CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application Serial No. 62/236,442, entitled "Pull-Tab Sealing Member with Added Stiffness and Function", filed October 2, 2015, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The invention relates, in general, to a sealing member or closure for a container and, more particularly, to a sealing member that includes a tab to facilitate removal of the sealing member.

Description of Related Art

[0003] It is often desirable to seal a bottle, jar, or other container with a closure to maintain freshness of the contents thereof or to indicate whether the container has been tampered with. However, it is also desirable that the closure be easy to remove by the user. For example, United States Patent No. 5,433,992 to Galda et al. describes a top-tabbed closure for a container which has a membrane for sealing the container and a sheet which is bonded to the top of the membrane, in a manner which leaves a tab portion of the sheet free. A user seeking to gain access to the contents of the container simply grips the tab with their fingers and by pulling on the tab, which is connected to the sheet, can remove the entire closure and access the contents of the container in a relatively convenient manner.

[0004] Referring generally to FIG. 1, a conventional top-tabbed closure is shown generally at the top of a bottle 10 as container seal 100. A cross-sectional view of seal 100, taken along line 2—2 of FIG. 1, which is not drawn to scale, is shown in FIG. 2.

[0005] Seal 100 includes a lower section 101, comprising a lower layer 110 which is formed of an adhesive, such as a hot melt adhesive or other sealants, for securing seal 100 to the top of bottle 10. Lower section 101 also includes a foil layer 120 and a polyethylene terephthalate (PET) layer 130 between foil layer 120 and lower layer 110. Seal 100 also includes an upper section 102 which includes an ethylene vinyl acetate (EVA) layer 170 having a PET top layer 180 disposed thereon. A bottom surface 150 of EVA layer 170 is surface treated and bonded to foil layer 120. Bottom surface 150 also bonds a paper release layer 140 to EVA layer 170. Thus, release layer 140 prevents EVA layer 170 from being completely bonded to foil layer 120 at bottom surface 150. Bottom surface 150 only bonds EVA layer 170 to foil layer 120 up to a boundary line 160 so as to permit a tab portion 200 to be graspable. However, this bond between upper section 102 and lower section 101 is strong enough so that pulling tab portion 200 can remove all of seal 100 in one piece.

[0006J Conventional container seals can exhibit disadvantages. For example, a paper release or information layer can be sensitive to exposure to moisture. Additionally, the use of PET release layers alone does not provide a fully satisfactory seal. Corrosion of foil layers can also present a problem. Also, conventional closures typically require containers to have smooth surfaces to insure proper bonding and release. Uneven heating during heat-sealing steps has also occurred. Many closures will not separate from the container satisfactorily when the tab is pulled, and tearing and unsatisfactorily incomplete removal has occurred.

[0007] Accordingly, a need exists for an improved container seal which overcomes the above-described drawbacks and provides advantages compared to conventional container seals.

SUMMARY OF THE INVENTION

[0008] The invention is directed to a pull-tab sealing member configured to be secured to a lip around an opening of a container. The pull-tab sealing member includes a bottom heat- seal sheet, a top laminate sheet, a layer to increase stiffness and improve heat barrier, and a tube portion.

[0009] More specifically, the pull-tab sealing member comprises: (a) a heat- seal laminate sheet comprising: a support layer having a bottom surface facing the container and a top surface on the opposite side thereof; a polymer layer disposed on the bottom surface of the support layer; and a heat-seal adhesive coating formed on a bottom surface of the polymer layer for securing the heat-seal laminate sheet to the container; (b) a bottom laminate sheet comprising: a first polymer support layer having a bottom surface facing the heat-seal laminate sheet and a top surface on the opposite side thereof; a first adhesive coating formed on the bottom surface of the first polymer support layer for securing the bottom laminate sheet to the support layer of the heat-seal laminate sheet; and a second adhesive coating formed on the top surface of the first polymer support layer; (c) a top laminate sheet (PA) comprising: a second polymer support layer having a bottom surface and a top surface; and an adhesive layer disposed on the bottom surface of the second polymer support layer; and (d) a tube portion comprising: a polymer tubed layer secured to a portion of the second adhesive coating of the bottom laminate sheet; and a tubed tab portion formed integrally with the polymer tubed layer and secured to a portion of the adhesive layer of the top laminate sheet (PA). The second adhesive coating of the bottom laminate sheet is secured to the adhesive layer of the top laminate sheet by a remaining portion of the adhesive layer of the top laminate sheet. The second polymer support layer, the tubed tab portion, and the portion of the adhesive layer there between form a tab portion.

