Abstract:
The disclosure relates to a zipper for a reclosable bag wherein the zipper is designed to make additional sound during operation, and further provide an increased tactile response. The zipper profile is manufactured by forming cuts in the profile, and then the profile is stretched so that the cuts become gaps. These gaps cause additional sound during operation of the zipper.

Description:
This application claims priority under 35 U.S.C. §119(e) of the following provisional patent applications, the contents of all of which are hereby incorporated by reference, in their entirety: 
     1. provisional application Ser. No. 61/417,655, filed on Nov. 29, 2010; 
     2. provisional application Ser. No. 61/417,675, filed on Nov. 29, 2010; 
     3. provisional application Ser. No. 61/417,535, filed on Nov. 29, 2010; 
     4. provisional application Ser. No. 61/444,217, filed on Feb. 18, 2011; 
     5. provisional application Ser. No. 61/484,956, filed on May 11, 2011; 
     6. provisional application Ser. No. 61/484,958, filed on May 11, 2011; 
     7. provisional application Ser. No. 61/484,959, filed on May 11, 2011; 
     8. provisional application Ser. No. 61/484,961, filed on May 11, 2011; 
     9. provisional application Ser. No. 61/484,964, filed on May 11, 2011; 
     10. provisional application Ser. No. 61/484,965, filed on May 11, 2011; 
     11. provisional application Ser. No. 61/484,967, filed on May 11, 2011; 
     12. provisional application Ser. No. 61/484,970, filed on May 11, 2011; 
     13. provisional application Ser. No. 61/484,972, filed on May 11, 2011; 
     14. provisional application Ser. No. 61/484,975, filed on May 11, 2011; 
     15. provisional application Ser. No. 61/484,978, filed on May 11, 2011; 
     16. provisional application Ser. No. 61/484,979, filed on May 11, 2011; 
     17. provisional application Ser. No. 61/484,984, filed on May 11, 2011; and 
     18. provisional application Ser. No. 61/515,104, filed on Aug. 4, 2011. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to a zipper structure for a reclosable package wherein at least one of the zipper profiles, typically including the female profile, is partially cut or excised, and then stretched, typically in order to obtain audible clicking sounds and a tactile feel during subsequent consumer operation. 
     2. Description of the Prior Art 
     In the prior art, it is known to deform zipper profiles. Examples of such deformed zipper profiles are disclosed in U.S. Pat. No. 4,189,809 entitled “Fastener Device and Method of Manufacturing”, issued on Feb. 26, 1980 to Sotos and U.S. Pat. No. 4,056,593 entitled “Method of Making a Fastener”, issued on Nov. 1, 1977 to de Navas Albareda. Additional prior art includes U.S. Pat. No. 6,299,353, entitled “Zipper for Reclosable Container with Apertures Passing Through Female Profile, issued to Piechocki on Oct. 9, 2001; U.S. Pat. No. 5,962,040 entitled “Apparatus for Making a Zipper for a Reclosable Thermoplastic Bag”, issued on Oct. 5, 1999 to Dais et al.; U.S. Pat. No. 5,647,100 entitled “Closure Member for a Reclosable Thermoplastic Bag” issued on Jul. 15, 1997 to Porchia et al.; U.S. Pat. No. 5,478,228, entitled “Apparatus for Making a Zipper for a Reclosable Thermoplastic Bag”, issued on Dec. 26, 1995 to Dais et al, and U.S. Patent Publication 2010/135600, entitled “Automatic Gripping Device with Extremely Flexible Hooks”, published on Jun. 3, 2010. 
     However, further improvements are sought with respect to the quality of the audible clicking sound and tactile feel when the zipper is opened and closed. 
     Additionally, further improvements are sought with regard to maintaining the strength of the closure of the resulting zipper (i.e., the balloon effect), particularly with respect to the seepage through the closed zipper when the zipper bag is filled with air. Similarly, further improvements are sought with regard to the production rates and manufacturing costs. 
