HK1237749B - Tabbed seal member - Google Patents

Description

Pull-tab sealing parts

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 62/127,545, filed March 3, 2015, which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates to pull-tab seals for containers, methods of making such pull-tab seals, and in particular to improvements for forming pull-tabs on sealing laminates for containers.

Background Art

It is often necessary to use a sealing member or inner seal to seal the opening of a bottle, jar, or other container. The cap or other closure is typically screwed onto or placed over the neck or other container opening. During use, the consumer typically removes the cap or other closure to access the seal and removes or otherwise separates the seal from the container to use or access the contents.

Initial attempts to seal container openings include an inductive or conductive inner seal that covers the opening of the container, with the seal typically conforming to the shape of the opening at the opening so that the circular container opening is sealed with a disc of approximately the same size as the opening and its rim or upper surface. These existing seals typically have a lower layer of heat-activated sealing material to secure the periphery of the seal to the rim or upper surface around the container opening. When the seal is exposed to high temperatures, the lower layer adheres to the container rim. In many cases, these seals include a foil layer to provide inductive heating to activate the lower heat seal layer. These existing seals are intended to provide good seals, but because there is nothing for consumers to grab in order to remove the seal, it is difficult for consumers to remove it. Typically, consumers need to use their fingernails to lift the edge of the seal because there is only a little or no sealing material to grab.

Other types of seals for containers include side tabs or other flanges extending outward from the peripheral edge of the seal. These side tabs are generally not fixed to the container rim, which provides a gripping surface for the user to pinch and separate the seal. However, these side tabs extend beyond the sides of the container rim and often extend into the threaded portion of the closure. If the side tabs are too large, the construction may negatively affect the seal's ability to form a good seal. When the closure or other lid is placed on the container, the side tab (and often the unsealed liner itself) can become deformed or wrinkled due to contact between the closure and the tab-like portion of the seal. To minimize these problems, the side tabs are typically small; therefore, very little surface area or material is provided for the consumer to grip to remove the seal.

Other types of seals include sealing components with a pull-tab defined at the top of the seal. One approach to these existing seals includes applying a partial layer of pressure-sensitive adhesive to secure the pull-tab to the foil layer. This type of top pull-tab seal offers the advantage of a larger pull-tab, which provides more gripping area for the consumer to grasp and separate the seal. In this approach, the pull-tab is formed by a full layer extending across the entire surface of the sealing component, but this full layer is only bonded to half of the seal to form the pull-tab. In other approaches, the seal may include a pull-tab composed of an additional full layer of film combined with a partial paper or polymer layer (called a separation layer or pull-tab seat) to form the pull-tab. This partial layer can also be inserted between the additional full layer of adhesive and the lower seal portion to prevent the pull-tab from sticking to the layer below that forms the pull-tab.

Summary of the Invention

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a perspective view of an exemplary pull-tab seal component;

FIG2 is a cross-sectional view of a pull-tab seal component including a release layer formed of a folded, wound, or cylindrical release film, paper, or foam layer, which may be a single or multiple layers or a coextruded layer;

FIG2a is a cross-sectional view of another pull-tab type sealing component having a two-part separation layer;

FIG3 a is a cross-sectional view of an exemplary folded separation layer having a dead fold;

FIG3 b is a cross-sectional view of an exemplary folded separation layer formed by bonding or welding two separate layers together;

FIG4 a is a cross-sectional view of an exemplary cylindrical separation layer;

FIG4 b is a cross-sectional view of an exemplary wound separation layer, which is not a tube, having a split formed therein when the ends are wound back upon each other;

FIG4 c is a cross-sectional view of an exemplary cylindrical separation layer formed from two separate layers (such that the cylinder is not a unitary or continuous tubular material) and thermally bonded or welded at opposing ends thereof;

5 is a cross-sectional view of a laminate sheet configured to have a tab seal die cut from the laminate sheet with exemplary spaced-apart release layers disposed therein;

FIG6 is an exemplary method of making a laminate sheet of the present invention;

FIG7 is a cross-sectional view of a tab-type sealing component including an asymmetrically folded separation layer in which a top portion of the separation layer is longer than a bottom portion of the separation layer;

FIG8 is a cross-sectional view of a tab-type sealing member including a top foam layer;

FIG9 is a cross-sectional view of a tab seal comprising a foamed or non-foamed barrier layer disposed beneath a foil layer;

FIG10 is a cross-sectional view of a tab seal including a barrier layer, which may be foamed or non-foamed, positioned above the foil but below the various separation layers described herein;

FIG11 is a cross-sectional view of a tab seal component including a segmented layer adjacent to various release layers herein to average pressure and/or thickness between the tab side and the non-tab side of the seal;

FIG12 is a tab seal comprising a foil layer that is moved over the various release layers herein so that the foil is positioned upwardly in the tab;

FIG13 is a pull-tab seal component including various release layers herein, each of which is directly bonded to a top polymer support layer;

FIG14 is another pull-tab type sealing component that does not include a separation layer but includes a partial layer of fusible material that is absorbed into the absorbent layer to form a pull-tab;

FIG15 is another pull-tab seal component including a layer having a segmented debonding or release agent, the debonding or release agent being present only in the portion of the layer configured to form the pull-tab;

FIG16 is a cross-sectional view of an exemplary tab seal constructed as a two-piece assembly having a wax bonded liner coated thereon;

FIG17 is a cross-sectional view of another two-piece assembly including a tab seal having a wax bonded liner coated thereon, the tab seal including a folded, wrapped, or cylindrical separation layer forming a tab and having no other layers in the upper laminate;

FIG17a is a cross-sectional view of the tab seal of FIG17 with the addition of a foamed polymer layer or a non-foamed heat distribution layer;

FIG18a is an extruded film having spaced pockets extruded therein;

FIG18b is a cross-sectional view of a tab seal comprising the extruded film of FIG18a, utilizing a pocket portion thereof to form a tab; and

19 is a cross-sectional view of a film laminate comprising an EVA layer bonded to a PET film with a portion of a polymer layer therebetween.

DETAILED DESCRIPTION

As mentioned above, tab seals are commonly used with lids or other closures on containers. The lid or other closure is typically screwed or otherwise secured to the mouth or neck of the container, trapping the tab seal between the top of the lid and the container rim. In many cases, the lid features an annular bead or downwardly projecting ring (sometimes called a bead) on the underside of its top inner surface. This bead is sized and positioned to roughly align with the upper die face of the container rim when the lid is secured to the container. This bead helps provide pressure to secure the seal to the rim die face. However, many existing seals include a foam layer or other low-melting-point polymer layer to provide support and/or insulation from the heat generated during the heat sealing process. In some cases, the interaction of the foam or polymer layer with the lid's bead during the lid sealing process can present problems. The heat from the lid sealing process, combined with the focused downward pressure from the bead on the foam layer or other low-melting-point polymer layer in the seal, can damage or degrade the foam or other polymer layer in the area above the container rim. In extreme cases, the polymer layer may melt, degrade, or the air cells in the foam may collapse.This disadvantage is more prevalent when the lid sealing process is over-sealed (i.e., when too much heat is applied or the heat is applied for too long during the lid sealing process).

