The present invention relates to a flexible package having a heat sealed closure and a reclosable or resealable closure associated with the heat sealed closure.
Packages are used to retain product for storage and shipment. Flexible packages are often utilized to retain product. The flexible packages are sealed, for freshness and preservation of the product, and have various means for opening the package to expose the product. Often, it is desirable to provide a resealable mechanism for preserving the unused portion of the product after initial opening.
Various types of mechanisms have been developed for reclosing or resealing a flexible package. Many of these mechanisms are separately manufactured articles, which are added to the package either in a subsequent manufacturing step or by the consumer, such as zippers, reclosable tapes or tabs, seal strips, clips and the like.
The challenge in making a closure mechanism having an adhesive for resealing the package lies in the strength of the seal. An adhesive suitable for forming the original package seal, which must have sufficient strength to prevent inadvertent opening of the package during shipment and must be maintained closed during storage, is generally different from the type of adhesive used for resealing. Cold seals, hot melts and heat seals provide good sealing strength and, thus, are suitable for forming the original or “permanent” package seal. Unfortunately, such materials do not generally have sufficient reseal capability. Pressure-sensitive adhesives can be repeatedly opened and reattached to suitable substrates and, thus, are suitable for creating a resealable closure. Pressure-sensitive adhesives typically do not provide sufficient closure strength to be reliable as an original package seal.
U.S. Pat. No. 5,382,472 to Yanidis et al. shows a resealable package formed by side-by-side coextrusion of pressure-sensitive adhesives and polymers to make straight lined areas that cause a rupture of the materials during opening of a heat seal. The heat seal layer within the laminate ruptures through to the adhesive layer and then delaminates from the adhesive layer, exposing the pressure-sensitive adhesive and providing a resealable surface.
U.S. Pat. No. 6,517,243 to Huffer et al. shows a flexible package with a closure tab formed as part of the outer layer of the bag laminate. The tab is formed by precision die cut or laser score of the outer layer in the area of a pressure-sensitive adhesive applied between the laminate layers. Separation of the tab portion from the outer wall of the laminate exposes the pressure-sensitive adhesive, which adheres to the inside surface of the tab.
U.S. Pat. No. 6,076,969 to Jaisle et al. shows a flexible package having a resealable closure formed by applying a layer of pressure-sensitive adhesive on the inner surface of at least one of the opposing portions of the package. A layer of cohesive is applied to the inner surface of the opposing layers, with the pressure-sensitive adhesive covered by a layer of cohesive. The pressure-sensitive adhesive has a greater affinity for the cohesive than for the inner surface of the package. When the opposing portions of the package are pulled apart, the pressure-sensitive adhesive is detached from the inner surface of the package (adhering to the cohesive bond). The exposed pressure-sensitive adhesive permits the opened package to be selectively resealed.
U.S. Pat. No. 6,502,986 to Bensur et al. shows a package having a resealable portion foamed adjacent a permanent seal at one end of the package. A pressure-sensitive adhesive is applied to the inner surface of one laminate layer. Heat seal coating members are applied over the pressure-sensitive adhesive. The heat seal members are then sealed by heat and pressure. When the two sides of the package are pulled apart during opening, heat seal coating separates and exposes the pressure-sensitive adhesive. The heat seal coating member may then be pressed against the opposing side of the package having the pressure-sensitive adhesive for resealing.
US 2005/0276525 to Hebert et al. shows a flexible package formed from a laminate having a built-in opening and reclose feature within a side wall of the package. Offset score lines are separately formed in the laminate layers to enable the opening of a flap portion on the outer layer and the simultaneous opening of a package opening formed in the inner layer and covered by the flap. A pressure-sensitive adhesive is exposed by the flap, when opened, adjacent the opening formed by the inner layer within the offset score lines.
The present invention relates to a sealing structure having a first panel with first and second surfaces. The first panel includes a sealable material defining at least a portion of the first surface. Within the first panel, a pressure-sensitive adhesive is provided between the sealable material of the first surface and the second surface material within the region of a fixed seal. A separation line is provided within the sealable material covering the pressure-sensitive adhesive. The separation line is positioned adjacent the fixed seal. A second panel is provided with an engaging surface having a sealable material thereon for forming the fixed seal with the sealable material of the first panel. The separation line for the sealable material of the first surface initiates separation of the adjacent parts of the sealable material upon application of an opening force to the fixed seal. The release of the sealable material exposes the pressure-sensitive adhesive. The sealable material of the first surface remains sealed to the sealable material within the engaging surface. The exposed pressure-sensitive adhesive forms a reclosable seal for the first and second panels.
