US2388568A - Sealing composition - Google Patents

Description

I Nov. 6, 1945. N, P NN N 2,388,568

SEALING COMPOSITION Filed March 4, 1942 Patented Nov. 6, 1945 UNITED STATES PATENT OFFICE.

QOM QSITIQN Nicholas J Penning, Milwaukee, Wis. Application March 4, 1942, Serial No, 433,367

11 Claims,

Crown bottle caps, those caps which are ap-- plied to beer and soft drink bottles, require a sealing member compressed between them and the rim of the bottle in order to effectuate a seal. These sealing members or seals, u as they are commonly called have conventionally been formed of a thin disc of cork or cork composition faced on the side exposed to the bottle contents with a disc of tin foil or the like, called a spot.

These seals have never been completely satisfactory because of a tendency for the formation 01f mold beneath the spot. They have, however, been more satisfactory than anything else com merciaily available, At the present time, in fact, even, these seals can hardly be said to be commercially available in view of the material shortage, especiallyin tin foil.

One reason that mother seal has been as satisfactory is because of; the difiieulty of avoiding the impartation of taste or odor to the contents oi the bottle, Even tastes or smells which most people would not notice would be noticed by enough, people so that the reputation of a product particularly in; the case of a beverage, would'be impaired. Another factor that must be taken into consideration is the pressure with which the caps are conventionally applied. A material which is too soft will flow under this pressure with the result that, when-the pressure is released, there may be leakage. On the other hand, it is necessary for the material t be yieldable in order to efiectuate a satisfactory seal. Another requirement is that the material should not be tacky-it should not adhere to the glass.

According to the present invention, the various requirements have been met by the. use of a ubbar and wood flour compositionsubstantially iree from any ingredients which will import taste or odor to the contents of the bottle and which can be manufactured at a sumoiontly low cost to be commercially practical! Of course, he price must be low enough to be practically insls ifioant in relation o t to al ost of t bottled be ra e,- The proper c nsistency is obtainedwithout th oo toi ul anization by heat by using a elativel high content of filler h ch is largely wood flour and by mixing he u be and fi ler i such a way as o av a large proportion of the natural rubber globules unbroken.

Additional advantages and objects of the invention will be apparent from the following description and from the-drawings, which showin cross section and more or less diagrammatically a bottle cap applied to a bottle and embody ng the seal oi the nro eu inven n,

althou h only one term, oi bottle tap and seal have been illustrated. tho io m of cap being tha for which the present n ent on s pa ticular y designed, it will. be evident that o e for of cars can be sed and that w de d pa tures may be made from tho oroi rred, oomp sition of th s al while retainin at least s me of the advanta es oi the present invention-,

F1111 details of the p eferred co position and its treatment given. n a o rdance wi h h requ ements oi R, @88 but are not intend for lim tation of; th sco e o the. invention e e cent as requir by the prior art.

in the drawing the. bottle oar? H. app ied o a b tle. .2 a conventional mann r and ineludes a conventional or mp d fl e which exerts a pressure on the uh orsid of an, annular bead 4 at th mou h of the bottle to hold t e can firm y bi ta Ho motio seal ng f, h bottle s ofi otuatocl. by a seal 6 with wh ch t present invention is par u ar y c no h dit may be inserte loose or cemented with adhesives lior toi e used in bottl aps, as a bumen for example,

As seen iron; he drawing. e sea 6 may coinrise a single; layer,v As pr vi sly mentioned, it is necessary for the seal. to be yieldable to effectuate the seal and. as a mat er oi act, it is a so necssary for it to be resilient so that alter the pressure used in applying the can released the seal will tend to expand and continue t ex rt a pressure against the bottle, arious ru ber ompsitions have been trie the past but e l been f u d to be unsot s a tor-y, e ther becaus they lacked the ri ht consistency or because they imparted taste to the contents of he bo tle,

ccord to the present inventi n. the preferred composition and method of formation of the seal l6 are as follows, the proportions. being by weight throughout:

Leaohed maple wood flour Pale crepe rubber fl ur-ore mixed y first apply ing the rubber to a standard ru ber mi l having its rolls heated to aoprozdmately 0 .1. and l Flying the wood flour thereto as soon as the rubber begins to level out, which will usually be in about one minute. The mixture should be removed from the mill as soon as the wood flour has been well incorporated and uniformly mixed through the rubber, which will usually be within four minutes more. After cooling, the mixture is then calendered, the rolls of the calender being warm, according to conventional practice, a temperature of 150 F. bei ng satisfactory.

It will be evident that wide departures can be made from the foregoing formula and treatment. Some departures will have no deleterious efiect. Others will cause a failure to obtain the full advantages of the invention but will still yield asatisfactory sealing composition. For example, considerable departure may be made from the milling temperature stated, but best results are obtained by having the temperature approximately as high as 300 F., since this permits a rapid mixing of the rubber and wood flour Without greatly breaking down the rubber. In other words, a substantial proportion of the rubber globules are retained unbroken in their original state. For those not skilled in the art,- it may be noted that rubber latex is formed of very minute rubber globules in an aqueous suspension, some resins and proteins being present in addition to the rubber molecules and water. In the course of forming pale crepe from this latex, most of the water is removed and a considerable proportion of the-other non-rubber ingredients are washed out, and it is probable that some of the rubber globules are broken. The brief mixing on the hot mill preferred, by maintaining as many as possible of the globules intact, results in a finished product which has the proper consistency without vulcanization. 1.