This melting and/or collapse of the airbag can result in exposure of the metal foil or other polymer layer in the laminate and/or in the peripheral area of the seal. In some cases, when the consumer lifts the tab to remove the seal, they are presented with an unsightly seal with an uneven top layer beneath the tab, which has an intact center portion and melted or damaged edges. In extreme cases, the outer periphery of the laminate beneath the tab can completely melt, exposing the metal foil or other layer beneath the tab.

Existing seals that include tabs, which are preferably completely confined within the perimeter of the seal and formed from partially separated layers, are susceptible to stress focal points at the joint or inflection joint where the tab pivots upward when the tab is pulled. Typically, as the tab is pulled, the stress radiates downward and away from this inflection joint into the layer below the tab, and in some cases, causes the layer immediately below the tab to tear at the inflection joint, or the tab to tear at the inflection joint. In some cases, these failures tend to be more problematic in existing tab-type seal designs when the layer immediately below the tab is a foamed polymer, but can also occur with other types of layers depending on the thickness, composition, and/or density of these underlying layers.

The various pull-tab seal components described herein provide a more robust pull-tab structure by providing additional supports under the pull-tab around the laminate and at the pull-tab pivot or turning joint between the upper part or upper laminate and the lower part or lower laminate. This robust structure provides concentric stability to the pull-tab seal component so that the pull-tab seal maintains consistent integrity at its peripheral edge around the container rim mold surface and the structural integrity of the radially inner portion away from the edge. The structures herein also provide turning stability by providing additional supports at the turning or pivot joint of the pull-tab, providing further strength and helping to dissipate tensile stress when the user pulls on the pivoting pull-tab. Therefore, the sealing components herein tend to maintain the integrity of the layer below the pull-tab at the peripheral edge and at the pull-tab turning joint during the heat sealing process and when the consumer pulls the pull-tab to remove the seal.

For example, the structures herein can provide a more rigid, non-foamed layer at the tab's pivot or hinge joint, and also provide a more rigid, non-foamed layer below the focus of the tab's tensile stresses to provide a stronger laminate structure when the tab is pulled. In embodiments of the present invention, the tensile stress is dissipated through the more rigid pivot or hinge joint, wherein the hinge is supported, in some embodiments, by a movable hinge joint of the same material that supports the rest of the tab. In some embodiments, the hinge and hinge joint are also configured to dissipate stress downward through a denser, more rigid layer below the tab's hinge joint, thereby providing a stronger tab to the container that can withstand a stronger heat seal bond.

In general, the concepts herein describe a sealing component for a pull tab of a container (or a laminate sheet for forming such a sealing component for a pull tab) comprising an upper component or upper laminate having a pull tab bonded to a lower component or lower laminate capable of being heat-sealed to a container mouth or opening. In one aspect, the sealing component herein comprises a pull or grip tab confined within an upper laminate portion completely within the perimeter of the sealing component. Various sealing components and laminates herein include improved structures to form a stronger and more robust tab as described above.

Turning now to more detail generally illustrated in the accompanying drawings herein, a pull-tab seal with a reinforced free tab is shown. In FIG1 , a common pull-tab seal 10 is provided in the form of a laminate 12 formed from a flexible sheet and/or extruded film material, a lower member or laminate portion 14 for bonding to a container rim 16, and an upper member or laminate 18, the upper member or laminate 18 being partially bonded to the lower member to form a free portion or grip tab 20 (at a hinged junction 21). The free portion or grip tab 20 is preferably completely defined within the perimeter 22 of the pull-tab seal 10. In use, by pulling on the tab 20, a user can pivot the tab upward at the hinged junction 21 as shown in FIG1 and use the tab to remove the seal from the container rim or other container portion 16. In one embodiment, the pull-tab 20 is pulled to remove the seal from the container rim in one piece.

FIG2 shows more details about how an exemplary pull tab 20 is formed in the context of the present invention. In the embodiment of FIG2 , the pull tab is formed from a folded, wrapped, or cylindrical separator 100 or sheet that includes a dead fold 101 therein. The folded separator 100 forms a top folded portion 102 and a bottom folded portion 104, with the top folded portion 102 being bonded to the layer above it and the bottom folded portion 104 being bonded to the layer below it. The dead fold 101 is between the top and bottom folded portions 102 and 104. Preferably, the folded separator 100 is not a tube or is made from a tube or any tubular material. The inside surfaces of the top and bottom folded portions 102 and 104 of the separator 100 are not bonded to each other, allowing the pull tab 20 to be formed at the dead fold or turning line because the top folded portion and any layers above it are not bonded or fixed to the layers below them, forming a free portion that can freely pivot upward.

In the embodiment of FIG. 2 , the seal 10 includes an upper laminate 106 having at least a supporting polymer layer 108 and an adhesive layer 110. The seal may also include a lower laminate 112 having a foil 114, an optional polymer layer 116, and a lower sealant or heat seal layer 118. The seal of FIG. 2 includes various layers, which are merely exemplary layers that may be included in the folded separation layer 100 to form a pull-tab seal component with a reinforced pull tab. Other layers may also be included as needed. For example, the seal of FIG. 2 may also include a foamed or non-foamed polymer layer above the foil and below the pull tab as further discussed herein.

In another embodiment, as shown in FIG. 2 a , another separation layer 100 a is shown, in which the separation layer 100 a is not a continuous folded sheet, wrap, or cylinder with a dead fold, but rather two separate layers 102 a and 104 a that are not bonded or integral to one another (and therefore do not include a dead fold). That is, the top portion 102 a can be a separate layer from the bottom portion 104 a, each bonded to the layer adjacent to it, but not to each other. More specifically, layer 102 a can be bonded to the layer above it, and layer 104 a can be bonded to the layer below it, but layers 102 a and 104 a are not bonded or adhered to one another.

