US3450327A - Round nestable paper container having a high gloss exterior finish and an interior and bottom wax coated surface - Google Patents

Description

June 1969 R. E. LUDDER ROUND NESTABLE PAPER CONTAINER HAVING A H GLOSS EXTERIOR FINISH AND AN INTERIOR AND BOTTOM WAX TED SURFACE Filed Oct. 25, 1967 v Sheet of 2 RODNEY E.LUDDER dd. ATTORNEY 3,450,327 GLOSS EXTERIOR TED CE 7 Z of 2 E. UDDER C A R HAVING A HIGH ERIOR AND BOTTOM WAX COA SURFA Sheet June 17, 1969 ROUND NESTABLE PAPER FINISH AND AN INT Filed Oct. 25. 1967 :7; w ll INVENTOR. RODNEY E LUDDER United States Patent 3,450,327 ROUND NESTABLE PAPER CONTAINER HAVING A HIGH GLOSS EXTERIOR FINISH AND AN IN- TERIOR AND BOTTOM WAX COATED SURFACE Rodney E. Ludder, Glen Head, N.Y., assignor to Owens- Illinois, lnc., Toledo, Ohio, a corporation of Ohio Continuation-impart of application Ser. No. 605,338, Dec. 28, 1966. This application Oct. 25, 1967, Ser. No. 677,906

Int. Cl. 865d 5/40, 25/14, 5/56, 5/62, 3/00 US. Cl. 229--3.1 6 Claims ABSTRACT OF THE DISCLOSURE A paper container having its interior coated with wax, means for preventing said wax from penetrating to the exterior surface of the side wall of the container and the exterior side wall of said container having a glossy scuffproof surface; means for preventing moisture penetration from penetrating towards the interior of the container through the bottom and lower end thereof; and method of producing same.

BACKGROUND OF THE INVENTION Field of the invention and description of the prior art This application is a continuation-in-part of my copend ing application Ser. No. 605,338 filed Dec. 28, 1966.

This invention relates to two-piece paperboard containers intended especially for the packaging of comestibles and more particularly for cottage cheese and other cultured dairy products, salads, butter, spreads and the like which require low gas and/or moisture barrier properties. It has been found that in the packaging of foods of this nature it is difficult to prevent the transmission of moisture vapor and the transmission of oxygen gas, the passage of both of which must be prevented in order to protect the flavor and freshness of the food. For example, it has been found that paperboard containers heavily coated with a suitable wax are much more 1mpervious to the passage of moisture vapor and oxygen gas than are many plastic containers. In the production of such heavily waxed paperboard containers, it is (llfil' cult to produce a highly glazed or glossy outer surface on the side wall of the container, which is especially desirable where the side wall bears fanciful designs often comprising multi-colors.

In the conventional heavily waxed two-piece paperboard containers, a heavy coating of wax is applied to the exterior surface as well as to the interior surface and a highly glossy exterior surface of the side wall is unobtainable without ruining the wax properties. For example, while it is possible to obtain high gloss on overall waxed food containers simply by cold quenching them while the wax is still liquid, this sets up surface stresses which crack under refrigeration and the containers fail rapidly offering no resistance to the food.

SUMMARY OF THE INVENTION According to the present invention, the side wall or body, comprises at least two plies which may be effected by a double wrap made of one sheet or a single Wrap comprising a plurality of sheets. In either event, an intervening blocking layer of material separates the inner and outer ply. The blocking layer may be in the form of an adhesive or glue which is impervious to the penetration of the hot wax applied to the interior of the container, or in the form of a blocking material which serves the same purpose, or a combination thereof. The purpose of such construction is to prevent the hot wax applied to the interior of the container from penetrating to the exterior surface of the container, which exterior surface is desired to be coated with a glossy finish, either by means of a high gloss wax or by means of a suitable coating of plastic material, in the manner well known in the art.

