WO2008142508A1 - Vent for resealable plastic bags - Google Patents

Abstract

In combination with a plastic film bag having a resealable closure and seal mechanism near the open end, an improvement for venting trapped air is an added vent slit. At least one slit aperture is cut laterally entirely through one side of the closure mechanism adjacent a corner proximal the open end. Also, indicia indicating where to fold for venting are optionally disposed proximal the slit aperture.

Description

VENT FOR RESEAIABLE PLASTIC BAGS

CROSS REFERENCE TO RELATED APPLICATION

This patent application is related to and claims priority from U.S. Provisional Patent Application Serial Number 60/930,539 filed May 17, 2007.

TECHNICAL FIELD

The present invention relates, in general, to resealable plastic film bags and, more particularly, this invention relates to an improved seal design to facilitate venting of air when closing and sealing resealable plastic storage bags.

BACKGROUND ART

Prior to the conception and development of the present invention, those making and using plastic bags which are meant to be air and water tight have tried various ways for decades to deal with venting excess gas from the bags. During closure of press-to-seal flexible plastic storage bags, it is commonplace for undesired air to get trapped, which makes the bag occupy more volume than necessary and could accelerate spoilage due to air contact. In certain cases, remedies were offered just to make the filled bags stackable in a compact manner. Mass- produced reclosable vent hole bags are commercially available for uses not concerned about air or liquid getting into the storage compartment of the bag. They simple punch one or more holes in at least one panel of the storage compartment interior of the sealing closure. However, for many applications, such as food storage, it is desirable to keep air out to avoid deterioration, and to keep any liquid in.

Yates disclosed in U.S. Pat. No. 2,361,344 a means to vent gasses generated inside an air tight package by providing a channel adjacent a seam wherein the channel opens slightly in response to greater inside pressure, thus allowing gas to escape. It automatically reseals once the pressure inside is nearly equal that on the outside. Another pressure-sensitive gas valve is that disclosed in U.S. Pat. No. 5,419,638, which teaches an unobstructed tortuous gas pathway. U.S. Pat. No. 3,133,691 also teaches a tortuous patch for venting thermoplastic bags with what appears to be a rather complicated construction.

Numerous others have proposed solutions to the problem in the form of one-way air valves that permit gas to be expelled, but not readily come back in. Examples are disclosed in U.S. Pat. No. 6,357,915 and U.S. Pat. No. 6,827,492. These two were developed primarily for packaging of bulk solids, and an alternative solution was offered by U.S. Pat. No. 3,937,395.

Resealable plastic film bags are presently mass produced in very high quantities in numerous sizes for various applications, most notably household food storage. These are typically referred to as zipper or Ziploc® bags, and are sealed by moving a slide or pressing one's finger along the closure mechanism. An important feature of these bags is the ability to prevent air or liquid flow into or out of the storage interior. One drawback to this is that gas gets trapped inside the bag, which increases the volume taken up besides being possibly detrimental to the contents. Consumers often do not realize this until the bag is closed, and attempts are then made to slightly open one corner of the closure and expel air. If too much is opened, some of the contents may spill out, or if not opened enough, the resultant pressure buildup may force nearly the entire closure to open. Hence, it often becomes a repetitive procedure to get air expelled and have a tight seal. One proposed solution is disclosed in U.S. Pat. No. 3,237,844, which employs both a continuous seam closure and an interrupted seam with at least one vent hole in between the two. Similarly, U. S. Pat. No 6,231,236 teaches a double seal closure with a vent hole in the outermost one, wherein air is expelled after the outer closure is sealed, and then the inner closure is sealed to maintain an air-tight closure. For what is otherwise a very simple and low-cost mass produced consumer item, these two approaches add considerably to the complexity and cost of manufacturing. Operation is also rather involved. DISCLOSURE OF INVENTION

The present invention overcomes entrapped air problems by providing, in combination with a plastic film bag having a press resealable closure and seal mechanism near the open end, an improvement for venting trapped air. At least one slit aperture is cut laterally through at least one side of the closure mechanism adjacent a corner proximal the open end. Also, indicia indicating where to fold for venting are optionally disposed proximal the center of the slit aperture.

In various preferred embodiments, the slit can be applied on either single track seals or double-track seals. In another alternative embodiment, a slit can be combined with a circular hole .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective schematic view of an embodiment of the present invention in a plastic film bag.

FIG. 2 is a perspective view illustrating the use of the present invention.

FIG. 3 is an enlarged sectional perspective view of a preferred embodiment showing a preferred location of the slit in the closure zone.

FIG. 4 is sectional view through the slit zone of an alternative closure seal on a plastic storage bag. FIG. 5 is a perspective view, partly in section, illustrating alternative slit locations on a double track seal. BEST MODE FOR CARRYING OUT THE INVENTION

Prior to proceeding to the more detailed description of the present invention it should be noted that, for the sake of clarity and understanding, identical components which have identical functions have been identified with identical reference numerals throughout the several views illustrated in the drawing figures.

