Patent Description:
Seals have been used on containers for many years, to prevent leakage or contamination of the substance within the container and to increase the shelf life of the product. For example, seals are used on containers for cosmetics, foods, drinks, medicines and other items in the form of creams, gels, powders, or liquids. Seals used for this purpose are typically placed over the opening of the container or, in some instances, within the cap on the container.

However, consumers often want to smell items having a fragrance or aroma, such as lotions, creams, body washes, shampoos, deodorants, perfumes, laundry detergents, air fresheners, coffee and spices, before purchasing the items. As a result, many products are sold today without seals because there is no commercially viable seal on the market that allows consumers to smell the scent of the product within the container. Specifically, prior art seals are essentially hermetic seals intended to prevent leakage of the product from the container and to limit air flow into and out of the container to preserve the product and maximize the product's shelf life. In so doing, they trap the scent or aroma of the product within the container.

As a result, scented products are often sold in containers without seals, so that consumers can remove the cap and smell the scent prior to purchase. The fact that many scented products are still sold in containers without seals today is evidence that the prior art seals do not allow adequate scent permeation and prevent leakage in a cost effective manner.

The absence of a seal increases the possibility of spillage during transportation and the chances that a product may be tampered with or tainted prior to sale to the consumer. It is not uncommon for consumers to go beyond simply removing the cap and smelling the item, by actually applying some of the product onto their body to sample the product and its fragrance. In so doing, the consumer may stick their fingers into the substance or on the opening where the substance comes out. Oftentimes, after sampling the product, the consumer closes the cap and returns the container to the shelf in the store.

This sampling of the product causes several problems. From the consumer's perspective, by placing their fingers into the substance and/or coming in contact with the opening where the substance comes out, the sampler may be contaminating the substance and spreading germs/bacteria. Additionally, each time a consumer samples the product and then returns it to the shelf, the volume of the substance within the container decreases. As a result, the consumer that eventually purchases the product is unknowingly purchasing less than a full container of a product that may have been contaminated and/or contain germs/bacteria.

From the retailer's perspective, consumers that sample products and then return them to the shelf sometimes do not place the cap on tightly, which may result in spillage if the container is tilted or falls on its side. Additionally, the shelf life of the substance within the container may be reduced or altered by the absence of a seal on the container or having been opened and exposed to the surrounding environmental conditions by a sampling consumer prior to sale. Also, the absence of a seal on a container may result in the substance contacting and/or accumulating within the cap on the container, which may cause spillage when the cap is removed and a less appealing presentation to the consumer. These situations may result in the retailer being unable to sell the product or generating product returns or charge-backs, which may have an adverse effect on the retailer's, product manufacturer's or distributor's reputation and financial performance. Additionally, the retailer, manufacturer and/or distributor may incur liability if a consumer is harmed by the contaminated product.

<CIT> discloses an method of forming induction heat-seal liners having the features of the pre-characterising portion of claim <NUM>.

<CIT> discloses a seal for containers is provided that allows the scent or aroma from the substance within the container to come through, while preventing leakage of the substance from within the container and/or physical contact of the substance by the consumer. More particularly, a seal is provided having at least one slit scoring fewer than all of the layers of the seal. The slit(s) will allow a consumer to sniff the scent or aroma released through the slit, while the seal remains secured to the container, extending shelf life of the substance, and preventing leakage, as well as, contamination, damage and/or reduced volume caused by consumers sampling the products.

<CIT> discloses a heat seal membrane with a tab. The seal has an upper element possessing constant thickness, and a lower element positioned opposite to the upper element. The lower element comprises a reinforcing film and a heat-sealing film applied on a lip of a container, in a direction of the lip. The upper element and the lower element are associated with each other by a permanent adhesive, to form a free tab arranged in the upper element. A conductive sheet is positioned in the upper element.

The present invention aims to provide a method of forming an induction heat-seal liner that allows a scent or aroma from a product to be detected through the seal, and/or allows a visual inspection of the product to be made through the seal, while the seal remains secured to the container. The present invention provides a method of forming a plurality of individual induction heat-seal liners according to claim <NUM>.