Figures 3a, 3b, 4a, 4b and 4c provide further examples of exemplary folding separation layers or sheets. These separation layers can be used with any of the pull-tab sealing components of the present invention. Figure 3a shows in more detail one type of exemplary folding separation layer 100, which can be a single layer (not shown), or as more specifically shown in Figure 3a, a multilayer laminate or coextruded film with more than one layer. The folding separation layer is not formed in the form of a tube, but is formed by flat sheets folded together. Two layers are shown in the figure, which form the folding separation layer structure, but the laminate or coextruded film can include other layers as needed for specific applications. In the example structure of Figure 3a, the folding separation layer 100 may include an inner layer 130, such as an internal supporting polymer layer, such as polyester (e.g., polyethylene terephthalate (PET)) or an inner paper layer. The folding separation layer 100 can have an outer layer 132, and the outer layer 132 can be a laminate or coextruded product with an inner layer. The outer layer 132 can be a heat-bondable polymer (such as ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), polypropylene, polyethylene, polyurethane, their copolymers and the like), a foamed polymer layer (such as a foamed polyolefin), another polymer layer having a lower melting point than the inner layer, and/or an adhesive layer. The inner layer 130 can also be a foamed polymer layer. The folding separation layer 100 can also include more than two layers and include any combination of the layers suggested above (polymers, foams, paper, adhesives, etc.). There can be a thin adhesive tie layer between the two layers, or even a 3-layer laminate with an adhesive bonding layer between the inner and outer layers. In some embodiments, as generally shown in Figure 2, the outer layer 132 allows the folding separation layer 100 to be bonded to the upper and lower laminates by heat bonding or adhesive bonding.

In another embodiment, the folding separation layer 100 may include a foamed polymer layer as an inner layer combined with an outer layer, which is a polymer support (e.g., PET, PEN, nylon, etc.) combined with an adhesive or a heat-bondable polymer (e.g., EVA). Alternatively, the folding separation layer 100 may also be a single foam layer or a single foam layer with a thin layer of adhesive on its outer surface.

In yet another embodiment, the folding separation layer 100 can be a paper layer with an adhesive or heat-bondable material (e.g., EVA, etc.) on its outer surface, or a laminated paper layer with an adhesive or any heat-bondable material on its outer surface. As further explained below, the separation layer 100 (in any of the above embodiments) can also be perforated with holes, slits, micro-pores, etc., as desired, to facilitate folding and remove air from the interior of the folding assembly.

FIG3 b shows another method for folding separation layer 100. In this method, upper folded portion 102 is a separate layer from bottom folded portion 104, so that the folded separation layer is not continuous and each folded portion is not integral with each other. In this method, the two portions 102 and 104 can be joined at welded joint 134 at one end of each folded portion using heat, adhesive, cold sealing, or other bonding. Here, as previously described in FIG3 a, layer 100 can be any single or multi-layer film or material.

In the manner of Figures 3a and 3b, the folded separation layer 100 is preferably not a tube and is not formed by any tubular material or film, but is formed by a flat sheet of film (or a multi-layer laminate as the case may be) which is then folded to form a dead fold 101 or joined to form a weld joint 136b before being inserted into the desired laminate, such as shown in Figure 2 or any other structure herein.

In another embodiment, as shown in FIG4 a, the separation layer 100 can be formed by a cylindrical material, sheet or film, or by tearing, cutting and/or folding the cylindrical material, sheet or film before inserting it into a laminate (such as the laminate of FIG2 ), or by inserting it into the laminate in the form of a folded cylinder and cutting it during punching to form the final pull-tab seal component, wherein the cylinder is subsequently cut to form the separation layer. As shown in FIG4 a, the separation layer 100 can also be a folded cylinder including two opposing dead folds 136a. As shown, the cylinder can also include multiple layers similar to those described above, and reference numbers are reused for consistency. The cylinder can also be a single layer, or as shown, a multi-layer laminate.

In a cylindrical embodiment (or even a folded sheet embodiment) of the separation layer 100, air entrapment within the cylinder is a problem that can easily arise when the cylinder is folded to create a dead fold, and inserting such a folded cylinder through a lamination process can also be problematic. Therefore, in some embodiments, the cylinder can be constructed of a perforated material or film to help release any trapped air. As shown, only a few perforations 138 are shown in FIG4 a, but it will be understood that the perforations can be one or more, or, in some cases, a plurality of cut lines, pinholes, micropores, notches, openings, etc., as desired, and any combination thereof, which allow sufficient air to pass through the film so that the cylinder can be folded flat without significant air entrapment that would prevent lamination and the cylinder from folding and remaining flat. If the cylinder comprises multiple layers, the perforations 138 can extend through all layers.

In one embodiment, the folded or cylindrical separation layer herein comprises a microporous polymer film or is formed by a microporous polymer film. The layer may have a plurality of micropores or microcavities 138 formed at or in at least one surface 142 and extending from at least one surface 142 into the body of the layer. The micropores may extend through the film and/or through multiple layers or may be a single perforated layer combined with inner and outer air permeable layers (such as a foam layer). The perforations 138 may be randomly spaced or distributed throughout the cylindrical layer 100 and its surface 142 and extend into and, in some cases, through the layer or layers forming the cylindrical separation layer 100 (or any other layer combined with the layer 100, or any type of separation layer described herein). It should be understood that the micropores shown in FIG. 4 a (and in other figures) are exaggerated for illustrative purposes. These perforations may have different shapes, sizes, structures, and spacings suitable for specific applications. As shown, the perforation generally extends inwardly from the outer surface 142 to the main body of layer 100, but the perforation can also extend inwardly from the opposite side, or can extend inwardly from both sides. Some perforations preferably extend through the layer or multiple layers forming the separation layer 100. Other perforations can only partially extend into the main body of the layer. An example of a suitable film can be from Nippon Pulp & Paper (Dusseldorf, Germany). In some ways, layer 100 can have an oxygen transmission rate (OTR) of approximately 5,000 cm ³ / (m ² × day × 1 bar) or higher (approximately 23 ° C, approximately 0% relative humidity) measured by ISO 15105-2/DIN 53380-3. In other cases, OTR is approximately 12,000 to approximately 15,000 cm ³ / (m ² × day × 1 bar), and in other cases, approximately 12,500 cm ³ / (m ² × day × 1 bar) or higher. Layer 100 may also have a water vapor transmission rate (WVTR) of about 150 to about 250 g/(m2×day), in other embodiments, about 200 to about 250 g/( ^m2 ×day), and in still other embodiments, about 226 to about 227 g/( ^m2 ×day), as measured by ISO 15106-3 at about 38°C and about 90%/ ⁰ % relative humidity.

