US2376899A - Sealing facing and closure - Google Patents

Description

. May 29, 1945.

I. F. BULATKIN SEALING FACING AND CLOSURE Filed Aug. 19, 1942 2 Sheets-Sheet l mvwgm y I. F. BULATKIN I 2,376,899

Patented May 29, 1945 .p ED STATES PATENT OFFICE I SEALING FACING AND CLOSURE Iliya F. Bulatkin, Baltimore, Md., assignor to Crown Cork & Seal Company, Inc., Baltimore, Md.', a corporation of New York ApplicationAugust 19, 1942, Serial No. 455,370

6 Claims. (Cl. 21539) ings are bound to exist through which the gases can escape.

In an attempt to increase the efiiciency ofsuch sealing media, the pulp board has been provided on its exposed face with a film of wax, with the idea that the Wax would conform to the irregularities in the facing material and container lip and thus provide an effective seal. It has been found, however, that such a wax film still afiords an unsatisfactory seal. The Wax film has tobe extremely thin, it has been found, and is inadequate to fill the irregularities against the escape of pressure. It might be thought that by merely using a film of substantial thickness greater sealing efficiency wouldb'e afforded, but

actually a properseal is not secured, for the wax either cracks or distorts in the area where it is pressed against the lip of the container, permitting leakage. If the wax is soft, it has a tendency to squeeze out, and if it is hard it has a tendency to fracture by reason of the crowning pressure which usually ranges from 450 to 600 pounds'per square inch. Out of a number of containers sealed by means of closures equipped with the pulp board facing with a relatively heavy wax film, a few will hold fairly high pressure without leakage, but most will leak quite readily at low of a meshed fibrous fabric, is embedded in the wax film, the fibers serving to sustain the wax against squeezing out and assuring that none will.

adhere to the container lip when the closure is removed. The object of the present invention is, therefore, to provide an improved and economical sealing facing in the form of cushion material having a coating of wax material on at least one face thereof, with fibrous material, in' the form of ordinary cheesecloth, for example, embedded therein.

, The invention Will bedescribed with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a fragment of a sheet or strip of facing material in accordance with the invention. Figure 1a is a section of the facing material of Figure 1 in a partly disassembled relation.

Figure 2 is a plan view of a sealing disc'in cordancewith the invention.

Figure 3 is a section on line 3--3 of Figure 2. I

Figure 4 is a bottom plan view of a cap equipped with the disc of Figures 2 and 3 and with a spot applied to the disc.

Figure 5 isa section on line 5-5 of Figure l. Figure 6 illustrates means for applying waxto a web of pulp board and a single web of fibrous material. 1

Figure 7 shows means for applying wax to web of pulp board and to webs of fibrous material, one on each face of the pulp board, and

Figure 8 shows means-for applying wax to a web of pulp board which has webs of fibrous material preliminarily affixed to both faces thereof.

Referring to Figure 1, reference numeral Ill designates a sheet of cushion material in the nature of pulp board whose thickness is preferablynot over .050 inch. Board of less thickness, for example, .030 inch or .040 inch, with proper density, will serve.

' Reference numeral ll designates a coating of wax, whichcoating has, for example, a thickness on the orderof .015 inch. This wax is preferably Formula No. 1

. Part by weight 160 F. M. P. Barnsdall amorphous wax 1 180 F. M. P. Barnsdall amorphous wax i 1 Formula No. 2

, Parts by weight Piccolite resin 8 Butyl stearate (plasticizer) 2 F. Barnsdall amorphous wax 45 F. Barnsdall amorphous wax 45 [In-Figure 8 reference numeral 28 Formula No. 3 1

Parts by weight 6 i Butylstearate (plasticizer) Resin piccolite 125 100 160 M. P. Barnsdall amorphous wax 100 Formula No. 4

After the waxhas been applied to the board and while it is still'warm, or after being re-warmed, a webof cheesecloth, as indicatedby the reference numeral [2, is applied to, thewax with pres-' sure seats to be'embedded therein, becoming an.

integral part of the wax coating as indicated at I a 1 Partsby weight Opal wax (synthetic wax of Du Pont) 60 cheeseclothserves very satisfactorily, but fabrics in the nature of cheesecloth made from any other 1 suitable fibers can be used.

In Figures 1 and 1a only one face of the pulp board body is shown as provided with the reinforced coating. Itwill be understood, however, that both faces of the board can be identically treated,- and ordinarily will be as a matter of conven'ience in assembling the discs and, closures. In Figures 2 and 3 reference numeral [4 designates a sealing disc punched from a sheet or strip coated on both sides, as above described, the'two I strata of reinforced wax material being indicated [3. I In Figure-lit is notjintended to imply'that the I I: wax II and cloth l2 are separate laminae, and'it may be assumed that where the cheesecloth appears alone it isjust about'to be pressed into the .Wax'in the manner. suggested in Figure 1a.

