US2273063A - Paper container - Google Patents

Description

Patented Feb. 17, 1942' UNITED STATES 1 ATENT OFFICE raran CONTAINER. Sidney Musher, New York, N. Y., assignor to Musher Foundation Incorporated New York,

N. Y., a corporation of New York Application August 5, 1m,- serm No. 351,546

5 Claims.

The present invention relates to paper containers and particularly to the manufacture of paper containers to be used for the wrapping of aqueous dispersion small amounts of glyceride or essential oils which are subject to oxidative deterioration.

It has now been found that most effective containers of the type above described may be made by first applying to the paper forming the con tainer a surfacing of an antioxygenic material and "particularly an antioxidant of vegetable character or of vegetative origin, which surfacing after thorough incorporation and combination with the paper base is coated or covered by a v waterproofing material such as a wax,'parafiin oil or even a glyceride oil or fat.

It has not been found satisfactory to apply these surfacings and coatings to the paperboard prior to being formed into a container or to the container after formation since apparently in either case a most efilcient and effective waterproofing and antioxidant effect is not obtained. It now, however, has been found to be particularly desirable to apply the surfacing of the antioxidant material to the paperboard while in fiat condition and before being cut and formed 3 into the bottle or container and then only to It has also been found most satisfactory to treat the paperboard or other paper material which is to be formed into the container with,

an aqueous dispersion of the antioxidant material which is partly in solution and partly in suspension. In this manner it has been found that the dissolved materials will be carried into the surface of the paper and absorbed therein and form a substantially uniform and homogeneous antioxidant coating over all of the fibers and surfaces of the paper.

In addition, impregnation of the paper will take place to a substantial extent below the surface thereof while at the same time the undissolved or suspended particles which should preferably be finely divided and of the order of finer than '75 to 100 mesh fall into and attach .themselves within the interstices or crevices on the face of the paper and apparently act together with the absorbed and dissolved material to give a most efiective synergistic eflect to the paramn film which is applied after the container has been actually formed by cutting and bending the paper.

The combined solution and suspension of the antioxidant is preferably applied. .to the paper stock before it is finely compacted or calendered when the surface thereof is quite absorbent and is in slightly acid condition.

Although the antioxidant material may be applied to the paper before it is compacted or calendered, it is desirably and most satisfactorily applied after a slight calendering or hardening operation so that there will not be too great a penetration of the antioxidant into the bodyv of the paper. 1

After the paper is then slightly hardened or calendered, leaving its surface softened so as to take up the combined suspension and solution apply the waterproofing wax, parafiin'or oil after the container has been completely formed.

By this method of procedure, even though the paraflin or other waterproofing material be applied in uneven thicknesses or in varying depths to the comers, recesses and crevices of the container and to the bend lines,- nevertheless the efiect of the antioxidant which is uniformly apof the antioxidant, the paper is calendered, preferably at a temperature of over 200 F. to 210 F. to assure that the surface will then be made substantially impervious and relatively resistant tofurther action of a solution while at the same time assuring a perfect combination of the suspended and ,dissolved antioxidant with the paper or paperboard.

Among the preferred antioxidants which may be utilized are the substantially raw unbleached cereal and grain flours, particularly oat fiour and dry milled maize flour. Less preferably there may be employed the seed, nut and fruit flours preferably in de-oiled condition, such as, for example, soya bean flour, sesame seed flour, peanut flour, cottonseed flour, corn germ cake flour, cocoa, 'tc.

Othe antioxygenic vegetative materials may also be employed and include the spice residues, such as clove residue, and cinnamon residue, particularly after removal of substantially all the essential oil content therefrom.

Other antioxygenic materials that may be employed include those high in cellulosic content such as cacao shells or other nut shells, straw or grass flours such as alfalfa, legume grasses,

6.9 and preferably to a pH of 5 to 6. The pH is important in order to obtain the maximum stabilizing results of the present invention. Where the pH is above 7.0, the protective effect normally exerted is very substantially reduced.

It is particularly desirable for the application of the antioxidant such-as of the cat flour to be made to the paper or paperboard as a surface sizing. For example, a mixture may be prepared comprising from 2% to of the antioxidant in water, and preferably about 10%, subjecting such water containing the antioxidant to thorough agitation and admixture, passing the paper or paperboard through such water-bath containing the antioxidant at the calender boxes or between the first drying rolls and the finishing ro or as part of a tub sizing operation.