Referring initially to FIG. 1, an embodiment of a resealable plastic film bag 11 with the improved venting mechanism, shown generally as 10, is illustrated in this perspective view. A storage interior is created by an upper sheet 12 and a lower sheet 14 fused at a seam 16 on three sides. An air-tight closure and seal mechanism 18 is positioned adjacent and parallel to a fourth edge which forms an opening for the bag. Mating portions of closure mechanism 18 are integral to plastic sheets 12 and 14. Typically, gripping ribs 17 are also built into the interior side of the bags closer to the opening than the closure mechanism. A narrow slit 20 is cut laterally through one portion of the closure mechanism 18 proximal one corner. Indicia forming a diagonal line 22 are inscribed across the corner and passing above approximately the center of the slit 20. This indicates to the user where and how to fold the corner so as to create a vent opening for when the user wishes to expel air. Upon release, the edges of the slit meet and form a loose but effective seal.

FIG. 2 illustrates the use of the invention, generally shown as 10, in combination with a common plastic freezer storage bag 11. Sealing of the bag 11 with pressure along the closure 18 has trapped air inside the bag. To expel the entrapped air, the corner 19 has been folded back along fold line 22 thereby slightly opening slit 20. With the bag on a hard flat surface, pressure is applied to the top surface 12. This forces trapped air out through the slit orifice 20. The user's other hand can be used to force out additional air as desired. The corner 19 is then released and flattened to restore the seal. Slits cut with a razor blade or utility cutter blade have been found to re-establish a liquid-tight seal when restored to an unfolded position.

FIG. 3 provides a perspective view, partly in section, of the invention applied to a plastic bag 11 with a single track seal designated by 18a and 18b. A slit 20 has been cut across and all the way through the seal member 18b near a corner of the opening end of the bag 11.

FIG. 4 provides an enlarged sectional view indicating a location of the slit 20 in the area of a typical pressure closure, in this case two flanges 30 on one side of the bag interlocking with two mating flanges 32 on the other side. Numerous alternative locations would also be acceptable, but the slit 20 should not cut into the sidewalls 12 or 14 below the closure flanges 30 or 32. However, it should create an air passage 40 into the sealed area between sidewalls 12 and 14 when the corner of the bag is folded and one edge of slit 20 moves to a separated position indicated by dotted line 24. The combination of the narrow slit 20 and the nature of the plastic reform a water-tight seal when restored to the flat unfolded position.

FIG. 5 provides a perspective view, partly in section, of a plastic bag with separated double seal members 18a and 18b, of the type employed on GLAD® freezer bags. Three acceptable vent apertures are shown, 20a, 20b, and 20c, although only one at a time would be used. As indicated by 20c, a drilled hole in combination with a slit can be acceptable, if properly located, and more rapid venting may be achieved. Also, slit 20a depicts how the slit does not need to be cut exactly perpendicular to the sealing tracks. A third option is shown as 20b, a slit extending beyond the sealing tracks part way to the open end.

While a presently preferred and alternative embodiments of the present invention have been described in sufficient detail above to enable a person skilled in the relevant art to make and use the same, it should be obvious that various other adaptations and modifications can be envisioned by those persons skilled in such art without departing from either the spirit of the invention or the scope of the appended claims.

INDUSTRIAL APPLICABILITY

During closure of press-to-seal flexible plastic storage bags, it is commonplace for undesired air to get trapped, which makes the bag occupy more volume than necessary and could accelerate spoilage due to air contact. Consumers often do not realize this until the bag is closed, and one or more attempts are then made to slightly open one corner of the closure and expel air. It is, therefore, one of the primary objects of the present invention to provide a liquid-tight resealable plastic storage bag with an easy-to-use air venting mechanism. The present invention will avoid expensive retooling to implement the venting solution. It is generally not intended for most slide zipper resealable plastic bags, but is for press-seal-type plastic film bags. Yet another object of the present invention is to provide a venting mechanism for plastic storage bags that will normally prevent liquids from escaping during both venting and non-venting periods.

Claims

What is claimed is:

1. In combination with a plastic film bag comprising: first and second film panels fused together along three edges and defining an open end and a closed end; and a press resealable closure and seal means proximal said first open end, wherein mating portions of said closure and seal means are internal profiles of a first predetermined width disposed substantially parallel edges of said open end forming a first portion on said first film panel and a second mating portion on said second film panel, the venting improvement comprising: at least one slit aperture of a second predetermined width and a predetermined length cut substantially laterally and entirely through from inside to outside at least one of said mating portions of said closure and seal means adjacent a corner proximal said open end.

2. The combination, according to claim 1, wherein said closure and seal means is a press seal zipper of substantially parallel interlocking tracks.

3. The combination, according to claim 1, further including a vent locating means disposed proximal said slit aperture to enable user to locate where to fold said plastic film bag to vent air after said closure and seal means has been closed

4. The combination, according to claim 3, wherein said vent locating means is at least one of a straight line and a printed word.

5. The improvement, according to claim 3, wherein said vent locating means is one of colored dye and ink that distinguishes it from surrounding material.

6. The improvement, according to claim 1, wherein said second predetermined width of said slit aperture is less than 1 millimeter when said seal and closure means is not folded.

7. The improvement, according to claim 1, wherein said predetermined length of said slit aperture is less than said first width of said closure and seal means.

8. The improvement, according to claim 2, wherein said slit aperture does not penetrate beyond either of said interlocking tracks in the direction of said closed end.

9. The combination, according to claim 2, wherein said slit aperture is an elongated slit ending with a circular opening located substantially central to said interlocking tracks.