The blank from which the side wall is to be made may be printed with the desired design and colors, as is customary in present practice of paper printing and coating, and thus provide a clear, high gloss finish, preferably by means of a thermosetting resin.

After the side wall and bottom of the container are assembled in the manner well known in the art, the interior of the container is coated by a special formulation of paraffin wax, which wax is prevented from passing to the highly glossy outer surface of the side wall but is permitted to penetrate the entire bottom of the container.

To provide moisture resistance from exterior sources, such as when nestable containers are placed in stacked relation and the bottom of one container is seated within the lid of a lower container which often acts as a depository for moisture, the bottom surface of the container is coated by a special formulation of paraffin wax. Alternately, the wax coating may be applied substantially to the ledge of the container bottom surface.

These coatings give the container the dual advantages of (1) an inner barrier to the transmission of moisture vapor and oxygen gas, thus protecting the flavor and freshness of the food product; (2) a superior outside finish which not only contributes additional holding qualities to the package but complements and greatly enhances the printed decoration of the container; and (3) an exterior barrier to the transmission of moisture through the bottom surface of the container, thus protecting both the bottom member and seal between the bottom member and the side wall.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings wherein like numerals refer to similar parts throughout the various views:

'FIG. 1 is a perspective top view of the container;

FIG. 2 is a sectional view taken at 2-2 of FIG. 1;

FIG. 3 is a somewhat diagrammatic view showing a cross section of a side wall of the container made from a single sheet comprising two plies;

FIG. 4 is a similar view showing a cross section of a side wall of the container made from a double wrap of a one-ply sheet;

FIG. 4a is a plan view on a somewhat reduced scale of the precut blank from which the double-wrapped side wall of the cup of FIG. 4 is made showing a printed pattern and the blocking coating on said blank;

FIG. 4b is a greatly enlarged sectional view taken at 4b4b of FIG. 4 showing the two-ply side wall fabricated from the blank illustrated in FIG. 4a and showing the relation of the interior =wax coating on the inner ply,

FIG. 6 is a similar view showing the drainingof the excess wax out of the mouth of the container;

FIG. 7 is a view similar to FIG. showing the second step of squirting or pouring wax into the container;

FIG. 8 is a greatly enlarged sectional view taken at 88 of FIG. 7 showing the two-ply side wall and the relation of the interior wax coating on the inner ply, the barrier between the two plies and the exterior glazed finish on the outer ply of the side wall; and

FIGS. 9, 10 and 11 inclusive, are longitudinal sectional views showing the coating of various portions of the container bottom.

Referring to the drawings, and more particularly to FIGS. 1 and 2, it will be seen that the container indicated in general as 9 comprises a tapered side wall designated in general as 10 and a bottom member designated in general as 11. The side wall 10 comprises an inner ply 12 and an outer ply 13 and an intermediate barrier comprising a blocking layer 14, which may be in the form of a blocking adhesive 14a (FIG. 4b), which is preferably polyvinyl alcohol or vinyl acetate, the preference being in the order named; or which may be in the form of a blocking coating 14b which (FIG. 4b) is preferably of a clay base, as for example, polyvinyl acetate and/or styrene butadiene latex combined with a clay material or titanium dioxide to obtain a white pigmentation to print upon. It is contemplated that other suitable adhesives may be employed, such as polyethylene or a starch adhesive, as well as a variety of suitable coatings, formulated to effect the desired barrier for preventing the passage of hot wax through the outer ply 13.

