WO1991017093A1

WO1991017093A1 - A composite closure, disk and package

Info

Publication number: WO1991017093A1
Application number: PCT/US1991/003030
Authority: WO
Inventors: Thomas H. Hayes; Lewis C. Lomaglio
Original assignee: Anchor Hocking Corporation
Priority date: 1990-05-07
Filing date: 1991-04-30
Publication date: 1991-11-14
Also published as: ATE110338T1; EP0527844A1; AU7796491A; DE69103627D1; DE69103627T2; EP0527844B1; ES2061243T3

Abstract

Composite closures (a1) comprising molded plastic or metal closure bands or rings (4) having separate disk-like covers (10) formed with cellulosic material inserted therein are described. Cellulosic disks (10) of the instant invention are resiliently conformable to at least a portion of sealing surfaces at the rims (11) of containers (2) for forming and maintaining effective seals therewith during use or other package handling. Cellulosic disks (10) of the present invention are sufficiently resistant to deflection and penetration caused by blunt objects, such as thumbs, for maintaining physical isolation of the interior of containers (2) and product integrity to which the closures are secured. Cellulosic materials selected for forming (10) disks of the present invention are preferably newsboard. Disks (10) of the instant invention may include print layers which are in the form of images which are near or duplicate photographic quality and are produced preferably by rotogravure printing techniques. Tamper indicating bands (3) on the closure bands or rings (4) are preferably positioned for being moved to their tamper indicating positions well before removal of the composite closures (1) break the seals between the disk-like covers (10) and sealing surfaces at the rims (11) of containers (2). Composite closures (1) of the instant invention may also form freshness seals with the container rims (11) when they are secured thereto for providing a sound, feel and/or smell of freshness when the freshness seals are initially broken upon opening the sealed containers (2).

Description

A COMPOSITE CLOSURE, DISK AND PACKAGE Field of the Invention

The present invention relates to a composite closure comprising a separate disk formed with a cellulosic material inserted into a container engaging band having a retaining lip defining a central opening, and a container sealed with the composite closure.

Background

Composite closures are well known in the art and are widely used which include a plastic or metal disk-like cover portion inserted into a circular molded plastic or metal band or ring with the band or ring providing threaded or other means for attaching the composite closure to a container. A separate sealing gasket is typically provided on the metal or plastic covers for forming a seal with the rim of a container. Tamper indicating means are provided sometimes in the form of a vacuum indicator button on the metal covers or in the form of a tamper indicating band as a portion of the molded plastic band or ring.

While such composite closures have found some acceptance in various packaging uses, including vacuum packaging of food, they are not without their drawbacks. For example, prior composite closures which rely upon metal disks have proven to be very costly and in some cases unsatisfactory especially when food packages are involved. Typically, metal disks employed with food packages are known to corrode and rust unless first treated with a protective coating. Metal disks also require the addition of a sealing gasket in order to form a proper seal between the disks and the rims of the containers. Still further, because metal disks are punched from metal sheets, litho line printing is currently relied upon to impart print layers in the form of for example images on the metal disks. Unfortunately, the quality of litho line printing is generally inferior, espe- cially as when compared to the quality of printing associated with process printing currently utilized on non-metal, rollable stock materials, such as paper or film. Moreover, the costs associated with printing on metal disks is generally expensive since each color printed thereon requires its own corresponding curing.

Composite or unitary plastic closures also present problems. For example, food containers sealed with unitary plastic closures or composite closures formed with molded plastic or metal rings and plastics disks typically have limited shelf life stability because of the porous nature of the plastic materials. Another problem presented by such plastic closures and in particular unitary plastic closures is that they are susceptible to what is known in the industry as "creep" or "back off," which is loss of seal security over time. It is believed that such plastic closures experience "creep" or "back off" following torquing due to the inherent relaxation properties of the plastic materials utilized to form such closures. Plastic disks, like metal disks and unitary plastic closures, also require the addition of a separate sealing gasket so that a proper seal can be formed between the plastic cover and a container rim. In addition, like metal disks, plastic disks are punched from plastic sheets. Consequently, litho line printing techniques are also relied upon to impart graphics onto the plastic sheets. The costs and quality associated with litho line printing techniques on plastic sheets are generally more expensive and inferior in quality as when compared to process printing costs and quality on non-plastic, rollable stock materials, such as paper or films. Unfor¬ tunately, unitary or composite plastic closures are likewise expensive to manufacture and in some cases unsatisfactory in performance.

With respect to composite closures which rely upon glass disks, they too are not without drawbacks. While glass disks are generally impervious to oxygen and function as good oxygen barriers, they require a sealing gasket, add excessive weight to the closures and containers sealed therewith, are general¬ ly susceptible to breakage and require individualized graphics, all of which prove to be very costly.

Consequently, there is a strong commercial need for a composite closure formed with a band or ring and a disk-like cover which is inexpensive to produce, yet during normal use and storage has the ability to form and maintain an effective seal with a container rim, has sufficient resistance to deflec¬ tion, breakage and penetration for maintaining phys¬ ical isolation of the interior of a container when sealed with the composite closure, has the ability to function as a good barrier, and has a print layer which preferably nears photographic quality.

Summary of the Invention

In brief, the present invention seeks to alleviate the above-mentioned problems and short¬ comings of the present state of the art through the discovery of novel composite closures and packages sealed therewith. Generally speaking, a novel compos¬ ite closure includes a disk-like cover formed with a cellulosic material inserted into a closure band or ring provided with a retaining lip which defines a central opening for sealing or closing the central opening when the composite closure is assembled and secured with or without vacuum to a container. The novel composite closures of the instant invention are suitable for sealing various types of complimentary non-food and food containers including those food containers wherein the vacuum is induced by steam.

