Reclosable package or bag with double zipper or similar configuratiion

Abstract

The zipper profiles have a complex shape, such as a double zipper configuration. The apparatus for the manufacture thereof includes an extrusion die and further includes a main or primary extruder for the supply of material, such as low density polyethylene, to form the tubing for the manufacture of reclosable packages, bags or pouches. The apparatus further includes at least one secondary extruder, or co-extruder, for the extruding of each reclosable profile onto the tubing. The speed of the co-extruders is controlled so as to control the extrusion of the reclosable profiles.

Description

This application is a continuation-in-part of application Ser. No. ______, filed Jul. 15, 2008, entitled “Method to Accurately Control Size, Velocity, and Relative Position Sets of Reclosable Mechanism” which claims priority of provisional application Ser. No. 60/961,752, filed on Jul. 24, 2007. The present application further claims priority under 35 U.S.C. §119(e) of said provisional application serial no. 60/961,752, filed on Jul. 24, 2007.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zipper for reclosable packages or bags wherein the profile includes a double zipper configuration.

2. Description of the Prior Art

In the prior art of reclosable packages and bags, it has been envisioned that complex zipper shapes, such as a double zipper configuration, could provide enhanced sealing capability and wide-spread customer approval.

However, in the prior art of the manufacture of zippers and similar devices for reclosable plastic film, bags or pouches, the velocity of the delivery of the resin to the profiles or to the locking elements, such as would be required for the manufacture of complex locking mechanisms, could not be accurately controlled by such elements as a choke device. This inability to accurately control the resin velocity made it difficult to extrude complex locking mechanisms at a reasonable cost and production rate.

Further prior art includes methods where the zipper tape is extruded, wound and then, in a secondary process, unwound, heated and attached to the film. Still further prior art may be found in published patent application US2005/0269733 A1 entitled “Method of and Apparatus for Forming Multiple Closure Elements”. Other prior art is found in U.S. Pat. No. 7,137,736 to Pawloski as well as U.S. published applications 2005/0271307; 2005/0271308; 2004/0234172 and 2004/0234173.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide complex locking mechanisms for reclosable interlocking elements, such as a zipper profile on a flexible film plastic package, bag or pouch, and the apparatus for the manufacture thereof, at a reasonable cost and production rate.

It is therefore a further object of the present invention to provide accurate control of the velocity of the resin flow delivered to the profile at its point of juncture with the film or tubing of the reclosable plastic package, bag or pouch.

It is therefore a still further object of the present invention to improve adhesion of closure elements to the body of the package, bag or pouch by preventing exposure of the contact surfaces.

These and other objects are attained by cooling the integral profile tubing and drawing it in a negative ratio whereby the circumference of the cooled and drawn finished tubing is less than the circumference of the die plate. The resin for the profile interlocking elements is delivered from a co-extruder through a separate channel, or several separate channels, to the die body and thence to the die plate, where the resin is joined to the film (tubing) at a controlled rate, with the control being the speed of the co-extruder drive.

DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIG. 1 is a schematic of an apparatus for the manufacture of the zipper profiles of the present invention.

FIGS. 2a-2y are various embodiments of zipper profiles of the present invention, which can be produced by the apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, wherein like numerals indicate like elements throughout the several views, one sees that FIG. 1 is a schematic of the apparatus 10 for the manufacture of the zipper profiles of the present invention. Extrusion die body 12 receives the material for the formation of the tubing (e.g. a tube or a film), such as, but not limited to, low density polyethylene, from primary extruder 14 and extruder material hopper 16 via supply channel 18. Supply channel 18 joins extrusion die body primary supply channel 20 which is formed within extrusion die body 12. Extrusion die body primary supply channel 20, in turns, feeds the material for the tubing to the extrusion die cavity 22 where the tube or film 100 is formed. Tube or film 100, typically in a cylindrical shape, exits from the mouth 24 of extrusion die plate 13, and therefore may be referred to as tubing (or as a low density polyethylene bubble). The tubing is typically drawn into a negative ratio and cooled. That is, due to the speed of the film and related factors, the circumference of the cooled and drawn finished tubing 100 is typically less than the circumference of the extrusion die plate 13, but in some applications may be the same size or even greater than the circumference of the extrusion die plate 13.

