US2318185A - Cap and method of making the same - Google Patents

Description

, L. SCHREYER 2,318,185

CAP AND METHOD OF MAKING THE SAME Filed Nov. 16, 1939 BY h/w w ATTORNEYS Patented May 4, 1943 car AND METHOD or MAKING THE smut:

. Leo Schreyer, Bratenahl, Ohio, assignor to Intel-national Elastit Corporation, a corporation of Ohio Application November 16, 1939, Serial No. 304,874

11 Claims.

This invention relates to plastic film and particularly to elastic film-like gelatin caps which are used to hermetically seal the closures of bottles and similar containers.

As conducive to a clearer understanding of this invention, it may be well to point out that hermetic seals of this type in the past'have consisted of thin film-like capsules or membranous coat ings. The former have been usually roughly preshapedand applied to the bottle closure and neck while in a plastic state so that when hydrated, the capsules would fit snugly over and aroundthe closures. The latter coatings have been applied simply by dipping the sealed mouth of the inverted container in a viscous liquid which, when dried in the air, hardened and formed a covering for the primary closure and bottle neck.

Th film-like capsules have been made generally of cellulose acetate or other cellulose derivatives and while they are vapor and water proof, they are not elastic, they are easily afiedted by climatic conditions and their colors are not clear but instead have a faded appearance. Their inelasticity makes them difflcult and expensive to apply to the bottle neck. Their inability to withstand climatic conditions makes them extremely hard and brittle under some conditions and soft and sticky under others. Their lack of luster and lifeless appearance makes them inattractive for commercial purposes. In addition, these capsules are highly inflammable and necessarily must be stored and shipped in liquid filled containers.

Gelatin capsules of this type were expensive to produce. Their appearance left much to be desired for commercial purposes. elasticity and became very fragile in the warmer and colder climates. While they were for most purposes better than cellulose derivative covers. their manufacture in large quantities did not lend itself to automatic production. Much hand labor had to be used to remove the cap forms from the pegs or mandrels on which they were dried and took shape.

The membranous coating applied to the closures in a liquid state necessitated the tipping of the bottle upside down. The tipping has certain obvious disadvantages. Also, such covers were not lasting and soon became too soft and sticky for convenient handling. However, their application did not cause air bubbles which frequently were hard to eliminate from the capsule type of seals.

It is therefore the primary object of this invention to provide a material which is relatively They also lacked a easy and-inexpensive to manufacture and use 'for the purposes mentioned. I

Another object is to provide bottle closure caps which are resilient before being applied and substantially inelastic thereafter; which are also non-inflammable, non-odorous, tasteless and'attractive in appearance.

A further object is to'provide a substance and an article of the type mentioned which is durable, moisture resisting, ether and gasproof and capable of withstanding extreme climatic conditions for long periods of time.

Still another object is to provide a gelatin capsule for sealing a bottle which capsule may be stored and shipped in' a dry and partially preformed state and which capsule is made ready for final application by the mere soaking of it in cold water for a relative short period of time, but which capsule becomes impervious to water after it is finally set.

A still further object is to provide a membranous capsule which may be made transparent or opaque, which may be colored or polished as desired and which may be printed on.

These and other objects as well as a further understanding of the invention maybe had by referring to the following description and claims.

Fig. 1 diagrammatically illustrates how a form or mandrel I is dipped into a liquid 2. This liquid may be the coating bath, whose major ingredient is gelatin, or it may be the fixing bath.

Fig. 2 is a cross-section, partially in elevation, showing the completed cap 3.

Preparatory to making a composition gelatinous material and applying the process of this invention, there is provided a rack or base on which a plurality of pegs or mandrels are mounted in rows. These mandrels serve as molds for the capsules and are slightly smaller in diameter than the necks of the bottles which are intended to be sealed with them. As these mandrels per se form no part of the instant invention and furthermore as their use and construction is well known to the art, a precise description of them is believed not necessary and hence will be dispensed with.

The process itself consists of three essential steps or operations. There is first, the preparation of the initial or base composition and the molding thereof; next, the preparation of the main body composition and its application to the base composition: and finally, the preparation of a fixing bathand treatment therein of the two combined aforementioned compositions. Each of these steps will now be described separately and in the order in which they take .place.

