US3587898A - Tamper-proof closure with plastic liner - Google Patents

Abstract

A TAMPER-PROOF CLOSURE WITH A PLASTIC LINER AND METHOD TO FABRICATE SAME. A HEAT SHRINKABLE PLASTIC LINER WITH AN OPTIONAL TAMPER-PROOF BAND REGION IS SHRUNK ABOUT THE THREADED PORTION OF A CONTAINER. AFTER THE CONTAINER IS FILLED WITH THE DESIRED PRODUCT, A METAL SHELL IS TELESCOPED OVER SAID LINER AND BONDED TO THE LINER OPPOSITE THE THREADED AREA. THE SHELL AND LINER ARE REMOVED BY ROTATION WITH THE OIPTIONAL TAMPERPROOF BAND ADHERING TO THE NECK OF THE CONTAINER.

Description

United States Patent lnventor John D. Northup Toledo, Ohio 778,256

Nov. 22, 1968 June 28, 1971 Owens-Illinois, Inc.

AppL No. Filed Patented Assignee TAMPER-PROOF CLOSURE WITH PLASTIC LINER 9 Claims, 4 Drawing Figs.

Int. Cl .i B65d 23/00, 865d 53/00 Field of Search 215140, 38 (A); 229/43 [56] References Cited UNITED STATES PATENTS 3,402,874 9/1968 Sternau v. 2 l 5/38-(AX) 3,417,539 12/1968 l-lirohama 215/38(X) FOREIGN PATENTS 678,389 1/1964 Canada 215/38 Primary Examiner-George T. Hall Attorneys- Philip M. Rice and E. J. Holler ABSTRACT: A tamper-proof closure with a plastic liner and method to fabricate same. A heat shrinkable plastic liner with an optional tamper-proof band region is shrunk about the threaded portion of a container. After the container is filled with the desired product, a metal shell is telescoped over said liner and bonded to the liner opposite the threaded area The shell and liner are removed by rotation with the optional tamper-proof band adhering to the neck of the container.

PATENTEBJUH28|971 8587.888

INVENTUR; JOHN D. NORTHUP 624% M; 6PM fyfeh ATroRmevS TAMPER-PROOF CLOSURE WITH PLASTIC LINER THE INVENTION This invention relates to a novel closure assembly and the method of forming the same. More particularly, this invention relates to a cap closure to be applied to a container by first shrinking upon the finished threads a heat-deformable plastic liner, and then applying an adhesive coated metal cap to form a closure which is tamper-proof, resistant to insect infestation, and easily removed by rotation. If desired, the plastic liner may have a tamper-proof band.

At the present time, there is a wide variety of cap closures currently in use which are designed to solve a multitudinous number of problems which are discussed below. One of these problems is insect infestation.

Insects lay eggs and larvae are commonly produced in the open space which exists between the neck of a container and the lower edge of a cap used to seal the container. When such a container is opened and any vacuum is released thereby equalizing the internal pressure of the container with the pressure of the atmosphere at the jar mouth, the inrushing air to the interior of the jar will pass by the region occupied by the insect larvae and cause some of the larvae to be transported into the container, causing contamination of the stored product.

Another problem relating to the design of closure is spillage. When containers are being filled with baby food products, or the like, they are frequently subjected to spillage of the food product onto the exterior threaded finish of the container. Upon later application of a closure by automatic machine which is insensitive to the cleanliness of the glass, any such food product smears between the closure and the glass. This often freezes the closure onto the finish of the threads, making removal by the housewife virtually impossible. Even when the cap is removed, the oxidized food product on the glass and cap is unsightly.

Creeping of the closure is also another problem. Minor deposits of stannic chloride or the like resulting from surface treatment of the glass when deposited upon the finished surface of the glass causes closures to slip or creep and loosen during handling of the filled containers subsequent to the processing of the food, thereby causing leaks and release of the vacuum. Food spoilage results.

In designing closure, it is desirable to consider the ease with which they can be applied to or removed from the container. From the standpoint of application, a closure which requires only a straight downward movement relative to the container is preferred over one requiring a rotational movement to screw it on. The reason for this is that such closures can be applied at a higher rate of speed and require less complicated equipment than screw-on closures. On the other hand, from the standpoint of removal, it is preferred that the closure removal be by a single unscrewing movement.

One form of closure cap presently exists which attempts to solve some of the problems heretofore illuminated. In this type of closure, the container is first filled with the desired product and, subsequently, the container is sealed with a closure which has a plastic liner deposited within it; The inherent disadvantage of this cap is that the plastic liner is applied to the container at the same time as the exterior cap members. Therefore, the cap does not solve the problem of spillage and later freezing of the product on the surface of the finished threads.

