US1788260A - Pbocess of pboducino closttbes - Google Patents

Description

Jan. 6, 1931. A. H. WARTH PROCESS OF PRODUCING CLOSURES Filed Jan. 7, 1927 Patented Jan. 6, 1931 A UNITED STATES PATENT, OFFICE ALBIN H. WARTH, OF BALTIMORE, MARYLAND, ASSIGNOK, BY MESNE ASSIGNMENTS, TO CROWN CORK & SEAL COMPANY, INC., 01 NEW YORK, N. Y., A CORPORATION OF NEW YORK rnocnss OF rnonncme oLosoBns A Application filed January 7, 1927. Serial No. 159,743.

and gases.

Closures of the well known crown cork type comprise a metal shell having a skirt and a resilient sealingdisk usually made of cork. For some uses, the sealing disks are given a non-absorbent, gas impervious and acid resistant facing of metal foil, e. g. tin' foil, or aluminum foil. Aluminum foil is characterized by the fact that it is substantially non-absorbent and gas impervious, and for thls reason the same and other materlals having similar characteristics are used toform facing disc or spots upon the cushion material of crown caps. Ordinarily this facing is of smaller diameter than the cork disks and such crowns are known in the trade as spot center crowns.

These spot center crowns have been produced in varlous ways. According to one method a slot orgroove is cut in the cork disk crowns so made the spots tend to loosen .as

the paste or glue is attacked by the packaged liquids. Furthermore, such method involves difiiculties in handling and in applying the paste or glue. According to still another method the spots are secured by an underlying tissue of gutta percha or coated paper.

In crowns so .made, like objections are met with. For. example, one difficulty in applying discs made from separate strips, such as,

gas-and acid-resistant material and the adhesive tissue strips, hasarisen from the necessity for feeding the two strips to the punch-v ing and assembly machine. There is not only difliculty in feeding the strips, but in cutting the separate tissue strip with a clean, sharp-edge so as to insure the binding stratum of adhesive being coextensive-in area with the disc of liquid resistant material. As will be understood, the adhesive stratum is intended to act not only as a cement, but also as a waterproof, non-absorbent, gas impervious medium for avoiding the possibility of the contents of a bottle getting between the 'facing disc and the material of the cap, either the metal shelf itself or a cushion disc of cork or composition cork.

Furthermore, when using superimposed strips of the facing material and of adhesive tissue, it was essential, to bond the adhesive tissue to both the material of the cushion disc in the cap and the facing material.

In preparing ,the rolls offacing material and adhesive tissue, the practice usually followed was to form a roll of the tissue in strips of the desired width, and to unwind this roll and a roll ofthe facing material hile feeding the two strips one over the er into the disc forming andassembling machine. This is a troublesome and expensive operation, because of the frequent breaka e of the adhesive tissue and the necessity for using fairly heavy tissue to minimize this tendency. This is due partly to the fact that the facing material was substantially non-elastic, while the adhesive tissue possessed a certain degree of elasticity, thus introducinga factor of diffi- "culty in securing a uniform paying of both the facing strip and the gutta percha tissue strip.

It is desirable, in the use of facing disks of the characterabove referred to, that the adhesive stratum be as thin as possible, and yet be continuous throughout the entire area of the facing disk, and particularly that it be uninterrupted about the edge of this disk, since at this point the disk should be firmly bonded so as to effectively seal the joint-about the edge of the facing disk. When cutting and applying the disks of material and adhesive, there is no means of ascertaining whether the desired conditions are present in the completed cap. Conseguently, there is alwayslikelihood of imper ectly faced caps being produced. r v

- With the above conditions in mind, I have provided material, in stripform, for facing 1w bottle caps, in which one surface of the strip is provided with a firmly adherent, continuous thin facing of adhesive, thus avoiding I s all necessity for assembling strips of facing material and of adhesive tissue preparatory to their use in the bottle cap facing machine,

' and all of the disadvantages growing out of bonded to this material, but has a smooth. surface finish of suflicient thickness" to form the desired firm bond between a disk cut from the strip and the material of the cap to which such disk is cemented.

Furthermore, adhesive tissue mustbe of a thickness to have suflicient inherent strength to permit of its being stripped from a roll in a mill for Working same, and to admit of its being cutto the desired width and to be handled in the Winding and the disk applying machines, and during the process of its production it has more or less of a-longitudinally extending grain, as distinguished from its normal granular formation.

In the application of heat, when bonding the facing material to the cap, when utilizing 'adhesivetissue, a tendency of the adhesive is to break up into slightly-isolated, small globules, thus interrupting the continuity of the bonding stratum. Whether this is due to irregularities in the surface of the facing strip, or to a shrinkage of the adhesive tissue when fused, I have been unable to determine. the stri sive is thoroughly distributed throughout'one face of the facing material, and the above conditions do not develop in the subsequent handling of the strips.

It is an object of the present invention to provide a method of producing .spot center crowns'such that the spots are easily and economically secured to the sealing disks and such that they are firmly secured and not liable to become loosened in use.