A disk or cover of the present invention is uniquely resiliently conformable to the rim of a container when the composite closure is secured to the container for forming and maintaining an effective seal therewith. Moreover, a disk or cover of the instant invention is sufficiently resistant to deflec¬ tion induced by for example blunt objects, such as a thumb, and is sufficiently resistant to penetration by similar blunt objects for maintaining physical isola¬ tion of the interior of a container including the contents therein when a composite closure of the instant invention is secured to a container. In addition, a disk or cover of the present invention may include a print layer in the form of an image which nears or duplicates photographic quality and imagery. The print layer may be, for example, positioned directly on the surface of a disk, onto a separate paper laminated to a disk, or reverse printed on a protective transparent layer likewise laminated to a disk. In a further feature, a disk or cover of the instant invention may be constructed with a cellulosic material in the form of a single layer or a plurality of layers laminated to one another via a suitable adhesive. While lamination techniques to form the discs or covers are preferred, the disks or covers can be constructed by other techniques such as spin welding, chemical treatment and fusion techniques. It has been surprisingly discovered that when a disk or cover of the instant invention is constructed with a plurality of such layers an unexpected increase in strength is imparted to such a disk or cover as compared to a disk or cover formulated with a single layer of equal thickness. Examples of cellulosic materials for use in accordance with the instant invention include chipboard, fiberboard, newsboard, paperboard, pulpboard and the like.

In still another feature of the instant invention, a disk may be constructed with additional layers of materials depending of course upon the ultimate use of the composite closure with which such disk or cover is used. For instance, in the packaging of food, a disk or cover of the instant invention may be edge coated and further constructed with an oxygen and/or moisture barrier layer, such as a poly- vinylidene chloride coating, a wax layer and/or an inner seal layer such as glassine, foil or a plastic film, all of which are customary in the trade.

Moreover, a disk or cover of the instant invention may further include a rigid plastic or metal layer for imparting additional strength and toughness thereto. To construct the disks or covers of the instant invention, the layers selected to formulate the composite disks or covers are preferably laminated to one another to first form a rollable composite laminate which is then die cut into appropriately sized disks or covers preferably at the point of lamination. The ability to pre-cut the disks or covers of the instant invention at preferably the point of lamination and prior to assemblage uniquely provides for a higher yield of the number of disks or covers cut from the composite laminates. From an aesthetic standpoint, and depending upon the use of the composite closure, it may be desirable to edge coat the raw edges of the pre-cut disks or covers of the instant invention since, when assembled, the disks or covers are visible from the tops of the composite closures. The pre-cut disks or covers can be collected and, if desired, their raw edges coated with a selected material and in particular a moisture impervious material, such as silicone, wax or the like, via rolling or spraying techniques. By edge coating the raw edges, this prevents wicking of oils, moisture or other contami- nants into the laminate structure via the uncoated raw edges which can cause discoloration, since the exte¬ rior surfaces are visible from the top of the assem¬ bled composite closures, and other undesirable effects like swelling or delamination, especially in vacuum induced steam environments.

It should be realized, however, that because a disk or cover of the instant invention is con¬ structed with an inexpensive cellulosic material which is resiliently conformable to the rim of a container for forming an effective seal therewith, the necessity for providing a separate sealing gasket as with metal and plastic disk-like covers or unitary metal or plastic closures available heretofore has been elim¬ inated. In addition, it should be realized that since a disk or cover of the instant invention is preferably constructed without metal or glass, the problems of corrosion, rust, breakage and weight commonly associ¬ ated with these types of disks, respectively, have likewise been eliminated. It should also be realized that the initial torque required to remove the com¬ posite closures of the instant invention from con¬ tainers is reduced as when compared to unitary closures, since it is not required to simultaneously break the thread engagement and seal engagement when initially opening containers sealed with composite closures of the instant invention. Rather, when removing the composite closures of the instant inven¬ tion from containers sealed therewith, the thread engagement typically will be first broken followed by a breakage of the seal engagement formed between the composite closures and containers. Still further, it should be realized that the porous, relaxation and creeping shortcomings normally associated with rigid plastic materials utilized to manufacture plastic closures have also been substantially eliminated by the unique composite closures of the instant inven- tion. And, as a further significant advantage unavailable heretofore, process printing techniques, such as rotogravure printing techniques, can now be relied upon to position a print layer of photographic quality on a disk or cover of the instant invention. Disks or covers of the instant invention therefore can now be constructed with print layers thereon in the form of for example images that near or rival photo¬ graphic quality. Thus, it should be realized that the instant invention also eliminates the necessity to rely upon the more expensive and lower quality litho line printing techniques commonly utilized heretofore to provide print layers on metal and plastic disks or covers.

