EASY OPEN WOVEN POLYPROPYLENE BAG

Abstract

The disclosure relates to a large package, typically with woven polypropylene walls, including an easy-open strip with a pre-activated peel seal. The easy-open strip achieves a high burst strength by configuring the pre-activated peel seal in shear mode in response to internal (product side) forces while achieving a low consumer opening force by configuring the peel seal in response to external (consumer side) forces.

Description

This application claims priority under 35 U.S.C. §119(e) of U.S. provisional application Ser. No. 61/152,571 filed Feb. 13, 2009, the disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Disclosure

The present disclosure pertains to a package or bag, particularly a large capacity easy-open package or bag with woven polypropylene walls wherein high burst capability and easy consumer opening capability are maintained.

2. Description of the Prior Art

Commercial packages or bags must have high burst characteristics to survive the distribution channel. This is particularly an issue for larger capacity packages or bags. A representative prior art large capacity reclosable package or bag having high burst capability and easy consumer opening is disclosed in commonly-assigned U.S. Published Patent Application No. 2008/0050052 entitled “High Burst Zipper Assembly For Large Reclosable Packages”, published on Feb. 28, 2008 with Anzini et al. as inventors.

Another way to maintain an easy opening feature is to use Zipper No. 584-001, available from Zip-Pak in Orangeburg, N.Y. This zipper includes a pre-activated peel-seal which is placed into a peel configuration for easy opening and in shear configuration during filling and drop testing.

Woven polypropylene bags are tough and robust as required by the demands of the distribution channel, but many typically are sewn and may require significant force to open, or require a tool, such as a knife or scissors to open the bag. The use of a tool is typically not a problem in industrial applications, but can be problematic in retail or consumer applications.

OBJECTS AND SUMMARY OF THE DISCLOSURE

It is therefore an object of the present disclosure to provide an easy open, high burst package, particularly an easy-open package, which may include woven polypropylene walls.

This and other objects are obtained by providing an easy-open package or bag, preferably including woven polypropylene walls, with an easy-open strip which incorporates a pre-activated peel seal into the flange design creating a peel configuration for easy opening and a shear configuration for high burst strength during filling and drop testing.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a perspective view, partially in phantom, of the package or bag of the present disclosure.

FIG. 2 is a cross-sectional view of the easy-open strip of the present disclosure with internal forces applied thereby putting the peel seal into shear mode.

FIG. 3 is a cross-sectional view of the easy-open of the present disclosure with external user opening forces applied thereby putting the peel seal into peel mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in detail wherein like numerals indicate like elements, one sees that FIG. 1 is a simple drawing of a large package or bag 10. Package or bag 10 includes front and rear walls 12, 14, respectively, which are typically made from woven polypropylene, and sealed together along first and second side seals 16, 18 However, those skilled in the art may see a range of equivalent materials after review of the present disclosure, such as but not limited to, multilayer laminates incorporating scrim, netting, gauze or woven materials, made from claf (heat-sealable, cross-laminated non-woven open-mesh fabric), or strong resin materials such as nylon, polypropylene, high density polyethylene, polystyrene or other similar substrates. The package or bag 10 is typically considered to be “large” within the common usage of the industry in that is designed to be filled with 14-50 pounds of product, although different capacities may be used. The product may include, but is not limited to, charcoal, pet food, livestock food, grain, seeds, sand, fertilizer, etc.

Package or bag 10 is illustrated with upper and lower easy-open strips 20, 20′, on the top and bottom ends, respectively, extending the entire width of the front and rear walls 12, 14 between first and second side seals 16, 18. However, some applications may require only the upper easy-open strip 20, with the lower easy-open strip 20′ replaced by a traditional sewn bottom. FIG. 1 shows the upper and lower easy-open strips 20, 20′ including thumb tabs 22, 22′.

FIGS. 2 and 3 show the structure of easy-open strip 20, which applies equally to easy-open strip 20′. As shown in FIG. 2, prior to the opening of easy-open strip 20, the front and rear walls 12, 14 meet at junction 24. Junction 24 typically includes a line of weakness such as a perforated line, laser scoring, or slit thereby adding to the strength of the easy-open strip 20 in the closed configuration, but allowing simplified initial opening or breaking by the user. Grippable thumb tabs 22 may be provided on one or both sides of junction 24 to assist in the initial opening or breaking by the user. Moreover, the line of weakness could extend partially or fully across the front and rear walls 12, 14 and could likewise extend into the side seals 16, 18.

First flange 30 is provided with first and second ends 32, 34. First flange 30 is typically made from polyethylene, but is not limited thereto. First and second ends 32, 34 of first flange 30 are sealed to rear wall 14 (front and rear walls 12, 14 may be considered to be interchangeable with respect to the orientation of easy-open strip 20) by first and second hard seals 36, 38. Those skilled in the art will recognize, after review of the present disclosure, that different materials used for front and rear walls 12, 14 may allow or require different methods for formation of first and second hard seals 12, 14, such as ultrasonic sealing. In the case of woven polypropylene front and rear walls 12, 14, first and second hard seals 36, 38 are typically formed by the adhesive methods taught in U.S. Published Application 2009/0297817 entitled “Sealant for Polyethylene Zipper for Polypropylene Film Substrate” published on Dec. 3, 2009 naming Olajide et al. as inventors. These adhesive methods include an evenly distributed polypropylene/polyethylene plastomer mix and further include extruding a coextruded blend of metallocene polyethylene/polypropylene plastomers onto the polyethylene zipper component, then applying a hot melt amorphous polyolefin (APAO) thereover and joining the polypropylene wall or substrate to the hot melt amorphous polyolefin.