In one embodiment, the microporous polymer film is a polyester layer, such as PET, which provides suitable rigidity and air passage through the individual perforations. In one embodiment, the polyester layer can be about 5 to about 23 microns thick, while in other embodiments, it can be about 10 to about 20 microns thick, and in yet another embodiment, it can be about 10 to about 12 microns thick. The polymer layer used in the separating layer herein can have a tensile strength of about 10 to about 20 kg/mm2 in the longitudinal direction and/or the transverse direction, and in some embodiments, the tensile strength in the longitudinal direction is greater than the tensile strength in the transverse direction. In some embodiments, the layer can also have an elongation at break of about 20% to about 25%, in other embodiments, about 10% to about 21%, and in yet another embodiment, about 14% to about 21%. In some cases, the elongation at break can be greater in the longitudinal direction than in the transverse direction.

In FIG4 b , the separation layer or sheet 100 can be approximately cylindrical in shape, but rather than being joined into a cylinder, it can be wrapped or folded upon itself so that the ends of the sheet of material abut each other, rather than being joined into a continuous or unitary tube. In this manner, the adjacent ends of the wrap form gaps 139 or other spaces that also allow trapped air to escape from the wrapped separation layer 100 when folded or laminated. Again, the wrapped (but not tubular) separation layer 100 of FIG4 b can include any single layer or multiple layers as previously discussed, and can also include holes, pinholes, slits, perforations, micropores, and the like.

FIG4 c shows another embodiment of a release layer or sheet 100 suitable for the various tab seals described herein. In this embodiment, the release layer 100 is a non-continuous (or non-integral) cylindrical release layer formed by two separate sheets or films that are welded, heat-sealed, or bonded at opposite ends 136 b. This embodiment may include or be composed of any of the previously described single or multi-layer films or materials described herein for release layers.

Turning briefly to Figures 5 and 6, exemplary laminate sheets 1000 and methods of making such laminates 1000 are provided, using the folded, wound, or cylindrical separators 100 shown in the previously discussed figures. In Figure 5, various separators 100 are shown inserted into a laminate of layers designed to form a tab-type seal 10 (i.e., typically from Figure 1 and other figures herein). Here, the separators 100 are shown generally, but for exemplary purposes, three different types of separators from Figures 2, 3, and 4 are shown in the same laminate (folded and welded on the left from Figure 3b, cylindrical in the middle from Figures 4a, b, or c, and folded on the right from Figure 3a), but it should be understood that such types of separators are not typically mixed within the same laminate 1000. Typically, only a single type of separator is used at a time. FIG5 is intended to illustrate various types of separation layers 100 inserted within a laminate 1000, and the separation layers 100 in FIG5 and 6 can be any of the previously described folded, wrapped, or cylindrical layers. The tab seal component can be die-cut from the sheet 1000 using conventional techniques, as shown by the dotted die-cut lines. It should be understood that any of the tab seal components herein can be formed using the sheet 1000 of FIG5 and the process of FIG6 by varying the configuration of the layers within the laminate sheet.

FIG6 shows various separating layers 100 folded, torn, or wrapped and directed into nip 1002, where the various layers of upper and lower laminates 106 and 112 are brought together to form a combined laminate sheet 1000. In some embodiments, the various separating layers 100 can be formed from the aforementioned perforated, torn, perforated, slit, or microporous films; thus, as the layers 100 enter nip 1002, trapped air between the upper and lower portions of the separating layer can escape through the film, facilitating the separation layer 100 to remain flat, folded, and substantially wrinkle-free at the nip. Because the various materials forming the separating layer 100 can include an adhesive or heat-bondable material on an outer surface, as the separating layer 100 and the other layers 106 and 112 enter nip 1002, the separating layer will subsequently bond to the layers above and below it upon application of heat. If a heat-bondable material is used, the nip can be heated. There may be a release coating on the inner surface of the release layer 100 so that the inner surface of the release layer of the top portion 102 does not adhere to the inner surface of the release layer of the bottom portion 104.

Turning to FIG. 7 , another exemplary tab-type seal 10 is shown. In this embodiment, the release layer comprises a folded layer 100 similar to those previously described, but in this embodiment, the upper folded layer portion 102 is longer than the lower folded layer portion 104, forming an asymmetric release layer. In this embodiment, the lower folded layer portion 104 does not have an outer edge that merges with and terminates at the outer edge or periphery of the lower laminate portion 112. That is, a gap or space 105 exists between the outer edge of the lower release layer portion 104 and the edge or periphery of the laminate 112, leaving the upper surface of the lower laminate 112 exposed and visible. This gap 105 can create a small space or other fingernail clearance, making it easier for the user to pivot the tab during use. Here, the asymmetric release layer 100 (i.e., the top portion is longer than the bottom portion) can also be any of the materials previously discussed as suitable for release layers, and can be a single or multi-layer film or laminate, and can be formed from a folded, wrapped, or slit cylindrical release layer. 7 , there are no particular limitations on the remaining layers in the laminate, and the asymmetric separation layer can be incorporated into any of the pull-tab seal components described herein. It should be understood that the asymmetric separation layer 100 can also have a shorter upper portion 102 and a longer lower portion 104.

Figures 8-10 illustrate exemplary tab seals with any of the aforementioned separation layers 100, and illustrate various embodiments or versions of the tab seals. Those skilled in the art will appreciate that the specific configurations depicted in these figures are not mutually exclusive, and that any layer in these figures may be used or interchanged with other layers in other embodiments. It should also be understood that the inclusion of a particular separation layer 100 or sheet in a single figure does not imply that the particular configuration of the tab seal depicted in that figure is limited to that separation layer. Any separation layer described herein can be used with any laminate structure of the present invention. Within these configurations, the layers within the assembly can be varied as needed for a particular application. For example, a foamed polymer or non-foamed polyolefin barrier layer 109 (such as described in U.S. Patent 8,057,896, which is incorporated herein by reference) may be provided at various locations within the laminate to provide the desired isolation and heat redirection required for a particular application. As discussed below, polymer foam is used in the embodiments for simplicity, but such a layer could also be a non-foamed heat-redistributing polyolefin layer, such as described in the aforementioned '896 patent.

More specifically, and in the manner of FIG8 , the top layer of the pull-tab seal can be a foamed or non-foamed barrier layer 109. For example, layer 109 can be a top foam layer, layer 110 can be a heat-bondable or adhesive layer (e.g., EVA or the like), layer 100 can be any of the aforementioned separation layers, layer 114 can be a foil, layer 116 is optional and can be a polymer support layer, such as, but not limited to, PET, PEN, nylon, etc., and layer 118 can be a heat seal or pressure-sensitive adhesive layer. The seal 10 is bonded to the container rim 16.

