US3465907A

US3465907A - Closure seal for containers having screw threaded necks

Info

Publication number: US3465907A
Application number: US758870A
Authority: US
Inventors: Henry J Dorn; Halford E Brockett
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1968-09-10
Filing date: 1968-09-10
Publication date: 1969-09-09
Anticipated expiration: 1986-09-09
Also published as: DE1932041A1; DE1932041B2

Description

Sept. 9,1969 H.J.DORN ET AL 3,465,907

CLOSURE SEAL FOR CONTAINERS HAVING SCREW THREADED NECKS H ELIIIII Ill INVENTORS v HENRY J. DORN HALFORD E. BROCKETT BY @w u ATT'Y.

Sept. 9', 1969 H. J. DORN ET AL CLOSURE SEAL FOR CONTAINERS HAVING SCREW THREADED NECKS Filed Sept. 10, 1968 2 Sheets-Sheet 2 W Y T 1 m w W Alllll) Ii m J c A W M 8 ll 1 N I. III] E E M r w mfi I 8 2 2 m T United States Patent 3,465,907 CLOSURE SEAL FOR CONTAINERS HAVING SCREW THREADED NECKS Henry J. Dorn, Pottsville, Pa., and Halford E. Brockett, Elmhurst, Ill., assignors to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Sept. 10, 1968, Ser. No. 758,870 Int. Cl. B65d 53/00 US. Cl. 215-40 5 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention This invention relates to new and useful improvements in container closures and more particularly to the closing and sealing of bottles and the like having a neck provided with screw threads.

The prior art It is known to effect top and side sealing of containers having an externally threaded neck by applying to the mouth of the neck a closure cap made of a permanently deformable metal such as aluminum having a crown to which a resilient sealing liner is secured and an annular skirt depending therefrom having a diameter greater than that of the thread.

The closure cap loosely applied to the container neck is deformed by a sealing head so that a portion of the crown is pressed towards the exterior sides of the mouth portion of the threaded neck whereby portions of the sealing liner are turned inward to form a side seal. This deforming operation is referred to in the art as reforming. The skirt portion of the closure is deformed to effect inter-engagement thereof with the threaded portion of the neck by means of thread rollers positioned symmetrically about the container which inwardly deform the skirt between adjacent thread ribs on the container neck.

Deformable closure caps of the type described above have been adapted to form tamper-proof closures. In the construction of tamper-proof closures, the deformable closure cap forms a removable top portion which is connected to a depending retaining ring portion by means of a series of fracturable bridge members with the retaining ring portion having its lower edge secured to the container by being crimped under an annular flange portion on the neck of the container.

Materials which can be used to form sealing liners in the tamper-proof closures of the type described above are generally rubber-like resilient materials which are flowable under the pressures to which the closure is subjected to during reforming. Plastisol compositions are preferred and are widely used as sealing liners for closures as they are easily applied materials characterized by resistance to acids, beverage, and food products and are relatively tasteless and odorless and are not affected by moisture.

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A serious problem has been encountered in using plastisol lined tamper-proof closures of the type described above is that in an undesirable number of cases, the mounted closure is tilted when applied to the container neck and when this happens the lower edge of the fracturable ring portion of the cap will not come in full contact with the annular flange during sealing. This phenomenon is referred to in the art as mis-tucking. Containers sealed with caps which are mis-tucked have an unattractive appearance and have very poor aesthetic appeal to the consumer.

The problem of mis-tucking using caps lined with liners formed from resilient materials such as plastisols is believed due to a failure of the liner to move freely under the reforming pressures during the sealing operation. In reforming a cap having the plastisol liner secured therein, the portion of the liner in the sealing area is caused to flow or be extruded by the sealing pressures exerted during the reforming operation to create the top and side seal for the container. If the plastisol liner is completely and strongly adhered to the interior cap surface, the extrusion of the plastisol liner material is impeded and a non-uniform pressure is applied to the closure which prevents the cap from being uniformly drawn down the container neck. This non-uniform drawing of the cap causes the cap to be applied to the container neck in a tilted or cocked manner.

SUMMARY OF THE INVENTION The problem of mis-tucking is substantially eliminated in accordance with the present invention wherein there is provided a closure for a bottle or the like container having a neck provided with screw threads and an annular shoulder at a position spaced from the mouth of the neck, the closure being fabricated from a deformable material and generally comprised of a crown portion and an annular skirt depending therefrom, the interior face of the crown being coated with a lacquer layer having a sealing liner composed of resilient material secured thereto, the liner having an outer peripheral annular sealing area and an inner central non-sealing area, the lacquer having a coating applied thereto which contacts the liner in the annular sealing area and creates a low order of adhesion between the liner surface and the lacquer layer so that the liner is strongly adherent to the lacquered interior surface of the crown in the inner central non-sealing area and poorly adherent or substantially non-adherent to the lacquered interior of the crown in the outer peripheral annular seal area.

By applying the plastisol or other resilient liner to the crown shell so that the annular sealing area portion of the liner is caused to be poorly adherent to the lacquered shell surface, free movement of the liner material necessary for sealing occurs, resulting in the closure being applied to the container neck in the correct upright position.