     SUMMARY AND OBJECTS OF THE DISCLOSURE 
     It is therefore an object of the present disclosure to provide further improvements in a zipper for a reclosable package, wherein a superior quality of the audible clicking sound and the tactile feel are achieved during opening and closing of the zipper. 
     It is therefore a further object of the present disclosure to provide such a zipper which maintains its closure strength. In particular, this strength should ideally be maintained when the zipper is filled with air, so that there is no more, or even less, seepage than would occur in a prior art zipper. 
     It is therefore a still further object of the present disclosure to maintain or increase the production speeds of the zipper, while maintaining or decreasing the production costs of the zipper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further objects and advantages of the disclosure will become apparent from the following description and from the accompanying drawings, wherein: 
         FIG. 1A  is a perspective view of a female element of a zipper profile of an embodiment of the present disclosure, including perpendicularly-oriented cuts. 
         FIG. 1B  is a perspective view of a female element of a zipper profile of an embodiment of the present disclosure, including inclined cuts. 
         FIG. 1C  is a side view of a female element of a zipper profile of an embodiment of the present disclosure, illustrating both the perpendicular-oriented cut and the inclined cut. 
         FIG. 2A  is a cross-sectional view of a female element of an embodiment of a zipper profile of the present disclosure, illustrating a preferred depth of cut into the female profile. 
         FIG. 2B  is a cross-sectional view of a two-pronged male element of an embodiment of the zipper profile of the present disclosure illustrating the preferred depth of cut into the male profile. 
         FIG. 2C  is a cross-sectional view of a single pronged male element showing an alternative cut in the male profile. 
         FIG. 3  is a perspective view of a further embodiment of a zipper profile of the present disclosure. 
         FIG. 4  is a perspective view of a female element of a further embodiment of a zipper profile of the present disclosure. 
         FIG. 5  is a perspective view of a female element of a still further embodiment of a zipper profile of the present disclosure. 
         FIGS. 6A and 6B  are perspective and top views, respectively, of a female element of a still further embodiment of a zipper profile of the present disclosure. 
         FIGS. 7A ,  7 B,  7 C,  7 D,  8  and  9  are perspective views of embodiments of double zipper and/or multiple male arrangements of the present disclosure. 
         FIG. 10  is a perspective view of an embodiment of the present disclosure including a multiple alignment zipper. 
         FIGS. 11 and 12  are perspective view of embodiments of the present disclosure including female profiles of a double zipper configuration. 
         FIG. 13  illustrates the escape of steam, such as that generated subjecting the package to microwave energy, through the zipper profile. 
         FIG. 14  illustrates an embodiment of the present disclosure, particularly for use with a powder product. 
         FIG. 15A  is a plan view of an embodiment of the present disclosure, prior to stretching. 
         FIG. 15B  is a cross-sectional view along plane  15 B- 15 B of  FIG. 15A , further including a male profile. 
         FIG. 16A  is a plan view of an embodiment of the present disclosure, after stretching. 
         FIG. 16B  is a cross-sectional view along plane  16 B- 16 B of  FIG. 16A , further including a male profile. 
         FIGS. 17A-17D  illustrate further embodiments of the present disclosure, particularly adapted to increasing the sound production of the zippers during operation. 
         FIG. 18  is a schematic of an apparatus and method used for stretching zipper in the present disclosure. 
         FIG. 19A  is a cross-sectional view illustrating the proportions of the zipper profiles prior to stretching of the male profile. 
         FIG. 19B  is a cross-sectional view illustrating the proportions of the zipper profiles after stretching of the male profile. 
         FIG. 20A  is a cross-sectional view illustrating the proportions of the zipper profiles prior to stretching of the female profile. 
         FIG. 20B  is a cross-sectional view illustrating the proportions of the zipper profiles after stretching of the female profile. 
