US2719660A - Method of preserving packaged materials - Google Patents

Description

0st. 4, 1955 J. M. ELLIS 2,719,666

METHOD OF PRESERVING PACKAGED MATERIALS Filed Feb. 10, 1950 2 Sheets-$heet 1 Mrzwmx Jam! M. 544/:

0a. 4, 1955 J. M. ELLIS 2,719,660

lETi'lOD 0F PRESERVING PAQKAGED MATERIALS Filed Feb. 10, 1950 2 sheets-sheet 2 FIG-4 INVENTOR. Jay/v M. [2.4/5

United States Patent METHOD OF PRESERVING PACKAGE MATERIALS John M. Ellis, Lafayette, cant. I Application February 10, 1950, Serial No. 143,527

12 Claims. (Cl. 226-68) This invention relates to a process of preserving oxidizable materials and to a composition and apparatus for carrying out the process.

In preserving liquids and semi-liquid, or plastic materials such as paints from the harmful effects of oxidation, a known method consists in evacuating the container, or introducing an inert gas under pressure into the head space of the container. These methods are effective and are suitable for a manufacturer, but they have a serious limitation in that, when the evacuated or pressurized vessel is opened, the protective vacuum or inert gas is lost. More often than not, a can of paint or other oxidizable material is not immediately consumed but is only partly consumed and is put away to be used again. Meanwhile the protective vacuum or inert gas'has been lost, air has gained access to the material and during the period of storage, oxidation and deterioration occur.

Methods such as pressurizing and evacuating are not suitable for use by the average consumer to obviate this difiiculty. Pressurizing with an inert gas requires the use of amaterial such as solid carbon dioxide which is difficult to store and handle, .or the use of a cylinder, a valve and other fittings if a pressurized gas is employed. Also the problem of sealing the container after pressurizing is diflicult for the ordinary consumer.

Evacuation is even less suited for use by the average consumer. Expensive evacuation equipment and fittings are required and the problem of sealing an evacuated container is diflicult.

It is an object of the present invention to provide a method of preserving oxidizable materials such as paints, which is adapted to use by the average consumer, and which requires no special skill and no expensive equipment.

It is a further object of the present invention to provide a method of preserving oxidizable materials such as paints, which utilizes an inert gas yet avoids the necessity 2. it is preferably of light construction so as to float on the surface of the paint or whatever material is to be preserved.. It will also be constructed of a material which is inert to the material to be preserved. Preferably it is constructed of aluminum foil and is sufiiciently shallow and/or is provided with gas deflecting features as described hereinafter, so that a heavy gas generated in the boat, will immediately sink to the surface of the liquid to be preserved. Alternatively, instead of a boat intended to float on the surface of the paint, any suitable vessel may be provided and attached to the lid, lip or wall of the can.

Carbon dioxide, being odorless, non-toxicpand inert as well as heavier than air, isthepreferred gas. It is generated chemically in situ preferably in the manner described hereinafter, at atmospheric pressure or at a low super-atmospheric pressure. It is generated in the boat while floating on the surface of the liquid content of the of high pressures and of pressurizing equipment and which solves the problem of sealing the container after a protective atmosphere of inert gas has been created.

It is yet another object of the present invention to providea simple apparatus, and also an inexpensive chemical composition, whichcan be employed by the average consumer without special skill or equipment, to create and maintain a protective atmosphere of inert gasin the head. space of a partly used container of oxidizable material.

ing the features of construction described hereinafter, and

container, which meanwhile has its lid removed or resting loosely on the container. As the gas is generated it will sink, to the level. of the liquid and will gradually rise in the head space of the container, displacing air therefrom until the head space is completely filled with the inert gas and is completely devoid of air. The lid of the container will then be replaced and firmly engaged with the container. If desired, a sealing compound may be applied, but with a suitable, press-fitting lid of the type employed on paint cans, or a screw lid provided with a sealing gasket, this is unnecessary. The seal provided by the usual closure of either type will, in conjunction with the' specific gravity of the protective gas, cut-down diffusion of the protective gas to a point of insignificance over a long period of time.