[0010] A portion of the bottom laminate ABA sheet may be secured to a portion of the top laminate sheet PA in a sufficiently strong manner such that when the adhesive coating at the bottom surface of the polymer layer of the heat-seal laminate sheet is secured to the container, the heat-seal laminate sheet and the bottom laminate sheet are removed by pulling on the tab portion.

[0011] The support layer may be formed from a metal foil. The first polymer support layer and the second polymer support layer may be formed from at least one of polypropylene (PP), polyethylene (PE), PP foam, PE foam, any polyolefin foam, paper, synthetic paper (sPP), and polyethylene terephthalate (PET). The heat-seal adhesive coating of the heat-seal laminate sheet may be heat-activated. The first adhesive coating, the second adhesive coating, and the adhesive layer may be one of a polyester coating, ethylene vinyl acetate, an ethylene- acrylic acid copolymer, and surlyn. The tube portion may be formed from at least one of PET, PP, heat resistant plastic, and paper.

[0012] At least one of the tube portion and the second polymer support layer may have words, symbols, logos, or any combination thereof printed thereon.

[0013] The invention is also directed to a container sealed with a pull-tab sealing member secured to a lip around an opening of the container. The pull-tab sealing member includes: (a) a heat-seal laminate sheet comprising: a support layer having a bottom surface facing the container and a top surface on the opposite side thereof; a polymer layer disposed on the bottom surface of the support layer; and a heat-seal adhesive coating formed on a bottom surface of the polymer layer for securing the heat-seal laminate sheet to the container; (b) a bottom laminate sheet comprising: a first polymer support layer having a bottom surface facing the heat-seal laminate sheet and a top surface on the opposite side thereof; a first adhesive coating formed on the bottom surface of the first polymer support layer for securing the bottom laminate sheet to the support layer of the heat-seal laminate sheet; and a second adhesive coating formed on the top surface of the first polymer support layer: (c) a top laminate sheet comprising: a second polymer support layer having a bottom surface and a top surface; and an adhesive layer disposed on the bottom surface of the second polymer support layer; and (d) a tube portion comprising: a polymer tubed layer secured to a portion of the second adhesive coating of the bottom laminate sheet; and a tubed tab portion formed integrally with the polymer tubed layer and secured to a portion of the adhesive layer of the top laminate sheet. The second adhesive coating of the bottom laminate sheet is secured to the adhesive layer of the top laminate sheet by a remaining portion of the adhesive layer of the top laminate sheet. The second polymer support layer, the tubed tab portion, and the portion of the adhesive layer there between to form a tab portion.

[0014] These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a perspective view of a conventional closure disposed over the mouth of a bottle;

[0016] FIG. 2 is a cross-sectional view of the closure of FIG. 1 taken along line 2—2;

[0017] FIG. 3A is an exploded cross-sectional view of the layers of material used to form a seal in accordance with the present invention;

[0018] FIG. 3B is an assembled cross-sectional view of the layers of material used to form a seal in accordance with the present invention;

[0019] FIG. 4 is a side cross-sectional view of a seal in accordance with the present invention;

[0020] FIG. 5 is a top plan view of a sheet used to form seals in accordance with the present invention; and

[0021] FIG. 6 is a demonstrative perspective view of an apparatus constructing sheets for forming container seals in accordance with the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0022] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention.

