a reclosable package comprising: first and second panels joined together along first and second side edges to form first and second side seals and sealed or connected at a bottom to form a receptacle having a mouth and an interior volume; a zipper installed in the mouth; and a strip of material having low-tack adhesive on both sides, the low-tack adhesive on one side of the strip being adhered to the first panel and the low-tack adhesive on other side of the strip being adhered to the second panel from the first side seal to the second seal at an elevation below the zipper, wherein the adhesive tape blocks access to at least a portion of the interior volume.
A further aspect of the invention is a method of making reclosable packages, comprising the following steps: (a) placing one side of a length of a double-sided adhesive tape in contact with a length of a web of packaging film along a first line of adhesion generally parallel to mutually parallel first and second edges of the length of web, the first line of adhesion being closer to the first edge than to the second edge; (b) joining the back of a length of a first zipper strip to the length of web along a first line of joinder generally parallel to the first and second edges of the length of web and closer to the first edge than to the second edge; (c) joining the back of a length of a second zipper strip to the length of web along a second line of joinder generally parallel to the first and second edges of the length of web and closer to the second edge than to the first edge; (d) placing product on a first area of the length of web located on one side of a centerline of the length of web generally parallel to the first and second edges; (e) folding the length of web along the centerline so that a second area of the length of web located on the other side of the centerline overlies the product; (f) placing the other side of the length of double-sided adhesive tape in contact with the confronting portion of the folded-over length of web along a second line of adhesion; and (g) respectively joining first and second portions of the length of web on one side of the fold line to third and fourth portions of the length of web on the other side of the fold line along first and second transverse lines of joinder that are generally parallel to each other and generally perpendicular to the first and second edges, whereby a receptacle is formed having a sealed interior volume with the product therein, the sealed interior volume being bounded by the fold line, the first and second transverse lines of joinder, and the adhesive tape.
Yet another aspect of the invention is a method of making reclosable packages, comprising the following steps: (a) adhering first and second sides of a strip of double-sided adhesive tape to first and second portions, respectively, of web material along first and second lines of adhesion that are generally parallel to each other; (b) joining first and second zipper strips to third and fourth portions, respectively, of the web material along first and second lines of joinder that are generally parallel to the first and second lines of adhesion, a distance between the first line of joinder and the first line of adhesion being generally equal to a distance between the second line of joinder and the second line of adhesion; (c) manipulating the web material so that the first and second portions of the web material confront each other and the third and fourth portions of the web material confront each other; (d) joining fifth and sixth confronting portions of the web material along a first transverse line of joinder generally perpendicular to the first line of joinder; and (e) joining seventh and eighth confronting portions of the web material along a second transverse line of joinder generally parallel to the first transverse line of joinder.
Other aspects of the invention are disclosed and claimed below.
Reference will now be made to the drawings in which similar elements in different drawings bear the same reference numerals.
A reclosable package comprising a receptacle 2 and a flexible plastic string zipper 4, operated by manipulation of a slider 10, is shown in
The receptacle 2 may be made from any suitable film material, including thermoplastic film materials such as low-density polyethylene, substantially linear copolymers of ethylene and a C3-C8 alpha-olefin, polypropylene, polyvinylidene chloride, mixtures of two or more of these polymers, or mixtures of one of these polymers with another thermoplastic polymer. The person skilled in the art will recognize that this list of suitable materials is not exhaustive. Although not intended in a limitative sense, it is noted that the thickness of the film is preferably 2 mils or less.
The string zipper 4 is disposed between the confronting top marginal portions of the front and rear walls, but has been represented as solid lines to reflect the fact that the front wall is optically transparent. Thus, during slider travel the side walls of the slider 4 pass over the top marginal portions of the front and rear walls of the receptacle, which are joined to opposing sides of the string zipper, as will be explained in more detail below.