With these general objects in view the invention consists in the method which will be impervious, such as metal foil, is coated with. a' substance that is devoid of tackiness when.

dry and has adhesive qualities when-soft. In

carrying out the method according to What is. considered the best practice the adhesive substance is such thatit can be applied cold, i.- e. at room temperatures, and .iswatrproof or insoluble incol'd Water. While various materials may be-used I have found a suitable adhesive in a 'solution'of damar gum and rosin in mineral spirit or turpentine, to which 7 In of my invention, however, the adheis added 57 or less of a vegetable oil such as soya bean or China-wood oil. The damar gum and rosin may 'be in the proportion of 35% to the whole. The adhesive may have a drier of lead resinate or the like in a proportion of 2% or less. This adhesive is water.-

proofhnd is not weakened by gases or acids,

such as are present in the bottle contents with which crown caps are usually employed.

While the coating may be applied to the this condition cannot be disturbed as a resultof the cutting of discs from this material when in strip form. Furthermore, the adhesive surface may be thoroughly inspected while producing the strip material, so that any iniperfect product may be discarded before it reaches the disc applying machine." In this connection it is noted that the spots may be conveniently assembled by feeding a strip of such assembling machinery being known in the art.

After the coating is applied to the metal foil it is dried. While this may be effected rapidly accomplished at a temperature of about 300 F. maintained for about 30 min utes. When dried the'coat-ing is devoid of tackiness so that the metal foil may be handled without difficulty or trouble. This is particularly advantageous when the metal foil is to be fed in strips because the appli' cation of the adhesive is carried out independently ofthe assembling steps. Moreover, the coating' gives the thin metal foil more or less body which facilitates feeding and cutting. Since-the adhesive is applied directly to the surface of the facing or spot material and firmly bonded thereto, there is no likelihood of difliculties arising as a result material over successive crown corks andcut- .t1ng out a disk which 1s deposlted on a cork,

,by air drying at room temperature it isinore of separation ofthe adhesive from the facing 1 strip during the spot forming operation,

either as a result of poor adherence or from suction or otherwise, such as frequently occurs when using superimposed strips of. facing. material and of adhesive tissue. Moreover, in handling this material the adhesive stratum is incapable of stretch or distortion relative to the spot strip as frequently occurs in the handling of separate strips of adhesivetissue and facing mat'rial where any stretch or distortion 'of the "adhesive stratum results in a defective cap and when .the stretch is extreme, tearing-of theadhesive tissue makes necessary the stoppage of the cap machine until thes'tripban be repaired I lifter thecoating isdry, the metal foil spots are assembled, coated side down, with the sealing disks. In case the metal foil is fed in a strip, spots may be cut out and deposited on the sealing disk,-as above set forth.

At the time of assembly the coating ma terial is softened to render it adhesive and the assembledunit is subjected to pressure.

In carrying out the invention according to what is now considered the best practice the coating will be softened by heat after the crown is assembled. In cutting discs from this improved laminated strip having an adhesive stratum bonded thereto, there is no tendency toward mutilation of the adhesive layer by reason of possible drag of the cutting dies..and each disc. as delivered from the die 1 to within a cap, will present a continuous uninterrupted adhesive surface upon the disc so as to insure, by the subsequent application of heat and pressure, a bond between the disc. and the cap cushion layer coextensive in area with the disc. a

This possibility of securing'a clean cut by the dies for forming the discs, both as to the non-absorptiveand gas inipervious, and as to the adhesive stratum, insures an effective bond entirely about the edge of the spot or disc. thereby presenting a continuous barrier of non-absorptive and gas impervious material at the space between the disc and the cap which Will effectively prevent the seepage of gas or fluid in a bottle between the disc and the portion of the cap to which it is applied.

Although the adhesive facing is sufficiently thick to provide an adhesive stratum or layer,

. it is sufficiently thin to avoid anytendency toward the expression during the application of pressure of any, of the adhesive from between the facing material and the portion of the cap to which it is applied. This may be accomplished in-any-suitable manner, as by a heated plunger or a plungeran'd heated table. The heat softens the coatingand renders it adhesiveand the. pressure serves to unite th metal foil spot to the cork.

Referring to the accompanying drawings,

there i sishown suitable mechanism for coat-- ing the strip and for cutting discs therefrom and adhesively uniting the disc to caps at the time of the assembly of the discs with the caps. In the drawings, Figure 1 is a diagrammatical view showing the coating of the strip.

Figure 2 is a longitudinal sectional view of a fragment of the strip. Figure 3 is a side elevational view partly in section showing one step; in the assembly operation. Figure 4 is a View similar to Figure-3 showing-the spot as it is cut and adhesively united to the cap at thetime of assembly.

Figure 5 is an interior face view of the completed cap,and

. shown in Figure 5.

' non-absorbent and gas impervious.