         FIG. 21  is a side plan view, partially in cross section, showing the joining of the male and female zipper profiles, so as to offset the partial cuts or gaps. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIGS. 1A ,  1 B and  1 C illustrate female zipper profile  102  of a zipper  100 . At the outset, zipper  100  is typically made of polymeric material, such as, but not limited to, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymers, ultralow density polyethylene, very low density polyethylene, elastomers, plastomers, metallocene linear low density polyethylene, metallocene polypropylene, or mixtures thereof, and parts of the zipper, such as the hooks or arms, may be made of one material while the rest of the zipper is made from a different material. Female zipper profile  102  includes first and second upwardly extending arms  104 ,  106 , terminating in respective first and second detent hooks  108 ,  110 , and thereby creating a female space  112  therebetween. Additionally, upwardly extending arms  104 ,  106  include a series of partial cuts  114 . As illustrated in  FIG. 1A  and the left side of  FIG. 1C , these cuts can be formed perpendicularly or at an angle to a longitudinal axis of female zipper profile  102 . In a typical application, it is envisioned that the depth of partial cuts  114  would be from ten to sixty percent of the height of the female zipper profile  102 , as illustrated in  FIG. 2   a . However, in some embodiments, such as, but not limited to double zippers wherein only a single zipper is cut, the depth of the partial cuts may be as much as eighty percent of the height of the female zipper profile  102 . It is a concern that further cutting may result in loss of strength, ballooning or distortion after the subsequent stretching step. The extent of the stretching step is typically, but not limited to, ten to forty percent of the length of the zipper material being stretched. This extent of stretching refers to the extent of the initial stretching and does not include any possible subsequent elastic retraction of the zipper after the stretching step has terminated. The female zipper profile  102  is combined with a male zipper profile  120  of  FIG. 2B , typically comprising a post element  122  arising from a base or flange  125  and termination in arrowhead-shaped detent head  126  which, in the engaged position, is engaged by first and second detent hooks  108 ,  110  of female zipper profile  102  (which also may be cut). 
     Typical dimensions for partial cuts  114  would be a cut and stretched gap width of 0.030 to 0.090 inches and a stretched gap distance center-to-center of 0.1875 to 0.3125 inches, but those skilled in the art may realize, after review of the present disclosure, that other spacing may be appropriate for different applications. For instance, when only one zipper of a double zipper profile is cut, the cut and stretched gap could typically have a width from 0.030 to 0.18 inches. 
     When the zipper  100  is subsequently stretched, the partial cuts  114  become gaps that provide improved audible and tactile features, without losing advantages of prior art zippers. After the partial cuts  114  are made, the zipper  100  is heated and then stretched. As stated above, the depth of the partial cut  114  is typically ten to sixty percent of the height of the female or male zipper profile, although some embodiments may have cuts as deep as eighty percent of the height of the female zipper profile (particularly if only one zipper profile of a double zipper profile is cut). The partial cuts  114  can be made after the zipper  100  has been extruded and cooled, or in some cases, while the zipper  100  is still warm from extrusion. Additionally, some embodiments may include an additional series of steps of heating, stretching and cooling after the initial steps of cutting, stretching, and cooling. Alternately, the pre-extruded zipper  100  may be fed from a spool. The partial cuts  114  can be made by a blade, a laser, an ultrasonic, or other similar apparatus. The partial cuts  114  can be made in only the female zipper profile  102 , only the male zipper profile  120 , or in both the male and female zipper profile  102 ,  120 . Additionally, the partial cuts  114  can be made in multiple profile zippers  100  such as shown in  FIGS. 3 ,  7 A-D,  8  and  9 . Furthermore, the double zipper constructions or double zippers with central sections, as shown in  FIGS. 7A-7D ,  8  and  9  can provide various combinations of the disclosed cut-and-stretch configurations in that a first zipper component  102 A of the double zipper can have the cut-and-stretch configuration while the second zipper component  102 B of the double zipper can be free of the cut-and-stretch configuration (in this configuration, a depth of the partial cuts  114  can be as much as eighty percent of the height of the profile). Part of the zipper  100  can have partial cuts  114 , or central sections  103  of the zipper  100  can have partial cuts  114 . In all cases, it is envisioned that the partial cuts  114  would become gaps after the stretching step occurs. Depending upon the depth of the partial cuts  114 , the typical percentage initial elongation involved in the stretching of the zipper can be from ten to as much as forty percent on a length-wise basis (prior to any possible subsequent elastic retraction after the stretching step has terminated). The female zipper profile  102  can be partially cut on one or both sides, or only one or both arms  104 ,  106  can be cut, or any combination (see  FIGS. 4 and 5 ). Similarly, the male zipper profile  120  or the single hook profiles can have one or even both hooks cut. The partial cuts  114  of the female zipper profile  102  can be opposite from each other or offset from each other. Alternatively, the partial cuts  114  can be made diagonally across the linear profiles (with respect to the longitudinal axis of the zipper  100  and the zipper profiles  102 ,  120 ) in one or more angles, and, for a female profile, either in one or both legs (see  FIGS. 6A and 6B ). Additionally, with respect to the stretching step, one profile may be stretched more than the other, or one profile may initially be longer than the other before stretching in order to compensate for differences in stretching. The resulting zipper maintains its strength as well as its leak-resistance (i.e., the ballooning effect). Moreover, the resulting zipper is resistant to deterioration and the interlocking elements are maintained in interlockable alignment. 