With these problems in mind, a closure was developed which could be applied with the simplest type of capping equipment at high speeds and yet could be easily removed without the use of tools and reapplied without difficulty.

The present invention includes a combined sleeve gasket member liner of shrinkable plastic applied over the finished threads and rim of a glass container and a straight or tapered nonthreaded metal cap shell adhesively bonded to the plastic liner in situ during the retorting to form a composite closure.

More specifically, the present invention utilizes an elastomeric or plastomeric liner telescoped over the finished threads of a container after the container IS formed and inspected in the glass plant. After the liner has been applied to the neck of the container. the container is processed by heating it within a tunnel or oven of suitable type and temperature to shrink the deformable plastic liner around the contours of the threaded finish. The plastic is selected from available plastic materials which are easily formed on known molding equipment at high rates of production. Such plastic may be a heat reacting shrink-type polyvinyl chloride.

The jar is now ready to be filled with the desired product. Any spillage which may result while the container is being filled will splash on the outside of the preshrunk plastic liner and not on the threaded finish. A thin-walled metal shell which has been previously interiorly lined with a heat reactive adhesive material is pressed telescopically over the formed, shrunken liner or in the alternative, a thin-walled metal shell is pressed telescopically over a formed, shrunken liner which is coated with a heat reactive adhesive material so that the metal of the closure shell is tenaciously bonded to the preshrunk liner at contact points opposite the threads of the container finish and opposite the adjacent horizontal surface of the rim portion of the neck of the container to form a one-piece integral cap.

One form of such a heat reactive adhesive suitable for bonding the metal shell to the plastic liner is a methyl methacrylate compound, an example of which is now shown.

Percent E oxy resin (Epon 1007) 16. 5 Methyl Methacrylate resin (Aeryloid A101) 7. 0 Diethylene triamine 0. 66 Methyl isobutyl ketone 25. 4O Methyl ethyl ketone 50. 44

In the case of containers containing baby food products, the entire package is sent to a retort where it is soaked in heat in order to process the food. In the retort, the heat is sufficient to react the adhesive to bind the metal shell and the shrunken plastic liner at the above-mentioned contact points. When the closure is used in conjunction with baby food products, it may be constructed with a domed or snap-button diaphragm (center diaphragm) as is now commonly used in lug-type baby food metal closures. Such snap-button closure is disclosed in US. Pat. No. 3,142,711, which is assigned to the assignee of the present invention. The interior of the container, if closured properly, then draws a vacuum to depress the button on the top of the metal shell.

Upon opening the container, a twisting motion of the outside metal shell will unscrew the plastic liner at the threads of the finish.

The torque necessary to remove the resulting cap and liner may be controlled by lubricating the glass prior to the application of the plastic liner or by including lubricants in the shrinkable plastic compound. Then, if food products are splashed onto the outside of the liner when the container is being filled or capped, the subsequent torque required to remove the cap will not be affected by the freezing of the product to the liner since this removal torque is determined from the earlier established contact between the shrunken plastic liner and the clean glass threads which occurred prior to filling. The package may be rescaled by turning the composite metal shell and plastic liner onto the jar finish.

A simple addition to the above-described closure assembly will also yield a closure which will solve the problem of tampering. It is an observable practice on the part of many shoppers to remove closure caps from food-containing jars in a retail store, sample the products with their finger, smell the contents, reapply the closure cap and too often return the already opened and no longer sterile packages to the store shelf for purchase by another unsuspecting customer. In order to help eliminate this problem, a closure was developed which utilizes essentially the same combination of plastic liner and metal shell heretofore-described However, the skirt of the plastic liner IS extended below the lower edge of the metal shell. In fonning the plastic liner. a circumferential or perforated score line is imposed at the lower part of the plastic skirt immediately below the lower edge of the metal shell. The interior surface of the plastic skirt below the score line may be treated with a heat reacting adhesive or in the alternative, the opposite annular recessed region of the glass neck below the neck finish may be treated with such an adhesive such that after the plastic liner is shrunken onto the glass finish contour, the heat treatment of the container will react the adhesive of the lower recessed neck region to bond that plastic band to the An example of such a heat-sensitive adhesive suitable to bond the liner to the glass is the polyvinyl acetate, polyvinyl alcohol type sold by the Borden Company under the trademark Elmer's Glue." The chemical composition of Elmers Glue" is believed to be a liquid emulsion of the polymerized addition product of acetylene and acetic acid, e.g., polyvinyl acetate.

Upon opening the container, a twisting motion of the metal shell will unscrew the plastic liner on the threads of the finish. The tamper-proof band region of the plastic liner below the score line will remain adhered to the glass and separate from the body of the liner along the score line. Thus, the ultimate purchaser of the product can easily determine whether the jar has once been opened.