Figure 9 is another version of the tab seal 10 with a barrier layer 109 (foamed or non-foamed) underneath a foil layer 114. In this version, the top layer of the seal is a polymer support layer 116. The other layers are similar to the previous figures.

10 shows another approach or embodiment where a foamed or non-foamed polymer barrier layer 109 is above the foil 114 and below the separation layer 100, such that the bottom portion 104 of the separation layer is not directly bonded to the foil layer 114, but rather directly bonded to the barrier layer 109. The remaining layers of this approach may be similar to those previously described.

FIG11 illustrates yet another approach or embodiment utilizing a segmented construction. In this approach, a segmented layer 200 is included adjacent to or abutting the release layer 100 (preferably within the same laminate plane when the tab is folded downward) to help provide more uniform and consistent pressure and thickness between the tabbed and non-tabbed sides of the seal. Because various folded, wrapped, and cylindrical release layers 100 tend to be thicker at the top and bottom portions 102 and 104 (when folded together), they are susceptible to thickness variations between the left and right sides of the seal. To help address this uneven thickness, the seal 10 may include a segmented layer 200, which may be layer 109, 114, or 116 (which may be a foil, foam, or polymer, as appropriate), above the top layer of the lower laminate 112 to help even out the thickness. The segmented layer 200 may be a polymer layer, such as PET, polyolefin, nylon, or combinations thereof, extending across portions of the seal and covering areas not covered by the release layer 100. Thus, the combination of the segmented layer 200 and the release layer 100 can cover the entire seal, and when combined in a laminate, the thickness of the segmented layer and the release layer 100 will be consistent and/or the same. The segmented layer 200 can have the same or consistent thickness as the upper portion 102 and the lower portion 104 of the release layer 100. As used herein, consistent means within a range of approximately +/- 5% to 10%.

In yet another embodiment, the pull-tab seal may be any of the previously discussed configurations, but without any foil or other induction heating layer. This type of seal may be constructed and/or sealed to the container using conductive heat or directly heating the container surface rather than via induction heating.

Figure 12 shows another kind of pull-tab sealing component 10, wherein foil layer 114 is moved to another position for specific application as needed.For example, foil or any inductively heated layer 114 can move upwards into upper laminate 106 from lower laminate 112 (as generally shown in previous construction).In this form, the cylindrical separating layer 100 of folding, winding or tearing can be below the foil in final laminate structure.More specifically, Figure 12 shows an example of this structure, optional foil layer 114 is on separating layer 100 and is positioned in upper laminate 106 inside and in the inside of the pull-tab that forms.Alternatively, separating layer 100 also can be included in any layer below in lower laminate 112 for special application as needed.For example, separating layer 100 can be below the isolation layer 109 or below the supporting layer 116 in the laminate shown in Figure 12. 12 may also include a second foil layer in the lower laminate (not shown) so that the construction comprises a double foil assembly, with one foil in the upper laminate 106 and another foil in the lower laminate 112. If used, this second foil layer may be between any of the layers in the lower laminate 112 or form the top surface of the lower laminate 112.

The folded, wrapped, or cylindrical separation layer 100 can also be directly bonded to the top layer (e.g., layer 108) of the upper laminate 106. This is illustrated in FIG. 13 , where the top folded portion 102 of the folded, wrapped, or cylindrical separation layer 100 is directly bonded to the upper polymer support layer 108. Here, layer 108 can also be directly bonded to the lower laminate 112 by adhesive or other bonding means, as desired. For example, when layer 108 is in an unfolded state, layer 108 can be directly bonded to the layer below it by using any of the multilayer structures shown in FIG. 3 and 4 . In this form, layer 108 can be a PET/EVA combination, or the separation layer can be a folded, wrapped, or cylindrical material of EVA/PET.

Turning now to various alternatives for forming a pull-tab seal, the configurations of Figures 14-15 provide pull-tab seals without any of the aforementioned separation layers. In these approaches, different types of deformable release materials, such as wax, talc, calcium carbonate, slip agents, polyethylene glycol (PEG) or polypropylene glycol (PPG), etc., can also be used to hinder or prevent the top laminate 1118 or 2118 from adhering to the lower laminate 1114 or 2114 to form the gripping tab 1120 or 2120, even without the previously described separation layer.

In FIG. 14 , tab 1120 may be formed via a partial layer, initially shown as layer 1152, which melts or flows during the induction heating process and is absorbed by the layer below or above it. For example, layer 1152 may be wax, PEG, or PPG, while layer 1142 immediately below (or immediately above) may be any absorbent layer or material configured to absorb the melted or flowable layer 1152 after induction heating. Thus, layer 1142 may be a paper layer, a foam layer, or any absorbent polymer layer. Layer 1142 may also be or include aligned or interwoven synthetic fibers. An example is SynthaSeal ^™ material. Thus, while no defined separating layer is formed in the resulting seal after heat sealing, the material forming layer 1152 is present during the initial sealing process and formation, and melts during induction sealing and is absorbed by the layer below (or above) it to form the tab, shown here as layer 1120. In this manner, it will be understood that the portions of the seal, shown as bond 1158, are bonded or secured together, while the layers above 1152 are bonded together and form tab 1120 (i.e., the portions of laminate 1118 above layer 1152 are not bonded to the portions of laminate 1114 below it to form a tab). Tab 1120 is capable of pivoting upward similar to that depicted in FIG. 1 .

Other exemplary layers in the embodiment of FIG. 14 may be an upper polymer support 1150 (PET, PEN, nylon, polyolefins, and copolymers thereof) and optional polymer layers 1148 and 1146 (or foamed or non-foamed polymer layers to provide insulation, support, and/or redirect heat, as desired; or any of the foamed or non-foamed polymer heat redistribution layers discussed above). Layer 1144 may be a heat-bondable layer such as EVA or EMA. Layer 1134 may be a foil, while layer 132 may be a heat seal or PSA. The structure may also include a barrier layer, as desired.

The wax, PEG, or PPG material 1152 may be a lane or strip of material applied to the upper surface of the lower laminate 1114 or the lower surface of the upper laminate 1118. Using FIG6 as a reference, the separation layer 100 of the prior art can be replaced with a lane of wax, PEG, or PPG applied to the mesh 108 or mesh 112 prior to application to the laminate station 1002.

14 shows the wax, PEG or PPG applied to the upper laminate 1118 and the absorbent layer 1142 in the lower laminate 1114. The reverse could be used to have the absorbent laminate 1142 in the upper laminate and the wax, PEG or PPG applied to the lower laminate.