As seen in FIG. 5, the container is formed in the manner well known in the art having a bottom member 11, with an interior surface 110 and an exterior surface 11b, which is secured in position as by providing a downwardly peripherally extending flange 110 which is disposed between the outer wall portion 100 adjacent the lower end of the side wall 10 and the inwardly and upwardly turned end or skirt 10d of said end to form a pedestal 18. The bottom flange 11c is peripherally sealed between the adjacent portions 100 and 10d of the side wall member 10 to provide a liquid-tight seal. At the lower end of the pedestal 18, intermediate and integrally formed with said outer wall portion 10c and said upwardly turned skirt 10d is a bottom ledge 102 on which the container 9 is generally supported. The complete bottom surface 11 as illustrated in FIG. 5, of the container 9, includes the bottom ledge 10e, skirt 10d and the exterior surface 11b, which is the portion of the bottom member 11 circumscribed by peripheral skirt 110. A suitable rolled rim or lip 15 is formed on the open end of the container as is customary and in a manner well known in the art.

In FIG. 3 there is shown the conventional formation of a side wall by a single wrap designated 10a which comprises at lease two plies of material adhered together by blocking adhesive with the ends of a single wrap multiply sheet secured together in a side seam 16; while in FIG. 4 there is shown the conventional manner of forming a side wall by two or more wraps of a single ply sheet wherein the plies are laminated together by means of an intervening adhesive, which may be a blocking layer, and the ends of the single ply sheet are secured together as by side seam 17, as is customary in the prior art. As above indicated, the outer surface of the side wall 10 commensurate with the outer surface of the container may be printed on the container blank before the side wall of the container is formed and, whether plain or with a design, its exterior surface may be provided with the desired high gloss. Preferably, the high gloss finish is provided by first printing and then coating with a thermosetting resin to provide a clear, high gloss protective finish, such as 13'.

In FIG. 4a, there is shown a plan view of the present blank by which the side wall member 10]) is formed in accordance with a preferred embodiment of the invention. The blank side wall is of a length to form the doublewrap container illustrated in FIG. 4 in which one-half of the blank, when formed, is the inner ply 12 and the other half the outer ply 13. The paperboard stock carries a coating as, for example, a polyvinyl acetate along with a binder which is preferably of a clay base material, and which may form the blocking coating as hereinafter discussed.

Preferably, the high gloss finish is provided by first printing upon one-half of one side of the wall 10b and then coating with a thermosetting resin to provide a clear, high gloss protective finish as 13. When the wall 10b is of this double-wrap construction, the blocking adhesive 14a is applied opposite the printed side of the blank. When wrapped this surface 14a contacts 14b. The blocking coating 14b is contained on the inner ply 12 so that, in assembled relation for a double-wrap container, we have illustrated in FIG. 4b an exterior high gloss coating 13', blocking coating 14b, outer ply 13, blocking layer 14, formed of either or both the blocking coating 14b and blocking adhesive 14a, inner ply 12 with an interior wax coating 12 hereinafter discussed in detail. Thus as illustrated in FIG. 4b, we have a container constructed in which the blocking layer 14 intermediate the inner ply 12 and outer ply 13 is comprised of both a blocking adhesive 14a and a blocking coating 14b. Depending upon the properties of the blocking adhesive 14a and the blocking coating 14b, either one or the com bination of the two may constitute the blocking layer 14 and prevent the penetration of the wax 12' from reaching the outer ply 13. An additional feature is that a secondary blocking layer 14 may be provided between the ouer ply 13 and the high gloss protective finish 13 in the form of blocking coating 14b to further assure the obt-ainment of a container free from unsightly wax marring on the exterior surface thereof and as a base for printing upon the container side wall 10.

After the side wall and bottom have been assembled to complete the paperboard container 9 for either a singlewrap or double-warp container, the container is suitably held in a holder designated 20 and a series of containers so held is carried on a conveyor with the longitudinal axes disposed in the horizontal plane. The containers are rotated about their longitudinal axes while moved forward by he conveyor and wax is squirted or poured into the interior of the containers as by nozzles 21. It will be noted that the container 9 shown in the drawings has a tapered side wall 10, which as is customary in the art, makes an angle of 4-7 to the central axis normally held in a horizontal plane. This slight angle is sufficient to cooperate with the rotation of the container to evenly spread the liquid wax applied through nozzle 21. However, to remove the excess wax the container is tipped as shown in FIG. 6 to substantially increase the side wall tilt and drain out excess wax 22. Of course, if it is desired to treat cylindrical containers, the holder 20 is held on the conveyor so that the container side wall is initially inclined at a suitable angle, say about 38, and thereafter tilted to a greater inclination to drain out excess wax 22. The increased tilt angle as shown in FIG. 6 may be effected at one or more points in the path of travel of the container, as by means of cam segments (not shown) as is well known in the art.