Other-ways of producing the composite webare shown'by way of example in Figures 6to 8. In

I Figure-fi reference numeral 20 designates arollof cheesecloth and 2| av roll of pulp board; The cloth andboard are led over heated. rol1s22 and of the sametoa winding roll 24. Rolls 22 and 23 are yieldingly urged together and suitably heated and in their bite support a quantity of melted wax 25 in contact with the webs. The webs pick up the wax in suitable thickness and are united thereby, the wax hardening sufiiciently before reachingroll 24 so that the windings. on .the latter will .not run together.

"23, respectively, and downwardly through'the bite I .In'Figure .7referencenumera1s 20aand 2t de signate rolls of cheesecloth and reference numeral, 21 a roll of pulp board. The cheesecloth isled over the-heated rolls 22c and 23a anddownwardly between the two while the board is led between thecloth webs at the bite of therolls.

a winding roll asin Figure 6. I 7 1 designates a composite web comprising a core of pulp board with facings of cheesecloth preliminarily affixed thereto as bypaste or glue which maybe spot-.

applied. ..The web is pulled between the rolls.22b and 23b and the wax bath as bya winding roll disposed below.

It isfnot necessary that the cheesecloth be completelyembedded inthe wax so that a smoothv wax surface exists and, as a matter of fact, in {ordinary practice the fiber strands show and can be felt on'the surface, although they are wax- I filled.

Cheesecloth has been mentioned as an inexpensive material which is readily applied and which can be obtained in suitable thickness. Its thick- I ness is preferably notmore thanfrom about .0050

H inch to .0060 inch." Its meshlwhich is a second.

;ary factor, may vary, for example, between, 32/36 J and 24/11 (English system). Ordinary cotton Wax is applied as before andthe; composite web is led to case.

will be understood that the disc could be annular, if desired. Since, the invention is thus susat 15 and 16, Figure 3, andthe pulp board at 11,

I While, sealing discs according to the invention may be used with any. type of. cap, the disc 14 of. Figures 2 and 3 is shown in Figures. 4 and 5 as assembledin a crown shell I8. If the packaged. substance is such that contact with the wax coating would be injurious, a spot may be applied to the exposed face of the disc, such spot being designated by the reference numeral |9, Figures iand 5.

When the crown of Figures 4 and 5 isappliedlto a container, the capping pressure cannot disintegrat'e, and squeeze. out the, wax coating at the lip, since the fibers hold the wax in place. Microscopicexamination of a removed closure shows many hairelike fibers shootingoff from themain fibers and assisting the'latter to sustainthe wax film. .The sealing efficiency is usually dependent upon the nature of the paper material and the kind'of wax used. If the 'Wax is plastic the seal ing efiiciency is greater than in the case ofhard Wax. With a suitable wax, fiber-reinforced, pressures of pounds and over are effectively held.

The pulp board or like material may be wax impregnated prior to coating, or not. A;single wax may be used, or a mixture of waxes, oracompound, ofwaxes, ora compound of wax and other modifying materials, such as resins, plasticizers, mineral fillers; pitches, and coloring agents may be used. A single wax or any suitable wax compo;-

sition is contemplated under the term wax material as used in the claims which follow, The

invention contemplates broadly the use of fibrous material in any form so long as'the fibers are arranged to sustain "the coating, but from the standpoints of ease of manufacture and efficiency in use, I prefer to use web material in the nature of'cheesecloth. In some situations it maybe desirable to use more than one layer of the fibrous mesh material, but ordinarily this will not be the While I have shown-a solid sealing disc it ceptible of variation by way of specific materials used and the form of the disc, it will beunderstood that I do not limit myself in these respects'except as in the followingclaims;

' Iclaim: k

l. Acontainer closure having therein a sealing disc comprising a pulp board disc having] on its exposed face a film of wax material, and, a disc of cheesecloth embedded in saidfilm.

2. A crown cap having fixed therein a sealing' disc comprising a pulp board disc having achees'ecloth disc adhesively affixed to the exposed face thereof, andv an adherent film of a wax material embedding said cheesecloth disc.

. 3'. For use as material for the sealing discs'of container closures, a web of pulp board having on at least one of its faces a film of a wax material, and, a, web of cheesecloth embedded in said v and a discof cheesecloth embedded in said film. 6. A sealing disc for a container closure, said disc comprising a 1 pulp board disc having a cheesecloth disc adhesively aflixed to a face thereof, and an adherent film 01 a wax material embedding said cheesecloth disc.

ILIYA F. BULATKIN!

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