The sealing structure may be applied to a flexible packaging for containing a product therein. A first flexible laminate sheet is provided preferably having a heat sealable material on the inner surface thereof. An opposing second flexible sheet is provided with a heat sealable material within an engaging portion thereof. The opposing sheet portions are sealed together to create an end seal for the package. A reclosable seal is formed as part of the end seal. The closable seal includes a pressure-sensitive adhesive applied to an inner surface of the first sheet under the heat sealable material. A separation line within the first sheet extends at least partially through the heat sealable material that is covering the pressure-sensitive adhesive, adjacent the end seal. The separation line causes the heat sealable material of the first sheet to separate from the first sheet upon application of an opening force to the end seal. The heat sealable material of the first sheet remains adhered to the heat sealable material of the engaging portion of the second sheet. The exposed pressure-sensitive adhesive forms a resealable seal for the open end of the package.
A method of making a flexible package having the structures is also contemplated by the present invention. The method and structure of the invention may be applied to a number of package forms.
For the purpose of illustrating the invention, the drawings show forms that are presently preferred. It should be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings.
In the drawings, wherein like numerals identify like elements, there is shown a number of embodiments of a package. In
As illustrated in the cross section of
In
Removal of the heat sealable material 30 exposes the pressure-sensitive adhesive 28 and creates the resealable closure 22. Prior to separation of the material 30 from the inner surface of the front panel 18, the end seal 14 has sufficient strength to store product within the flexible package during shipment and storage. As illustrated in
Preferably, the die cut is positioned on one side of the package; thus, one portion of the inner ply within the heat sealed region will ride with the engaged portion upon application of the separation force, as shown in
The package 10 in
Other forms of packages having features of the present invention are illustrated in
In
In
The multiple die cut lines 120 provide additional encouragement for the separation of the inner heat sealable material to expose the pressure-sensitive adhesive. The die cut 118 above the heat seal further provides for separation of the inner heat sealable material from the pressure-sensitive adhesive at the position of the top seal 106. Providing multiple lines 120 makes it more likely that the package will open adjacent the top seal 106, providing separation of the heat sealable material from the inner surface of the associated package wall.
In
As shown in
A lifting tab 220 is provided at the bottom edge of the flap 210. The tab 220 is preferably not sealed to the front panel 206 of the package 200 or is releasably sealed by a pressure-sensitive adhesive so that it may be removed from the package wall. Upon lifting the tab 220, a force is applied to the flap 210, causing the sealing area 218 to disengage from the front panel 206 of the package 200. The amount of seal created within the central area 216 defined by score lines 214 is sufficient to cause the central portion to adhere to the inside surface of the flap 210 and separate from the front panel 206. Removal of the central area material 216 is caused by separation along the score lines 214 and exposes the pressure-sensitive adhesive 222 within the laminate material of the front panel 206. Once opened (
The amount of the exposed pressure-sensitive adhesive 222 within the front panel 206 may vary as desired. A transverse bar may be provided (defined by transverse score lines extending from one side edge to the other) as contemplated in the other embodiments. In addition, the upper edge 212 of the front panel 206 may serve as an upper edge of the material removed from the package 200. If the seal 218 is to be in the form of a heat seal, the flap closure may be required to be made prior to final construction of the package, so as to avoid also sealing the inner surfaces of the package during creation of the seal 218. Further, a heat seal material is included on the outside surfaces of the package as well as on the inside surfaces so that the inside surface of the flap adheres to the outside surface of the front panel. A space is contemplated to be provided between the score lines 214 and the sealed area 218 and between the score lines 214 and the central sealing area 216. Dynamic registration of all of the score lines with the sealing area is required in order to create this spacing.
Although the invention has been described and illustrated with respect to a number of embodiments, it should understood by those skilled in the art from the foregoing that various other changes, omissions and additions may be made therein and thereto, without departing from the spirit and scope of the present invention.
The present application claims the benefit of the filing date of U.S. provisional application No. 61/164,211, filed Mar. 27, 2009.
Number | Date | Country | |
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61164211 | Mar 2009 | US |