The above and further advantages and features of various embodiments of the invention will be understood by referring to the following description in conjunction with the accompanying drawings in which:.

<FIG> illustrate one embodiment of an induction heat-seal liner <NUM> formed according to one embodiment of the method of the invention. <FIG> shows the liner components as multiple layers, prior to lamination to form the integral liner <NUM> shown in <FIG>. The liner <NUM> includes:
a top closure-facing layer <NUM>, a bottom heat-seal bonding layer <NUM>, and an intermediate metal-foil layer <NUM> disposed in a thickness direction (TD) between the top and bottom layers, the top, bottom and intermediate layers being bonded to form an integral induction heat-seal liner <NUM>, the metal-foil layer <NUM> having a central opening <NUM> surrounded by a continuous metal-foil portion <NUM> configured to lie above a container rim <NUM> surrounding an open mouth <NUM> of a container body <NUM>, and the bottom layer <NUM> having a heat-seal bonding area <NUM> configured to lie above the container rim <NUM> that is activated by heating of the continuous portion <NUM> to heat-seal bond the bottom layer <NUM> to the container rim <NUM>.

As shown in <FIG>, the multiple component layers of the unassembled liner include in serial order from top to bottom: top layer <NUM>; intermediate metal-foil layer <NUM>; and bottom layer <NUM>, the bottom layer including an upper layer <NUM> and a lower heat-seal bonding layer <NUM>. The layers <NUM>, <NUM>, <NUM> (<NUM> and <NUM>) are shown stacked in a thickness direction TD aligned with a central vertical axis CA of the container body <NUM> and closure cap <NUM>. In this embodiment the container mouth has an annular rim <NUM>, lying between a rim inner circumferential diameter RID and a rim outer circumferential diameter ROD, with the liner <NUM> having a matching liner outer circumferential diameter LOD equal to ROD of the container rim. The liner outer diameter LOD can be equal to or greater than the rim outer diameter ROD.

In various embodiments, the top, intermediate and bottom component layers <NUM>, <NUM>, <NUM> may each comprise a single layer, or multiple layers; they may include adhesive layers for adhesively laminating the layers together to form the integral liner <NUM>, as described hereinafter (adhesive layers A shown in <FIG>).

As shown in <FIG>, the liner is configured to lie between the annular container rim <NUM> and an inner top wall <NUM> of the cap <NUM>, in order to seal an open mouth <NUM> of the container <NUM>. The lower heat-seal bonding layer <NUM> has a continuous peripheral portion <NUM> that lies over and is heat-seal bonded to the rim <NUM>, the bonding being activated by induction heating of the metal-foil portion <NUM> that in turn heats the bonding portion <NUM>.

The cap <NUM> is sized to cover the open mouth <NUM> of the container <NUM>; the cap includes a cylindrical top wall <NUM> having a peripheral sidewall <NUM> extending downwardly from the outer periphery of the top wall <NUM>. The inner surface 64IS of the cap sidewall, and the outer surface 84OS of the container mouth, include complimentary threads 64THR and 84THR that are disposed in a radial space RS between 64IS and 84OS. In use, the liner <NUM> is disposed in the cap <NUM> adjacent the inner top wall <NUM>, and the cap is then twisted down onto the container rim <NUM> by threadably engaging 64THR and 84THR to secure the liner between the cap inner wall <NUM> and the container rim <NUM>. The sealed container <NUM> can be readily opened (e.g. by the consumer) by untwisting the cap (in the opposite direction) to unthread 64THR and 84THR, allowing the consumer to remove the cap and then remove the heat-seal liner <NUM> by peeling the liner from the rim (this later step may be aided by providing a pull tab (e.g., <NUM> as shown in <FIG>) on the liner to facilitate grasping the liner and pulling it away from the container rim).

