US2013119A - Container closure - Google Patents

Description

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A. IH. WARTH Sept 3 35.

CONTAINER CLOSURE F'iled Jan. 9, 1934 2 Sheets-Sheet 1 Sept 3, 1935. A. H. WARTH www@ CONTAINER vCLOS URE Filed Jan. 9, 1954 2 Sheets-Sheet 2 Patented Sept.l 3, 1935 UNITED 4STATES CONTAINER CDOSUR Albin n. wenn, Baltimore, Md., minor to Crown Cork t Seal Company, Inc., Baltimore, Md., a corporation of New York Application January 9, 1934, Serial No. 705,938

2 Claims.

The present invention relates to closures for Vcontainers and has as its object to provide such a closure having a, sealing coating of improved characteristics.

5 Coating strata on the exposed undersurfaces of closures have long been used in the art. but heretofore they have had to be carefully selected with reference to the characteristics of the particular container contents. Coatings satisfactory for l0 use on closures for containers filled with one prod- -uct are frequently unsatisfactory for association with other contained products, and the greatest care must be observed to insure the use of a suitable coating.' For example, coatings satisfactory for use on closures for containers filled with an acid product may be entirely unsatisfactory for use with an alkaline product. An oil varnish coating, it may be stated, is not suitable for use with an alkaline product since zo the effect of the alkali is to saponify the oil and thus destroy the coating.. c

Apart from these considerations, 'due regard-- must be had to the physical characteristics of the coating. It must be stable, odorless, tasteless, and readily handled. It should also have the attribute of mobility. that is, under application pressures, whether moderate or extreme, it should be able to accommodate itself to the minute irregularities present in the container 30 finish against which it seats in use. In other words, the coating should have some capability of flow so that it will conform somewhat to the opposed seating surface under ordinary application pressures. Oil varnishes possess this last 35 attribute to a high degree, but as above intimated,

voil varnishes have other serious disabilities.

In short, heretofore no universal coating material has been found, and by this I mean there has been found no coating material having the 4a desired physical qualities and yet of such composition as to be entirel-y unaffected as the result of contact with `any of substantially the entire range of products ordinarily put up in bottles, `lars and the like. l

I have discovered that lacquers having a vinyl resin base completely fill the requirements above discussed. The vinyl resin base ordinarily vinyl acetate resin or a mixture of vinyl acetate and vinyl chloride resins, is transparent, odorless,

tasteless and in a suitable solvent isreadily applied to a clean surface to form a thin impervious adherent coating. In spite of the fact that the coating is tough and firm, it has the sealing characteristics `of the best of oil varnishes. It is stable, chemically inert, and is resistant to acids,

in any ordinary strength, to alkalies and to salts. It is ideal for use in the case of pharmaceutical preparations, foods, and beverages, and may be truly said to be of universal application.

'Ihe vinyl resin lacquer is applied to the exposed inner surface of removable closures of all types, such as screw closures, lug closures, friction closures,.and closures of the crown type. While the coating may be applied directly to the closure shell or blank in some instances, I ordinarily prefer to apply the coating to a facing layer and to interpose a cushion liner between the facing material and the closure shell. 'I'he coating may be very advantageously used for foils such as zinc, tin, lead, and compositions and most particularly aluminum foil. Aluminum foil is obtainable in very light weights adequate for ordinary purposes. By reason of its light weight the aluminum foil, in the practice of the invention, is preferably mounted on a light weight paper not only for the purpose of facilitating handling but also for the reason that as compared to tin foil, for example, it lacks comformability, unmounted, by reason of its relative stiffness.v The foil is united with the paper by means of a thermoplastic adhesive and this adhesive may be a suitable Vinyl resin solution if desired, the adhesive stratum then serving as an auxiliary to the exposed vinyl resin coating stratum in enhancing sealing efficiency. For many types of closures an even heavier cushion insert may be desirable. The mounted aluminum foil in this case may be affixed to a base of cardboard or the like. In some cases the aluminum foil maybe applied directly to a cushion liner, such as cork.

I prefer to use the vinyl resin coating asV an adjunct to a foil facing sinceifoil basa smooth ne textured surface to which the lacquer may be most effectively applied, and I preferaluminum foil on account of its cheapness due tothe light weight which may be satisfactorily used. Since aluminum foil is easily affected through contact 4with many substances and since through such contact it may adversely aifect the substances, it must ordinarily be provided with a protective coating of some nature. In view of the universal effectiveness of a vinyl resin coating the combination of the aluminum foil and the vinyl resin coating is extremely advantageous from all points of view. As above mentioned, however, the lacquer may be applied directly to the closure material as to the exposed inner surface of a cap of metal or other material.