Secondary extruders 30, 34 include respective secondary extruder material hoppers 32, 36 supplying material, such as resin (which may be colored or uncolored), for the formation of the reclosable profiles. The use of colored resin allows the user to see and handle the profiles more easily. The resin, or similar material, may be the same in secondary extruders 30, 34 or may be different (including such characteristics as color). It is envisioned, however, that the primary extruder 14 would supply a flexible, soft and pliable material while the secondary extruders 30, 34 would supply a more rigid, robust material for forming reclosable profiles 102, 104. The resin, or similar material, is provided via respective secondary supply channels 38, 40 (typically implemented as heated hoses) and respective secondary die body supply channels 42, 44 to the die plate, where it is joined to the tubing 100 at a controlled rate (as well as a controlled temperature), with the control being the speed of the drive of the secondary extruders 30, 34, thereby forming reclosable profiles 102, 104 on tubing 100. The resin (or other material) from the secondary extruders 30, 34 for forming the reclosable profiles 102, 104 does not come into contact with the material (tube or film 100) from the primary extruder 14 until it reaches the extrusion die plate 13 typically approximately one half inch (although other distances are envisioned) before both exit the extrusion die body 12. The control of the speed of the drive of the secondary extruders 30, 34 and or control of the temperature of the resin or similar material provided to the secondary supply channels 38, 40 (is, in turn, typically controlled by CPU 200 or a similar processing device) thereby provides the ability to extrude more complex shapes of the interlocking elements than was previously possible. Additionally, it is envisioned that as many as nine, or even more, secondary extruders may be used, with respective material supplies and secondary supply channels to form the various complex shapes. FIGS. 2a-2y are representative of a sample of the many profile shapes that are possible with various embodiments of the present invention which, applicant believes, have been difficult, if not impossible, to obtain with the prior art, particularly with respect to multiple interlocking elements formed on a single profile.

The resulting configuration typically has many or all of the following advantages:

• • 1. the velocity and speed of the resin for the locking mechanism is controlled separately from that of the tubing;
  • 2. the velocity of the resin for the interlocking elements is controlled accurately and separately from that of the tubing;
  • 3. the distance between sets of profiles is controlled;
  • 4. more complex locking mechanisms may be manufactured;
  • 5. the cooling rate of the interlocking elements is accurately controlled;
  • 6. more complex multiple interlocking elements are possible;
  • 7. interlocking elements with separators between the interlocking elements can be provided;
  • 8. the shapes, construction and structural characteristics of the interlocking elements are controlled, including profiles with multiple interlocking elements;
  • 9. the tubing may have two or more sets of profiles, each set provided with separate sources of profile control;
  • 10. the separate resin source can be a co-extruder (or secondary extruder);
  • 11. the profiles are provided with multiple interlocking elements;
  • 12. a co-extruder (or secondary extruder) can provide resin flows to several sets of profiles or a separate co-extruder (or secondary extruder) can be used for each resin flow;
  • 13. the flow of resin to the profiles can be controlled, so that the profiles cool at a controlled rate; and
  • 14. the speed of the profile extrusion can be controlled so that the speed of the profile extrusion and the speed of the film extrusion are equal when the profile and the film come into contact with each other.

FIGS. 2a and 2b illustrate open and closed configurations of a first embodiment of the present invention. First reclosable profile 102 includes first and second male elements 202, 204, while second reclosable profile 104 includes first and second corresponding female elements 206, 208, supported by respective first and second stems 207, 209 and further including inverted J-shaped hooks 210, 212, 214, 216 for engaging the first and second enlarged terminal arrowhead-shaped ends 218, 220 of respective first and second male elements 202, 204. The use of J-shaped hooks on the female elements and arrowhead-shaped ends on the male elements results in improved closing capabilities of the zipper. The first and second enlarged terminal ends 218, 220 are illustrated as being slightly more pronounced or enlarged on the interior or in-board side of the zipper 100, thereby making the resulting package somewhat resistant to inside (sometimes called “pinch grip”) or inboard opening and more receptive to conventional outside or outboard opening by separating the edges of film. Of course, the zipper 100, along with terminal ends 218, 220, can be oriented so that the package is more receptive to interior or in-board (pinch-grip) opening. In other words, one side of the enlarged terminal arrow-shaped ends controls one function and the other side controls a different function.

The double zipper embodiment of FIGS. 2a and 2b, as well as the following embodiments which include multiple zippers, provides for redundancy in that if one zipper fails, the other zipper may maintain the closing. These embodiments further provide for increased surface area engagement as well as a user tactile impression which is more robust and secure. Moreover, these embodiments include a narrow interface between the bottom of the profiles which is isolated and protected against deformation from draw down or draw up of the underlying film. These embodiments further allow the zipper and film to be bonded at the molecular level.

FIG. 2c illustrates a further embodiment a reversal of first male element 202 and first female element 206 from the embodiment of FIGS. 2a and 2b.

FIG. 2d illustrates a further embodiment with a third male element 222 between first and second female elements 206, 208 and a corresponding third female element 224, supported by stem 225, between first and second male elements 202, 204.

FIG. 2e illustrates a further embodiment with a single male element 202 with adjacent guide elements 230, 232 and a single female element 206 including a guide element 234 extending laterally, immediately below inverted hook 212.