Alternatively, the partial layer of material in FIG14 is represented by element 1152, which can be talc or calcium carbonate applied to the upper or lower laminate to prevent the pull-tab portion 1120 of the upper laminate from adhering to the layer below it. Similar to the application of a wax pattern, the talc or calcium carbonate can be applied in the form of a lane or strip to the upper laminate or strip-shaped lower laminate or partial layer corresponding to the pull-tab in the final product. The talc or calcium carbonate is positioned where the pull-tab is designed to form and is applied only to a portion of the seal, such as the portion corresponding to, for example, area 1152 in FIG14. The talc or calcium carbonate prevents or hinders the pull-tab portion in the upper laminate 1118 from adhering to the lower laminate portion 1114 underneath the pull-tab.

FIG15 shows another alternative way to form a pull-tab seal component without a separation layer. In this way, the lower layer 2144 in the upper laminate 2118 is a film layer having a modified or segmented debonding agent (such as a modified slip agent) mixed therein, as shown by the area 2152 in the figure. The debonding agent or slip agent 2152 is only partially provided in the film 2144 in the area 2152 corresponding to the pull tab. In an exemplary use, the debonding agent or slip agent is spread in large quantities on a surface (such as the lower surface of the top laminate 2118) and substantially prevents the film surface 2144 from adhering to the layer below it, and then forms the pull tab 2120. In one embodiment, the debonding agent or slip agent is fatty acid amide, silica, talc, calcium carbonate, erucamide and/or oleamide, and combinations thereof.

The pull-tab seal component of Figure 15 may also include other layers. Those shown in Figure 15 are merely exemplary and may vary. For example, the seal may include an upper polymer support 2150 (PET, PEN, nylon, polyolefin) and optional polymer layers 2148 and 2146 (or foamed or non-foamed polymer layers to provide isolation, support, or redirect heat as needed; or any foamed polymer or non-foamed heat redistribution layer as discussed above). Layer 2144 may be a heat-bondable polymer film (EVA, EMA, polyolefin, etc.) with a segmented debonding agent or slip agent 2152 as described above. In the exemplary lower laminate, layer 2142 is an optional polymer film (PET, PEN, nylon, polyolefin, etc.), polymer foam, or non-foamed heat redistribution layer as described above. Layer 2134 may be a foil, while layer 2132 may be a heat seal layer or a pressure sensitive adhesive (PSA).

In some cases, it will be understood that the sealing components described herein function in a one-piece or two-piece sealing component configuration. A one-piece sealing component typically includes only a sealing component bonded to the container rim. A lid or closure may also be used with it. A two-piece sealing component includes a sealing component temporarily bonded to a liner, as discussed herein. In this configuration, the sealing component is bonded to the container rim, and the liner is configured to separate from the sealing component during heating so as to be retained in the lid or other closure used on the container. In a two-piece configuration, for example, a wax layer may be used to temporarily bond the upper surface of the sealing component to the liner. During induction heating, the wax layer melts and is typically absorbed into the liner. Thus, the liner is separated from the sealing component. The liner then typically remains in the lid, while the sealing component typically remains adhered to the container rim. Other types of detachable layers (besides wax) may also be used to provide a temporary bond between the seal and the liner. Any exemplary tab-type sealing component of the present invention may also be combined with a liner bonded to the top surface of the tab-type sealing component with wax. In some cases, there may be a paper layer as the top layer in the lower laminate, and it absorbs the wax, and the liner is foam.

An example of such a two-piece assembly is shown in Figures 16 and 17, which show a two-piece pull-tab seal 10 with a wax layer 90 bonded to an absorbent pad 92. It should be understood that any pull-tab seal herein can be constructed in this manner, and the structure in Figure 16 is not limiting but merely exemplary. Figure 17 also shows another form of pull-tab seal, using the aforementioned folded, wrapped or cylindrical separation layer 100 and no other upper laminate (except one of the separation layers 100 herein), so that the upper portion 102 of the separation layer 100 forms a pull-tab 20 without other structures. In the embodiment of Figure 17, it is shown as a two-piece seal and liner, but it will be understood that the pull-tab seal of Figure 17 can also be bonded without a liner and wax. In this embodiment, the separation layer 100 can include any of the features previously discussed in Figures 2, 3, 4, 5 and 7.

The tab seal of Figure 17 may also include a foamed polymer or non-foamed heat distribution layer below the separation layer 100 and above the foil 114. This alternative structure is shown in Figure 17a. In Figures 16, 17 and 17a, the other layers are consistent with those described above and, therefore, will not be discussed further here.

FIG18 a shows another exemplary method for forming a separator or layer 100 suitable for use with any of the present invention's tab seal configurations. Here, a film 2000 is formed that includes an extruded and integrally defined cavity 2001 within an extruded film. The cavity 2001 can be bubbles, air pockets, voids, or the like spaced apart around the polymer film. The pockets 2001 extend across the film in the form of a lane or strip, either laterally or longitudinally. The film 2000 of FIG18 a can then be inserted into a laminate sheet, such as sheet 1000 replacing the separator 100, and when die-cut, form the tab seal of FIG18 b. When the tab seal is die-cut, this exemplary tab seal or laminate is produced. The laminate of FIG18 b can include a polymer support 2108 (PET, PEN, nylon, or polyolefin), a foil 2114, an optional polymer layer 2116, and a heat seal or PSA 2118. However, it should be understood that any of the pull-tab seal components described herein may utilize the cavity separation layer film 2000 in place of the separation layer 100 previously discussed.

Figure 19 shows another laminate comprising PET 3000 bonded to EVA 3001, with a spacer layer 3002 positioned between the EVA 3001 and the PET 3000. In this manner, the PET and EVA are bonded together on opposite sides of the spacer layer. The spacer layer is not bonded to either the PET or the EVA.

Now describing in more detail the various layers described in the examples above, any of the structural polymer layers mentioned (e.g., 108, 116, 130, 1150, 1148, 1146, 2146, 2150, 2148, 2142) can be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon or other structural polymer layers, and in some embodiments, can be about 0.5 to about 5 mils thick, and in other embodiments, about 1 to about 3 mils thick. In other embodiments, these layers can be non-foamed polyolefin polymers. The polymer support layer can be selected from a plurality of suitable non-foamed materials that can provide structural support at relatively thin thicknesses. For example, the polymer material can be a uniaxially oriented polymer or a biaxially oriented polymer, such as uniaxially oriented polypropylene and biaxially oriented polypropylene. The support layer can also be a copolymer and/or a blown film layer. In one embodiment, the support layer can be oriented only in the transverse direction. In some embodiments, these axially oriented polymers can have a modulus of elasticity in the machine direction of greater than about 2,000 N/ ^mm² . In other cases, the film can have a modulus of elasticity in the transverse direction of about 4,000 N/ ^mm² or greater. Some films can be biaxially oriented and have both the machine and transverse elastic moduli mentioned above.