THE DRAWINGS In order that the invention may be clearly understood, some embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which- FIGURE 1 is a sectional view of one form of closure cap according to the invention.

FIGURE 2 is a plan view into the open face of a lacquered closure shell according to the invention.

FIGURE 3 is a like view with a formed liner in place.

FIGURE 4 illustrates the manner of carrying a method of sealing using a closure cap as shown in FIGURE 1.

FIGURE 5 illustrates the reforming of the cap and the interengagement of the skirt with the threads of the neck of the container.

It is to be understood that although the figures illustrate a tamper-proof closure, the present invention is applicable to closures which do not contain retaining rng portions and are not tamper-proof.

Referring to the drawings, FIGURE 1 illustrates one form of closure cap according to the invention, the closure 10 being made of permanently deformable material such as tinplate or aluminum and comprising a crown portion 11, skirt portion 12 and a retaining ring portion 13 formed integrally with the skirt portion 12 and extending downwardly from the lower end of the skirt.

The retaining ring portion 13 of the closure 10 is secured to the lower end of the skirt portion by means of a series of fracturable bridge members 14. By securing the retaining ring portion 13 to the cap 10 in this manner, the ring may be easily severed from the cap portion when the cap is twisted relative to the retaining ring.

As illustrated in FIGURE 2, the interior upper face of the cap 10 is coated with an internal lacquer layer 15. The lacquer can be of the usual type used for coating the interior of closures. If a plastisol liner is used, a suitable lacquer is a solvent solution containing a vinyl chloride-vinyl acetate copolymer with a small amount of maleic anhydride in the vinyl copolymer and also containing a phenolic resin modifier. Such a lacquer applied to metal and baked at 350 F. for 10 minutes gives good adhesion of a hot shaped vinyl chloride resin plastisol liner.

As illustrated in FIGURE 3 a resilient liner or cushion 16 which has a thicker annular portion or sealing ring 17 for engagement with the container lip and a thin central portion 18 is provided in the cap shell 11.

Intermediate the lacquer layer and the sealing liner 16 in the area of the cap interior face encompassed by the annular or sealing ring 17 of the sealing liner is applied a thin coating material 19 which material creates a low order of adhesion between the liner 16 and the lacquered cap shell in the sealing ring area of the liner.

The sealing liner 16 can be made of any material which provides a resilient liner and which is flowable under the pressures to which the closure is subjected in the reforming operation. Suitable materials from which the liner may be formed include rubber/resin blends, including blends based on neoprene, nitrile, natural, styrene-butadiene, and ethylene-propylene rubbers; vinyl resin compositions, including plastisols of vinyl chloride polymers and blends of vinyl resins, polyurethane rubbers and rubber gaskets prepared from solutions or latices and flowed and solidified in position in the closure shell. These materials may be modified by the addition of various additives to impart desirable properties such as fillers, plasticizers, tackifiers, curing agents and antioxidants.

Plastisols are preferred as materials from which the sealing liner can be formed. Useful plastisols for the liner composition include fine granules of vinyl chloride polymers such as polyvinylchloride or copolymers of vinyl chloride with up to about 20 weight percent of a copolymerizable ethylenically unsaturated monomer such as vinyl acetate, vinylidene chloride, dibutyl maleate and mixtures of such monomers, the polymer granules being suspended in a conventional primary vinyl resin plasticizer such as an alkyl phthalate such as dioctyl phthalate or an epoxidized oil such as epoxidized linseed oil, a dicarboXylic acid ester, a triaryl phosphate or a combination of plasticizers.

Thus, the sealing liner composition can be composed in parts by weight of:

The plastisol may be deposited in the cap shells by various known techniques, one being the so-called flowed in technique wherein the plastisol composition in an uncured, pastelike condition is squirted from one or more nozzles into the cap shells which are turned upside down on a chuck rotating at high speed. Due to centrifugal force the sealing liner material will assume the desired contour and shape. After being thus deposited or flowed in the liners are cured by a heating operation according to known procedures and using known equipment. The cured liners will permanently adhere to the lacquered interior of the shell except in the outer peripheral annular sealing area which has been coated with a Icoating which substantially destroys the adhesion of the liner in this area.

The coating material 19 may be of any material which creates a low order of adhesion between the liner and the lacquered shell. Thus the coating material 19 may be a material which is strongly adherent to the lacquered surface of the shell and substantially non-adherent to the liner or conversely the coating material 19 may be one which has greater adhesion to the liner than to the lacquered shell surface.

One class of materials which have been found to be strongly adherent to the lacquered cap shell surface and substantially non-adherent to a plastisol liner are lithographic inks available to the printing art, which inks may be conveniently applied to the lacquered surfaces using conventional printing methods, e.g., silk screening, offset lithography, rotogravure and the like.

FIGURES 4-5 illustrate the method of closing and sealing a bottle when using the cap shown in FIGURE 1. FIGURE 4 illustrates the position of the parts preparatory to the closing and sealing of the mouth of the neck 20, of a bottle being stood on a support, not shown, and the neck aligned with a closing and sealing head 21 which in a known manner, is arranged to be reciprocated into and out of engagement with the closure cap 10 which has been loosely applied to the neck 20.

