US2149378A - Process of packaging - Google Patents

Description

March 7, 1939. E. N. wlNsLow PROCESS OF PACKAGING Filed April 1, 1937 PAPA/FIN Mun/rom- [aw/m0 M Mmszow 147 ram/v5) Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE signor to E. I. du Pont de pany, Wilmington, Del

aware Nemours & Coma corporation of Del- Application April 1, 1937, Serial No. 134,285

5 Claims.

This invention relates to packaging and is particularly directed to processes for packaging corrosive chemicals wherein a cap is applied to a stoppered receptacle and a sealing medium then 5 introduced between the cap and the stopper.

In the packaging of chemicals for transportation numerous problems are presented which are not elsewhere encountered in the packaging arts. Thus, in the packaging of corrosive liquids such as acids and the like, the ever present possibility of leakage constitutes such a hazard that every available precaution must be taken to confine eifectively the contents within the containers. So acute is this particular problem that federal regulation has been invoked to the extent that no packages'may be accepted for transit by a common carrier unless they are of a type approved by the government authorities.

Corrosive liquids are commonly packaged in containers known to the trade as C. P. acid bottles. These bottles are of the type wherein the lip projects slightly beyond the neck to provide an annular shoulder and wherein the neck is fitted with a ground glass stopper. It is to be under- 25 stood however that notwithstanding the implication of the name, the use of C. P. acid bottles is neither confined toacids nor to chemically pure (C. P.) substances. While a ground glass stopper in itself provides 30 anadequate seal its tendency to become dislodged under the condition of handling in transit requires that adequate means be provided to seal or securely fasten it in its proper position. This tendency of the stopper to become dislodged is 35 augmented by pressure variation within the air space of the bottle due to variations in the ambient temperatures during transit. Consequently, before the stopper is sealed or securely fastened in place it is desirable that steps be taken to pro- 40 vide a reduced pressure Within the air space.

Heretofore the customary practice has been to seal the stopper in place with plaster. Plaster of Paris suitably admixed with water to form a paste of desired consistency was molded by hand about the stopper and the neck of the bottle and secured in place by abinding of muslin. Upon setting, the plaster provided an exceedingly hard and tenacious encasement which, due to its interlocking engagement with the shoulder on the bottle neck, could not be removed except by chip- Gil ping or'otherwise breaking it away. This operation besides being tedious and onerous was frequently accompanied by breakage of the bottle neck.

The disadvantages attending the use of the plaster seals led to the use of paraffin. Paraffin heated until it was plastic enough to be freely Worked with the hands was molded about the stopper and the neck and bound with muslin fol- 5 lowing substantially the same procedure used in connection with the plaster seal.

The application of the parafiin was subsequently simplified by the use of strip parafiin. These strips heated to a plastic condition were wound about the juncture of the stopper and the neck of the bottle and molded in place by hand. The excess paraffin was then trimmed away and the top of the bottle dipped in melted parafiin.

Instead of dipping as above indicated a rubber cap was also applied after the molding and trimming of the parafiin. This cap, similar in shape to a thimble and provided witha bead at its open end, was tightly stretched over the sealed stopper and about the neck of the bottle with the bead engaging beneath the shoulder on the neck of the bottle.

Although satisfactory seals were produced with paraflin, particularly in conjunction with the rubber caps, the processes were uneconomical and disadvantageous in that the parafiin had to be molded into place by hand and then trimmed away. The necessity of maintaining the paraffin at a proper plasticizing temperature so that it could be readily worked was also decidedly inconvenient.

A further disadvantage arose not so much from the uneconomical procedure as from the inherent limitations of the processes involved. Irrespective of how much care was taken in the molding of the paraflin in place it was not possible to secure intimate penetration of the sealing medium into and about the juncture of the stopper and the neck of the bottle. Furthermore the seals soproduced were layered and unhomogeneous.