In an alternative embodiment of my invention, which may be carried out with the same appara'fuginstead of generating an inert gas a material may be placed in the boat which absorbs oxygen from the air in the head space.

Suitable apparatus for carrying out the method of the invention is illustrated in the accompanying drawings, in which Figure 1 is a vertical sectional view, more or less diagrammatic, of a can of paint or the like and the dispensing boat and composition of the invention, showing the same at the start of operations.

Figure 2 is a similar view showing the can and boat at the conclusion of operations.

Figure 3 is a view similar to that shown in Figure l, with the vessel containing the operative material suspendedwithin the containerfrom the lip thereof.

Figure 4 is a view similar to that of Figure 2 with the vessel containing the operative material suspended from the lid and within the container.

Referring now to these drawings, a can 10 is illustrated I having a press-fitting lid 11 andit is shown partly filled with a liquid material 12, such as paint, which is oxidizable. A shallow boat 13 is provided which, may be constructed of heavy aluminum foil or light. gauge sheet aluminum. This boat is notched at its rim, as shown at 14, and it is provided'with a cap 15 having a downwardly and outwardly slanting annularflange or rim l6. The cap 15 is seated on the notched rim, asshown. A gas generating composition 17 is placed. inthe boat 13 to various ways. If the heavy, inert gas has a characteristi odor or color, either per se or as an'impurity, such will In any event, an accurate gauging of the displacement is not critical provided any error lies on the side of over displacement; i. e., provided more than sufiictent mert gas is generated. This may be insured, and wtll au tomatically insure complete displacement, by proportronrng the chemical reagents in the manner described hereinafter, so as to generate a predetermined and sufficient amount ofinert gas.

In Figure 2 a complete blanket of protective inert gas is shown and the lid 11 is closed and sealed. It will be seen thatthe boat 13 is left in the closed, sealed can. This may be safely done provided the can is to be left stationary and right side up. Otherwise, it should be fished out at the conclusion of the displacement operation, as by hand or with a pair of tongs.

If the boat is left in the can, it is advisable to allow the chemical reaction to go to completion before closing the lid, or to calculate the quantities: of reagents relative to the available head space; otherwise, continuation of this chemical reaction may occur and an unduly high pressure may develop in the can after it is closed.

As shown in Figure 3, the vessel is an envelope 13a of impervious material, having a front portion 27 and a rear portion 26, containing the operative mixture 17 and sealed at all four edges. ing'condition by tearing otf the top, edge thereof, peeling down the front edge 29 to expose the contents, and folding back the rear edge 28 so that it engages and hooks over the inner upper rim of the container 10; In this manner the edge 28 will be retained between the can rim and the lid 11 without destroying the seal of the container. portion of the container 130 extends into the liquid 12 or not, so long as the opening is above the liquid level.

In Figure 4 the vessel 13 has serrated openings 14 with outwardly extending tabs 14a, having pressure sensitive adhesive 19 thereon for instantaneous engagement and holding with the interior of the can lid 11, as shown.

. In generating the inert gas, I may use any of a variety of materials. Preferably, however, I employ pelleted The vessel is placed in operat-:

It makes no difierence whether or not the lower Y solids capable of forming carbon dioxide when treated I with a small amount of water. Thus, in one of the pre ferred embodiments of the invention, I provide dry acidic pellets of citric acid or oxalic acid and dry basic pellets of sodium bicarbonate or other solid material capable of yielding carbon dioxide when mixed with the acid pellets and a small amount of water. More generally stated, in this embodiment of the invention I provide a pellet or pellets capable of yielding carbon dioxide on treatment with water or with water and a mild acid, and in those cases where an acid reagent is needed I also provide an acid pellet of mildly acid nature sufficient to liberate carbon dioxide from the basic pellets.

These pellets, both basic and acid, may be formed from the pure reagents, or each reagent may be mixed with an inert diluent. And in another embodiment of the invention the reagents may be pre-mixed and formed into Citric acid Sodium bicarbonate Sodium citrate (2) 0003 2NaHCOt NasC'sOl 28:0 200;

Oralie acid Sodium oxalate These equations oinit the water of crystallization normally present in crystals of citric and oxalic acids, and, of course, as is known, the presence of added water is required for the reactions to occur at normal temperatures.