An advantage of these closures is that the liner may be supplied by the bottle manufacturer prior to shipment to the food processor. The liner serves to reduce chipping of the rim of the bottle in transit. After the bottle is filled by the processor with the desired product, the metal shell can be applied by the processor.

Keeping in mind the solution of the above-described problems, and the solution of other problems which may be hereinafter disclosed, it is an object of the present invention to provide a novel closure assembly which may be formed with simple equipment.

It is a further object of the present invention to provide a reusable cap closure which is sealed by forcing it downwardly on the container without intentional rotation, but yet which can be easily removed by rotation.

It is an additional object of the present invention to provide a cap construction having a seal which prevents infestation of mold or insects between the cap and the container.

It is another object of this invention to provide a closure which will not slip or creep during handling, subsequent to processing the food, thereby causing leaks and releasing any vacuum formed in the container.

It is a still further object of the preset invention to provide a closure assembly having a shrunken plastic liner formed over the contours of the finished threads, and a metal shell telescoped over said liner, such that any spillage of the food product will lodge on the plastic liner rather than on the bare glass surface of the threads, thereby facilitating subsequent removal of the composite metal shell and liner from the container.

Another object of the present invention is to provide a tamper-proof closure with a tamper-proof band region in the plastic liner separated by a score line to visibly indicate whether a jar, or such container, has been tampered with or subjected to unauthorized breaking of the original hermetic seal.

Still another object of the present invention is to provide a new and improved method of forming a closure assembly by first applying a shrinkable plastic liner over the finished threads and rim of a glass container, and then applying telescopically a straight or tapered nonthreaded metal cap which is adhesively bonded to the plastic liner in situ during retortation to form a composite closure.

An object of the present invention is to provide a method of forming a tamper-proof closure assembly by first applying a shrinkable plastic liner which has been circumferentially perforated with a scoreline and adhesively bonded to the glass below the scoreline and adding telescopically thereto a straight or tapered non-threaded metal cap which is adhesively bonded to the plastic liner in situ during retortation to form a composite closure.

Also, an object of the present invention is to provide a method of filling and sealing a container by applying a shrinkable plastic liner, with an aperture in the top portion thereof, over the finished threads and rim of a glass container; filling said container through said aperture with the desired product; and then applying telescopically a straight or tapered nonthreaded metal cap which is adhesively bonded to the plastic liner in situ during retortation to form a composite closure.

The attainment of the above, and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawing forming a part thereof:

IN THE DRAWINGS FIG. 1 is a fragmentary sectional view of a container with the sleeve gasket plastic liner, and an optional tamper-proof band applied prior to heat processing.

FIG. 2 is a view similar to FIG. 1 showing the liner after heat shrinking it into conformity with the threaded finish.

FIG. 3 is a fragmentary sectional view of a container with a deformable plastic liner, and a tamper-proof band heat shrunk over the finished threads of the container, and a metal shell superimposed upon the plastic liner.

FIG. 4 is a fragmentary sectional view of the container and a closure of FIG. 3, but without the tamper-proof band.

Referring now, in more detail and by reference numerals, to the drawings which illustrate a preferred embodiment of the present invention, there is provided a container 10 having a neck portion with helical threads 11 on the outer surface thereof. The neck has an interior wall 17 and terminates at its upper end in an annular rim 18. A preformed heat-deformable plastic liner 12 is superimposed upon the container 10 and has a cylindrical skirt 14 with an optional circumferential scoreline or perforated tear line 19 at a lower part of the skirt and an annular rim gasket portion 15 is joined at a corner radius 16.

The annular rim gasket 15 of liner 12 is in contact with the container rim 18 and extends radially inwardly to a point generally aligned with the interior wall 17 of the container. Such construction permits the container to be later filled with food products prior to the application of metal shell 23.

If a tamper-proof band is not desired, the preformed plastic liner is severed along the same circumferential line that would have formed the score line. However, if the tamper-proof feature is desired, the interior surface 20 of skirt 14 below scoreline 19 is treated with a heat reacting adhesive or in the alternative, the opposite annular recessed region 22 of the glass container below the neck finish is treated with an adhesive such that after liner 12 is shrunken onto the glass finish contour, the heat treatment of the container will react the adhesive to bond the plastic band to container 10 at recessed region 22 below the scoreline.

After a glass container has been formed in a glass plant, annealed and lined in single order through inspection equipment, it passes an assembly point whereat plastic liners 12 are placed over the jar finish. The liner is positioned such that the annular rim gasket portion 15 of liner 12 contacts container rim 18 while cylindrical skirt 14 contacts helical threads 11 at the outermost points thereof.

