US2118262A - Nonfogging container for moisture containing materials - Google Patents

Description

' May 24, 1938.

L. L. M GRADY ET AL NONFOGGI NG CONTAINER FOR MOISTURE CONTAINING MATERIALS Filed 001;. 4, 1954 jmamama Patented May 24, 1933 mirth STATES PATENT orricr.

' NoNroGome comma FOR morsroan oom'smmomi'rnmats Leon L. McGrady, Rochester, N. Y., and Charles G. Rittenhcuse, Chicago. IlL, assignors, by

mesne assignments, to Eastman Kodak Company, Jersey City. N. 1., a corporation of New Jersey Application ombu- 4, 1934, Serial No. 14am ,4 Claims. (o1. zoo-44).

This invention relates to the art of packaging,-

and, more particularly to a non-fogging type of carton for the packaging of moisture-containin materials, such as fruit, berries, .and other food products, as well as numerous other articles of commerce.

As is well known, there is a growing. tendency among producers, especially producers of food- I stufl's, fruits, vegetables and the like, to sell their products in package form rather than in bulk.

, This tendency has been the outgrowth, not only of a demand on the part of the public for more sanitary and attractive products, but also of recognition by the producers of the fact that packaged goods, generally speaking, keep better than when exposed in bulk; Regenerated cellulose and cellulose derivative thin sheeting has come greatly into vogue in the packaging art as a result of this modern-trend and, 'so far as preservation of the products themselves are concerned, has

terials commonly used in packaging possess drawbacks which prevent them from being universally accepted. For example, it has been found that when moisture-containing materials, such as fruit, vegetables, berries and the like, are scaled up or enclosed in containers consisting of, or comprising, cellulosic material, such as regenerated cellulose or cellulose acetate, the moisture 30 evolved from the packaged goods condenses and tainer. In. the case of regenerated cellulose the material absorbs the moisture and causes shrinkage or distortion which adversely affects the transparency of the material as well as producing an unsightly package. On the other hand, cellulose acetate and similar types of cellulose derivative sheeting are much less subject to shrinkage and distortion, but due in to the fact that this type of sheeting does notv absorb moisture to any considerable extent, condensation of themoisture takes place within the package, thereby fogging or sweating the inside surfaces of cellulose derivative material by the ging action makes it impossible for the prospective purchaser to examine the contents of the package without opening it and thus seriously affects its salability'. -As is well known, it is the clear, glistening transparency or cellulose derivative and regenerated cellulose wrapping materials which give them their exceptional appeal to the public and it is obvious that anything which adversely affects this transparency, such as the con o5 densation of moisture or the distortion of the been highly successful. However, all of the maforms droplets on the inside surfaces of the condeposition of minute droplets of water. This fog-' ,material, re'ndersit unsatisfactory for use in a large number of fields in which it could otherwise be satisfactorily employed.

It is, accordingly, one of the objects of the present invention to provide a material which may be successfully employed in the manufacture of a non-fogging type of container for moisture-containing materials, especially such materials as fruit, vegetables, berries and the like. Another object is to provide a container for moisture-containing materials which is not susceptible to fogging or appreciable distortion from the effects ofmoisture. A further object is to provide a containeryat least a portion of which consists of a cellulose derivative material, at least one side of which is provided with a coating which will prevent the accumulation of minute droplets of moisture in the form of I fog. A still further object is to provide a substantially moistureproof container composed of, or including, a cellulose derivative material sheet material moistureproofed on one side andprovided with an ad- ,herent coating of special character on the other coating comprising an adherent substance possessing a high degree of wetability and use of this material in the production of containers, either constituting the complete structure of the. container, or a portion thereof, as would be the case in the manufacture of the so-called window type of carton. D

In the following examples and description, we have set forth several of the preferred embodiments of our invention, but it is to beunderstood that they are included merely for purposes of illustration and not as a limitation thereof.

In the accompanying drawing,

Fig. 1 is a cross-section, on a greatly exaggerated scale, through a sheet of cellulose derivative material having on one side a highly wetable coating. I

Fig. 2 is also an exaggerated cross-section through a sheet. of material-similar to the ma terial of Fig. 1, but also including a moistureproof coating in addition to the wetable coating.

Fig. 3 is a perspective view of a window carton in accordance with our invention.

Fig. 4 is a perspective view illustrating a slightly difierent embodiment of our invention.

As indicated abbve, we have discovered that the fogging or sweating of cellulose derivative containers made from, or including, cellulose derivative material may be prevented by coating the inner surface of the material, that is the surface which is to be used-on the inside of the parent fllm thereon and which has a high *degree of wetability is considered as coming within the scope of our invention. It may be mentioned in this connection that wetable material may be applied directly to the surface of the cellulose ester sheeting or the sheeting may be provided with any of the customary substrate, such as subs of cellulose nitrate or other cellulose esters.

According to one form of our invention, we may employ cellulose acetate sheeting as the material from which the container is to be made. This sheeting may be, either a thin material of the order of .00088 to .015 inch in thickness, or a thicker type, such as a sheeting running from the .003 to .02 inch in thickness, depending uponthe use to which it is to be put. If it is desired merely to provide a -window in a carton formed of waxed cardboard, for example, the sheeting may be of one of the thinner types. If, however, the whole container is to be composed of the material, it should preferably be of one of the thicker types of sheeting in order to withstand the mechanical strains to which it is subjected in use. In some cases the cellulose derivative material may be cast in the form of a cylindrical or other type of container, provided with ap propriate metallic or non-metallic end walls. The last two types of containers are practically completely transparent.