I have now found that by capping the bottle and then sealing, certain of the disadvantages of the prior art may be avoided. By first applying the cap and then introducing a sealing medium,

I dispense with the necessity of hand molding and trimming the sealing medium. as the cap acts as a mold to confine and shape the sealing medium about the juncture of the stopper and the neck. Similarly, due to the confining action of the cap, I may introduce the sealing material in a liquid state, under pressure if desired, so that intimate contact with and penetration into and about the juncture of the stopper and the neck of the bottle is afforded, and so that a unitary solidified mass of sealing medium is provided.

It is an object of my invention to avoid certain of the disadvantages of the prior art. It is a further object of my invention to provide processes which are economic and which may be carried out with a minimum of handling and manipulation. It is a further object of my invention to provide a package which may be fabricated in a simple and expeditious manner, which effectively safeguards the contents in transit and which is easily opened when desired. Further objects of my invention will be apparent hereinafter.

Referring now more specifically to a particular embodiment of my invention I have illustrated in the accompanying drawing a quartersectional side elevation of my improved package showing the manner in which the sealing medium is introduced.

The particular construction and advantages of my improved package which consists briefly of a glass bottle l, a ground glass stopper 2, a rubber cap 3, and a parafiin seal 4, will be readily apparent from following description of the manner of its fabrication.

My preferred process which is particularly adapted to the packaging of corrosive liquids in C. P. acid bottles of the type illustrated at l consists briefly of the steps of filling, evacuating, stoppering, capping and sealing.

The filling and evacuating are effected in the usual manner, care being taken to provide sufficient gas space as indicated at 5 to accommodate volume changes in the contained liquid. Ordinarily with 5-pint bottles of the type illustrated the liquid level should not exceed about eight and one-half inches from the bottom of the bottle. The relative size of gas space for these conditions is illustrated substantially to scale in the accompanying drawing.

The rubber cap is then applied so that it exerts sufficient'tension on the handle 6 to hold the stopper in place and is securely fastened to the bottle neck I by the engagement of the bead 8 beneath the shoulder 9. It is desirable, however, that the stopper be wedged firmly in place as for example by a light tap with a mallet, so that too much reliance need not be placed upon the rubber cap holding it firmly in position.- It is important also that a certain amount of care be employed in applying the rubber cap in order to tension it evenly about the neck of the bottle so as not unduly to constrict at any point the free space about the stopper. The cap may be applied with apparatus suitably designed to expand it over the neck of the bottle.

Melted paraiiin is then injected into the confines of the rubber cap where it flows about the juncture of the stopper and the neck of the bottle and solidifies under the confining action of the rubber cap. The injection of the melted paraffin is effected by means of the hypodermic needle illustrated at l0 to which melted paramn is supplied by a suitable pressure gun.

The amount of the melted parafiin injected may be controlled by the use of a pressure gun adapted to deliver measured amounts of parafiin upon each actuation. -An ordinary oil gun of the type having a pistol grip and a triggerlike actuating lever may be employed. Thus the operator need only to pierce the rubber cap and actuate the pressure gun once or twice to complete the sealing of the bottle.

The injection of the melted paraflin in this manner causes a slight bulging of the" rubber cap due to the compression of the air entrapped within the confines of the rubber cap. Upon the withdrawal of the needle, however, this entrapped air immediately leaks out thru the puncture allowing the cap to return to its normal position prior to the solidification of the melted parafiin.

The quantity of parafiin introduced should be sufficient to form a relatively heavy annular mass about the stopper as indicated at 3. It should not, however, be injected in amounts which would cause excessive bulging of the rub ber cap or which would materially cover the handle portion of the stopper. The extent to which the rubber cap is bulged by the injection of the paraffin may be used as a visual indicator by which the operator may judge approximately the amount of paraflin introduced.

The parafiin so injected penetrates into every available crevice and as shown at H, slightly exaggerated for the purpose of illustration, penetrates between the stopper and the neck substantially to the point of juncture. This point of juncture varies somewhat with the different bottles depending upon how well the stopper is ground in the neck, but ordinarilyit is well within the neck of the bottle.

The extent of the penetration of the paraflin depends upon the rate of its solidification which in turn depends upon the temperature of the melted parafiin as well as the temperature of the bottle. The minimum temperature at which the melted paraffin can be conveniently handled will insure adequate penetration. Consequently the bottle may be relatively cold, that is, not heated above room temperature more than is incidental to the filling and evacuating. Furthermore if the stopper is inserted loosely or is unground a hotter bottle may cause the parafiin to run thru past the stopper and into the bottle.