The head 21 is provided with an arched opening so shaped that when the head is moved towards the cap, the portions 22 of the arch engage the outer peripheral portion of the cap 10, and during continued downward movement of the head, deforms the crown 11 to effect tailoring of the crown 11 about the mouth end of the neck causing the sides and top of the mouth end of the neck to be sealed into and against the sealing liner as shown in FIGURES 4 and 5. During the deformation of the crown portion 11, the sealing ring portion of the liner is caused to flow or extrude by the application of top pressure to the outer peripheral portion of the cap to form a side seal with the outer sides of the mouth end of the neck 20.

When the cap has been applied, and the seals formed as described above, the major portion of the skirt 12 is deformed to effect inter-engagement thereof with the threaded portion of the neck 20. This step is performed in a known manner by the use of a spinning roller or rollers 26, FIGURE 5, the construction and operation of which being well known in the art, are not described herein.

Following the formation of the threads in the major portion of the skirt 12, the lower portion of the retaining ring is crimped under the annular flange 28 of the bottle in the usual manner using known means for this purpose.

This invention is further illustrated by the following examples:

EXAMPLE I Aluminum closures formed of a crown having an outside diameter of 1% inches and a depending skirt having a retaining ring attached thereto of the type illustrated in FIGURE 1 of the drawings were provided with a layer of vinyl lacquer over the entire inner surface. A continuous ring of a printing ink having a width of 0.150 inch was printed over the inner surface lacquer layer in the outer peripheral sealing area of the liner beginning at the edge of the skirt sidewall as shown in FIGURE 2 of the drawings. A continuous pad of a plastisol sealing composition having an outside diameter of 1.050 inches comprised of an annular sealing portion having a width of 0.140 inch and a thickness of 0.028 inch and a center nonsealing area having a thickness of 0.005 inch was then applied to the inner lacquered surface of the crown as shown in FIGURE 3 of the drawings. The plastisol liner was substantially non-adherent t0 the interior of the closure in the peripheral sealing area of the cap to which the printing ink had been applied.

The plastisol lined closures were engaged on screw threaded 28 02. bottles as illustrated in FIGURES 45 of the drawings using conventional closing machines at a rate of 220 bottles per minute (b.p.m.). After application of the closure caps, the bottles were examined for mistucks. The number of mis-tucks per 220 bottles capped in this manner was 10.

By way of contrast, the procedure of Example I was repeated with the exception that the lacquer layer was not printed with a printing ink in the outer peripheral annular sealing area prior to the application of the plastisol liner, and there was total adhesion of the liner to the interior of the lacquered shell. The number of mis-tucks per 220 bottles using these closures was 45.

EXAMPLE II The procedure of Example I was repeated with the exception that the printed lacquer, plastisol lined closures were applied to 16 oz. bottles at 460 b.p.m. The number of mis-tucks per 460 bottles was found to be 2. 7

By way of contrast, the procedure of Example II was repeated with the exception that the interior lacquer layer was not printed with a printing ink in the outer peripheral annular sealing area prior to the application of the plastisol liner and there was total adhesion of the liner to the lacquered shell. The number of mis-tucks per 460 bottles was 42.

What is claimed is:

1. A container closure made from a permanently deformable metal material for application to containers having a screw-threaded neck and an annular shoulder at a position spaced from the mouth of the neck, said closure being comprised of:

a removable top portion, said top portion being comprised of a crown and an annular skirt depending therefrom,

the crown having an internal lacquer layer thereon and containing a resilient sealing liner,

the liner comprising an outer peripheral annular sealing area and an inner central non-sealing area,

The lacquer having a coating in the outer peripheral annular sealing area of the liner which renders the annular sealing area of the liner poorly adherent to the lacquered surface, so that the liner is strongly adherent to the lacquered interior surface of the crown in the inner central non-sealing area of the liner and poorly adherent to the lacquered interior surface of the crown in the outer peripheral annular sealing area of the liner.

2. The closure of claim 1 having a retaining ring portion formed integrally with the top portion of the closure and projecting downwardly from the lower edge of the skirt, at least one of the upper edges of the retaining ring portion being secured to the bottom edge of the skirt by means of at least one fracturable bridge member, the lower edge of the retaining ring being adapted to be crimped about the annular shoulder of the container forming a tamper-proof closure.

3. The closure of claim 1 wherein the coating material applied to the lacquer layer in the outer peripheral annular sealing area is strongly adherent to the lacquer and substantially non-adherent to the liner.

4. The closure of claim 1 wherein the coating material applied to lacquer layer in the outer peripheral annular sealing area is a printing ink.

5. The closure of claim 1 wherein the sealing liner is formed from a plastisol composition.

References Cited UNITED STATES PATENTS 3,411,650 11/1968 Mumford 2l540 3,411,649 11/1968 Mumford 2l540 FOREIGN PATENTS 240,251 9/ 1964 Austria.

GEORGE T. HALL, Primary Examiner US. Cl. X.R. 21542