The base composition has for its main purpose the prevention of the gelatinous compound adhering to the mandrels after the compound is fixed and dried. In its preparation:

.5 kilogram of gelatin and 1.5 kilograms of regular bone glue are allowed to soak in a quantity of soft cold water until both the gelatin and the glue have absorbed as much water as possible and until both substances have stopped swelling; the bone glue is an impure form of gelatin so that the major ingredient of the inner layer or base composition is gelatin;

8 grams of soluble starch are dissolved in warm water and stirred constantly until the solution is semi-transparent or has an opalescent appearance;

50 grams of gum arabic are thoroughly dissolved in about .5 liter of hot water;

To 100 c. c. of 96% alcohol, which has previously been denatured by a small quantity of 90% carbolic acid, add 7 grams of phenol or some hydroxyl derivative which is a good preservative for the gelatinous composition;

10 grams of boric acid crystals are dissolved in approximately 150 c. c. of hot water;

160 c. c. of 50% neutral Turkey red oil is prepared, or in its stead 160 c. c. of sulfonated castor oil is used;

170 c. c. of glycerin having a Baum hydrometer test or density of 30 is likewise prepared;

c. c. of some anti-bactericide, mould preventative or sterilizing solution is thoroughly mixed with 15 c. c. of water;

And a last solution is made by slowly mixing 15 liters of oxgall with 75 c. c. of a 90% solution of carbolic acid.

The pieces of softened gelatin and glue are placed in a large double boiler, the temperature of which is maintained at 40 C. by automatic means and thermostatic control. The opalescent starch solution is added thereto. The gum arabic solution is next added and the mixture is thoroughly homogenized.

When the aforementioned compounds are mixed thoroughly, the alcohol, boric acid, Turkey red oil. glycerin and sterilizing solutions are each added to the viscous mass in the double boiler in the order just stated. After these solutions are thoroughly mixed with the mass, small quantities of the oxgali solution are slowly mixed therewith until the entire quantity of approximately 16 liters is thoroughly infused and mixed.

The aforementioned compound is then transferred to a vacuum-pan or vacuum-boiler in which it gradually cools and remains for about twenty-five minutes. Quantities of this cooled mixture are then poured into long troughs and the cap forms or mandrels are dipped therein. When removed, the mandrels have a coating of the materials, which when dried is very thin and The main body composition or second coat consists of 15 kilograms of pork strip gelatin which is allowed to soak in softened cold water. The gelatin should be of the: type and quality that has a high melting point and after it has swollen to its maximum size and has absorbed as much water as possible, it is placed in a large double boiler, the temperature of which is automatically maintained between 54 and 57 C.

One and fifteen-hundredths kilograms (1.15 kilograms) of salt are boiled in a quantity of water and when dissolved are thoroughly mixed with the gelatin. It is important that salt be used which does not have iodine or similar chemicals in it.

A solution of one liter of water, 2.5 liters of denatured alcohol and 28 grams of a good phenol sterilizer is made and mixed with the salted gelatin. The mixture is slowly but thoroughly stirred and agitated until all the lumps disappear and the mass has a smooth even consistency.

Eight hundred c. c. (800 c. c.) of glycerin are directly added to the mixture and thoroughly mixed with it.

Twenty grams (20 grams) of boric acid are dissolved in hot water and added to the mass.

Twenty grams (20 grams) of pure light Vaseline are next added thereto.

Twenty-five c. c. (25 c. c.) of a liquid sterilizer are mixed with a like amount of water and then added to the gelatinous mixture.

One hundred and fifteen c. c. (115 c. c.) of Turkey red oil or sulfonated castor oil is mixed therein.

After the entire gelatinous viscous mass is homogenized thoroughly, any suitable coloring matter may be added to the compound.

At this point the material is tested with a viscosimeter and if it gauges a consistency of 28 or 29, it is in proper condition. If it happens to be too thick, water is added to soften it, or if on the other hand it is too fluid, it should be cooked a while longer.