FIG. 2f illustrates a further embodiment wherein, as compared to the embodiment of FIG. 2e, guide element 232 is replaced by two guide elements 236, 238 on second reclosable profile 104 and wherein the lateral guide element 234 is removed and two guide elements 240, 242 are oriented to one side of female element 206, wherein guide element 240 is received between guide elements 236, 238 and guide element 242 is received outward adjacent from guide element 242.

FIGS. 2g and 2h illustrate further embodiments wherein the first reclosable profile 102 includes a first female element 300 and a first male element 302 and the second profile 104 includes a second male element 304 which is engaged by the first female element 300 and further includes third and fourth male elements 306, 308 which engage the first male element 302 therebetween upon closing. Stem 301 supports female element 300.

FIG. 2i illustrates a further embodiment wherein first reclosable profile 102 includes first, second and third male elements 310, 312, 314, terminating in a respective first, second and third cylindrical bulbous elements 316, 318, 320. First and second male elements 310, 312 are separated by first space 322 while second and third male elements 312, 314 are separated by second space 324. Second reclosable profile 104 includes fourth and fifth male elements 326, 328, terminating in respective cylindrical bulbous elements 330, 332. In the closed configuration, fourth and fifth male elements 326, 328 are received within first and second spaces 322, 324, respectively, with the first through fifth cylindrical bulbous elements 316, 318, 320, 330, 332 forming an interlocked engagement between the first and second reclosable profiles 102, 104.

FIGS. 2j-2y illustrate various embodiments similar to that of FIG. 2i, but with variations in the first through fifth bulbous elements 316, 318, 320, 330, 332, such as arrowhead, half arrowhead, double arrowhead, detent hook and similar shapes.

Furthermore, FIGS. 2s, 2x and 2y illustrate embodiments which further include guide element 400 on second reclosable profile 104, adjacent to either fourth or fifth male element 326, 328.

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.

Claims

1. A zipper for a reclosable package or bag, the zipper including first and second interlocking profiles, the zipper formed a method including the following steps:

providing a primary extruder;

providing at least one secondary extruder;

providing an extrusion die plate with a primary channel for receiving primary material from the primary extruder for forming a film; and

providing the extrusion die plate further including at least one secondary channel for receiving secondary material from the at least one secondary extruder for forming the first and second reclosable zipper profiles.

2. The zipper of claim 1 wherein the method for forming the zipper further includes the step of providing a control device for controlling velocity of flow of the secondary material to provide desired shapes of the reclosable zipper profiles.

3. The zipper of claim 2 wherein the first interlocking profile includes first and second male elements and the second interlocking profile includes first and second female elements for receiving the respective first and second male elements.

4. The zipper of claim 3 wherein the first and second male elements terminate in respective first and second enlarged elements.

5. The zipper of claim 3 wherein the first and second enlarged elements include a first side which is more enlarged than a second side.

6. The zipper of claim 5 wherein the zipper is more easily separated when force is applied to one side rather than another side.

7. The zipper of claim 3 wherein the first and second female elements are supported by respective first and second stems.

8. The zipper of claim 3 wherein the first and second female elements each include two J-shaped arms for engaging the respective first and second enlarged elements of the respective first and second male elements.

9. The zipper of claim 2 wherein the first interlocking profile includes a first male element and a first female element and the second interlocking profile includes a second male element and a second female element, wherein the first and second female elements receive the respective first and second male elements.

10. The zipper of claim 9 wherein the first and second male elements terminate in respective first and second enlarged elements.

11. The zipper of claim 9 wherein the first and second enlarged elements include a first side which is more enlarged than a second side.

12. The zipper of claim 11 wherein the zipper is more easily separated when force is applied to one side rather than another side.

13. The zipper of claim 9 wherein the first and second female elements are supported by respective first and second stems.

14. The zipper of claim 9 wherein the first and second female elements each include two J-shaped arms for engaging the respective first and second enlarged elements of the respective first and second male elements.

15. The zipper of claim 2 wherein the first interlocking profile includes first and second male elements and the second interlocking profile includes first and second female elements for receiving the respective first and second male elements, and wherein the first interlocking profile further includes a third female element between the first and second male elements and the second interlocking profile further includes a third male element between the first and second female elements.

16. The zipper of claim 15 wherein the first, second and third male elements terminate in respective first, second and third enlarged elements.

17. The zipper of claim 15 wherein the first, second and third enlarged elements include a first side which is more enlarged than a second side.

18. The zipper of claim 17 wherein the zipper is more easily separated when force is applied to one side rather than another side.

19. The zipper of claim 15 wherein the first, second and third female elements are supported by respective first, second and third stems.

20. The zipper of claim 15 wherein the first, second and third female elements each include two J-shaped arms for engaging the respective first, second and third enlarged elements of the respective first, second and third male elements.