In yet a further feature of the instant invention, a closure band or ring may be constructed with tamper indicating means for indicating positive tampering prior to loss of seal formed between the disk or cover and a rim of a container to which the composite closure is secured. A closure band or ring of the instant invention includes a skirt portion which depends downwardly from the retaining lip, and may be provided with threads which are directed inwardly for cooperative engagement with threads on a container for securing the composite cap to the container. The skirt portion of a closure band of the present invention may also include lift means for engaging the disk and breaking the seal between the disk and the container rim during removal of the composite closure from the container, but preferably after tampering has been indicated, e.g., after a tamper indicating band has been broken. In this embodiment, the lift means may be the upper inwardly directed thread positioned on the skirt portion of the closure band and/or an independent structure strate¬ gically located between the retaining lip and the upper inwardly directed thread positioned on the skirt portion of the closure band. To further indicate that the sealed con¬ tainers have not been tampered with, the disks or covers of the instant invention can be uniquely secured to the container rims in such a manner, such as via a microencapsulated or contact adhesive, to form a freshness seal so that when the seal formed therebetween is initially broken, a sound, smell and/or feel of seal freshness is generated. It should be appreciated that such a freshness seal can be formed so that it ruptures at or subsequent to the time the thread engagement seal formed between the closure band and container and/or tamper indicating means are initially broken.

It has been surprisingly discovered that the composite closures of the instant invention form seals with containers that are superior to those formed with unitary plastic closures available hitherto. More¬ over, it is presently believed that the seals formed between the composite closures and containers dis- closed by the instant invention approach, if not rival, the quality of seals formed between current metal closures and containers.

The present invention is therefore predi¬ cated upon the realization that a novel composite closure which has superior graphics, has excellent seal qualities, is light in weight, and does not rust, corrode, break, leak or require sealing gaskets can be inexpensively produced. Thus, it can be appreciated that certain drawbacks associated with composite and unitary closures available heretofore have now been overcome, and that the special features and unique advantages of the composite closures of this invention make them highly effective as closures for various types of packages including food packages.

Other and further features of the instant invention will become apparent upon an understanding of the illustrative embodiments about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice. Thus, it should be understood that the particular composite closure embodying the invention is shown herein by way of illustration only and not as a limitation of the invention. The princi¬ ples and features of the instant invention therefore may be employed in various and numerous embodiments without departing from the scope of the instant invention.

Brief Description of the Figures

A preferred embodiment of the instant invention has been chosen for purposes of illustration and description and is shown in the accompanying figures, forming a part of the specification, wherein: Fig. 1 is a vertical cross-sectional view of a sealed package in accordance with the instant invention; and

Fig. 2 is an enlarged vertical cross- sectional view of a portion of a disk or cover forming a seal with a surface of a rim of a container in accordance with the present invention as shown in Fig. l.

Description of the Invention

By way of illustrating and providing a better appreciation of the present invention, the following description is given concerning the compos¬ ite closures, the disks or covers and packages sealed therewith of the instant invention.

The composite closure 1 is applied to and seals a container 2, such as glass or plastic, with the integrity of the seal preferably being indicated by a tamper indicating band 3 forming the lower portion of the closure band or ring 4. Closure band 4 may be constructed with any suitable rigid plastic or metal material commonly employed in the industry.

As illustrated in Figs. 1 and 2, closure band 4 is formed with a skirt portion 5 including inwardly directing threads 6 for engaging cooperating threads 7 at the container mouth 8. A radially inwardly directed flange or retaining lip 9 is formed at the top of the closure band 4 which defines a central opening 13. Together with the skirt portion 5 it forms a cover engaging corner forcing the disk or cover 10 into sealing engagement with at least a portion of the surface of the container rim 11 as depicted in Fig. 1. When cover or disk 10 is proper¬ ly inserted into closure band 4, it completely closes central opening 13.

When removing the composite closure 1 from container 2, inwardly directed upper thread 6 will eventually engage and lift disk 10 from the container rim 11 thereby breaking the seal formed therebetween. As an alternative, skirt portion 5 can be provided with an additional structure independent of the threads (not shown) positioned between retaining lip 9 and upper thread 6 for accomplishing the same when upper thread 6 is spaced substantially apart from disk 10. When following any one of these preferred con¬ structions, the seal formed between disk 10 and container rim 11 will remain intact even though tamper indicating band 3 has been first moved to a tamper indicating position. Of course, this is not to say that the composite closures must be constructed so that the seals formed between disks or covers 10 and container rims 11 are broken only after tamper indi¬ cating bands 3 are broken. Rather, the present inven¬ tion also contemplates that the upper threads 6 or the structures independent of threads 6 can be strate¬ gically positioned on closure bands 4 so that when the thread engagements between the closure bands 4 and containers 2 and/or tamper indicating bands 3 are originally broken, the seals formed between the disks or covers 10 and container rims 11 are simultaneously broken.

The tamper indicating band 3 forms a lower portion of the closure band 4 and it is attached to the skirt portion 5 of the closure band 4 at a line of weakness comprising a circular slot 12 extending through the skirt portion 5. The circular slot 12 extends completely around the closure band or ring 4 and the tamper indicating band 3 is connected to the skirt portion 5 by a plurality of break-way internal bridges (not shown) . As an alternative, the tamper indicating band 3 may be attached to the skirt portion 5 of the closure band 4 at a line of weakness com¬ prising an interrupted through-slot (not shown) . In this alternative form, the through-slot would also extend completely around closure band 4, but would be interrupted periodically by break-away portions integrally extending between the skirt portion 5 and the tamper indicating band 3 (likewise not shown) . Other lines of weakness or tamper indicating means available to those versed in this art may be used with the composite closures of the instant invention. The tamper indicating band 3 has an inwardly directed continuous hook 14 for engaging a cooperating outwardly directed bead 15 on the container 2. The hook 14 has a sharply tapered lowered surface 16 to facilitate its passage over the container thread 7 and the container bead 15 during the container sealing operation. The upper surface 17 of the hook 14 insures its engagement with the container bead 15 so that when an adequate breaking force is applied to composite closure 1, the tamper indicating band 3 is freed from the skirt portion 5 of closure band 4. The lower edge of the tamper indicating band 3 and the inwardly directed hook 14 of tamper indicating band 3 also act as a barrier for glass particles or dirt or other contaminants during package shipment and storage to keep the contaminants out of any space behind the closure band 4 such as the circular space illustrated at 19 in Fig. 1.