The package shown in
In accordance with one embodiment of the invention, an internal hermetic seal 50 is disposed inside the receptacle at an elevation above the packaged product (not shown) and below the string zipper (see also
Reclosable packages within the scope of the present invention may be similar to the exemplary package shown in
Still referring to
For the sake of completeness, the string zipper and slider in accordance with one embodiment will be described in greater detail. However, it should be appreciated that the structure disclosed hereinafter is exemplary only, and that structures of the zipper and slider may be varied without affecting the structure and function of the tamper-evident internal hermetic seal disclosed herein. For example, the invention is not limited in its application to packages having slider-operated string zippers. Instead the slider-zipper assembly could be of the type wherein the zipper strips are attached to the receptacle by way of flanges or fins. Alternatively, the package could have a flanged or string zipper without a slider.
Referring again to
The sealing bridge 12 and the base 14 are resiliently flexible self-supporting structures having a thickness greater than the thickness of the package film. The male closure elements are integrally formed with the base 14, while the female closure elements are integrally formed with the sealing bridge 12. The upper margins of the walls 2 a and 2 b of the package are joined to the backs of the sealing bridge 12 and the base 14 respectively, as seen in
The end face of the upper edge of the base 14, which carries the male closure elements 20 and 28, is inclined at about a 45° angle to facilitate loading of the slider onto the zipper from above without snagging on a comer of the upper edge. The topmost portion 46 of wall 2 b is sealed against this inclined end face. Similarly, the topmost portion 48 of wall 2 a is sealed against the curved back of the gripper jaw 16. The bottom edge of the base 14 cooperates with a retaining ledge on the slider to increase the slider-pull-off resistance. For the same purpose, a rib 26 is formed on zipper part 6, the rib 26 cooperating with a retaining ledge on the other side of the slider.
In the slider-zipper assembly shown in
The slider 10 comprises a top wall 32, a pair of side walls 34 and 36 connected to opposing sides of the top wall 32, the top wall 32 and side walls 34, 36 forming a tunnel for passage of the string zipper therethrough. The ends of the slider are open to allow the zipper to pass through. The width of the tunnel is substantially constant along the section that is divided by the plow 44 and then narrows from a point proximal to the end of the plow to the closing window at one end face of the slider. The narrowing section of the tunnel is formed by substantially planar, inclined interior surfaces (not shown in
The slider 10 in this particular example also comprises a plow or divider 44 that depends downward from a central portion of the top wall 32 to an elevation below the lowermost portions of each side wall. The plow 44 is disposed between opposing sections of the zipper parts that pass through the tunnel. The tip of the plow 44 is truncated and has rounded edges and flattened comers at opposing ends for facilitating insertion of the plow between the zipper profiles without snagging during automated slider insertion. The plow 44 comprises a beam having a cross-sectional shape that is a rectangle with rounded comers. The axis of the beam is generally perpendicular to the top wall of the slider. As the slider is moved in the opening direction (i.e., with the closing end leading), the plow 44 pries the impinging sections of zipper parts 6 and 8 apart.
Although the slider in the disclosed embodiment has a plow, the string zipper, if suitably designed, could be actuated by a slider that has no plow or separating finger.
In the embodiment depicted in
The slider may be made in multiple parts and welded together or the parts may be constructed to be snapped together. The slider may also be of one-piece construction. The slider can be made using any desired method, such as injection molding. The slider can be molded from any suitable plastic, such as nylon, polypropylene, polystyrene, acetal, polyketone, polybutylene terephthalate, high-density polyethylene, polycarbonate, or ABS.
Improved slider designs are disclosed in U.S. patent application Ser. No. 10/412,438, entitled “Molded Sliders for Actuating Zippers of Reclosable Packages”. In one such design, each retaining ledge on the interior surface of the slider side walls is replaced by a pair of retaining teeth spaced apart at opposite ends of the slider.