[0023] The layers of material used to form a seal in accordance with the present invention are shown in both an exploded and assembled view in FIGS. 3A and 3B, respectively as laminate sheet 1000. FIG. 4 illustrates a cross-sectional view of a seal obtained from the laminate sheet 1000 when cut along line A-A. The relative thicknesses of the layers shown in FIGS. 3A and 3B are not to scale. Furthermore, the construction shown is provided for purposes of illustration only, and is not intended to be construed in a limiting sense.

[0024] The layers used to form a seal are constructed from a heat-seal laminate sheet HS comprised of layers (040-042), a bottom laminate sheet ABA comprised of layers (030-032), and a top laminate sheet PA comprised of layers (010-011). More specifically, heat-seal laminate sheet HS may include a polymer layer 041 between a foil layer 040 and heat-seal adhesive 042. Foil layer 040 may be formed of a moisture proof material such as aluminum foil or any other suitable metal foil. Foil layer 040 may be about 0.0005 to 0.0020 inches thick.

[0025] Polymer layer 041 may be formed of PET or any other suitable material, and may have a thickness ranging from about 0.0004 to 0.0015 inches. Other suitable materials include nylon, PEN, and polypropylene. The bottom surface of heat-seal sheet HS is coated with a sealant or adhesive 042. Sealant or adhesive 042 may be a heat-activated adhesive. The type of adhesive is based in part on the characteristics of the container. Suitable adhesives (as used herein, the term sealant will include adhesives suitable for adhering a container seal in accordance with the present invention to a container) include polyester coatings, ethylene vinyl acetate, polypropylene, ethylene-acrylic acid copolymers, surlyn, and other materials known in the industry.

[0026] Top laminate sheet PA is formed with a polymer support 010 that includes an adhesive layer 011 on a bottom surface thereof. Polymer support 010 may be formed from a strong heat resistant sheet-like material, which can maintain its strength at small thicknesses and which has high pull strength. An example of such a material is PET, and other suitable materials include PEN, PP, and nylon. Adhesive layer 011 is advantageously formed of any industry standard thermoset adhesive and may be from 0.0001 to 0.003 inches thick.

[0027] Top laminate sheet PA attaches to a tubed tab portion 020 of a tube portion T, which is integral with a polymer tubed layer 021 of the tube portion T. Tube portion T is comprised of PET or a similar polymer that is extrudeable thermoplastic with heat resistance and relative shrink-free features. The polymer tubed layer 021 is adhered to a portion of the adhesive coating 030 of the bottom laminate sheet ABA. Tubed tab portion 020 is bonded to a portion of the adhesive layer 011 provided on the bottom surface of a polymer support layer 010 of the top laminate sheet PA. integral polymer tubed layer 021 and tubed tab portion 020 are positioned such that they are folded up and away from the bottom laminate sheet ABA to provide a gripping tab portion once the layers are dissected along line A— A in FIG. 3B as shown in FIG. 4. The tab portion is for removing the heat-seal laminate sheet HS from the top of the container.

[0028] A uniform bond strength is achieved by securing a portion of the adhesive layer 011 to tubed tab portion 020 and securing the remainder of the adhesive layer 011 to the adhesive coating 030 provided on the top surface of the support layer 031. This uniform bond strength prevents top laminate sheet PA from de-laminating from bottom laminate sheet ABA when a user applies a force to the gripping tab portion formed from the polymer support layer 010, the tubed tab portion 020, and the portion of the adhesive layer 011 therebetween.

[0029] Integral polymer tubed layer 021 and tubed tab portion 020 are comprised of PET or a similar polymer that is extrudeable thermoplastic with heat resistance and relative shrink- free features, it may be white colored or clear, and may have words, symbols, logos, or the like printed thereon. The interior surfaces of the integral polymer tubed layer 021 and tubed tab portion 020 may include a release agent formed of a coating of release material . Release material may include various known heat resistant coatings such as silicone release coatings.