The strip of facing material should have the characteristic of aluminum foil. That is to say, it should present one surface which is This strip may be fed from a reel 10 to a reel 11, suitably separated so that the adhesive coatingma-y be applied and hardened between the time any portion of the strip leaves the reel 10 and is wound upon the reel 11. For the purpose of applying the adhesive, the same may be maintained in a trough 12, positioned beneath an adhesive applying roll 13, between which and a roll 14, the strip passes, so that as the rolls are rotated the adhesive is applied to the undersurface thereof. As will be understood. the adhesive hardens between the time it is applied and the winding of the laminated strip upon the reel 11.

The completed spot material or liner is illustrated in Figure 2, and comprises the layer 15 of non-absorbent and gas impervious material, such as aluminum foil having on one surface the coating 16 of adhesive, which is preferably of the character hereinbefore described. This adhesix e is waterproof or liquid resistant. and will be normally hard,

i. e. non-tacky. at room temperature so that the material may be conveniently handled in strip form. but quickly softens under the application of heat. becoming tacky. so that upon the application of pressure. the laminated disc will be adhesively retained in the cap. The preferred method of applying the material to the cap is to utilize. at the time of assembly. both heat and pressure to unite the. spot to the cork or cushion material insert or facing of the cap.

In Figures 3' and 4, there is shown a suitahesively unitingit to the cork insert at the time the strip ispuncbed from the disc and assembled with the cap.

The cap 17 is of the conventional crown type having an interior facing 18 of cushion material, such as composition cork retained in the cap as by an adhesive layer 17 the cushion discan'd adhesive may be applied to scends .it will cut from the strip, which is fed 1 ble mechanism for applyingthe disc and adby any suitable means (not shown), a spot or facing 22 of the character illustrated in Figures 5 and 6. The spotor disc is preferably of smaller diameter than the cap fac-. ing so as to form a substantially centrally disposed spot which leaves around its edge an exposed portion of the cushion material adapted, to engage the edge. of a bottle neck, the spot being of sufficient size to close the bottle mouth and prevent contact of the contents with the cushion material.

As will be observed (Figures 3 and l) as the punch descends, it cuts from. the strip a spot of the size shown in Figure 5, and continued downward movement presscsthis disc upon the cushion layer 18.

The punch 20 may be maintained at an elevated temperature, as by means of a burner 23, andthe temperature should be suflicient to fuse -or soften the adhesive coating and make it tacky so that, at the time the disc is assembled with the cap, the heat and pressure will cause the disc to be adhesively united to the surface of the cushion material with suffi- 'cient permanency to insure that the position will be retained and avoid likelihood of displacement of the disc thereafter.

The assembled unit is then permitted to cooland the cooling may advantageously be coupled with pressure. for example. by a plunger. Cooling may be effected in any suitable manner, being carried out to the congealing point of the coating material.

The resulting crown has a firmly secured metal foil spot which is not liable to become loose in use owing to the fact.that the adhesive substance is not soluble in liquids more commonly sealed by crown corks. Moreover, when the metal foil is assembled with the sealing disk it is already prepared for being stuck in place. the sticking being accomplished by the simple application of heat and pressure. The coating operation is a simple one and the coatedmetal foil is easily handled because the dry coating is not tacky.

A cap made in accordance with this method possesses the advantage of a substantially uniform and complete distribution of the adhesive layer throughout each spot br facing and having another surface to be exposed to the contents of a capped container, cutting from said strip a facing spot having one surface completely coated with said adhesive with a cap disposed beneath the portion of the strip-from which the spot is cut, whereby the cutting operation positions thespot upon the cushion material with the coating between the spot and the cushion material, and upon assembly applying simultaneously to the spot pressure and sufiicient heat to "render the adhesive tacky, thereby causing the spot to adhere to the cushion material, and thereafter permitting the adhesive to cool and harden.

2. The improved method of manufacturing caps of the type having an interior disc of cushion material provided on its exposed face with a center spot, which comprises pro viding metal foil spot material in strip form having one surface formed of an exposed continuous coating of water resistant adhesive which is normally hard at room temperature but becomes tacky upon the. application of heat and having another surface to be ex posed to the contents-of a capped container,

cutting from said metal foil strip a facing spot having one surface completely coated with said adhesive with a cap disposed bem hand.

y ALBIN H.- WARTH.

disc. The method has the advantage of v eliminating the labor of associating-a sepa rate adhesive strip and a strip of facing material, and the further advantage of enabling higher speeds to be maintained in the facing spot applying machine. The elimination of the danger of breakage of a separate adhesive tissue strip avoids the frequent stoppage of the machine, which was unavoidable due to the handling of the, somewhat fragile and elastic adhesive tissue.

What is claimed is: 1. The improved method of manufacturing caps of the type having an interior disc of cushion material provided on its exposed face with a center spot, which comprises providing spot material in strip form having one surface formed of an exposed continuous coating of water resistant adhesive which is normally hard at room temperature but be- I comes tacky upon the application of heat

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