When the pressure gun is not in use, I'have found it expedient to keep it in a heated inolosure to prevent the solidification of the melted paraffin. A small heating plate may be sufficient for this purpose although a heated inclosure such as a small oven is preferred.

It is particularly important to guard against solidification of the paraffin within the hypodermic needle. Qtherwise the excessive pressure developed by the gun may cause the needle to be shot off. As a precautionary measure it is advisable that the needle be wired or otherwise securely fastened to the gun. Additional protection against injury from or to the needle may also be provided by a looped wire guard so arranged as not to interfere with the puncturing of the cap. 7

7 As has been previously indicated, the nature of the package may be readily understood from a consideration of the process of its fabrication. It is principally characterized by the solidification of the molten parafiin about and within the juncture of the stopper and the neck in the, form of an annular ring. When the stopper is removed, as may be accomplished easily by lightly tapping or applying finger pressure alternately on one side and then the other of the handle, this annular ring usually remains intact in the form of an annular guard to prevent the corrosive liquid from running off the stopper proper onto the handle or onto the hand of the user.

While I have described my invention as comprising primarily the steps of evacuating and sealing a container, it is readily apparent that in certain circumstances the sealing may follow immediately after the filling without any interven-' ing steps other than the stoppering and capping. Thus where a liquid having a high vapor pressure is packaged, the atmosphere within the gas space i may consist principally or perhaps wholly of the is made small enough vapor of the liquid packaged, or with ammonium hydroxide, of a mixture of ammonia and water vapor. With such liquids the pressure within the bottle would be governed almost completely by the vapor pressure of the contained liquid so that little if any improvement could be effected with any means of evacuation. Similarly, the conditions of exposure during storage and handling may not be severe enough to require evacuation or the stopper may be so securely fastened in place as to admit of greater variations in pressure.

Under these circumstances and particularly in connection with the packaging of ammonium hydroxide, considerable breathing may occur. The gases so discharged have a tendency to bulge the rubber cap necessitating the provision of breather holes. In the prior practices this was accomplished by pin-pricking each cap after its application. It is readily apparent that in my improved process the hypodermic needle, besides functioning to inject the sealing medium also eliminates the necessity of individually pinpricking each cap.

In the preferred embodiment above described I have disclosed the formation of the seal by the application of a rubber cap and the injection of melted paraflin. It is to be understood, however, that Within the broader aspect of my invention other types of caps, other sealing mediums, and other methods of introducing the sealing medium may be employed.

Although I have found elastic caps, such as the rubber cap described, to be particularly advantageous because of the eifective manner in Which they hold the stopper in place and mold the sealing medium about the juncture of the stopper and the neck of the bottle, it is apparent that any cap capable of acting as a mold to form and shape the sealing medium may be employed. The cap of course must be impervious to the sealing medium and should be relatively inexpensive material so as not materially to increase the cost of production.

I have produced satisfactory seals by simply tying a thinsheet of rubber about the neck of the bottle and introducing the sealing medium in the manner previously described. I have also produced excellent seals by the use of shrinkable caps. In the case of the latter it is preferable that the cap be pierced before it has completely dried so as to avoid the possibility of the taut material splitting. Similarly, I may employ caps made of other materials such as aluminum, lead, paper, synthetic fabrics, gelatin and the like.

It isnot essential that the cap completely inclose the stopper. I am able for example to employ a relatively shallow rubber cap provided with a central opening thru which the handle of the stopper projects. Preferably this opening to encompass tightly the stopper in order to provide a completely confined space into which the sealing medium may be injected. It is to be understood, however, that any cap, whether it forms a complete inclosure or not, may be employed providing it forms a confined space about the neck of the bottle to receive and shape the sealing medium about the juncture of the stopper and the neck of the bottle.