Turning now to Fig. 2, it illustrates a preferred disk or cover 10 in accordance with the instant invention. The preferred material for the disk or cover 10 is a cellulosic material. By the term "cellulosic material", it is used herein in a broad sense and is meant to include any cellulose- derived material which can be used to construct a disk or cover which is resiliently conformable to at least a portion of a surface at a rim of a container when compressed thereon so that an effective seal can be formed therebetween. The cellulosic material should also impart to the disk certain rigidity, toughness and strength so that the constructed disk is somewhat flexible, yet sufficiently resistant to deflection and penetration caused by blunt objects, such as a thumb, during normal use and storage. In other words, when the cellulosic material is the essential material relied upon to form a disk of the instant invention, it should not form a disk which is so rigid that it cannot resiliently conform to at least a portion of the sealing surface at a rim of a container and form an effective seal therewith when compressed by a closure band thereon. Nor should the cellulosic material form a disk which is so flexible and weak that it cannot maintain an effective seal and physical isolation of the interior of the container during normal use and storage. Examples of cellulosic materials include chipboard, fiberboard, newsboard, paperboard and pulpboard. One type of newsboard especially suitable as a cellulosic material for constructing a disk of the instant invention is a fibrous cellulosic material supplied by Halifax, P.O. Box 368, Roanoke Rapids, NC 27870, under product name Newsboard.

It should be appreciated to those versed in this art that while a disk or cover of the instant invention may be formed with a single layer of news¬ board or other cellulosic materials, it is preferred to construct a disk or cover with a plurality of layers of newsboard or other cellulosic materials having a combined thickness on the order of about 50 mils. It has been surprisingly discovered that when a disk is formulated with a plurality of cellulosic fibrous layers, an increase in strength and rigidity is imparted to such a multi-layered disk as compared to a disk formulated with a single layer of the same cellulosic fibrous material and having equal thick¬ ness. It is believed that the increase in strength is attributable to the fact that board fibers forming the cellulosic layers are not in alignment and the stiff- ness of adhesive. When selecting a plurality of layers, it is preferable but not critical for the layers to have unequal thicknesse's.

It should also be appreciated by those versed in the art that a disk of the instant invention may have any suitable diameter corresponding to a closure band to form a composite closure for a selected container rim. Preferably, the disks of the instant invention will typically have standard diame¬ ters in the range of about 30 mm to about 120 mm. While the thicknesses of the disks may vary, they will nevertheless depend upon the diameters of the disk and materials selected to construct same. For instance, disks constructed with Newsboard supplied by Halifax in accordance with the instant invention and having diameters on the order of about 30 mm to about 38 mm will have thicknesses on the order of about 30 mils or more whereas disks having diameters in the range of between about 38 mm and 83 mm will have thicknesses of between about 30 mils and about 65 mils or more. Larger disks having diameters of about 83 mm to about 120 mm will have thicknesses on the order of between about 50 mils and 65 mils or greater. It should be appreciated that the thicknesses recited herein represent only suggested thicknesses when a two Halifax newsboard layer disk is constructed, and that the thicknesses may vary for other disks depending upon the properties of the cellulosic materials and number of layers selected to construct the disks. In any event, a disk should have a thickness sufficient to accomplish the objectives of the instant invention, i.e., to construct a disk which is sufficiently resilently conformable to at least a portion of a surface at a container rim when compressed thereon for forming an effective seal therewith, yet sufficiently resistant to deflection and penetration caused by blunt objects. Referring now more specifically to Fig. 2, an outer protective layer 20 formed with a transparent polyester film is laminated to a printed paper 21 via a water base adhesive 27, such as an adhesive supplied by Sancap, 16125 Armour St., Alliance, Ohio 44601, under product no. 1522. As an alternative to a polyester film, the outer protective layer may be produced from other materials such as latex, lacquer or other coating materials, polypropylene, poly¬ ethylene, and polyamides, all of which are well known to those versed in this art. The outer protective layer preferably has a thickness on the order of about 1/2 to about 2 1/2 mils and serves to protect and limit scuffing of the print layer and upper surface of disk 10.

Printed paper 21 is typically constructed with 32# paper supplied by American Packaging Corp. , 300 South Verity Parkway, Middletown, Ohio 45044, under product no. 32# els. The print layer (not shown) is imparted to the paper via printing tech¬ niques, such as rotogravure print techniques, flexog- raphy and offset lithography. It should be appre- ciated that the print layer may, as an alternative, be reverse printed onto an outer transparent protective layer 20 or onto the top surface of a cellulosic layer 22, which has been preferably calendered and coated with a clay coating. It should be also appreciated that when a print layer is applied directly to a cellulosic layer, the layer preferably has a reduced thickness, e.g., about 10 mils, for improving handling during printing whereas the corresponding second cellulosic layer has an increased thickness, e.g., about 50 mils. Moreover, to acquire a print or image which approaches photographic quality, the print layer is preferably formed via rotogravure process print technology. It should therefore be appreciated that printing on disks of the instant invention can be uniquely and amazingly accomplished by process printing since the materials printed thereon are in the form of rollable stock materials. Thus, printing on the disks or covers of the instant invention is not only substantially cheaper than conventional litho line printing currently relied upon to impart print and image layers to sheet materials to form metal or plastic disks, but substantially superior in quality when compared thereto.