The liner of the present embodiment provides a number of advantageous features that will now be described. One feature of the liner is to provide the metal-foil layer <NUM> with a central opening <NUM> (a through hole in the thickness direction TD); this positions the peripheral metal-foil area <NUM> (surrounding the central opening <NUM>) where it is most useful for induction heating, i.e., over the container rim, and reduces the amount of metal foil material required. The central opening <NUM> in the foil also enables the liner to be see-through, wherein the user can view (visually detect) the contents (product P) in the sealed container, without removing the heat-seal liner <NUM> from the container rim <NUM> (as shown in <FIG>). This may be advantageous for sale or display purposes, e.g., allowing a visual inspection of the product prior to purchase, without removal of the seal (and avoiding contamination of the product by a prospective purchaser). To provide this feature, the other layers of the liner (i.e., top and bottom layers <NUM> and <NUM>) of the liner, or at least a central viewing area CVA of the other layers that overlie the central opening <NUM>, must also be made of materials that allow visibility into the sealed container. Another beneficial feature is to provide a liner that allows an aroma from the product to pass through the central opening <NUM> and the CVA of the other layers <NUM>, <NUM> of the heat-seal liner. This again may be advantageous for sale or display purposes. Various materials to accomplish these purposes are described below.

As shown in <FIG>, and described below in one method embodiment for making the liner <NUM>, adhesive layers A may be provided between the top layer <NUM> and the intermediate layer <NUM>, and between the bottom layer <NUM> and the intermediate layer <NUM>, to enable adhesive lamination of all liner components to form an integral liner <NUM>. In this embodiment, the adhesive A has flowed into the central opening <NUM> during lamination, to fill the opening with adhesive 42A; this may strengthen the overall liner structure. However, to maintain the CVA (central viewing area through all liner layers aligned within OD of central opening <NUM>) the adhesive area 42A must also be of a see-through material (by see-through it is meant that a person is able to perceive (detect) with a human eye, the interior contents P of the container). Similarly to allow for aroma detection by a human nose, the adhesive area 42A must provide for aroma penetration in the CVA. As noted previously, the adhesive layer(s) may be included as part of (a component layer of) any one or more or the top layer <NUM>, intermediate layer <NUM>, or bottom layer <NUM>.

<FIG> are schematic views of one method embodiment for making a plurality of liners of the type shown in <FIG>, i.e., by laminating together three component sheets that form the top, intermediate (metal foil) and bottom layers of the liner respectively. <FIG> shows a hole punch <NUM> forming the central openings <NUM> in an intermediate (metal-foil) layer sheet (<NUM>-sheet), followed by the top <NUM>-sheet, hole-punched intermediate <NUM>-sheet and bottom <NUM>-sheet layer sheets) being sent through the nip of a pair of rotating rollers <NUM> for forming a laminated composite sheet or web (<NUM>-sheet or <NUM>-web). The laminated sheet-<NUM> is then wound on a large roller <NUM> (e.g., for storage/transport prior to subsequent processing). <FIG> shows a subsequent hole punching step for forming a plurality of individual liners <NUM> by cutting completely through the thickness direction of the composite sheet <NUM>-sheet (i.e., hole punching to form the outer diameter LOD of each liner <NUM>). Alternatively, the steps of <FIG> can be combined into one sequential in-line process by eliminating the step of winding onto the large roller <NUM> prior to hole punching the individual liners.

<FIG> shows an alternative liner embodiment <NUM> (similar to <FIG>) that includes a further support layer <NUM> for structurally supporting the metal-foil layer prior to, during and/or after assembly. The view of <FIG> is similar to that of <FIG>, showing the separate component (top, intermediate, bottom) layers of the liner in a spaced-apart, vertically-aligned position (in the thickness direction TD) between the cap <NUM> and container rim <NUM>, with like layers of the liner bearing similar reference numbers but in a "<NUM>" numbering series. In this embodiment the liner <NUM> includes in serial order from top to bottom: a continuous uppermost layer <NUM>, a support layer <NUM> having a central opening <NUM> surrounded by a continuous peripheral area <NUM> (here the layers <NUM> and <NUM> together comprising a top layer <NUM>); an intermediate metal-foil layer <NUM> having a central opening <NUM> and a surrounding continuous metal-foil peripheral area <NUM>; and a bottom layer <NUM> (including an upper layer <NUM> and a lower layer <NUM>, the same as in the <FIG> embodiment). In various embodiments, the support layer <NUM> can be provided above or below the metal-foil layer <NUM>, and can be a component of any of the top, intermediate or bottom layers as desired by a particular application.