As noted above, certain of the advantages of my invention may be obtained with caps other than the rubber cap illustrated. It is also apparent that certain of the advantages of my invention may be obtained when the sealing medium is introduced in other ways than by injection with a hypodermic needle. For example, where the cap does not completely inclose the stopper and does not provide a completely closed space for the reception of the sealing medium, the sealing medium may be poured in from any convenient pouring spout. Similarly where the cap is constructed of material not easily pierced with the needle the sealing medium may be included in solid form within the cap at the time of its application and subsequently caused to be come liquid, as for example, by the application of heat.

As disclosed in the preferred embodiment of my invention, I prefer to use parafiin as the sealing medium as I have found it to possess properties particularly suited for my purpose. Besides being relatively inert to the majority of chemicals, it is easily liquefied at low temperatures. In the liquid state it is sufliciently fluid for ready extrusion thru a hypodermic needle. It is, likewise, sufficiently fluid to flow readily about and into the juncture of the ground surfaces. In the solid condition it is sufiiciently firm to retain its shape under normal conditions of handling but is neither hard nor brittle. Likewise it does not adhere to the glass so tightly as to render removal diflicult.

It is to be understood however that I may employ any readily liquefied sealing medium which is sufficiently fluid in the liquid state to flow easily about the stopper and the neck of the bottle under the confining action of the applied cap. Preferably I employ, particularly in those instances wherein a glass stoppered bottle is employed as the container, such material as is sufficiently fluid to penetrate between the stopper and the neck to the point of juncture. For this purpose I prefer to use materials having substantially the same properties, though not necessarily to the same degree, as paraffin, such as cements, gels, waxes, resins, and the like, which are sufficiently fluid in the liquid state to be readily extruded thru a hypodermic needle.

As has been previously indicated, it may be desirable under some circumstances to eliminate the step of evacuation. It is also apparent, particularly with containers which do not present the same problems in regard to the evacuation as the glass stoppered bottles, that other ways of producing evacuation may be employed.

While my invention is particularly useful in sealing glass stoppered bottles because of the numerous difficulties encountered in sealing this type of bottle, it is nevertheless capable of being used effectively in conjunction with other types of stoppered containers.

I claim:

1. In the production of a package comprising a stoppered container, a cap about the stopper and engaging the container to form a confined space about the juncture of the stopper and the container, and a normally solid sealing medium within the confines of the cap to seal said juncture, the process for sealing the juncture of the stopper and the container which comprises applying the cap and thereafter piercing the cap and injecting the sealing medium in its liquid state thru the puncture into the confines of the cap, whereby the sealing medium flows about the juncture of the stopper and the container and solidifies under the confining action of the cap.

2. In the production of a package of a corrosive liquid comprising a glass-stoppered bottle, an elastic cap about the stopper and engaging the neck of the bottle to form a confined space about the juncture of the stopper and the neck of the bottle, and a wax seal within the confines of the elastic cap for sealing said juncture, the process for sealing the juncture of the stopper and the container which comprises applying the elastic cap and thereafter piercing the cap and injecting melted wax thru the puncture into the confines of the cap, whereby the cap serves as a mold to form and shape the seal.

3. In a process for sealing a glass-stoppered bottle provided with a rubber cap to form a confined space about the juncture of the stop-per and the neck of the bottle, the steps comprising piercing the rubber cap and. injecting melted paraffin thru the puncture into the confines of the rubber cap, whereby the parafiin flows about the juncture of the stopper and the neck of the bottle and solidifies under the confining action of the rubber cap,

4. In a process for packaging material in a stoppered container, the steps comprising stoppering, applying a cap to form a confined space about the juncture of the stopper and the container, and then piercing the cap and injecting through the puncture a normally solid sealing medium in its liquid state into the confines of the cap, whereby the sealing medium flows about the juncture of the stopper and the container and solidifies under the confining action of the cap.

5. In a process for packaging a liquid in a glass-stoppered bottle, the steps comprising stoppering, applying a cap to form a confined space about the juncture of the stopper and the neck of the bottle, and then piercing the cap and injecting melted wax through the puncture into the confines of the cap whereby the wax flows about the juncture of the stopper and the neck of the bottle and solidifies under the confining action of the cap.

EDWARD N. WINSLOW.

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