The wax employed is preferably a compostion comprising 99.5% of fully refined paraffin wax having a melting point of 132-l34 F. and /a% of a polyethylene additive, such as one made by Eastman Chemical Company known in the trade as C13. This formulation of wax is applied in two steps, the first at about 255 F. and after the excess has been drained from the container as shown in FFIG. 6, a second application is made with the above composition at about 180 R, such as by means of a nozzle 23. After the second application the excess wax is drained from the container and the container is dried.

As will best be seen in FIG. 8, the wax not only coats the interior surface of inner ply 12 to provide the interior wax caoting 12, but partially penetrates the same to inhibit flaking. While this wax coating thus applied is prevented from passing through the paper-adhesive laminate to the exterior surface of the side wall 10, it does penetrate entirely through the bottom 11 of the container and a complete penetration through the bottom of the container is desirable so that the bottom is fully covered and the extra wax on the bottom adds strength to the corner and center portions of the container and also further assures a sealing fillet between the bottom member 11, and side wall 10.

For those containers stored or filled in a moisture laden or wet environment, it has been found desirable to provide a protective coating of wax on the complete bottom surface of the container, or parts thereof, in a manner to prevent the moisture from saturating the seal between the outer wall portion 100, upwardly turned skirt d of the wall 10 and the downwardly extending flange 11c therebetween. In practice, the filled containers are often stored in refrigerators and the bottom ledge 102 of the pedestal rests within the lid of a lower stacked container. The lid often contains a degree of condensation, such as water, that upon storage for several days tends to saturate the ledge 10e, upwardly turned skirt 10d and downwardly extending flange 11c to efiect a separation of the adhesive at the juncture therebetween which affects the structural rigidity of the container. When the skirt 10a becomes saturated. it starts to return to its original flat shape thereby applying a force on the overlapped seal which has a tendency to crack the seal.

Referring more particularly to FIGS. 9, 10 and 11, we have illustrated an exterior was coating on the bottom surface, which wax may be of the same type 12 as used to interiorly coat the container, and which wax is applied either subsequent to the application of the interior wax as decribed above or thereafter.

In FIG. 9, the bottom surface 11 is wax coated while the container is mounted generally vertically on a holder designated 25 and, which may be rotated, while the wax is applied as by squirting to pouring it on to the ledge 10e thereof by nozzle 26. Preferably when the entire bottom surface is to be coated the container and supply of melted wax are maintained in horizontally spaced relationship and moved along a defined path relative to each other to coat the surface thereof. Controlling means 27 is provided, which may be in the form of an outer guard means in the form of funnel 28 and an inner guard means in the form of funnel 29, mounted for relative movement with respect to each other in any conventional manner not shown, to confine the area of application of the wax and then move the container and control means relative to each other for waxing of the next container. The spacing at the mouth of the funnels is substantially equal to the width of the ledge 10e to assure that the wax substantially coats the ledge only and not the exterior high glass finish.

FIG. 10 illustrates the invention wherein the bottom ledge 10c and skirt 10d are coated with the wax particularly the junction between the latter and bottom member 11a, The nozzle 26 is positioned within the confining means 27 formed by the outer funnel 27 and inner funnel 29 and the latter terminating in spaced relation to the upwardly turned skirt 10d which is wax coated with the ledge 10e.