Apparently these compounds form some combination with the cellulose of the paper packaging materials, such combination being of a physical or chemical nature, with the result that the combination of the paper material and the antioxidant has been activated to develop marked antioxygenic and stabilizing activity. In applying these antioxidants to the paper pulp packaging material, it has been found most suitable to apply them with non-oxidizing substantially neutral sizing materials, and particularly with,hydroxylated aliphatic compounds as these aid most satisfactorily in obtaining the desired results, such sizing including glycerine and its related sizing compounds, carbohydrates such as starch and sugars, dextrin and carbohydrate gums such as gum arabic, karaya, tragacanth, etc.

Less preferably there may be utilized as the $12- ing carrier'the high molecular weight proteins and protein containing materials such, as casein, soya proteins, partly or wholly coagulated gelatin or glue, etc. Rosin wax sizes may also be present in the tubs along with the antioxidants that are utilized.

A particularly desirable method of application is for the finely divided antioxidant in water suspension to be sprayed or allowed to flow on the moving sheet of paper or board at the wet end of the paper machine and immediately before such paper or board comes in contact with the hot drying rolls.

When the antioxidant is applied as a tub sizing or at the calender stacks, to the extent that the paraflining.

antioxidant adheres to the surface of the paper or paperboard, and is subsequently dried on the surface of that paper or paperboard during the manufacturing operation, there will be applied approximately from 0.1% by weight to 5% by weight of the finely divided antioxidant against the weight of the paper or paperboard.

Where the antioxidant in water suspension or solution is allowed to flow on or is sprayed on the wet end of the paper machine and on to the sheet of paper as it moves to the heated rolls, there may be applied any desired percentage of the antioxidant to the paper or paperboard as the amount that is applied to the paper or paperboard may definitely be controlled when applied in this manner. The antioxidant adhering to the surface of the paper or paperboard will not be dependent upon the amount that is picked up by the paper or paperboard as would be the case if it were passing through a bath of the suspended antioxidant.

In the case of certain of the antioxidants and particularly where the antioxidants are not completely water soluble, such as where the spice residues or'cacao shells are employed, the antioxidant may, less preferably, be added directly to the heaters and along with the paper stock. For example, between 1% and 5% by weight of the antioxidant may be mixed with the paper stock in the heaters and the paper manufactured containing the antioxidant as part of the finished stock.

In any event, these antioxidants are applied so as to be present in a substantially invisible and inappreciable form. Moreover, the antioxidant should become a part of the paper or paperboard so that it cannot be readily removed from the paper or paperboard after manufacture thereof.

The application of the antioxidant should desirably be made immediately before the paperboardreaches the heated drying rolls so that after the antioxidant has been applied, the paperboard is subjected to a temperature of 212 F. and preferably at about 220 F. Paperboard containers formed of ground pine stock treated in this manner are very substantially resistant to deterioration.

It has been observed that where the antioxidant is applied to the paperboard following the heat treatmentand at the very end of the manufacturing operation and where the paperboard is not subsequently subjected to a temperature of as high as about 212 F. for example, retardation of the development of characteristic objectionable paperboard and other oil odors is not nearly as great as where the antioxidant is applied prior to the high heat treatment.

The antioxidant may be sized only on that surface of the paperboard which is to be the inner surface of the container after forming and Where desired, and where the paperboard used for the container is made of a series of laminated papers, the antioxidant may be applied'to and become a part of the single sheet which will be on the inner surface of the finished food container.

After the paperboard has been made with application of a uniform quantity of the antioxidant thereto, it is cut out so as to form the base for the container and then is formed into the container, whether it be cylindrical or cone shaped, square or rectangular. The antioxidant is present on the inner surfaces of this container.

The formed container may 'then be treated with paraffin, paraffin oils or waxes or even glycerlde aavaoaa The parafiin may also be applied to the container by spraying both on its inner and outer surfaces until the desired coating is made.

The antioxidant is completely covered by the uneven film of the parafiin or similar waterproofing material and, although it is completely away from contact with the product packaged in the paraffin, nevertheless affords unusual protection to the packaged product.

Where, for example, the container is used for the packaging of milk, cream, orange juice, beverages, and other liquid oxidizable compositions, and even where the highly oxidizable fraction is contained dispersed in the aqueous medium of the composition, the oxidation of said fraction is substantially'inhlbited and the milk, cream or similar product is protected against oxidized, tallowy and rancid off-flavors.

In the packaging of milk, for example, the butterfat globule occupies the discontinuous phase and is separated from the antioxidant of the container by boththe waterproofing. wax

covering the antioxidant and by the aqueous medium in which the fat globules are dispersed. In spite of there being no contact between th antioxidant and the oxidizable fraction of the milk, however, the oxidation is very materially retarded and the original flavor of the milk is retained to a marked degree.