Then the container and the preformed plastic liner is passed through a heating process where the plastic liner is shrunk to conform to the contours of the glass finish and straight skirt 14 is transformed into molded skirt 14', as shown in FIG. 2.

FIG. 2, similar to FIG. 1, shows the plastic liner after it has been heat shrunk to conform with the threaded finish. Plastic liner 12 is transformed to shrunken liner 12'; liner skirt 14 is transformed to shrunken skirt l4; rim gasket 15 is transformed to shrunken gasket 15; etc. The container is filled with the desired food product, and a metal shell 23 is telescoped over the container and the fitted liner to form a composite closure as shown in H65. 3 and 4.

FIG. 4 illustrates a composite closure which is formed by telescoping a nomthreaded metal shell 23 over container and shrunken plastic liner 12. The metal shell is characterized by a cylindrical skirt 24 which may be either straight or tapered, and a top panel 28 completely covering the opening to the container joined to the skirt at comer radius 30. When the metal shell is superimposed upon shrunken plastic liner l2 to seal the container, the shell is tenaciously bonded to the deformed liner at contact points 26 and 27, opposite the outermost points of helical threads 11 of the jar finish and at the point opposite the adjacent surface of rim gasket portion 15. Such bonding is effected by the action of heating the package in the area of the heat-reactive adhesive material which has been applied either to the interior of the metal shell or in the alternative to the exterior of shrunken liner.

If, as shown in FIG. 3, the composite closure includes a tamper-proof band, the edge 25 of metal shell 23 is not extended below scoreline 19 so that the scoreline is visible for easy detection.

When opening the container, a twisting motion of metal shell 23 will unscrew plastic liner l4 deformed upon threads 11 of the glass finish. When a tamper-proof closure is provided, the tamper-proof band region 22 of skirt 14' below scoreline 19 will adhere to the glass and separate from the body of liner 12 along scoreline 19.

The container may be resealed by turning the composite of liner l2 and metal shell 23 on the jar finish.

It can be seen from the foregoing that the present invention provides a novel reusable closure assembly which can be easily applied to a container, and which eliminates the problems of insect infestation, slipping or creeping of the closure cap, and spillage and subsequent freezing of the closure to the finished threads. With these and other problems in mind which may be disclosed, it it understood that the foregoing is a description of preferred embodiments of the invention, and that various modifications may be made without departing from its spirit and scope.

lclaim:

l. A package comprising in combination a container having a neck portion and a rim portion and a closure assembly which includes a plastic liner of substantially uniform thickness covering the rim portion of said container with an annular skirt extending axially from the mouth of the container and conforming to the finish contour of the neck portion thereof, a shell telescoped upon said liner having a top panel portion and a cylindrical skirt extending axially from the top panel, said shell contacting the liner skirt only at a plurality of contact points located around the rim of said container, and means to bond said shell to said liner at the contact points on the finish of the neck of the container.

2. The combination as claimed in claim 1 wherein the closure assembly includes a plastic liner covering the rim portion of the container, which liner has an aperture therein allowing said container to be filled prior to the application of the telescoped shell.

3. The combination as claimed in claim 2 wherein the aperture within said liner consists of an annular opening, the edge of which is generally aligned with the interior wall of the rim of the container.

4. A package comprising in combination a container having a threaded neck portion and a rim portion, and a closure assembly which includes a liner of substantially uniform thickness with a top thereon covering the rim portion of said container, and an annular skirt extending axially from the mouth of the container and conforming to the contour of the finish of the threaded neck portion thereof, a shell telescoped upon said liner having a top panel portion and a cylindrical skirt extending axially from the top panel, said shell contacting the liner skirt only at the crest of the threads, and means to bond said shell to said liner at the threaded neck portion of said container.

5. The combination as claimed in claim 4 wherein said liner comprises a heat-shrinkable plastic material.

6. The combination as claimed in claim 5 wherein the top of the liner covering the rim portion of the container includes an aperture therein allowing said container to be filled prior to the appllicationpf the telescoped shell.

7. e combination as claimed in claim 6 wherein the aperture within said liner consists of an annular opening, the edge of which is generally aligned with the interior wall of the rim of the container.

8. The combination as claimed in claim 5, wherein the annular skirt of the liner includes a scoreline or perforated tear line below the lower edge of the skirt of the shell, and means to bond that portion of said liner below the scoreline or perforated tear line to the container so that upon application of a twisting torque to said shell, the portion of the liner below the scoreline or perforated tear line will adhere to the container.

9. The combination as claimed in claim 4 wherein the bonding means consists of a heat-reactive adhesive applied between the telescoped shell and the liner so that the liner will adhere to the shell upon application of a twisting torque to said shell.

Images