If the material gauges properly, it is immediately poured into a closed pressure boiler which is being heated at a constant, automatically regulated temperature oi between 54 and 58 C. It is kept in vacuum and so heated until the composition "breaks." That is, at a certain time. approximately thirty minutes after being put into the vacuum boiler, an end-point is reached and further reaction of the aforementioned chemicals ceases. At this point the alcohol vapors which are drawn out of the material by the vacuum, are drawn oil through suitable conduits and allowed to escape. It should be particularly noted that a temperature of 69 C. is not reached in the vacuum boiler as at that temperature, the mass peptonizes and undergoes certain fundamental changes which make the material unsuited for the purposes intended.

When this second quantity or main mass of material has been properly prepared, mixed and treated, it is poured into long troughs and the mandrels heretofore referred to, and which mandrels are still covered with the dried initial or base composition, are dipped into it. After the second immersion, the main coat is allowed to dry. The second coat, however, is many times thicker and heavier than the base coat.

The third and last step in the process, sometimes referred to herein as the fixing, hardening or glazing operation is the most, important and its materials and steps must be measured and timed with great accuracy.

A first solution is made of 3500 grams of Pure chrome alum and liters of water.

A second solution is made of 2500 grams of potassium dichromate crystals dissolved in 100 liters of water.

A third solution is similarly made of 3000 grams of pure potassium alum.

A fourth container contains a quantity of a 40% solution of formaldehyde.

Next, 10 liters of the first solution, 5 liters of the second solution, 1.2 liters of the third solution and 2.9 liters of the formaldehyde solution are thoroughly mixed with 400 liters of water. Hence the hardening or condensing bath contains 350 gms. of chrome alum, 125 gms. of potassium dichromate, 36 gms. of potassium alum,and about 1044 gms. of formaldehyde. The standard solution of formaldehyde contains 40% of formaldehyde by volume, and about 37% of formaldehyde by weight. It contains from 36-38 gms. of formaldehyde in 100 cc. Therefore 2.9 liters of said solution contains from 1044 gms. to 1082 gms. of dissolved formaldehyde. In this final mixture the caps, while still on the mandrels, are dipped for two and one-quarter (2%) minutes.

The mandrels are then taken out, inverted and the caps permitted to dry in normal daylight or in the presence of ultra-violet rays. After drying, the caps fall off the mandrels of their own accord. and are sorted, stacked and packed for delivery or for subsequent application on bottle closures.

As the fixing bath weakens, small quantities of the four solutions are added so that its Strength is regenerated and maintained and so that proper chemicalreaction may be had on the caps during their two and one-quarter (2%) minute immersion.

Before the caps are applied to the bottles, they are soaked in cold water for about one hour after which time they become soft, pliable and elastic. When dried on the bottles, they contract evenly and make an air-tight seal. Thereafter they are impervious to moisture and are not affected by temperature or atmospheric conditions.

The caps may be printed on either after or before the fixing or third step. However, if the caps are printed on before the fixing operation, the ink used must not contain oil or any greasy substance as such substances have a deleterious efiect on the fixing solution.

By way of further explanation; the oxgall, which is an organic, fatty blood product, has certain properties which prevent the compound from melting below a temperature of 50 C., also it, because of its unctuous nature, facilitates removal (dropping ofi) of the finally formed capsules from the mandrels. The starch and gum arabic both of which have the qualities of very easily absorbing water, cause an internal pressure that facilitates and in part causes the removal or dropping ofi of the finally formed capsules from the mandrels. The gum arabic and the starch also contribute certain qualities of expansion and flexibility. The Turkey red oil aids or hastens the mixing of the oils with the water and tends to prevent the formation of air bubbles in the compound. The boric acid, as an antiseptic, assists or supplements the other sterilizing agents in preventing the formation of moulds and helps preserve the final composition.

Salt increases the density and specific gravity of the compound and thereby gives the final product a more brilliant and attractive appearance. The alcohol lowers the boiling point of the liquids and also increases its smoothness. The glycerin assists in the general homogenization of the materials.

Of the fixing bath, the first solution, containing chrome alum as a tannin, hardens and sets the material and regulates hygroscopic action of the gelatin. The second solution, containing potassium dichromate, causes the capsules to be affected by actinic rays and to become polymerized thereby. The third solution, containing potassium alum, affects only the outer exposed surface of the capsule so that it takes on a hard, smooth and glossy surface. As gelatinous substances have a tendency to lose or absorb color, the formaldehyde reacts in a manner which revives and enhances the natural color of the article, and

in addition hereto, is a hardening agent.