In short, the invention is not limited to use with closures of any particular design, make-up; or

material. and is susceptible of many variations. A number of practical embodiments are shown in the accompanying drawings solely by way of example, and the further description will proceed with reference to these drawings, of which Figure l is a face view partly broken away of a paper mounted foil provided with a vinyl resin coating,

Figure 2 is a face view of a paper mounted coated foil in turn mounted on a relatively heavy cushion sheet,

Figure 3 is a cross section of the sheet shown in Figure 1,

Figure 4 is a cross section of the sheet shown in Figure 2,

Figure 5 shows in cross section a composition cap of the screw type provided with a liner of the make-up shown in Figure 2,

Figure 6 is a cross sectional view of a lug cap provided with a liner of the make-up shown in Figure 1,

Figure 'l is a bottom plan view of a crown cap provided with a spot of the material shown in Figure 1,

Figure 8 is an enlarged cross sectional view on the line 8-8 of Figure 7,

Figure 9 is a cross sectional view of a disc closure having a coated single ply facing aflixed directly thereto,

Figure l0 is a cross sectional view of a cap of the friction type faced with a single ply of coated material,

Figure ll is a cross sectional view of a bottle top and screw closure to the undersurface of which latter the coating is directly applied,

Figure 12 shows in cross section a liner comprising a varnished foil mounted on relatively thick cushion material,

Figure 13 shows a disc closure in cross section, the closure comprising a facing of the material shown in Figure 1,

Figure 14 is a cross sectional view of a closure cap provided with a varnished spot, and

Figure 15 is an enlarged cross sectional view of a portion of a bottle top and screw closure provided with a liner of the material shown in Figures 2 and 4.

Referring to the drawings, Figures 1 and 3 show a preferred form of liner material. Reference numeral designates a lamination of thin aluminum foil preferably not over .001 inch in thickness. The foil should in any event not be substantially less than .0005 inch in thickness, since below this point it is apt to be porous, and preferably it should not be less than .00065 inch in thickness. The foil is shown as united with a thin paper lamination 2i by means of a thermoplastic adhesive 22. The paper is preferably a light-weight bond but this is not essential, as other types of paper may be used. The paper used is ordinarily about .003 inch in thickness but there is, of course, no limitation in this respect. As mentioned above, the adhesive 22 may have a vinyl resin base if desired, but for the best results the adhesive in any case should be thermoplastic and water insoluble.

Applied to the exposed face of the foil 20 is a coating 23 of vinyl resin lacquer and the formula for the lacquer, while subject to variation, may be as follows:

Vinyl acetate resin 100 grams Abalyn (methyl abietate) 1/2 gram N-butyl acetate 400 cc. Acetone 100 cc.

mula is typical:

Vinyl acetate and chloride resins 100 grams Methyl isobutyl ketone 250 cc. Toluol 150 cc. Dl-butyl ketone 50 cc. Xylol 50 cc.

Di-butyl cellosolve phthalate (plasticizer) 25 cc.

Nitrocellulose may be made an ingredient of the vinyl acetate resin lacquer if it is desired to enhance the adhesiveness of the lacquer, as for use in uniting the foil and paper laminations.

The vinyl resin coating is ordinarily applied by brushing or spraying and no very great thickness is necessary. Ordinarily, the lm ranges around .0005 inch in thickness but this may be varied. As will be understood, relatively thin films of this character, as distinguished from a sheet, do not interfere with the function of the foil as a part of the sealing medium. Stated another way, the film is of such thinness that the foil does not lose its identity as a sealing means.

1n Figures 2 and 4 the two-ply material of Figures 1 and 3 is shown as being mounted on a relatively thick cushion layer such as cardboard, this base layer being designated by the reference numeral 24. The paper layer 2l is adhesively ailxed to the base 24 by means of an adhesive 29 of any suitable nature such as a casein adhesive.

Figure 5 shows a disc 25 of the material of Figures 2 and 4 associated with a cap 26 having a composition body or shell. The disc is retained in the top of the shell by the threads, as here shown, but it may be adhesively aillxed, if desired. Upon application of the cap the paper and cardboard layers yield to permit the coated foil to seat effectively against the container finish. The paper layer of itself has an appreciable measure of compressibility and may be used without the thick base with satisfactory results. I have shown in Figure 6 a cap 21 of the lug type having a body or shell provided with an adhesively affixed disc 2B of the two-ply material of Figures 1 and 3.