Stoichiometric calculations will show, assuming pellets of pure reagents, that in Equation 1 approximately 7 grams of pellets (in the proper stoichoimetic proportions) will yielrLl liter of CO: (S. T. P.). In Equation 2, about 6.5 gramsfof pellets will yield 1 liter of CO2. In the reaction represented by Equation 2, a 0.75 gram pellet of oxalicacid dihydrate and a 1 gram pellet of anhydrous sodium bicarbonate will yield to pint of CO2. Pellets of this size provide a convenient unit for household use. Thus, if it is estimated that a partly used paint can has one quart of head space, four each of these pellets will be employed to yield approximately the correct volume of CO: at normal temperature and atmospheric pressure.

It will be apparent that similar calculations can be readily made for other pellets, taking into account water of crystallization, purity and the amount (if any). of -diluent. It will also be apparent that a complete kit can readily be provided for use by the house holder, comprising a boat as described above, a supply of pellets in a suitable container or containers and a set of instructions including a scale for estimating the number of pellets to be used.

The instructions will also indicate how much water to use to bring about the reaction. In this connection it is necessary to use only a few drops of water when only a few pellets, of the order of 10, more or less, are used. No precise control over the amount of added water need be exereized, and adding it drop by drop in accordance with predetermined instructions will sufiice. These instructions can be arrrived at empirically without any difficulty. At the conclusion of the reaction the pressure can be equalized by leaving the lid of the container open to allow escape of excess gas, or if need be more pellets and water may be added to generate more gas.

It will be apparent that other means than solid pellets may be used to generate the heavy gas. Thus a liquid reactant such as vinegar or dilute acetic acid may be reacted with a solid bicarbonate, or a charged liquid such as carbonated water may be used. Thus a small bomb of the latter may be placed in the boat and punctured to liberate carbon dioxide slowly. However, solid pellets are preferred.

As stated hereiuabove, instead of generating an inert gas such as carbon dioxide; a material may be placed in the boat which absorbs oxygen from the air in the head space. To this end a chemical absorbent or a physical adsorbent for oxygen may be used. In employing a chemical absorbent such as pyrogallic acid or sodium sulfite, the general procedure described above may be used. The absorbent material may be pelleted and the pellets may be provided of a convenient size. Thus, pellets may be employed of a size calculated to absorb all of the oxygen in, say, /5 pint of air at normal atmospheric temperature and at standard pressure. The user will, as in the case of C02 generating pellets, estimate the volume of head space'and will employ a moderate excess of the unit pellets, calculated to absorb all the oxygen in the head space.

By the term absorb as used in the appended claims it is intended to include both absorption and adsorption phenomena unless otherwise expressly qualified.

It will thus be apparent that a method is provided for protecting an oxidizable liquid or other material such 'as paints, and that a simple kit and paraphernalia are provided for executing this method. The method and the kit are simple and they lend themselves to use by the average consumer, such as a householder, who wishes to protect paint in a partly used container to prevent skin formation thereon. The method and kit are applicable, of course, to other oxidizable materials, such as fruit juices, coffee, etc. Difficulties inherent in the usual pressurizing and evacuating methods are obviated.

I claim.

1. A method of preserving the unused portion of oxidizable materials and the like, comprising providing a resealable container partly filled with said material leaning head space above the surface thereof in said container, suspending a container within said head space, providing said container with dry reagents including a mixture of citric acid and sodium bicarbonate, adding water to said reagents to generate carbon dioxide in situ in the head space above the material, and then closing the container.

2. A method of preserving the unused portion of oxidizable materials and the like, comprising providing a resealable container partly filled with said material, suspending a vessel within and from the lip of said container, providing dry reagents including oxalic acid and sodium oxalate for said vessel, adding water to said reagents to generate carbon dioxide in situ in the head space above the material in such manner as to fill the head space from the surface of the material upwardly, continuing said generation until the air therein has been substantially completely displaced, and then closing the container.

3. A method of preserving the remainder of partially used oxidizable materials and the like, comprising providing a resealable container partly filled with such material, suspending a vessel within and from the lip of said container, placing in said vessel solid reagents capable of reacting to generate a heavy gas when moistened, adding water to initiate the generation of heavy gas allowing reaction to occur until the air in the head space has been displaced, and then closing the container.

