Patent Application
20130089280
The present invention generally relates to sealable bags, and more specifically, a plastic bag that includes both permanent and temporary sealing structures.
Sealable bags are used for many different applications, such as shipping, food packaging, biohazard disposal, etc. Sealable bags generally include a permanent or a temporary sealing structure, depending on the application. Some sealable bags include a peelable seal, or a permanent seal that must be unsealed before the bag can be used. Other sealable bags include a permanent seal or fusion seal that must be removed from the bag to permit access to the interior of the bag. However, an initially sealed bag may not be preferable, because repeated use of the bag before permanent sealing may be desired.
In one aspect of the present invention, a plastic bag generally comprises a first panel having four edges, and a second panel having four edges. The first panel and second panel define a bag interior and an opening to permit access to the bag interior. A permanent sealing structure is configured to permanently seal the first and second panels to close the opening and prevent access to the bag interior such that the bag cannot be re-opened without destruction of the bag. A release liner strip overlies the permanent sealing structure to prevent the permanent sealing structure from sealing the first and second panels until activation by a user. A resealable sealing structure is configured to repeatedly and nondestructively seal and unseal the first and second panels to close the opening and prevent access to the bag interior.
In another aspect of the present invention, a plastic bag generally comprises a first panel having a bottom edge, first and second side edges, and a top edge, and a second panel having a bottom edge, first and second side edges, and a top edge. The first and second panels are joined at the respective bottom edges and first and second side edges to define a bag interior and an opening between the respective top edges permitting access to the bag interior. A permanent adhesive layer extending continuously between the first and second side edges of at least one of the panels is configured to permanently seal the top edges of the first and second panels together to prevent access to the bag interior. A first release liner strip extends continuously between the first and second side edges of one of the panels and overlies the permanent adhesive layer, such that the permanent adhesive layer cannot seal the top edges of the first and second panels until the first release liner strip is removed. A resealable sealing structure extends continuously between the first and second side edges of at least one of the panels at a location closer to the bottom edge than the permanent adhesive layer. The resealable sealing structure being configured to repeatedly and nondestructively seal and unseal the first and second panels together to prevent access to the bag interior. A perforation line extends between the first and second side edges of the first and second panels between the permanent adhesive layer and the resealable sealing structure. The perforation line is configured to allow removal of a portion of the panels to permit access to the bag interior after the first release liner strip has been removed and the panels have been sealed by the permanent adhesive layer. The resealable sealing structure, permanent adhesive layer and first release liner strip are configured to permit repeated and nondestructive access to the bag interior before the first release liner strip has been removed and the panels have been sealed by the permanent adhesive layer.
Other objects and features will be in part apparent and in part pointed out hereinafter.
Corresponding reference characters indicate corresponding parts throughout the drawings.
Referring to
The joined panels 12, 14 define a bag interior 22 for receiving items placed in the bag 10. The top edges 24, 26 of the panels 12, 14 are initially unsecured along their length to define an opening 28 permitting access to the bag interior 22 and its contents. In the illustrated embodiment, a continuous band or layer of pressure sensitive adhesive 30 extends along the inner surface of the back panel between the sides thereof, near the top edge 26 of the back panel. Other configurations of the band of pressure sensitive adhesive are within the scope of the present invention. For example, the band of pressure sensitive adhesive can extend along the front panel 12, or both panels can include a band of pressure sensitive adhesive.
A release liner strip 32 initially separates the adhesive band 30 from the inner surface of the front panel 12. The release liner strip 32 extends continuously along the entire length of the adhesive band 30, e.g. continuously between the side edges of the back panel 14. In the illustrated embodiment, a bottom edge 34 of the release liner strip 32 extends below the adhesive band 30, and a top edge 36 of the release liner strip extends above the top edge 26 of the back panel 14. Other configurations of the release liner strip are within the scope of the present invention.