There may also be an adhesive layer (not shown) to bond the layers together. For example, a thin adhesive layer (not shown) may also be used to secure the layers together as needed for a particular application and may be, for example, about 0.2 to about 0.5 mil (or less) adhesive such as coated ethylene vinyl acetate (EVA), polyolefins, 2-component polyurethanes, ethylene acrylic acid copolymers, curable two-part urethane adhesives, epoxy adhesives, ethylene methacrylate copolymers, and similar adhesive materials.

The laminate may also include a polymer foam layer, such as layer 109, 1148, 1146, 2148, or 2146. For example, the polymer foam may be a polyethylene foam layer. Other suitable polymer foam materials include polypropylene or propylene-ethylene copolymer. Polyethylene foam is preferred because it has the required bonding properties and bond strength to the foil layer. The thickness of any foam layer can be at least about 0.003 inches, more preferably at least about 0.005 inches, and in some embodiments, about 0.003 to about 0.010 inches. If the thickness is too thin, the heat of the induction sealing process will melt the foam. In addition, the desired bond strength may not be achieved. Furthermore, if the foam is too thin, it will provide less compression, and the bond obtained by induction heating will become less reliable. When the foam thickness is greater than about 0.010, or even 0.008 inches, the benefits begin to cease, and the cost and bulk of the material can cause problems in the case of induction bonding processes. In some embodiments, the polymer foam layer may have an internal burst strength of about 2000 to about 3500 grams per inch. In some embodiments, the foamed polymer layer may also have a density of less than 0.6 g/ml, and in some cases, from about 0.4 to less than about 0.6 g/ml. In other embodiments, the density may be from about 0.4 g/ml to about 0.9 g/ml. In other embodiments, the foamed polymer layer may be from about 1 to about 5 mils thick.

The pull-tab sealing component can also include a non-foamed heat redistribution or heat distribution layer, which can be layer 109, 1148, 1146, 2148 or 2146. The non-foamed heat distribution layer can be a non-foamed heat distribution polyolefin film layer. In one embodiment, the non-foamed heat distribution polyolefin film layer is a blend of polyolefin materials, such as a blend of one or more high-density polyolefin components combined with one or more lower-density polyolefin components. Suitable polymers include, but are not limited to, polyethylene, polypropylene, ethylene-propylene copolymers, blends thereof, and copolymers or blends with advanced alpha-olefins. In one embodiment, the non-foamed heat distribution polyolefin film layer is a blend of about 50% to about 70% of one or more high-density polyolefin materials, and the rest is one or more low-density polyolefin materials. The blend is selected to obtain an effective density to provide a heat seal to the container and to separate the liner from the seal in one piece.

In one embodiment, the effective density of the non-foamed heat-distributing polyolefin layer can be between about 0.96 g/ml and 0.99 g/ml. Densities above or below this range may yield unacceptable results because the layer provides too much insulation or fails to distribute heat effectively. Alternatively, the non-foamed heat-distributing layer can be a blend of about 50% to about 70% high-density polyethylene in combination with low- to medium-density polyethylene to effectively achieve the above density range.

Additionally, the effective thickness of the non-foamed heat distribution layer is selected to achieve this performance in combination with density. One effective thickness approach may be from about 2 to about 10 mils. In other approaches, such a layer may be from about 2 to about 5 mils thick, in other approaches, from about 2 to about 4 mils thick, and in still other approaches, from about 2 to about 3 mils thick. Thicknesses outside of this range are unacceptable because the layer may not provide adequate insulation or effectively distribute heat as needed to achieve the dual performance characteristics of gasket separation and seal adhesion.

Suitable adhesives, hot melt adhesives, or sealants for the heat sealable layer of the bottom layer (e.g., layers 118, 1132, 2118, 2132) may include, but are not limited to, polyester, polyolefin, ethylene-vinyl acetate, ethylene-acrylic acid copolymer, sarling resin, and other suitable materials. In one embodiment, the heat sealable layer of the bottom layer may be a monolayer or multilayer structure of approximately 0.2 to approximately 3 mils thick. In some embodiments, the heat sealable layer may be selected to have a composition similar to that of the container, and/or may include the same polymer type as that of the container. For example, if the container comprises polyethylene, the heat sealable layer will also comprise polyethylene so. If the container comprises polypropylene, the heat sealable layer will comprise polypropylene so. The combination of other similar materials is also possible.

In one embodiment, any film or foil layer (such as layer 114, 1134, 2114 or 2134) can be one or more layers configured to provide induction heating and barrier properties to the seal. A layer constructed to provide induction heating is any layer that can generate heat when exposed to an induced current, wherein eddy currents in the layer generate heat. In one embodiment, the film layer or foil layer can be a metal layer, for example, aluminum foil, tin and the like. In other embodiments, the film layer can be a polymer layer combined with the induction heating layer. The film layer can also be or include an atmospheric barrier layer, which can slow down the migration of gas and moisture at least from the outside to the inside of the sealed container, and in some cases, also provide induction heating at the same time. Therefore, the film layer can be one or more layers configured to provide such functions. In one embodiment, the foil or film layer is a metal foil of about 0.3 to about 2 mils, such as aluminum foil, which can provide induction heating and act as an atmospheric barrier.

Adhesive layer or heat activated adhesive layer (for example, 110,1144,2144 and 3001) can comprise by heat activated or heating and realize any polymeric material of bonding characteristic.In a kind of mode, this heat activated adhesive layer can have the density of about 0.9 to about 1.0 gram/milliliter and the peak melting point of about 145 ° F to about 155 ° F.The melt index of adhesive layer can be about 20 to about 30 grams/10 minutes (ASTM D1238).Suitable example comprises ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA), polyolefin, 2-component polyurethane, ethylene acrylic acid copolymer, curable two-part urethane adhesive, epoxy resin adhesive, ethylene methacrylate copolymer, their combination and similar bonding material.