     In particular, laser cutting or transverse direction slitting of the profiles can be used. Two-dimensional laser scoring could slit or cut part of the legs of the female profile at different pitches in order to create a torturous, or at least non-linear, path without cutting the bottom section of the female profile. It is expected that the resulting zippers would continue to show acceptable ballooning properties in that there is still enough closure contact to impede the flow of air through the closure when the closure halves are mated. Similarly, the partial cuts could be created by scoring, with processing through a high tension treated section to stretch the zipper would create a gap through which particles could fall. The zipper could be stretched once, or even 2-10 times, typically from 10 to 40 percent on a length-wise basis. The zipper could be annealed with heat to equilibrate or relax the plastic and reduce camber, followed by a step of cooling the zipper with a second water bath or similar apparatus to set the shape before joining and spooling. In some applications, stretching may be omitted. 
     Low density polyethylene, as well as other similar materials, may be used in the embodiments shown in  FIGS. 7A-D ,  8  and  9  and other similar embodiments. However, in order to increase the sound or noise generated by the operation of the zippers, the tips of the profiles  102 ,  120  may be made from higher modulus resins. The noise is created by the flipping of the tips and connected arm or leg causing vibration which turns into sound. Replacing the resin with high modulus resin is expected to make the opening and closing operations noisier. A second or additional material, such as a high modulus resin, may be introduced into only the tips or hooks of the profile during manufacture. Alternately, larger portions or even the entire profile can be made of these materials. Non-exclusive examples of resins that will work to create more sound with standard polyethylene resins include medium density polyethylene, linear low density polyethylene, polypropylene and copolymers, higher order polyolefins, including, but not limited to polymethylpentene-like TPX resin and cyclic olefin copolymers like Topas resin, or any high density or high tensile modulus material or combinations thereof. It is noted the low density polyethylene typically has a 0.2 modulus, GPa whereas the listed material typically have a 0.8-2.6 modulus, GPa. Moreover, the zipper base or flange can be made from a different material or materials than the locking portion (i.e., legs) of the zipper. 
     Further embodiments are shown in  FIG. 10  wherein a multi-alignable zipper profile  300  has partial cuts or notches  114  made in the transverse direction (with respect to a longitudinal axis of the zipper  100  and the zipper profiles  102 ,  120 ) straight across or on a bias by use of a high-speed serrated blade, oscillating circular blade, laser cut, or similar cutting device. A rotating wheel with blades that run parallel to the axis of rotation (with possible skewing of the blades from parallel to make a bias cut) may also be used. The partial cuts or notches  114  may be intermittently placed at a predetermined spacing so that, after stretching, the multi-alignable profile will cross track at the point when the serrated notch is reached thereby reducing the void created when cross tracking as well as providing a smoother feel when closing longer multi-alignable profiles. 