Providing the support layer <NUM> with a central opening <NUM> enables benefits both in the final (laminated) liner assembly <NUM>, such as preventing wrinkling or tearing of the metal-foil layer <NUM>. It also provides benefits during manufacture, e.g., in the process of <FIG> (described further below), starting with a sheet of a support layer material and a sheet of a metal-foil material in planar, face-to-face engagement (together comprising the intermediate <NUM>-sheet of <FIG>), the two sheets can be hole-punched at the same time by initial hole punch <NUM> forming central openings <NUM>, <NUM>, in both the support layer <NUM> and metal-foil layer <NUM> simultaneously.

In one embodiment, a polymer film (forming support layer <NUM>) can be applied to one surface of a metal-foil sheet (forming metal-foil layer <NUM>) by an adhesive lamination process, e.g., use of a solvent adhesive to bond the layers. The central openings <NUM>, <NUM> in both the support layer <NUM> and the metal-foil layer <NUM> can be the same size as the rim inner diameter RID, or can be less than RID (e.g., the size can be adjusted depending on the desired visibility through the liner, and/or aroma penetration through the liner, based on the various material properties and dimensions of the liner layers).

<FIG> illustrate an alternative embodiment, referred to as a dual heat-seal liner, configured to be induction heat-sealed on its opposing top and bottom faces to the cap interior top wall and the container rim (e.g., during the filling/capping step at the product filler) to form a non-removable closure assembly. Containers with a non-removable closure (cap/liner) assembly, are commonly used for food products such as ketchup, mayonnaise, salad dressing and other products that can be conveniently packaged and dispensed through a dispensing aperture of a squeezable container assembly without removing the closure. In the embodiment of <FIG>, the dual-heat seal liner <NUM> includes at least one central opening <NUM> extending in the thickness direction TD through all component layers <NUM>, <NUM>, <NUM> so as to form a dispensing aperture <NUM> extending through the entire thickness of the liner <NUM>. This liner can be used with a cap <NUM>, as shown in <FIG>, also having a dispensing aperture <NUM>, wherein the cap <NUM>, liner <NUM> and container <NUM> together form the non-removable closure assembly configured to be used (by the consumer) to dispense a product P held in the container body <NUM> without removal of the cap <NUM> or of the induction heat-seal liner <NUM>. The cap has a hinged closure lid <NUM>, such as a flip top, for closing the dispensing aperture <NUM> when not in use (and to protect the product P from spoilage). Typically the manufacturer does not want the container to be re-filled, and thus the liner includes, in addition to the heat-seal bottom layer <NUM> for induction heat-seal bonding to the container rim <NUM>, a heat-seal top layer <NUM> for induction heat-seal bonding to the inner top wall <NUM> of the cap, rendering the cap non-removable from the combined (dual induction heat-seal bonded) cap, liner, and container assembly.

<FIG> shows one method of making the dual-seal liner <NUM> of <FIG>. A sequential in-line process is shown in which three layer sheets <NUM>-sheet, <NUM>-sheet, and <NUM>-sheet are provided for forming the top <NUM>, intermediate <NUM> and bottom <NUM> layers respectively. In this embodiment, an initial hole punch <NUM> forms central openings <NUM> in the intermediate (metal-foil) sheet <NUM>-sheet, the three sheets are then fed between a pair of rotating rollers <NUM> to laminate the sheets together to form a composite sheet or web <NUM>-sheet, and then at least one common liner ID hole punch <NUM> forms the liner inner diameter through all three sheet layers (to form the liner ID). Subsequently a further liner OD hole punch <NUM> is used to form the liner outer diameter LOD for a plurality of liners <NUM>. In various embodiments, the outer diameter LOD of liner <NUM> and the liner inner diameter LID (of central opening <NUM>) can be made (e.g., punched) either simultaneously (e.g., by using a single liner ID/OD hole punch <NUM> as shown in <FIG> with inner and outer cutting rings to form the inner and outer liner diameters of the annular liner), or sequentially (typically punching <NUM> first and <NUM> second) as in <FIG> with hole punches <NUM>, <NUM>.