As further shown in Fig. 2, the non-printed side of print layer 21 is laminated to one side of a first layer of newsboard 22 which has a preferable thickness of about 20 mils via a water base adhesive 26, such as Sancap product no. 1769. The other side of newsboard layer 22 is laminated via the same water based adhesive 26 to newsboard layer 23 which has a preferable thickness of about 30 mils. The underside of newsboard 23, as shown in Fig. 2, is laminated via adhesive 26, such as Sancap adhesive product no. 1769, to a barrier layer 24 formed with Kraft paper having thereon a polyvinylidene chloride coating, commonly known as saran, and supplied by Sancap under product no. X265. A wax layer 25 which, among other things, reduces friction is then coated onto barrier layer 24 using standard techniques concerning wax layer appli¬ cation well known to those versed in this art.

It should be appreciated that additional or other materials may be substituted for those described hereinabove to construct a composite disk 10 of the instant invention. For instance, the print layer may be printed upon aluminum foil, metallized polyester film or polyvinylidene chloride. The barrier layer 24 may be formulated with aluminum foil, metallized polyester film, homopolymers and copolymers of vinyl alcohol, and homopolymers and copolymers of vinyl acrylate, all of which known in the art.

In addition to the layers illustrated in Fig. 2 to construct disk 10, depending upon the use of the composite closure 1, a disk of the instant inven- tion may include an inner seal layer (not shown) to further protect the contents within a container from contamination, leakage, gain or loss of vapor, gas or moisture, preserve sterilized condition, provide venting, maintain partial vacuum, prevent loss of flavor or aroma, and/or provide a form of tamper evidence. The inner seal layer may be constructed with a homogeneous or heterogeneous material also well known in this art. Examples of homogeneous materials include cellulosic materials such as paperboard, felt, cork, polymeric materials such as synthetic rubber, synthetic plastic foams or polystyrene, polyethylene and other polyolefins, flow-in or printed compounds such as plastisol, water-based dispersions, or solvent solutions or dispersions of synthetic rubbers and aliphatic or aromatic solvents, and plasticizers. Examples of heterogeneous materials which can be used to form an inner seal layer include coated papers such as varnish paper, i.e. yellow oil paper, glassine, wax, vinyl-coated polyvinyl chloride paper, poly¬ vinylidene chloride coated paper, polyvinylidene film lamination, polyethylene coated paper, laminated papers with foils or polymeric films, foils such as lead, tin or aluminum and films such as cellophane, polyvinylidene chloride, polyester, and polyethylene.

Still further, the instant invention contem¬ plates the use of an inner seal formed with any of the above mentioned heterogeneous materials or combina¬ tions thereof which is bonded in such a manner to allow it to separate from the upper base structure of a disk and adhere to the mouth 8 of container 2 via contact adhesives, heat or pressure sealing during removal of a composite closure of the instant inven¬ tion from a container. When such a layer is employed, it provides in addition to seal security an additional form of tamper indication. These techniques con¬ cerning inner seal bonding to container rims are likewise known by those versed in this art.

The instant invention also contemplates the use of a freshness seal formed between the container rim and for example the barrier layer or inner seal layer of the disks or covers. The freshness seal can be accomplished, as discussed hereinbefore, by applying an adhesive to such layer or to the container rim so that when the seal therebetween is broken a freshness sound, smell and/or feel is produced. It should be appreciated that when freshness seals are desired, the adhesive selected to formulate such a seal should have a bonding strength less than that of the adhesives selected to formulate the composite disks or covers of the instant invention so that the layers of the composite disks or covers will not separate from one another when the freshness seals are broken. An example of an adhesive suitable for use to form the freshness seal is a contact adhesive, such as CS1597X available through SANCAP, which can be coated onto for example the exposed barrier or inner seal layer on the underside of the disk or cover, or onto the container rim. It is believed that SANCAP adhe- sive CS1597X is derived from SANCAP's adhesive CS1597 wherein the content of adhesive in CS1597X is reduced to reduce the bonding strength thereof so that the adhesive is effective for this freshness seal purpose. It should be appreciated that the composite closures of the instant invention can be constructed so that the freshness seal is broken either at or subsequent to the time the thread engagement between the closure band and container rim and/or tamper indicating means are broken. For example, the lift means can be positioned on the skirt portion 5 such that when a tamper indicating band 3 connected to the skirt portion 5 is broken, the lift means breaks the freshness seal either at substantially the same time or thereafter. In any event, it should be realized that the freshness seal provides an additional form of tamper indication and an appearance of freshness.

Figs. 1 and 2 illustrate a composite closure 1 of the instant invention in its sealed position with the disk or cover 10 held tightly against the con¬ tainer rim 11 by the retainer lip 9 of the closure band 4 with a portion of newsboard layer 23, barrier layer 24 and wax layer 25 resiliently pressed into sealing engagement with a portion of the sealing surface of container rim 11 to form a seal therewith. The deep impression created by the compression of disk 10 uniquely and advantageously enhances seal security.