     Additionally, in lieu of laser or mechanical cutting device, the extrusion of the zipper profiles  102 ,  120  may be done so that the desired interlocking element breaks either randomly or at a specific periodic spacing. Similarly, additional steps of re-heating, cooling and re-stretching can cause a random or nearly random pattern of breakage. This breakage can be induced by the use of dissimilar polymers (i.e., low tensile strength in profile and high elasticity in web), the introduction of dissimilar materials extruded by metering two or more types of polymers that will cause a point of breakage when stretched in the weld line of zippers, brittle polymers, weakening agents, contaminants, foam agents or similar materials or compounds. 
     Further embodiments are shown in  FIGS. 11 and 12 . The disclosed female profiles  102  of a double zipper are formed first by the step of extrusion, followed by the step of stretched partial cuts  114  into the female profiles  102 A and  1028 . The partial cuts  114 , which become gaps after the step of stretching, do not detract from the positive closing experience of the double profile, and creates an audible and tactile sensation when the package is re-opened by the consumer. In  FIG. 11 , the double zipper profile has been preferentially cut and stretched, thereby resulting in a zipper profile with one continuous female zipper profile  102 A and one discontinuous female zipper profile  102 B. This results in additional advantages of easy alignment of the double profile, tactile feedback by way ergonomic centerline spacing of the profiles and audible feedback when the package is opened. Additionally, the zipper in  FIG. 11  will typically provide a closure that will demonstrate package ballooning, even after the first time opening of the package by the consumer. 
     The zipper thereby achieves easy closure in that the repeating format of a profile segment followed by a space allows zipper mis-alignments up to five degrees while maintaining closing ease in a press-to-close zipper. Depending upon profile shape, materials resulting cut and stretch strength, and other requirements of the specific application, the space and profile distances may be varied. Additionally, the opening and closing of the offset leg segments will vibrate thereby providing positive tactile and audio feedback to the consumer. This may even be accomplished by transverse direction laser scoring in the absence of subsequent stretching. Moreover, such zippers may be applicable for powder-resistant applications. Typically, the use of a zipper profile with a high contact area will maintain the ballooning effect. However, adjusting the degree of the ballooning characteristic via manipulation of the contact area will allow this zipper to self-vent in a microwave or similar application. 
       FIG. 13  illustrates how partial cuts or gaps  114  can be placed in the transverse direction across the female zipper  102 , optionally followed by a stretching step, in order to allow for evacuation of gas as a result of microwaving or other heating. 
       FIG. 14  is a perspective view of a female zipper profile  102  wherein the product side of the female zipper profile  102  as embodied by arm  106  includes the partial cuts  114 , which have been transformed into gaps by a stretching while the arm  102  on the consumer side is left intact. This results in a powder-resistant zipper wherein powder product which may otherwise accumulate within the female zipper profile  102  and interfere with the proper sealing of the zipper will tend to fall through the partial cuts or gaps  114  back into the product area of the container without jamming the zipper or escaping from the package. Subsequent package handling may cause further powder product to pass through partial cuts or gaps  114  into the product container. Additionally, this configuration can be used to allow steam to escape during microwave or other heating. It should be noted that while the partial cuts  114  are deeper than the sixty or eighty percent of the height of the profile, the partial cuts are typically formed on only one side of the female zipper profile  102  in order to maintain the strength of the profile. 
       FIGS. 15A ,  15 B,  16 A and  16 B illustrate an embodiment of a powder-resistant zipper  100 .  FIG. 15A  illustrates that slits  140  are cut into the web or base  124  of female profile  102 .  FIG. 16A  illustrates that the female profile  102  is then stretched so that slits  140  are transformed into apertures  140 ′. Powder product can then pass through apertures  140 ′. This process is advantageous over the prior art of simply punching the apertures  140 ′ in that typically little or no slugs or other plastic waste is formed by the formation of slits  140 . 