Also advantageous in this embodiment, the metal-foil layer <NUM> can have an initial central opening <NUM> that is larger (e.g., of greater diameter) than the common central opening <NUM> (liner ID), and the material(s) of the top and/or bottom layers <NUM>, <NUM> (or adhesive A forming part of those layers) is then allowed to flow into or otherwise fill the space defined by the initial central opening <NUM> (in the metal-foil layer <NUM>), so as to fully or partially fill that space with adhesive 242A. The fully or partially filled space provides an area that surrounds the periphery of the central opening <NUM> in the metal-foil layer <NUM>, in order to prevent the product P that is being dispensed through the common central opening <NUM>, from reaching the metal-foil peripheral portion <NUM> of layer <NUM>. This prevention (of product to metal-foil contact) will reduce the damaging effects of such contact which may include one or more of corrosion of the metal-foil layer, delamination of the liner layers, and/or a defective heat-seal bond with the container rim or the inner top wall of the cap.

The liners described herein may be manufactured from various materials and by various methods to achieve the aforementioned advantages.

As used herein the top, bottom and/or intermediate layers may be single layer or multi-layer embodiments, wherein one or more layers is provided as a coating layer, and/or one or more layers are continuous or less than continuous across the liner area (in a direction transverse to the thickness direction).

In various embodiments, the top, bottom and/or intermediate layers may include one or more polymer materials, such as polyolefins (e.g., polypropylene (PP) or polyethylene (PE) based polymers), polyesters (e.g., polyethylene terephthalate (PET) based polymers), polyamides (e.g., nylon based polymers), including copolymers, and blends thereof. Furthermore, one or more paper layers may be present.

In various embodiments, the metal-foil layer may be formed of one or more of metals, such as aluminum (Al), tin, copper or steel.

The liner may be formed by any one of various lamination methods, including adhesive lamination, extrusion lamination or thermal lamination (without adhesives). For adhesive lamination, the adhesive layers may comprise one or more of the top, bottom or intermediate layers, adjacent to the intermediate metal-foil layer, and/or between other layers of a multi-layer structure. The adhesive (glue) can be applied to the top or bottom layers, e.g., a PET heat seal layer, or to a polypropylene layer. It may be less preferred (e.g., more difficult) to apply adhesive to the metal-foil layer because of the central opening.

The induction heat-seal bonding material may be included in the top and/or bottom layers as a surface layer, e.g., as a solvent coating to a base film (e.g., DuPont Teijin Mylar CL Polyester Film), as an extrusion coating to a base film (e.g., as a hot melt adhesive), or as a distinct layer. The induction heat-seal bonding materials may comprise one or more polymer materials that bond in a temperature range of from <NUM> to <NUM> degrees Celsius. Representative materials include polyolefin, polyester and nylon materials. Typically the heat-seal material is a continuous layer across the entire liner area (transverse to the thickness direction TD); however it can be a partial layer that is applied only to the liner periphery where needed to bond to the container rim (i.e., a continuous peripheral area around the periphery of the liner).

The material used for the cap and container will depend upon the particular application. In one embodiment, the cap is made of polypropylene (PP), and the container is made from polyethylene terephthalate (PET), polypropylene (PP) or polyethylene (PE). The container may be made from an injection molded preform, the body portion of which is blow molded to form the container body. The rim may have an OD in a range of <NUM>-<NUM>, and a wall thickness in a range of <NUM> to <NUM> inch (i.e. <NUM> to <NUM>). For the non-removable closure embodiment, the dual heat-seal bonded cap, liner and container assembly can preferably withstand a torque or at least <NUM> inch-pounds, and more preferably <NUM> inch-pounds, without loss of the dual heat-seal bonds or distortion of the cap or container.