In addition to the vegetative antioxidants,

there may also be employed aromatic antioxygenic materials including hydroquinone, aiph'anaphthol, catechol, naphthylamine, aminophenols, gum guaiac, vanillin, and the various phenolated, butylated, ethylated and propylated derivatives of either of the above.

The vegetative antioxygenic materials may be treated to render them more readily adaptable for use in accordance with this invention. For example, the cereals .such as oat groats, may be subjected to the action of steam under pressures of 100 to 200 pounds or more per square inch and desirably to temperatures over 200 F.

The vegetative antioxidants may'thereupon be finely divided and are found to be more readily dispersible in the tubs through which the paperboard passes and exercise marked antioxygenic effectiveness, I

In the case of the seed flours, particularly in deoiled condition and of de-oiled spice residues,

said materials may be boiled in an acid medium such as by boiling in a 2% acetic acid solution for 1 to 4 hours, followed by neutralization where desired, and drying, and the seed flours such as .soya flour or the spice residues will have enhanced antioxygenic efiectiveness.

There may also be employed in accordance with the present invention other antioxygenic materials including milk-solids-not-fat, in caramelized or pre-boiled condition.

Rubber, latex or cellulose acetate or resinous overcoats do not function as satisfactorily as wax overcoats.

The method of formingthe container pursuant to the present invention is diagrammatically illustrated upon the accompanying drawing which is by way of illustration and not by way of limitation.

i in

In the drawing: H

Fig. 1 is a fragmentary cross-section of a sheet of board upon an enlarged scale to, be used in forming a milk container.

Fig. 2 is a fragmentary cross-section upon enlarged scale similar to Fig. 1 showing a surfacing layer of antioxidant material appliedto the board.

Fig. 3 is a view 'ofa section of board according to Fig. 2, upon a small scale as compared to Fig. 2, showing the bend lines by which the section of board is to be folded to form a rectangula'r container.

Fig. 4 diagrammatically illustrates in perspective view, upon an enlarged scale as compared to Fig. 3, the container which is formed from the board of Figs. 2 and 3.

Fig. 5 is a fragmentary sectional view of one of the corners of the container, upon an enlarged scale as comparedto Fig. 4 showing the position of the antioxidant coating or surfacing upon the interior face of the container.

Fig. 6 is a top perspective view of the container of Fig. 4, with the closure open, illustrating one method of, spraying the waterproofing or paramn coating upon the interior and xterior of the container.

In Fig. 2 is shown an antioxidant coating as,

for example, a finely divided raw or unbleached cereal or seed flour such as oat flour or a water or alcohol extract thereof which may be applied by spraying or sprinkling the antioxidant or passing the board over a roller carrying the antioxidant material or even by passing it through a bath of the sizing material.

Fig. 3 shows a section of the board the fold lines l2, l3, l4 and I5, the edges of the board l6, l1, "and I9 having been'cut from a large section of the continuous strip of board l0 after it has been surfaced with the antioxidant material II. It will be noted that the board of Fig. 3 is then folded into the container 0 of Fig. 4.

The container C is provided with a cover 20, and a bottom 2|. The cover 20 has an opening 22, closed by the closure member 23, which is stapled to the cover 20. The paraflin then may be applied by spraying through the spray nozzle 25, or the entire container may be dipped into a paraflin bath. Other waterproofing materials may also be employed.

The final, container has an ID, with exterior coating of ,paraffln 26, an interior undercoating of the an and an interior overcoat of the parcontainer with a waterproofing paraffin wax composition.

3. A method of forming a paper container which comprises treating the paperboard material with an aqueous dispersion of an antioxygenie cereal and causing said paperboard to absorb and take up said antioxidant over the entire surface thereof, pressing said paperboardto harden the surface thereof and to cause a thorough combination between the antioxidant and the paper surface, cutting and forming the paperboard to a container, and then-coating the con-- tainer with paraffin.

4. A method of forming a paper container which comprises treating the paperboard material with an aqueous dispersion of hydroquinone and causing said paperboard to absorb and take up said hydroquinone over the entire surface thereof, pressing said paperboard to harden the surface thereof and to cause a thorough combination between thehydroquinone and the paper surface, cutting and forming the paperboard to acontainer, and then coating the container with 5.. A method of forming a paper container which comprises treating the paperboard material with an aqueous dispersion of an antioxygenic finely divided oat flour and causing said paperboard to absorb and take up said antioxidant over the entire surface thereof, pressing said paperboard to harden the surface thereof and to cause a thorough combination between the antioxidant and the paper surface, cutting and forming the paperboard to a container, and then coating the container with paraffin.

SIDNEY MUSHER.

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