FIG. 11 illustrates the invention wherein the entire bottom surface 11 including the skirt 10d, bottom ledge 10a and the exterior surface 11b, enclosed by the skirt 10d, are coated as by positioning the nozzle 26 in spaced relation to the bottom 11 and providing control means 27 in the form of the funnel 28 having a diameter at its base substantially equal to the outer diameter of the container. Alternately, the bottom member 11 and skirt 10d may be wax coated by reducing the diameter of the control means 27. The holder can be simultaneously rotated relative to the nozzle 26, in any conventional manner to properly disperse the wax being applied or the holder and nozzle 26 may be maintained in fixed relationship to each other. In addition the wax is applied through the nozzle 26 in timed relation to the positioning of the container in overlapping relation thereto. The container may be intermitt'ently stopped when the wax is applied thereto.

Thus in accordance with the present invention applicant has invented a packaging container of the nestable type which for the first time combines many ideal characteristics not heretofore available in a single container. The invention permits the obtainment of a high exterior glossy finish which has long been desired for beauty and texture to properly attract the eye of the consumer, and still have the qualities that permit the storage of the container for prolonged periods of time, due to its wax coated interior and bottom surface. The wax coated bottom permits the container to remain on a damp or moistened surface for a considerable period of time without affecting the structure of the container and more importantly the contents contained therein.

Having thus described my invention with particularity with reference to its preferred form, it will be obvious to those skilled in the art, after understanding my invention, that other changes and modifications may be made therein without departing from the spirit and scope of my invention, and I aim in the appended claims to cover such changes and modifications as are within the scope of the invention.

What is claimed is:

1. A paper container, comprising (A) a tapered side wall member and a bottom member secured thereto in sealing engagement therewith at one end thereof to form a bottom on which the container is supported, said side Wall extending upwardly and outwardly from said bottom member and terminating in an open top having a peripheral lip,

(B) said side wall member comprising an inner ply and an outer ply with an intervening blocking layer of material,

(C) an exterior high gloss finish on said outer ply with an intervening blocking layer of material,

(D) an interior wax coating on said inner ply, said blocking layers serving as barriers preventing said interior wax coating from penetrating to and marring said exterior high gloss finish, and

(E) an exterior wax coating on said bottom, said exterior wax coating serving as a barrier preventing moisture from penetrating and separating the seal between said side wall member and said bottom member whereby said container may be positioned on a wet surface for prolonged periods of time without affecting the structural rigidity thereof.

2. A paper container as set forth in claim 1 wherein said blocking layer between said inner and outer plies comprises a blocking coating on said inner ply, and a blocking adhesive between said blocking coating and said outer ply and securing said outer ply and said coated inner ply together.

3. A paper container as set forth in claim 2 wherein said blocking adhesive is a starch adhesive, and said blocking coating is a clay base coating.

4. A paper container as set forth in claim 1 wherein said blocking layer between said inner and outer plies is polyvinyl alcohol.

5. A paper container as set forth in claim 1 wherein said interior wax coating is a composition comprising approximately 99.5% of a fully refined parafiin wax having a melting point of about 132134 F. and 0.5% of a polyethylene additive.

6. A paper container as set forth in claim 1 wherein said bottom includes (a) a bottom ledge integrally formed with said side wall member at the closed end of the container and on which the container is supported, and

(b) an upwardly extending skirt integrally formed with said bottom ledge,

7 8 (c) the exterior surface of said bottom member being 2,774,692 12/1956 Shelley et a1. 117-155 circumscribed by said skirt, 2,853,222 9/ 1958 Gallagher 2293.1 X and said exterior wax coating is disposed on and extends 2,999,765 9/1961 Boenau 2293.1 X continuously over said ledge, skirt, and bottom member 3,137,432 6/1964 Rein et a1. 2293.1 exterior surface. 5

References Cited DONALD F. NORTON, Primary Examiner.

UNITED STATES PATENTS C1. X'R 1,448,329 3/1923 Bohlman 2293.1 11795; 229-1.5

2,399,338 4/1946 Ford.

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