In one adhesive lamination method embodiment, the three component layers (top, intermediate, bottom) of the liner can be laminated in one step, by first applying adhesive to the top and bottom layers and sending all three layers (with the hole-punched metal-foil intermediate layer in the middle) through a nip of a pair of rotating rollers as shown in <FIG> or <FIG>. Alternatively, a sequential process can be used to join the layers.

In one heat lamination method embodiment, a support film of PET/EAA can be used (e.g., Dow Primacor Ethylene Acrylic Acid) that adheres well to Al foil to form the intermediate layer. All three layers (top and bottom, with the intermediate layer in between) are then sent through a nip of a pair of rotating rollers as shown in <FIG> or <FIG>, while applying heat and pressure to form the integral liner.

The shape of the container rim, and complementary liner shape, is not required to be disc (circular) or annular (ring-shaped). Other rim shapes can be utilized, including any multi-sided shape with straight or curved sides, having sharp or rounded junctions between the sides. Another embodiment shown in <FIG>, similar to the <FIG> embodiment. The <FIG> embodiment includes a cap <NUM>, liner <NUM>, and container <NUM> assembly where the container rim <NUM> and the liner <NUM> are generally rectangular in shape (in cross section transverse to the thickness direction TD), with two opposing relatively straight right and left outer side edges 393A and 393B, two opposing outwardly-bowed front and rear outer side edges 394A and 394B, and rounded corners <NUM> there between. The liner includes a pull tab <NUM> as previously mentioned to assist in removing (pulling) the liner <NUM> off of the container rim <NUM> to access the product P held in the container body <NUM>. The container <NUM> is designed to hold an aromatic product, and the scent of the product (held in the container body) can be detected (by a human nose) through a CVA of the liner (defined by inner edge 340IE of the intermediate metal-foil layer <NUM>). Here the CVA may allow just aroma detection, or alternatively can allow both visual detection and aroma detection of the product in the container (through the CVA of the liner), or just visual detection. <FIG> shows the metal-foil intermediate layer <NUM>, having a central opening <NUM> surrounded by a peripheral metal-foil area <NUM>, the latter for activating heating of the heat-seal bonding material <NUM> for bonding to the container rim <NUM>.

Claim 1:
A method of forming a plurality of individual induction heat-seal liners (<NUM>; <NUM>) comprising:
a) providing top (<NUM>; <NUM>), intermediate (<NUM>; <NUM>) and bottom (<NUM>; <NUM>) sheets for forming top (<NUM>; <NUM>), intermediate (<NUM>; <NUM>) and bottom (<NUM>; <NUM>) layers respectively of a plurality of individual induction heat-seal liners (<NUM>; <NUM>);
b) laminating, by adhesive, extrusion or thermal lamination, the sheets together to form a laminated composite sheet with the intermediate sheet laminated between the top and bottom sheets; and
c) forming individual liners from the laminated composite sheet by cutting through the composite sheet in a thickness direction to form the plurality of individual induction heat-seal liners;
each individual liner being an integral liner comprising an adhesive, extrusion or thermally laminated body characterised by the top, bottom and intermediate layers of the body being bonded to form a top closure-facing layer (<NUM>; <NUM>), a bottom heat-seal bonding layer (<NUM>; <NUM>), and an intermediate metal foil layer (<NUM>; <NUM>) disposed in a thickness direction between the top and bottom layers lamination,
the metal foil layer of each individual liner having a central opening (<NUM>; <NUM>) surrounded by a metal foil portion (<NUM>; <NUM>) configured to lie above a container rim (<NUM>; <NUM>) surrounding an open mouth (<NUM>) of a container body (<NUM>; <NUM>), and the bottom layer having a heat-seal bonding area (<NUM>) configured to lie above the container rim that is activated by heating of the metal foil portion to induction heat-seal the bonding area to the container rim,
wherein the central opening in the metal foil layer is formed prior to the laminating step; and
during the laminating step one or both of the top and bottom sheets, or a layer of adhesive (A) used in adhesive lamination, fills or partially fills the central opening in the metal foil.