Preferably, the adhesive band 30 is a type of adhesive that adheres strongly on contact with the material of the panels 12, 14. Thus, once the panels 12, 14 are sealed to each other by the adhesive band 30, they cannot be unsealed without destruction of the bag. Preferably, the adhesive band 30 is arranged so that the panels are sealed from side-to-side such that the bag interior is air and/or liquid tight. The adhesive band 30 is a permanent adhesive layer that permanently adheres the panels 12, 14 to each other. In one embodiment, the panels 12, 14 are formed of a thermoplastic sheet material, such as polyethylene or polypropylene, and the adhesive band 30 includes an adhesive that adheres strongly on contact with thermoplastic sheet material. An example of such an adhesive is a hot melt glue marketed by National Starch and Chemical Corporation, New York, N.Y., under the registered trademark “DURO-TAK.”
In one embodiment, the connection of the panels 12, 14 along the side edges of the bag 10, represented by the fusion lines 18, 20, terminate at or are discontinued at the bottom edge 34 of the release liner strip 32, so that the release liner strip delimits an unconnected or free top marginal portion in both panels. As a result, the front panel 12 can be folded away from the release liner strip 32 and the back panel 14 at the top of the bag 10 for easy access to and removal of the release liner strip. In order to form the bag 10 with this feature, the release liner strip 32 is preferably formed of a material that is both easily releasable from the adhesive band 30 and prevents the formation of the fusion lines 18 and 20 during formation of the bag 10. For example, the release liner strip 32 can be formed from high density polyethylene coated with silicone on one surface to enable its release from the adhesive band 30, and the release liner strip can additionally include a silicone coating on the side facing the front panel 12. As a result of the silicone coating on both sides, heat fusion of the panels 12, 14 is prevented over the width of the release liner strip 32. Alternatively, the strip 32 can be formed of paper coated with silicone on only one side to enable release of the strip from the adhesive band 30. A material such as paper will also prevent the formation of a fusion line through both layers of the plastic material forming the panels 12, 14. It is understood that this feature may be omitted, and the side edges of the panels may be fused along their entire lengths within the scope of the present invention.
The bag 10 also includes a resealable sealing structure extending continuously between the side edges of the bag along one or both of the panels 12, 14. In the illustrated embodiment, the resealable sealing structure is a second continuous band or layer of pressure sensitive adhesive 40. However, other resealable sealing structures are within the scope of the present invention, such as a zippered seal (e.g., a Zip-Loc® type sealing structure).
The second continuous band or layer of pressure sensitive adhesive 40 extends along the inner surface of the back panel 14 between the sides thereof, below the first adhesive band 30 but still located near the top edge 26 of the back panel. Other configurations of the band of pressure sensitive adhesive are within the scope of the present invention. For example, the band of pressure sensitive adhesive 40 can extend along the front panel 12, or both panels can include a band of pressure sensitive adhesive.
The second adhesive band 40 provides a temporary and releasable seal between the panels 12, 14. Preferably, the second adhesive band 40 is arranged so as to provide a temporary air and/or liquid tight seal of the interior space 22 when sealed. The panels 12, 14 can be sealed, unsealed, and resealed by the second adhesive band 40 repeatedly and nondestructively. Accordingly, a release liner strip is not required for the second adhesive band 40. However, a release liner strip similar to the strip 32 described above can be provided to overlie the second adhesive band 40 within the scope of the present invention. In one embodiment, the adhesive band 40 includes an adhesive that repeatedly and releasably adheres on contact with thermoplastic sheet material. An example of such an adhesive is a double-coated clear polyester film tape marketed by International Tape Company, Windham, N.H., as Product 6342XL.
The bag 10 further includes an opening structure for removing a top portion 42 of the bag to open the bag after it has been sealed by the permanent adhesive band 30, as will be described in more detail below. In the illustrated embodiment, the opening structure comprises a perforation line 44 extending between the side edges of both panels 12, 14, defining a tear line to allow a user to remove the portion of the bag 10 above the perforation line that includes the permanent adhesive band 30. The perforation line 44 is located between the permanent adhesive band 30 and the temporary adhesive band 40. Other opening structures are within the scope of the present invention, such as a score line, a notched line of weakness, intermittent perforation, or partial slitting. However, cuts extending through the entire thicknesses of the panels 12, 14 are desirable because they make the bag 10 easier to tear and a controlled direction.
Use of the bag 10 will now be described with reference to
As seen in
To open the bag 10 after it has been sealed by the permanent adhesive band 30, a user tears the bag along the perforation line 44, as shown in
Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above products without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