4. A method of preserving the unused portion of oxidizable materials and the like, comprising providing a resealable container partly filled with such material, suspending a vessel within and from the lip of said container, placing in said vessel solid reagents capable of reacting to generate carbon dioxide when moistened, adding moisture to initiate the reaction, allowing reaction to occur until the air in the head space has been displaced, and then closing the container.

5. A method of preserving the remainder of oxidizable materials and the like, comprising providing a resealable container partly filled with such material, suspending a vessel within and from the lip of said container, placing in said vessel reagents capable of reacting when moistened to generate carbon dioxide, moistening said reagents to generate carbon dioxide, allowing said reaction to occur until the air in the head space has been displaced, and then closing the container with said vessel therein.

6. A method of preserving the unused portion of oxidizable materials and the like, comprising providing a releasable container partly filled with such material, placing a boat on the surface thereof, placing in said boat a mixture containing an alkali metal bicarbonate and a solid acidic substance capable of reacting with the bicarbonate to liberate carbon dioxide, moistening said acidic substance and bicarbonate to liberate carbon dioxide, allowing said reaction to occur until the air in the head space has been displaced, and then closing the container.

7. The method of preserving the remainder of partially used oxidizable materials comprising providing a resealable container partly filled with such material, placing a boat therein on the surface of the material, placing in the boat pellets of solid reagents capable of reacting to produce a heavy gas when moistened, adding water in quantity sufficient to initiate reaction and liberate sufficient heavy gas to displace the air in the head space above the material, allowing reaction to proceed until such displacement occurs, and then closing the container.

8. The method of preserving the remaining portion of oxidizable materials comprising providing a resealable container partly filled with such material, placing a boat therein on the surface of the material, placing in the boat pellets of sodium bicarbonate and pellets of a solid acid capable of reacting with the bicarbonate, when moistened, to liberate carbon dioxide, adding water in quantity suf ficient to initiate reaction and liberate sufiicient carbon dioxide to displace the air in the head space above the material, allowing reaction to proceed until such displacement occurs, and then closing the container.

9. A method of preserving the remainder of partially used oxidizable materials and the like, comprising unsealing a container of such material originally packaged in sealed condition and having a resealing closure, removing a portion of said material from said container leaving it partially filled, introducing into the head space of said container above the material a substance which is operable to remove the oxygen therein, and then resealing the container.

10. A method of preserving the remainder of partially used oxidizable materials and the like, comprising unsealing a container of such material packaged in sealed condition and with a resealing closure, dispensing a portion of said material leaving the container partially filled, placing a vessel within the head space of the container and above the material, containing chemicals capable of producing a heavy inert gas by the addition of another chemical, adding the required chemical for the reaction, generating a heavy inert gas in situ in the head space above the material and then resealing the container.

11. A method of preserving partially used oxidizable materials and the like comprising unsealing a container of such material having a press-fitting lid which is supplied in sealed condition, dispensing a portion of said material, introducing into the head space of the container above the remaining portion of the material a substance which is operable to absorb the oxygen therein, and then resealing the container.

12. A method of preserving the unused portion of oxidizable materials and the like comprising unsealing a container of such material originally supplied in sealed condition with a resealing closure, dispensing a .portion of said material leaving the container partially filled, introducing into the head space of the container above the remaining material a chemical absorbent for oxygen in a quantity sufficient to absorb the oxygen in said head space, and then resealing the container.

References Cited in the file of this patent UNITED STATES PATENTS 113,619 Boldemann Apr. 11, 1871 639,674 Edwards Dec. 10, 1899 697,641 Miller Apr. 15, 1902 962,036 Martini June 21, 1910 1,371,724 Berg Mar. 15, 1921 1,406,380 Heath et a1. Feb. 14, 1922 2,027,429 Hansen Jan. 14, 1936 2,054,492 Young .1.. Sept. 15, 1936 2,159,835 Waters May 23, 1939 2,170,531 Kahn Aug. 22, 1939 2,221,520 Kcssel et a1 Nov. 12, 1940

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