This form of disk 10 has a number of advan¬ tages. One advantage is the resistance of the composite closure 1 to lose seal security due to minor dimensional changes in the closure band 4 or cover 10 during normal handling and storage. Even though the closure band 4 may move outwardly and/or upwardly with a corresponding upward or radial movement of the disk 10, either the top sealing surface or the side sealing surface of container rim 11 will remain in sealing contact with disk 10 due to the deep impression created by the compression of disk 10 by closure band 4 over the sealing surface of rim 11 of container 2. Moreover, the deep impression illustrated in Fig. 2 enhances seal security since it creates a longer path along which oxygen, other gases or contaminants must travel before entering into or escaping from the interior of the container, respectively. This improved seal security is believed to be attributable to, inter alia, the resiliently conformable, rigid and strength properties of the disks of the instant invention. It should therefore now be apparent that the disks of the present invention can be constructed without the necessity of coating to prevent corrosion or rust or adding sealing gaskets therewith to form proper seals as required with metal or plastic disks availabl heretofore. Another s nificant advantage associated with the disks or covers of the instant invention is the improved quality of the graphics and costs to accomplish same. As mentioned hereinbefore, it is now possible to provide disks of the present invention with graphics thereon which near photographic quality. This is possible since a print layer can now be formed on selected materials as they are unrolled via roto¬ gravure printing techniques. The printed materials can then be easily and inexpensively laminated to the cellulosic material relied upon to form the disks or covers of the instant invention. The disks of the instant invention can be constructed as follows. Once a pattern or image has been selected and printed on a paper or a clay coated cellulosic layer or reverse printed on a transparent layer, such as the barrier layer, and the other various layers selected for a desired disk are lam¬ inated to one another in appropriate order to form a composite laminate, as described above, the composite laminate may be rolled at point of lamination and stored until further processing. To form the disks, the composite laminate can be unrolled and punched using standard techniques well know to those versed in the die cutting or punching art to generate disks of a selected diameter and thickness and having the appro¬ priate images positioned correctly thereon. While the composite laminates may be rolled and stored, it is nevertheless preferable to punch the disks or covers therefrom as the composite laminates are formed. Once the disks or covers have been punched, they can then be collected and edge coated via, for example, rolling or spray coating the raw edges with a selected mate¬ rial, such as with silicone, wax and the like, for rendering the raw edges thereof impervious to moisture and other contaminants.

The invention will now be further described with reference to the following example.

Example

The disk constructed in this example has a thickness of about 65 mils and a diameter of 3.160 inches for use with an 82 mm closure band and is suitable for use as, for example, a composite closure for a container containing salad dressing, mayonnaise, baby food products, jams, jellies, peanut butter and other food products or like.

A top outer layer, used as a protective layer, in the form of a high gloss transparent poly- ester film of about 0.5 mil is laminated to a pre- rotogravure printed clay coated (one side) 32# paper.

The 32# paper is supplied by American Packaging Corp. under product no. 32# els. The top outer layer is supplied by ICI under product name Clear Polyester Film. A water base adhesive supplied by Sancap under product no. 1522 bonds the top outer layer polyester film to the printed surface of the 32# printed paper. The adhesive is dried prior to adding another lamina.

Two layers of newsboard are laminated to one another via a water base adhesive supplied by Sancap under product no. 1769. The top layer of newsboard supplied by Halifax under product name Newsboard has a thickness of about 20 mils. The second layer of Newsboard supplied by Halifax under product name Newsboard has a thickness of about 30 mils. The underside of the printed paper is laminated to the upper surface of the 20 mil thick newsboard layer via water base adhesive supplied by Sancap under product no. 1769.

Once dried, a barrier sheet supplied by Sancap under product no. X265, which is formed with yellow craft paper coated with a polyvinylidene chloride (saran) layer of about 0.75 mil, is adhered to the underside of the 30 mil newsboard laminate via Sancap adhesive, product no. 1769. A wax layer of about 1.5 mils is coated to the exposed underside of the barrier sheet using standard techniques to com¬ plete the construction of a composite laminate of the instant invention. Disks or covers having the above- mentioned diameters can then be punched therefrom. Disks which are constructed as described in this example but having varying diameters, are analyzed for the following deflection characteristics, all of which are believed to be within accepted limits:

The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and any changes coming within the meaning and equiv¬ alency range of the appended claims are to embraced therei .

Having described our invention, we claim:

Claims

1. A composite closure for sealing a container having a sealing surface at its rim, said closure comprising: a closure band having a retaining lip bounding a central opening and being removably secur- able to the container; and a separate disk positionable between said retaining lip and the sealing surface for closing said central opening, said disk having sufficient resis- tance to deflection and sufficient resistance to penetration for maintaining physical isolation of the interior of the container to which said closure is secured, said disk including a layer comprised of a cellulosic material, said layer being resiliently conformable to at least a portion of the sealing surface for forming and maintaining an effective seal therewith so that, when said closure is secured to the container, the container remains effectively sealed during normal use and storage.

2. A composite closure of claim 1, said layer comprising newsboard.

3. A composite closure of claim 2, said layer having a thickness of at least about 30 mils.

4. A composite closure of claim 1, said layer comprising a cellulosic material selected from a group consisting of chipboard, fiberboard, paperboard and pulpboard.

5. A composite closure of claim 1, said layer having a thickness in the range of between about 30 mils and 65 mils.

6. A composite closure of claim 1, said layer including at least two separate layers wherein each said layer is comprised of a cellulosic material.

7. A composite closure of claim 6, each said layer comprising newsboard.

8. A composite closure of claim 7, said layers having a combined thickness of at least about 60 mils.

9. A composite closure of claim 6, each said layer comprising a cellulosic material selected from a group consisting of chipboard, fiberboard, paperboard and pulpboard.

10. A composite closure of claim 6, one said layer having a thickness of at least about 30 mils, the other said layer having a thickness of about 20 mils.