In place of wood flour, any other ground fibrous cellulose may be usedfor example, ground corncobs or corn stalk 'pith. For many uses, however, as for example with beer, care must be taken to choose one which will not impart a taste to the contents of the bottle. I have'determined that, considering availability, the very best from a wide variety of possibilities is rock maple ground to a flour, and that it is improved by the leaching process mentioned. Quite a few others might be found that would be satisfactoryfor anyigiven purpose, especially if leached to remove taste-imparting or'taste destroying ingredients. Of course, non-cellulosic fibrous materials could also be'used if they meet the other tests. They should, however, be in very small particles comparable to .the particle size of wood flour, rather than in lon fibers. It is believed to be desirable for the small particles to themselves be composed of a plurality of extremely fine fibres so that they will tend to interlock with one another and prevent flowing of the finished product under the pressure of capping the bottle. 7 H

It is not necessary that all of the filler be of this fibrous nature. Fairly satisfactory resultshave been obtained with only of the total Weight composed of wood flour, the remainder of the filler being a mineral such as clay. The seal should not be tacky enough to stick toglass and hence total filler content should be about 60% to about 80% of the total weightif all wood flour, or the equivalent thereof inreducing tackiness. r

Although pale'crepe rubber i's'preferred, any other rubber or similar rubber-like substance, in-' cluding synthetic rubber, which will not impart a taste or smell, and which will yieldthei proper consistency of the finished product may'beused. The consistency should'be similar to that of pork,

. impervious to moisture.

are,cut to a half-hour curing with the'vapor of' a small amount of sulphur chloride in a closed container at room temperatures, a temperature of about 70 F. having been specifically found to be suitable.

A suitable substance may be included if desired for rendering the individual wood flour particles One suitable substance is that known as Flex Wax C sold by Glyco Products Company of New York city. It is nontoxic and insoluble in alcohol and in water and melts to a liquid at about F. and does not affect the taste or smell of beverages in contact therewith. The wax may further be identified as that specific wax disclosed in the publication "Chemicals by Glyco, copyright 1940, especially at page 34. Properties of this Wax include the following: Color-tan, luster-dull, flash point- 257 C., specific gravity at 20 C.-.820, soluble in hot tallow oil, hot naphtha, hot mineral oil,

and hot vegetable oil, the solution in vegetable oil gelling when cold. It is mixed simultaneously with the wood flour and rubber and is substantially sorbed (probably absorbed) bythe flour.

Five per cent of the weight of the mixture to' which it is added is preferred, but from 3 to 20% may be used advantageously. Being sorbed, it has little efiect on' the proportions that should be used aside from the wax.

A seal produced in accordance with the foregoing disclosure, even without the treatment with. sulphur chloride, produces a more satisfactory, seal than any known befor this invention. It is.

adequately impervious to liquids and gas; it is immune to alcoholic and aqueous solutions; it imparts no detectable taste or odor to such solutions or beverages; and it has the proper consistency including resistance to flow and resiliency. Furthermore, it can be made at a very low cost because of the fact that its major ingredient, wood flour, is very inexpensive and the further fact that it requires no vulcanization and hence may be made simply by brief mixing and calendering. In the formin which the composition is surface-vulcanized with; sulphur chloride, it can be used in contactwith hydrocarbon solvents. For this purpose it will not ordinarily need to be free from taste or odor imparting ingredients. When..vlucanized throughout with sulphur chloride, it is suitable for numerous other uses where it may be subjected to pressures considerably greater than the conventional bottling pressures.

'Iclaim: I l w r 1. A bottle-sealing composition consisting essentially of 25 parts by weight of pale crepe rubber, and approximately 75 parts of rockmaple wood flour thoroughly mixed therein; said rubber being substantially unbroken-down, and said compound having such a consistency that it will yield resiliently but will not appreciably flow under conventional bottle-sealing practices.)

,2. A bottle cap comprising a, disc of. metal having a crimped flange therearound anda preformed sealing member inserted therein formed of the composition set forth in claim 1.

3. The method of making bottle seals, which consists essentially in boiling rock maple wood flour in water, decanting the water, applying pale crepe rubber to a hot mill, adding the wood flour to the rubber as soon as the rubber begins to level out until the wood flour is about 75% of the total by weight, removing the mix as soon as the wood flour has been well incorporated, calendering the mix, and cutting the seals from the resulting sheet.

4. A composition consisting essentially of unvulcanized rubber, and a filler consisting mainly of maple wood flour, with the filler comprising 60-80% of the weight.

5. A sealing composition consisting essentially of unvulcanized rubber matrix and a filler in a proportion equivalent in eliminating tackiness to 60% by weight of wood flour, a portion of the filler, comprising at least 33% of the matrix weight, comprising maple wood flour.

6. A sealing composition consisting essentially of unvulcanized rubber matrix and a filler in a proportion suflicient to prevent the rubber from sticking to glass, a portion of the filler, comprising at least 33% oi. the matrix weight, comprising maple wood flour.

7. A bottle sealing disk having the composition set forth in claim 6.

8. A bottle-sealing composition consisting essentially of 25 parts by weight of pale crepe rubber, and approximately to parts of maple wood flour thoroughly mixed therein, the said rubber being substantially unbroken-down; and said compound having such a consistency that it will yield resiliently but will not appreciably flow under conventional bottle-sealing practices.

9. A bottle-sealing disc formed of the composition set forth in claim 8.

10. A bottle-sealing composition consisting es- 7 sentially of pale crepe rubber and at least twice the weight thereof of maple wood flour thoroughly mixed therein; the said rubber being substantially unbroken-down, and said, compound having such a consistency that it will yield resiliently but will not appreciably flow under conventional bottle-sealing practices.

11. A bottle-sealing disc formed of the composition'set forth in claim 10.

* NICHOLAS J. PENNJNG.

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