In Figures 7 and 8 I have shown a spot facing 29 of the material of Figures 1 and 3 adhesively aflixed to the cork liner 30 of a crown body or shell 3|, the spot functioning as described in the patent to McManus, No. 1,339,066, May 4, 1920.

In Figure 9 I have shown a. closure of the disc type, the closure comprising a. body-in the form of a ductile dise 32 provided with an overall facing 33 which is adhesively amxed by a thermoplastic adhesive and which has applied to its exposed surface a coating 3l of vinyl resin. The layer 33 may be one of the softer foils or of cellulosic substance. In Figure 10 I have shown a similar layer 35 applied to a cap 36 of friction type, the layer being in the form of a disc slightly overlying the inner lower marginal portion of an annular gasket 31 and having on its exposed face a coating 38 of vinyl resin.

In Figure l1 I have shown a metal screw cap 31 threaded on the upper end of a bottle neck Il.

The exposed lower surface of the metal shell or body has a coating 39 of vinyl resin applied directly thereto, and a compressible annular gasket 40 is interposed between the cap and the bottle. The cap may be stamped from a pre-coated metal sheet and in this case, the entire inner surface of the shell will be protectively coated, as shown. On the other hand, the vinyl resin lacquer may be applied, as by spraying, to the formed shell and the coating may be localized on the flat inner surface, if desired. When the lacquer is applied in this way, the gasket may be applied prior to the setting of the lacquer so as to be adhesively retained in place thereby.

In Figure 12 I have shown a liner material which contemplates a layer of foil 4I directly bonded to a cushion base 42 such as cardboard by means of a thermoplastic adhesive 43, such as vinyl resin, the exposed face of the foil carrying a coating layer 44 of vinyl resin. Discs of this material may be used'in the manner indicated in Figure 5.

Figure 13 again shows a closure of the disc type. In this figure, however, the ductile body member 45 has 'applied thereto a facing 46 of the material lshown in Figures 1 and 3. It will be evident that the thickness of the materials and of the adhesive and coating strata areconsiderably exaggerated in this view as well as in other views of the drawings. Actually the material of Figures 1 and 3, for instance, is of slight thickness, as will be understood.

In Figure 14 I have shown a crown cap 41 having a cork liner 48 to which is directly applied a spot facing 49 of aluminum foil by means of a thermoplastic adhesive 50, the exposed face of the foil having a coating layer 5I of vinyl resin. Ordinarily, I prefer to use a paper mounted aluminum foil even when a thick cushion liner is used since the paper enhances the sealing action of the foil.' However, the unmounted foil may be used, particularly in the case of closures such as crown -caps which are applied with a high application pressure.

In Figure 15 I have shown a portion of a metal screw cap 52 and a portion 53 of a bottle neck with which the cap is associated. The cap includes a. facing layer 54 of the material shown in Figures 2 and 4. Figure 15 shows how the layers 2| and 24, being assumed to be paper and cardboard respectively, are compressed between the shell and the lip of the bottle. It will also be noted that the vinyl resin coating 23 has owed slightly at the edges of the neck under the pressure, materially enhancing the sealing effect; 'I'he vinyl resin, as above mentioned, behaves substantially as a long oil varnish under sealing pressures.

If desired, the vinyl resin lacquer maybe colored, the coloring agents being chosen which are acid and alkali resistant, as Hansen yellow for a yellow lacquer.

It will be understood that the present disclosure is merely illustrative and not restrictive of the invention as defined in the following claims.

I claim:

1. A container closure including a sealing cushion comprising a base of relatively thick and compressible substance, a facing of foil on said base and affixed thereto by means of a stratum of thermoplastic adhesive, and a protective sealing film of vinyl resin lacquer on the exposed surface of said facing, said film being of such thinness that the foil does not lose its identity as a sealing means.

2. A liner for container closures comprising a facing of relatively thin metal foil, not exceeding substantially .0010" in thickness, having on its exposed surface a film of vinyl resin lacquer, a layer of paper beneath said metal foil united to the metal foil by a fllm of thermoplastic adhesive, and a. base layer of relatively thick cushion material to which said paper layer is adhesively united, said lacquer film being of such thinness that the foil does not lose its identity as a sealing means.

ALBIN H. WARTH.

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