       FIGS. 17A-17D  illustrate cross-sectional views of zippers  100  wherein additional elements have been added to increase the sound production further during opening and closing operations of the zipper  100 , such as by slapping, resonating and double clicking. In  FIG. 17A  illustrates a male profile  120  with post element  122  and two transverse elements  402 ,  404  parallel to each other, along with female profile  102  wherein hook  108  is downwardly obliquely oriented into space  112  while hook  110  is horizontally oriented. In  FIG. 17B , male post element  122  is L-shaped, hooks  108 ,  110  are horizontal and lower hook element  111  is placed under second hook  110  in female element  102 . In  FIG. 17C , transverse element  402  is placed above the arrowhead-shaped detent head  126  on post element  122  of male profile  120 . In  FIG. 17D , male element  120  includes a single transverse element  402  on post element  122  and lower hook element  111  is placed under first hook  108  in the female profile  102 . 
       FIG. 18  is a schematic of a process and apparatus  1000  used for the stretching of zipper  100 . In particular, apparatus  1000  is intended to provide for heating and stretching of the zipper  100  to the desired elongation and to maintain tension during cooling. Pre-extruded and spooled zipper  100  is unwound through a first nip drive  1002  and passed through a hot air chamber or similar heating device  1004 , and upon exiting therefrom, cooled by air knife  1006 , typically fed by a venturi air cooler. Through combinations of temperature setting, nip speeds, and cooling placement, zipper  100  is stretched, typically with minimal or no profile deformation or web waviness. The zipper  100  is then passed into a second nip drive  1008 , running at a higher speed than the first nip drive  1002  thereby causing stretching of the heated zipper  100 . The zipper  100  is then passed under tension to a zipper profile joining core  1010  through a third nip drive  1012  which is separated from the second nip drive  1008 . 
     While the zipper  100  is typically joined as it passed through the hot air chamber  1004 , other embodiment may be implemented wherein zipper  100  is unjoined as it passes through the hot air chamber  1004  thereby allowing the profiles and the inside of the webs to heat more quickly. Furthermore, the cold air from air knife  1006  is applied to the outside of the webs only. This rapid cooling sets the webs by stopping their ability to yield. The profiles, however, remain hot and continue to elongate under tension created between the second and third nip drives  1008 ,  1012 , under ambient conditions. When the profiles are rejoined (if necessary) at zipper profile joining core  1010 , there is no deformation. Additional cooling may be added prior to the third nip drive  1012 , in order to shorten the distance required for cooling, as long as the profiles have elongated sufficiently. 
     Typical characteristics of the apparatus  1000  of  FIG. 18  are that the zipper is typically always in a straight line so that tension typically does not create forces over the roller to deform the profiles; lower durometer nip rollers are used to eliminate deformation (a belt puller could be substituted); cooling, typically by cold air or water, should be applied to the flanges immediately after heating to stop the flanges from elongating (profiles typically should remain heated); tension typically should be maintained in the zipper, thereby allowing the profile sections to elongate, after the webs have stopped elongating; and the zipper typically should be unjoined to allow faster heat transfer to the profiles. It is further noted that, in order to maintain the contact area and the proper functioning of the zipper, the design of the zipper profiles should be altered so that the dimensions of the profile are the same after stretching as a similar zipper that is not designed for stretching. It is noted that some embodiments may stretch only one zipper profile or that one zipper profile may be stretched more than the other.  FIGS. 19A and 19B  illustrate the cross-sectional profile proportions before and after stretching the male profile  120  while  FIGS. 20A and 20B  illustrate the cross-sectional proportions before and after stretching the female profile  102 .  FIGS. 19A ,  19 B,  20 A and  20 B illustrate the reduction in cross section which may be expected from stretching the profiles  102 ,  120 , but are not necessarily intended to be to scale. 
     As shown in  FIG. 21 , the rejoining of the zipper profiles  102 ,  120  (such as is done by zipper joining core  1010  of  FIG. 18 ) may be configured so as to alternate the partial cuts or stretched gaps  114  in female profile  102  with those of male profile  120 , so that the partial cuts or stretched gaps  114  of one profile are centered upon the uncut portion of the other profile. This configuration has been found typically to transmit the tactile vibrations, during and closing, more effectively to both sides of the package, and to more effectively maintain opening force performance than configurations wherein the partial cuts or gaps  114  of both zipper profiles are aligned with each other. 
     Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.