Second flange 42 is provided with first and second ends 44, 46. Second flange 42 is typically made from polyethylene, but is not limited thereto. First end 44 of second flange 42 is attached to first flange 30 between first and second hard seals 36 and 38 by a releasable connection 48. Releasable connection 48 is typically, but not limited to, a pre-activated peel seal 48 and is illustrated as such. However, peel seal 48 may be replaced with many different kinds and compositions of zipper profiles including press-to-close, double zipper profiles, zipper profiles with a slider, hook and loop, mushroom fields, all male profiles, all female profiles, etc. Second end 46 of second flange 42 is attached to front wall 12 by third hard seal 50 which is typically formed similar to first and second hard seals 36, 38 as described above.

As shown in FIG. 2, when internal (product side) forces act on the closed easy-open strip 20, the pre-activated peel seal 48 is put into shear mode, which requires a much larger opening force than peel mode. The increased strength of the peel seal 48, along with the strength added by the intact junction 24 provide for a relatively strong configuration.

On the other hand, as shown in FIG. 3, when the junction 24 has been broken by the consumer and external (consumer side) forces are applied to the easy-open strip 20 (such as by grasping one of the tabs 22 and the edge of front wall 12), the peel seal 48 is in peel mode, which requires a much lower opening force than shear mode. Additionally, the strength which was otherwise added by junction 24 has been eliminated in FIG. 3. This provides the consumer with easy access to the contents of package or bag 10.

First and second flanges 30, 42 could alternatively be made of polypropylene, but the hard seals 36, 38, 50 would still be formed from glue as heat sealing to the highly oriented woven tapes of front and rear walls 12, 14 is a narrow latitude (10 degrees Centigrade, at best), without film distortion and resultant poor cosmetic quality. Those skilled in the art will recognize, after review of this disclosure that some applications could have first and second flanges 30, 42 formed from such materials as high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymers, ultra low density polyethylene, very low density polyethylene, elastomers, plastomers, metallocene linear low density polyethylene and metallocene polypropylene, but not limited thereto. It is noted that such terms as “high density”, “medium density” and “low density” as used above are terms of art which would be understood by those skilled in the art.

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 easy-open strip for a package, including:

a first flange for connection to a first wall of a package;

a second flange with a first end and a second end, the first end of the second flange being connected to the first flange by a releasable connection, and the second end of the second flange being for connection to a second wall of a package.

2. The easy-open strip of claim 1 wherein the first flange has a first end and a second end, and wherein the first end of the first flange and the second end of the first flange are for connection to a first wall of a package.

3. The easy-open strip of claim 2 wherein the first and second ends of the first flange are for connection to a first wall of a package by respective first and second hard seals and wherein the second end of the second flange is for connection to a second wall of a package by a third hard seal.

4. The easy-open strip of claim 1 wherein the releasable connection is a peel seal.

5. The easy-open strip of claim 1 wherein the releasable connection is chosen from the group consisting of a press-to-close profile, a zipper profile with a slider, a hook and loop profile, mushroom fields, all male profiles and all female profiles and are made from material chosen from a group consisting of polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymers, ultra low density polyethylene, very low density polyethylene, elastomers, plastomers, metallocene linear low density polyethylene and metallocene polypropylene.

6. The easy-open strip of claim 4 wherein the first and second flanges are chosen from a group consisting of polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymers, ultra low density polyethylene, very low density polyethylene, elastomers, plastomers, metallocene linear low density polyethylene and metallocene polypropylene.

7. The easy-open strip of claim 1 wherein the first and second flanges are for connection to respective first and second walls chosen from a group consisting of polypropylene, woven polypropylene, claf, nylon, polypropylene, polystyrene, and polyethylene.

8. The easy-open strip of claim 7 wherein the first, second and third hard seals include a polypropylene/polyethylene plastomer mix.

9. The easy-open strip of claim 8 wherein the first, second and third hard seals further include a hot melt amorphous polyolefin.

10. A package, including:

a first wall and a second wall joined together at respective edges thereof, thereby forming at least one end;

an easy-open strip for the at least one end, the easy-open strip including; a first flange for connected to the first wall; a second flange with a first end and a second end, the first end of the second flange being connected to the first flange by a releasable connection, and the second end of the second flange being connected to the second wall.

11. The package of claim 10 wherein the first flange has a first end and a second end, and wherein the first end of the first flange and the second end of the first flange are connected to the first wall.

12. The package of claim 11 wherein the first and second ends of the first flange are connected to the first wall by respective first and second hard seals and the second end of the second flange is connected to a second wall by a third hard seal.

13. The package of claim 10 wherein the releasable connection is a peel seal.

14. The package of claim 10 wherein the releasable connection is chosen from the group consisting of a press-to-close profile, a zipper profile with a slider, a hook and loop profile, mushroom fields, all male profiles and all female profiles and are made from material chosen from a group consisting of polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymers, ultra low density polyethylene, very low density polyethylene, elastomers, plastomers, metallocene linear low density polyethylene and metallocene polypropylene.

15. The package of claim 10 wherein the first wall is joined to the second wall over the easy-open strip by a line of weakness.

16. The package of claim 15 wherein the line of weakness is chosen from the group consisting of a perforated line, a slit, and a line formed by laser scoring.

17. The package of claim 16 further including grippable tabs proximate to the line of weakness.

18. The package of claim 11 wherein the first and second walls are chosen from a group consisting of polypropylene, woven polypropylene, claf, nylon, polypropylene, polystyrene and polyethylene.

19. The package of claim 11 wherein the first and second flanges are chosen from a group consisting of polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, cyclic olefin copolymers, ultra low density polyethylene, very low density polyethylene, elastomers, plastomers, metallocene linear low density polyethylene and metallocene polypropylene.

20. The package of claim 12 wherein the first, second and third hard seals include a polypropylene/polyethylene plastomer mix.