[0030] Bottom laminate sheet ABA can be formed by adhering adhesive coatings 030/032 to the support layer 031 by extmsion or other common coated means. Suitable adhesives include ethylene acrylic acid copolymers, curable two-part urethane adhesives, and epoxy adhesives. As used herein, the term adhesive will include curable adhesives, heat-activated adhesives, and thermoplastics.

[0031] With reference to FIG. 6, an apparatus in accordance with the present invention for forming a laminated sheet 1000 from which seals can be obtained is shown generally as apparatus 600.

[0032] A bottom heat-seal laminate sheet HS including a bottom laminate sheet ABA is fed to a nip where a pressure roll 610 meets a hot roll 620. A top laminate sheet PA is also fed into the nip between pressure roll 610 and hot roll 620. Top laminate sheet PA includes a support layer 010 and an adhesive layer 011. Top sheet PA is fed into the nip between rolls 610 and 620 such that adhesive layer 011 faces adhesive coating 030 of the bottom laminate sheet ABA. Strips 330 of polymer tubing 020 are combined with and inserted between top laminate sheet PA and the combination of heat-seal laminate sheet HS and bottom laminate sheet ABA in a parallel spaced arrangement. After heat from hot roll 620 joins top laminate sheet PA, polymer tubing 020, and the combination of heat-seal laminate sheet HS and bottom laminate sheet ABA, a laminate sheet 1000 as shown in the assembled view of FIG. 3B results.

[0033] Laminate sheet 1000 is shown in plan view in FIG. 5. To form seals in accordance with the present invention, circular (or other appropriately shaped) portions 410 are die cut from sheet 1000. As can be seen in FIG. 5, a boundary 415 is established at the center of each strip of polymer tubing 330. When each circular portion 410 is die cut from sheet 1000, the strip of polymer tubing 330 is cut through a center portion thereof (as shown by line A— A in FIG. 3B) creating a u-shaped structure formed of polymer tubed layer 021 and tubed tab portion 020. This u-shaped structure thereby forms the tab portion. The inside surface of the strips of polymer tubing 330 may be coated with a release agent (not shown).

[0034J The following example is provided for purposes of illustration only and is not intended to be construed in a limiting sense.

[0035] A 1 mil aluminum foil sheet 040 was adhered to a 0.5 mil PET film 041 with adhesive. A 1.5 mm sealant film 042 was then adhesive-laminated to the PET surface of the foil/PET laminate thereby forming a heat-seal laminate sheet HS. A bottom laminate sheet ABA was constructed of 1 mil EVA (030/032) on both sides of PP film (031) having a thickness of 4 mils. The top laminate sheet PA was adhered to the bottom laminate sheet ABA with a thermal bonding process after strips of tubing 020 were inserted therebetween. Circular seals, approximately 1.5 inches in diameter, were die cut from the strips, with a central region of the strip of tubing extending approximately down the midpoint of the circle, to yield tabs having a base running down the middle of the seals from edge to edge.

[0036] One advantageous method of attaching container seals in accordance with the present invention to the tops of containers is with heat activated adhesive. The adhesive may be heated through induction heating by utilizing a metal foil support in the bottom sheet of the seal, such as an aluminum foil support sheet.

[0037] Container seals in accordance with the invention were found to bond well to the top surface of a container, without the need to oversize the seal and have portions of the seal extend beyond the top edge of the container, providing a neater appearance. Container seals, in accordance with the invention, were also found to provide adequate sealing even when the top surface of the container was not substantially smooth, such as in the case of containers having mold lines or other imperfections on the top surface thereof. Container seals in accordance with the invention were also shown to exhibit substantially improved water resistance compared to container seals in which paper is exposed or in which a metal foil surface is either exposed or covered with only paper. Thus, container seals in accordance with the invention were shown to exhibit reduced corrosion from exposure to water or juices.

[0038] In addition, further details of the top laminate sheet PA, bottom laminate sheet ABA, and tube portion T are provide in United States Patent No. 8,348,082, which is hereby incorporated by reference in its entirety.

[0039] Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements. Furthermore, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.