It has been found from experience and repeated tests that a gelatinous film-like material made in accordance with this invention has an inner surface which is approximately one-half as hard as the outer surface. This is because the four aforementioned solutions each affect the outer material during the two and one-quarter (2%) minute'immersion in a different manner and to a diflerent degree. The hardness or texture of the final cap varies gradually between its inner and outer surfaces, with the result that the article has all the advantages ofa soft pliable cap combined with those of a hard inelastic cap.

The major ingredient'of the improved bottle cap is gelatin. The inner layer and the outer layer are of different compositions. The outer layer is more viscous than the inner layer.

One of the many advantages of this product over other similar articles is that the gelatinous seal may be made very thin but durable, thereby saving material. Also such seals will not be affected by chemicals such as, ether or alcohol. This feature being particularly valuable in the bottling of medicines, perfumes, fermented or distilled liquors and many such products. Another advantage is that the caps may be applied rapidly by persons with relatively little training or experience and also no special or expensive machines are required to affix them.

It will now be clear that there is provided by this invention a method and composition for making plastic film and articles therefrom which accomplishes the objects of the invention. While the invention has been described in a specific form and while certain broad general terms have been used, it is to be understood that the embodiment of the invention as described is suggestive only and is not to be considered in a limiting sense as no limitations upon the invention are intended other than those imposed thereon by the scope of the appended claims.

I claim:

1-. A method of making a cap which consists in forming the cap blank with an inner layer and an outer layer which is integral with said inner layer, said layers being of respectively difi'erent compositions, the major ingredient of each layer being gelatin, and treating said blank only at its layer being more viscous and containing a greater proportion of gelatin than the inner layer, and treating said composite blank only at the outer surface of its outer layer with a fixing bath which hardens the outer layer more than the inner layer. f

3. A method according to claim 2 in which the hardening liquid contains chrome alum, potassium dichromate, potassium alum and formaldehyde.

4. A method or making a cap whose major ingredient is gelatin, which consists in forming a cap blank with an inner layer and with an outer layer which is integral with the inner layer and whichis thicker than the outer layer, the major ingredient of each said layer being gelatin, said outer layer having a greater percentage of gelatin than the inner layer, treating said blank with a hardening liquid which has a greater hardening eflectupon the outer layer than on. the inner layer.

5. A method according to claim 4 in which the inner layer is substantially free from salt (NaCl) and in which the outer layer has salt in the percentage of more than 7% of the gelatin.

6. A cap comprising an inner layer and an integral outer layer which is thicker than said inner layer, the major ingredient of each layer being gelatin, said inner layer containing suflicient ox-gall to render the cap substantially nonadherent to a dipping form on which said cap is formed.

7. A cap comprising an inner layer and an outer layer which is thicker than the inner layer and which is integral with the inner layer, the major ingredient of each layer being gelatin, the

proportion of gelatin-in the outer layer being greater than in the inner layer, a major propor tion of the gelatin in the inner layer being bone glue, each layer containing ingredients additional to the gelatin, the inner layer including ox-gall, the outer layer containing petrolatum, each layer containing a suflicient proportion of a substantially neutral sulfonated oil to provide a uniform mixture ofthe gelatin and of the other ingredients of the respective layer.

' of gelatin, the inner layer including starch and gum arabic, the respective proportions of gelatin and of starch and of gum arabic in said inner layer being substantially 2000 to 8 to 50.

10. A bottle cap whose major ingredient is water-insoluble and hardened gelatin, said cap being resilient in the dry condition and becoming soft and pliable when soaked in cold water. the outer surface portion of the cap having a larger percentage of gelatin and being harder than the inner surface portion of the cap.

11. A bottle cap whose major ingredient is water-insoluble and hardened gelatin, said cap being resilient in the dry condition and becoming soft and pliable when soaked in cold water, the outer surface portion of the cap having a larger percentage of gelatin and being harder than the inner surface portion of the cap, said outer surface portion containing salt in the proportion of substantially seven per cent of the gelatin in said outer surface portion.

LEO SCHREYER.

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