11. A composite closure of claim 1, said disk having on at least one surface thereof a print layer.

12. A composite closure of claim 6, said disk . having on at least one surface thereof a print layer.

13. A composite closure of claim 1, said compos¬ ite closure cap further having means for indicating tampering therewith.

14. A composite closure of claim 13, said closure band further having a skirt portion depending downwardly from said retaining lip, said tamper indi¬ cating means comprising a tamper indicating band positioned at the lower edge of said skirt portion and being detachably connected thereto for being discon¬ nected therefrom during removal of said composite closure from the container.

15. A composite closure of claim 14, said tamper indicating band including a radially inwardly directed container engaging bead positioned to engage a coop¬ erating bead on the container for tearing said tamper indicating band free of said cap ring during removal of said composite closure cap from the container.

16. A composite closure of claim 14 wherein the means for detachably connecting said tamper indicating band comprises a circular slot extending through said enclosure band and a band connected to said closure band by internal bridges intermittently spaced.

17. A composite closure of claim 14 wherein the means for detachably connecting said tamper indicating band comprises an interrupted circular slot.

18. A composite closure of claim 14, said cap ring further having lift means positioned between said sealing lip and the lower edge of said skirt portion for engaging said disk after said tamper indicating band has been disconnected from said cap ring during removal of said composite closure cap from the con¬ tainer.

19. A composite closure of claim 1, said closure band being a molded plastic cap band.

20. A composite closure of claim 1, said closure band being a metal cap band.

21. A composite closure of claim 1, said closure band further having a skirt portion depending down¬ wardly from said sealing lip, said skirt portion including inwardly directed threads for engaging cooperating threads on the container for securing said closure to the container.

22. A composite closure of claim 1 wherein the edges of said disk are coated with a material.

23. A composite closure for sealing a container having a sealing surface at its rim, said closure comprising: a closure band having a retaining lip bounding a central opening and being removably secur- able to the container; and a separate disk positionable between said retaining lip and the sealing surface for closing said central opening, said disk comprising a cellulosic material and being resiliently conformable to at least a portion of the sealing surface for forming and maintaining an effective seal therewith, said disk having sufficient resistance to deflection and to penetration for maintaining physical isolation of the interior of the container to which said closure is secured so that, when said closure is secured to the container, the container remains effectively sealed during normal use and storage.

24. A composite closure of claim 23, said cellulosic material being newsboard.

25. A composite closure of claim 23, said cellulosic material being selected from a group consisting of chipboard, fiberboard, paperboard and pulpboard.

26. A composite closure of claim 23, said disk including at least two separate layers, each said layer consisting essentially of a cellulosic material,

27. A composite closure of claim 26, said cellulosic material being newsboard.

28. A composite closure of claim 26, said cellulosic material being selected from a group consisting of chipboard, fiberboard, paperboard and pulpboard.

29. A composite closure of claim 23, said disk having a thickness of at least about 30 mils.

30. A composite closure of claim 23, said disk having a thickness in the range of between about 30 mils and about 65 mils.

31. A composite closure of claim 26 wherein at least one said layer has a thickness of at least about 30 mils.

32. A composite closure of claim 23, said disk including a print layer on at least one surface thereof.

33. A composite closure of claim 32 wherein said print layer is a printed layer on paper, said printed paper being positioned on the one said surface of said disk.

34. A composite closure of claim 32 wherein said print layer is a printed layer on a transparent film, said printed transparent film being positioned on the one said surface of said disk.

35. A composite closure of claim 32 wherein said print layer is a printed layer in the form of an image near photographic quality.

36. A composite closure of claim 32, said disk including a transparent protective layer positioned on the one said surface of said disk.

37. A composite closure of claim 33, said disk including a transparent protective layer positioned on the printed paper.

38. A composite closure of claim 23, said disk including a barrier layer.

39. A composite closure of claim 38, said barrier layer comprising a polyvinylidene chloride coating.

40. A composite closure of claim 38, said disk further including a wax layer.

41. A composite closure of claim 40, said disk further including an inner seal positioned on said wax layer.

42. A composite closure of claim 41, said inner seal being formed of a material selected from a group consisting of paper, metal and plastic.

43. A composite closure of claim 23, said closure band further having means for indicating tampering therewith.

44. A composite closure of claim 23, said closure band further having a skirt portion depending downwardly from said retaining lip, said skirt portion including inwardly directed threads for engaging cooperating threads on the container for securing said closure to the container.

45. A composite closure of claim 23, said closure band being a molded plastic cap band.

46. A composite closure of claim 23, said closure band being a metal cap band.

47. A composite closure of claim 23 wherein the edges of said disk are coated with a material.

48. A composite composite closure for sealing a container having a sealing surface at its rim, said closure comprising a closure band having a retaining lip bounding a central opening and being removably secur- able to the container, and a separate disk positionable between said retaining lip and the sealing surface for closing said central opening, said disk including a.) a protective transparent layer, b.) a print layer, c.) a first layer comprising a cellu¬ losic material, d.) a second layer comprising a cellulosic material, and e.) a barrier layer, said disk being resiliently conformable to at least a portion of the sealing surface for forming and main¬ taining an effective seal therewith so that, when said closure is secured to the container, the container remains effectively sealed during normal use and storage.

49. A composite closure of claim 48, said print layer comprising a printed layer on a layer comprised of paper.

50. A composite closure of claim 48, said print layer comprising a printed layer on a surface of said transparent layer.

51. A composite closure of claim 48, said print layer comprising a printed layer on a surface of said first layer.

52. A composite closure of claim 48, said transparent layer comprising a polyester film.

53. A composite closure of claim 48, said first and second layers being newsboard.

54. A composite closure of claim 53, said first layer having a thickness of about 20 mils and said second layer having a thickness of about 30 mils.