The ultrasonic welding assembly 110 comprises an ultrasonic horn 96 and an anvil 98. The string zipper material 4 is intermittently advanced through the gap separating the horn and the anvil. During each dwell time, the horn is displaced toward the anvil, e.g., by means of an air-actuated cylinder (not shown), and activated to transmit ultrasonic wave energy into a respective portion of the thermoplastic zipper material being pressed between the horn and anvil. During this operation, the thermoplastic zipper material is softened and deformed into a slider end stop structure. This slider end stop structure will be bisected later when the packaging film and string zipper are cut in the cross direction using a hot knife that both severs and seals the film.
Alternatively, the string zipper material could be ultrasonically stomped to form slider end stop structures at a different site and wound on the supply spool, which is then transported to and mounted on the bag making machine. The pre-stomped string zipper material can then be unwound from the spool and fed to the zipper sealing station.
In either case, the drawn string zipper material is passed through a zipper guide 120 that is laterally situated between an edge of web 2 and the adhesive tape 50 adhered to the web. In its simplest form, the zipper guide may be a tube that maintains the zipper in the proper position and orientation relative to the web 2, which in this case is parallel to the edge of the web and overlying the marginal web portion disposed between that edge and the adhesive tape, as seen in
Downstream from the first zipper sealing station 122, a mass of product 70 is placed on the web 2 on the same side of the fold line F as the adhesive tape 50 and the string zipper material 4, as seen in
As seen in
In the next stage of manufacture, a respective slider 10 is inserted onto the string zipper 4 by a slider insertion device 80, generally depicted in
After each slider insertion, the web/zipper/slider/adhesive tape assembly is advanced one package width. A cross sealing station (not shown in the drawings) is located downstream from the slider insertion device. After each package-width advance, the web is cross sealed by a pair of opposing reciprocating vertical heated sealing bars at the cross sealing station. These vertical sealing bars form a cross seal that extends from the fold in the web to the edges of the web. Slider insertion and cross sealing occur during the same dwell time at different locations along the tensioned web. A cutting station is located downstream of the cross sealing station. The cutting station comprises a knife for cutting the web and zipper along a vertical line that generally bisects each cross seal, thereby severing an individual package from the web/zipper/slider/adhesive tape assembly. Alternatively, cross sealing and cutting can be performed concurrently using a hot knife. The end result is a package having product hermetically sealed by the adhesive tape, which partitions the interior volume of the package at an elevation just below the slider-operated string zipper.
In the example shown in
Alternatively, the zipper and adhesive tape could be continuously attached to the web so that the dancer assembly could be placed after the zipper sealing station and that both zipper bases could be sealed at the same time to a folded web by drag sealers on either side of the zipper.
While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
As used in the claims, the verb “joined” means fused, bonded, sealed, adhered, etc., whether by application of heat and/or pressure, application of ultrasonic energy, application of a layer of adhesive material or bonding agent, interposition of an adhesive or bonding strip, etc. As used in the claims, the term “string zipper” means a zipper comprising two interlockable closure strips that have substantially no flange portions. In the method claims, various lines of joinder are identified by the adjectives “first”, “second”, and so forth, which identifiers should not be construed to imply any order in which the various recited steps of the claimed method are performed. Furthermore, as used in the claims, the term “line of joinder” should be construed broadly to encompass a line of joinder as well as a band- or strip-shaped zone of joinder having a finite width.
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|U.S. Classification||383/5, 383/211, 383/64, 383/61.2|
|International Classification||B65D33/25, B65D33/34|
|Cooperative Classification||B65B61/005, B31B19/90, B65B61/188, B65B9/073, B65D33/2591, B31B2219/9019, B31B2219/9009|
|European Classification||B65B9/073, B31B19/90, B65D33/25C, B65B61/00C, B65B61/18E|
|May 3, 2004||AS||Assignment|
Owner name: ILLINOIS TOOL WORKS INC., ILLINOIS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:CRUNKLETON, GREGORY H.;LINTON, BASIL C.;FENZL, ERIC J.;REEL/FRAME:015298/0273
Effective date: 20040427