In one embodiment, the heat-activated adhesive layer is EVA. Generally, EVA is effective for heat-activated adhesive layers due to its heat-bonding properties, allowing it to easily bond to layers and form a bond to the layers that is stronger than the internal breaking strength mentioned above. In one embodiment, the heat-activated adhesive layer may have a vinyl acetate content of about 20% to about 28%, with the remaining monomer being ethylene, in order to achieve bond strength and, in some cases, internal breaking strength to provide the improved seal described herein. A vinyl acetate content below 20% is insufficient to form the strong structure described herein. As mentioned above, the heat-activated adhesive layer may have a selected thickness relative to the total thickness of the upper laminate to help achieve the sealing function. If the heat-activated adhesive layer is too thick when the foamed polymer layer is positioned above it, it will be difficult to achieve a satisfactory bond, and if there is too much volume or mass of the heat-activated adhesive layer, it will easily seep out of the seal during subsequent induction or conduction heating. If the heat-activated adhesive layer is too thin, the bond strength to the lower laminate will be insufficient, causing the pull tab to be peeled off the lower laminate when the seal is removed. If the adhesive layer is too thin, the tab will not have sufficient internal strength to prevent tearing. In one embodiment, the adhesive layer can be about 0.5 to about 2 mils thick, in other embodiments, about 0.5 to about 1.5 mils, and in other embodiments, about 0.5 to about 1.0 mils. However, as needed for a particular application, the thickness can be varied to achieve the desired bond and internal strength.

The layers of the sealing component are assembled via a sheet of the layers described in a thermal lamination process. Adhesive coating and/or extrusion lamination can also be used. During lamination, heat is applied to the mesh to activate the various heat-activated layers in the laminate structure to form the sealing component. The final laminate sheet of the sealing component can be cut into disks or other shapes of appropriate size as needed to form a container closure assembly or a pull-tab sealing component. Punching generally cuts through each separation layer 100 so that the separation layer forms a grip pull-tab. The cut sealing component is inserted into a lid or other closure, which in turn is applied to the neck of the container for sealing. A screw cap can be screwed onto the open neck of the container, thereby clamping the sealing component between the open neck of the container and the top of the lid. Then heating or induction current or other sealing methods are applied to the bottom subassembly of the layer of the sealing portion that forms the neck of the container.

It should be understood that the details, arrangements of materials and processes, laminates, laminate/substrate assemblies, and combinations thereof are described and illustrated herein for purposes of explaining the properties of the present product and method, and that variations therein may be made by one skilled in the art within the principles and scope of the embodied product and method as expressed in the appended claims. For example, laminates and assemblies may include additional layers in the laminates and various layers shown and described as needed for specific applications. If desired, adhesive layers, not shown in the figures, may also be used to secure the various layers together. Unless otherwise indicated herein, all parts and percentages are by weight.

Claims (21)

1. A pull-tab seal for bonding to an annular edge surrounding a container opening, the pull-tab seal comprising: The lower component includes at least a sealing layer for bonding to the circumferential edge of the container; An upper component, the upper component comprising one or more layers and partially bonded to the lower component, and including a free portion of the upper component not bonded to the lower component; A bend joint, formed by partial bonding between the upper and lower components, allows the free portion of the upper component to pivot away from the lower component to form a gripping pull tab; and A folded sheet having a first fold, a second fold, and a dead fold, wherein the first fold is bonded to the free portion of the upper component, the second fold is bonded to the portion of the lower component below the free portion, the dead fold is aligned with the bend, and the inner surface of the first fold is not bonded to the inner surface of the facing second fold. The folded sheet is asymmetrical, with one of the first or second folds extending to the periphery of the pull tab seal, and the other of the first or second folds having a distal end spaced apart from the periphery of the pull tab seal. 2. The pull-tab sealing component as claimed in claim 1, wherein the folded sheet is a polymer film comprising one or more polymer layers. 3. The pull-tab sealing component as claimed in any of the preceding claims, wherein the folded sheet is non-tubular. 4. The pull-tab sealing component of claim 3, wherein the folded sheet comprises an inner polymer layer and an outer polymer layer, the outer polymer layer being a thermally activated polymer and forming an adhesive between the first fold and the free portion of the upper component, and forming an adhesive between the second fold and the portion of the lower component below the free portion. 5. The pull-tab sealing component of claim 4, wherein the inner polymer layer is polyethylene terephthalate and the outer polymer layer is one of the following: ethylene vinyl acetate, ethylene methyl acrylate, polypropylene, polyethylene, polyurethane and copolymers thereof. 6. The pull-tab sealing component as claimed in claim 5, wherein the inner layer is a polymer having a melting point and the outer layer is a polymer having a melting point lower than that of the inner layer. 7. The pull-tab sealing component as claimed in claim 5, wherein one of the inner folded layer or the outer folded layer is a foamed polymer. 8. The pull-tab sealing component as claimed in claim 4, wherein one of the inner folded layer or the outer folded layer is a foamed polymer. 9. The pull-tab sealing component as claimed in claim 1 or 2, wherein the folded sheet comprises an inner polymer layer and an outer polymer layer, the outer polymer layer being a thermally activated polymer and forming an adhesive between the first fold and the free portion of the upper component, and forming an adhesive between the second fold and the portion of the lower component below the free portion. 10. The pull-tab sealing component of claim 9, wherein the inner polymer layer is polyethylene terephthalate and the outer polymer layer is one of the following: ethylene vinyl acetate, ethylene methyl acrylate, polypropylene, polyethylene, polyurethane and copolymers thereof. 11. The pull-tab sealing component of claim 9, wherein the inner layer is a polymer having a melting point and the outer layer is a polymer having a melting point lower than that of the inner layer. 12. The pull-tab sealing component of claim 9, wherein one of the inner folded layer or the outer folded layer is a foamed polymer. 13. The pull-tab sealing component as claimed in claim 1 or 2, wherein the folded sheet comprises a porous polymer membrane. 14. The pull tab sealing component as claimed in claim 1 or 2, wherein the first fold is thermally welded to the second fold. 15. The pull-tab sealing component as claimed in claim 1 or 2, wherein the lower component comprises one or more of the following: a foil layer, a polymer support layer, a foamed polymer layer, and a non-foamed heat distribution layer. 16. The pull-tab sealing component as claimed in claim 1 or 2, wherein the upper component comprises one or more of the following: a foil layer, a polymer support layer, a foamed polymer layer, a non-foamed heat-distributing layer, and a heat-bonding polymer layer. 17. The pull-tab sealing member as claimed in claim 1 or 2, wherein the top surface of the upper member is wax bonded to the gasket. 18. The pull tab sealing member as claimed in claim 1 or 2, further comprising a partial layer between the upper member and the lower member, forming a partial bond between the upper member and the lower member. 19. The pull-tab sealing component of claim 18, wherein the thickness of the partial layer is consistent with the thickness of the folded sheet when folded. 20. The pull-tab sealing component of claim 1, wherein the folded sheet includes a plurality of micropores, the size of which allows air to pass from the inside of the folded sheet to the outside of the folded sheet. 21. A laminated sheet configured to form a pull-tab type sealing member as described in any of the preceding claims.