55. A composite closure of claim 48, said barrier layer including a polyvinylidene chloride coating.

56. A composite closure of claim 48, said disk further including a wax layer.

57. A composite closure of claim 56, said disk further including an inner seal layer, said inner seal layer being formed of a material selected from a group consisting of paper, metal and plastic.

58. A composite closure of claim 48, said disk further including an inner seal layer.

59. A composite closure of claim 48, said composite closure further comprising means for indi¬ cating tampering therewith.

60. A composite closure of claim 48, said closure band further having a skirt portion depending downwardly from said retaining lip, said skirt portion including inwardly directed threads for engaging cooperating threads on the container for securing said closure to the container.

61. A composite closure of claim 57, said closure band further having a skirt portion depending downwardly from said retaining lip, said skirt portion including lift means positioned between said retaining lip and the lower edge of said skirt portion for engaging said disk after said tamper indicating means has been moved to its tamper indicating position and during removal of said cap from the container.

62. A composite closure of claim 48, said closure band being a molded plastic cap band.

63. A composite closure of claim 48, said closure band being a metal cap band.

64. A composite closure of claim 48 wherein the edges of said disk are coated with a material.

65. A sealed package comprising a container sealed with said composite composite closure of claim 1.

66. A sealed package comprising a container sealed with said composite composite closure of claim 23.

67. A sealed package comprising a container sealed with said composite composite closure of claim 48.

68. A separate disk for use with a closure band for forming a composite closure for sealing a con¬ tainer having a sealing surface at its rim wherein the closure band is provided with a retaining lip defining a central opening and being removably securable to the container, said separate disk being positionable between said retaining lip and the sealing surface for closing the central opening when positioned within the composite closure, said disk having sufficient resis¬ tance to deflection and sufficient resistance to penetration for maintaining physical isolation of the interior of the container when the composite closure is secured to the container, said disk including a layer comprised of a cellulosic material, said layer being resiliently conformable to at least a portion of the sealing surface for forming and maintaining an effective seal therewith so that, when the composite closure containing said disk therein is secured to the container, the container remains effectively sealed during normal use and storage.

69. A separate disk of claim 68 wherein the edges thereof are coated with a material.

70. A separate disk for use with a closure band for forming a composite closure for sealing a con¬ tainer having a sealing surface at its rim wherein the closure band is provided with a retaining lip defining a central opening and being removably securable to the container, said separate disk being positionable between the retaining lip and the sealing surface for closing the central opening when positioned within the composite closure, said disk comprising a cellulosic material and being resiliently conformable to at least a portion of the sealing surface for forming and maintaining an effective seal therewith, said disk having sufficient resistance to deflection and to penetration for maintaining physical isolation of the interior of the container when the composite closure is secured to the container so that, when the compos¬ ite closure containing said disk therein is secured to the container, the container remains effectively sealed during normal use and storage.

71. A separate disk as claimed in claim 70 wherein the edges thereof are coated with a material.

72. A separate disk for use with a closure band for forming a composite composite closure for sealing a container having a sealing surface at its rim wherein the closure band is provided with a retaining lip defining a central opening and being removably securable to the container, said separate disk being positionable between the retaining lip and the sealing surface for closing the central opening when positioned within the closure band, said disk including a.) a protective transparent layer, b.) a print layer, c.) a first layer comprising a cellu¬ losic material, d.) a second layer comprising a cellulosic material, and e.) a barrier layer, said disk being resiliently conformable to at least a portion of the sealing surface for forming and main- taining an effective seal therewith so that, when the composite closure containing said disk therein is secured to the container, the container remains effectively sealed during normal use and storage.

73. A separate disk of claim 72 wherein the edges thereof are coated with a material.

74. A separate disk of claim 72 wherein said print layer is produced by the process of rotogravure printing process.

75. A separate disk of claim 72, said disk further including means for forming a freshness seal with the sealing surface so that when the freshness seal is broken therebetween a freshness sound, feel or smell is generated.

76. A sealed package comprising: a.) a hollow container having a rim and a sealing surface at its rim; b.) a composite closure, said composite closure including a closure band having a retaining lip defining a central opening and being removably secured to said hollow container, and a separate disk positioned between the retaining lip and the sealing surface for closing the central opening, said disk having sufficient resis¬ tance to deflection and sufficient resistance to penetration for maintaining physical isolation of the interior of the hollow container to which said co - posite closure is secured, said disk including a layer comprised of a cellulosic material, said layer being resiliently conformable to at least a portion of the sealing surface for forming and maintaining an effec¬ tive seal therewith so that said hollow container remains effectively sealed by said composite closure during normal use and storage; and c.) means for forming a freshness seal between said separate disk and the sealing surface so that when the freshness seal is broken, a freshness sound, feel or smell is produced.

77. A sealed package of claim 76 wherein the edges of said disk are coated with a material.

78. A sealed package of claim 76, said layer comprises: a first layer comprising a cellulosic material; and a second layer comprising a cellulosic material.

79. A sealed package of claim 78, said disk further including: a.) a protective transparent layer; b.) a print layer; and c.) a barrier layer.

80. A sealed package of claim 78, said disk further including an inner seal layer.

81. A sealed package of claim 78 wherein the edges of said disk are coated with a material.

82. A sealed package of claim 79 wherein the print layer is produced by the process of process printing.

83. A sealed package of claim 79 wherein the print layer is produced by a rotogravure printing process.