Assuming that the sheet material is composed of cellulose acetate,it is coated in accordance with our invention with one of the following compositions:

I. Gelatin 5 Glacial acetic acid c.c 50

' Water v 10 Methyl alcohols c.c 5 Acet c c 500 Percent by II. Casein 1.0

onium hydromde (28%- aqueous solution) 2.0 Sodium hydromde 0.5 Glycerine- 2.0 Water 24.5 Methyl alcohoi 50.0 Acetone- The solution applied in any convenient manner known to those skilled in the art, such a by subbing, beading, spraying, or the ka Beach and J-.G. McNally N05 2,019,648. cases, the moistureproof coatingmay be applied ariaaea gardless of the particular method employed, there is deposited upon the surface of the cellulose derivative sheet a thin film or coating of adherent material oi high wetability.

Referring to Fig. 1 of the drawing, A rep resents the ba'se sheet of cellulose acetate, while 3 represents the coating of highly wetable ma terial deposited thereon. in Fig. 2 there is shown a slightly different form of the material in which the base sheet A is provided on one side-with the wetable coating B and on the opposite side. with a moistureproof coating 0. The moistureproof layer may be composed of a mixture of gum and wax and applied to the sheeting in accordance with the procedure set forth in the copending application of N. F. Beach, Serial No. Li91, "filed July 17, 1931. The moistureprooi coating may, however, comprise a layer of gum applied next to the sheeting, followed by a layer of wax in accordance with the procedure set forth in the U. S. patent to N. F. In some wetable layer.

In the manufacture of a carton in accordance with our invention, one may first form the carton, as shown in Fig. 3, of waxed paper, cardboard, wood or similar material, P and provided with a cutout or window opening W.- An appropriately sized window S is cemented around the edges of the cutout portion W with an appropriate cement, thereby forming a substantially moistureprooi package.

' in the form of our invention illustrated in Fig. 4, represents a cellulose derivative container of cylindrical form which may be fabricated from the cellulose derivative sheeting produced as described above, or'may be cast from a suitable cellulose derivative molding composition and coated. on the inside with a thin layer of the adherent wetable material. The container K may be provided with appropriate metallic or nonmetallicend closures E.

It is obvious that many changes in the specific method of carrying out our invention are possible and we are, accordingly, not limited to any particulariorm thereof, except by the appended i Many types of cellulose derivative sheeting may be employed in making containers in accordance with the invention. For example, we may employ moisture'proofed or unmoi'stureprooied cellulose acetate, cellulose propi'onate. cellulose butyrate, as well as certain of the mixed cellulose organic esters, such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetatestearate, and others. We may even use cellulose nitrate sheeting, although it is not to be preferred due to its high degree of inflammability and instability.

- As stated above, our inventionis particularly r cterlzed by the fact that containers or the window wrtions of window cartons made in accornce therewith will. not log or sweat due to the detion oi droplets of moisture. This feamoisture within'a package, in the form of minute droplets which appear to the eye as fog. This cannot take place with the material described herein due to the fact that the moisture forms a continuous film over the surface of the wetable material, thus preserving substantially perfect transparency of the original'sheeting. This same effect of course takes place regardless of whether the cellulose derivative materialis thick or thin,

all that is necessary being that it shall be coated on its inner surface with the adhesive film of wetable material.

' Our invention is also characterized by the fact that the material described herein is not subject to wrinkling or unsightly distortion due to shrinkage or swelling, which is one of the most outstanding defects of regenerated cellulose sheeting when used for packaging moisture-containing materials.

It will readily be seen that when we employ a moistureproof type of sheeting, in accordance with the invention, we are enabled to maintain the moisturewithin -the package at a constant value, since the moisture cannot escape through the moistureproof sheeting. Notwithstanding that the moisture is retained within the package, as indicated above it does not give rise to fogging or unsightly distortion due to the presence of the wetable film thereon.

Our invention is of especial value in the packaging of fruits, vegetables, berries, and other food products containing in their natural state a considerable amount of moisture. It is now possible by the use of packages produced as described herein to package almost any type of moisturecontaining materials with highly satisfactory results. This opens up a large field which has, heretofore, been closed to the manufacturer of transparent cartons, and, likewise, has solved for the producer of many types of grown and artificially manufactured food products the problem of packing and shipping such products in transparent containers of the type which have been so widely successful in other fields.

Having thus described our invention, what'we declare is new and desire to secure by Letters Patent of the United States is:

' gelatin.

1. A window-type carton adapted for packaging moisture containing materials without fogging of the window portion thereof, comprising side and end walls at least one of-which has a window opening therein, a permanently transparent sheet of cellulose derivative material which is relatively non-absorptive of moisture closing the window opening, said sheet havin on its inner surface a thin, adherent, non-fogging coating of solid, transparent, relatively moisture absorptive material.

.2. A window-type carton adapted for packaging moisture containing-materials without fogging of the window portion.thereof/comprising side and end walls at least one of which has a window opening therein, a permanently transparent sheet of cellulose derivative material which is relatively non-absorptive of moisture closing the window opening, said sheet having on its inner surface a thin, adherent, non-fogging coating of gingof the window portion thereof, comprising side and end walls at least one of which has a window opening therein, a permanently transparent sheet of cellulose derivative material which is relatively non-absorptive of moisture closing the window opening, said sheet having on its inner surface a thin, adherent, non-fogging coating 01' solid, transparent, relatively moisture absorptive material and having on its outer surface a moisture-proof coating.

LEON L. McGRAD CHARLES G. RI'I'IENHOUSE.

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