US2932575A

US2932575A - Art of packaging

Info

Publication number: US2932575A
Application number: US714094A
Authority: US
Inventors: Robert R Scion; Fred J Bock
Original assignee: Milprint Inc
Current assignee: Milprint Inc
Priority date: 1958-02-10
Filing date: 1958-02-10
Publication date: 1960-04-12
Anticipated expiration: 1977-04-12

Description

April 12, 1960 R. R. SCION ET AL ART OF PACKAGING Filed Feb. 10, 1958 ART OF PACKAGING Robert R. Scion, Green Bay, and Fred J. Bock, Thiensville, Wis., assignors to Milprint, Inc., Miiwaukee, Wis., a corporation of Delaware Application February 10, 1958, Serial No. 714,094

6 Claims. (Cl. 99- 178) The present invention relates generally to improvements in the art of packaging, and relates more particularly to improvements in the construction and production of wrappers and/or flexible containers having an inner surface coating of thermoplastic material.

A primary object of the invention is to provide an .improved commodity wrapper or flexible container having an inner surface coating of wax or the like and so constructed as to avoid or at least minimize seepage or migration of the coating'material through the seams of the ifinal package.

In the packaging of cheese and similar commodities, it is common practice to utilize Wrappers or pouch-like containers formed of flexible sheet material such as regenerated cellulosic film interiorly surface coated with a thermoplastic material such as Wax or the like. In

such instances, the product is enclosed within the wrapper or pouch, and the adjoining wax-coated marginal edges of the wrapper are brought into face-to-face relation and sealed by means-of heat and pressure to protectively confine the commodity. Where processed cheese is being packaged, it is usual practice to first place the wrapper or pouch within a relatively rigid box or carton of definite size and shape and to then pour the cheese while in heated and flowable condition directly into the wrap- .per for hardening and setting and to thereafter heat seal the exposed mouth portionof the wrapper, finally enclosing the product within the carton by placing a cover thereover. In still other instances, the product enclosed in the sealed package may be overwrapped with another flexible wrapper or it may likewise be enclosed in an outer objectionable and causes adhesion or sticking of the wrapper to the adjacent inner surfaces of the outer box or carton or of the flexible overwrap as the case may be, thereby creating difliculty in opening and gaining access to the final package.

It is therefore a more specific object of this invention to provide an improved flexible commodity container which obviates the aforesaid difficulties and objections and an improved method of and apparatus for producing the same.

Another specific object of our invention is to provide a novel and improved wax-coated pouch-like flexible container in which the wax coating is substantially confined to the interior of the container at all times.

Another specific object of the invention is to provide an improved method of producing wax-coated pouch-like containers which is extremely rapid, economical and efficient and which may be readily exploited with the aid of novel and improved apparatus.

Patented Apr. I2, 1960 Another specific object of the invention is to provide a flexible coated pouch-like commodity container having a novel and improved mouth construction which adds rigidity for facilitating opening and filling operations While also confining the coating to the interior of the wrapper in the final sealed package assembly.

Still another specific object of the present invention is to provide an improved commodity container comprising, superimposed plies of flexible packaging material secured to each other along opposed marginal edges to provide an access mouth, the adjacent inner surfaces of the plies being coated with a thermoplastic material with at least one of the plies along the marginal edge of the access mouth being folded inwardly upon itself toward the interior of the container to thereby provide an uncoated lip within which the coating material is confined upon closure and sealing of the mouth.

An additional specific object of the present invention is to provide an improved method of producing flexible containers which comprises, coating one surface of a flexible sheet witha thermoplastic material, creasing a marginal edge of the sheet along a line extending parallel to the edge to form a laterally extending tab, folding thetab along the crease inwardly firmly against the coated surface of the sheet, superimposing two plies of the coated sheet with the coating in face-to-face relation, and finally applying heat and pressure to opposed coated marginal edges of the superimposed plies to unite the same and form a container having an access mouth in which a marginal edge is of double thickness.

A further specific object of the invention is to provide improved apparatus for performing the steps of the method thus defined.

These and other specific objects and advantages of the invention will become apparent from the following detailed description.

A clear conception of the features constituting the present improvement and of the steps of the improved production method may be had by referring to the drawing accompanying and forming a part of this specification wherein like i reference characters designate the same or similar parts in the several views.

Fig. 1 is a perspective view diagrammatically depicting the initial step of applying a thermoplastic coating to a web of flexible packaging material used in fabricating the improved wrapper;

Fig. 2 is a somewhat enlarged fragmentary perspective View diagrammatically depicting the next series of steps in the fabrication of the wrapper, namely the creasing and folding of a marginal edge of the coated web;

Fig. 3 is another perspective View showing one of the improved wrappers folded and marginally sealed to provide a pouch-like container, a portion of the wrapper being broken away for the sake of clarity;

Fig. 4 is still another part-sectional perspective view of the pouch-like wrapper with a cheese batch packaged therein;

Fig. 5 is a fragmentary transverse section showing a cheese batch confined within a somewhat modified wrapper illustrating the closure of the month by heat and pressure scaling to provide a tin type seal;

Fig. 6 is a perspective view of a completely assembled prior art package, portions of the outer carton being broken away to illustrate the previously existing objecttionable seepage or migration of coating material past the seams; and

Fig. 7 is a fragmentary view of a somewhat modified Wrapper sheet in which the wax. coating has been omitted from one edge.

While the invention has been specifically shown .and described herein as being especially advantageously "ap- 'plicable to pouch-like containers formed of regenerated cellulosic material interiorly coated with wax and adapted for use as a liner or inner Wrap in the packaging of processed cheese introduced to the container in molten condition, it is not desired or intended to thereby unnecessarily limitthe scope or utility of the invention since the improvements might also be advantageously utilized in the production of wrappers of various types and formed of diverse materials for use in packaging other heat flowable commodities. It is also contemplated that various specific descriptive terms used herein shall be given the broadest possible interpretation consistent with the disclosure.

Referring to the drawing, Fig. 5 is illustrative of the prior art in which the cheese or other product is packaged in a flexible wrapper 8 having an all over wax coating on its inner surface, the coated wrapper sheet 8 being fabricated into a pouch-like container and then inserted within an upwardly open rigid container 9 with hot processed cheese in molten condition then being poured into the wrapper 8. After the pouch-like wrapper 8 confined within the rigid container 9 is filled with the proper amount of cheese, the interiorly wax-coated marginal mouth portion 10 of the flexible wrapper is sealed by application of heat and pressure to protectively enclose the cheese batch, and a relatively rigid cover is then placed over the container 9 to finally close the same and form the assembled package. Since the wax coating at the marginal edges 10, 11 of the flexible wrapperS is softened to a more-or-less flowable state during activation in the heat sealing process, this Wax bleeds and migrates or seeps outwardly through the seams as illustrated at 13, and due to the tackiness of the Wax, the flexible wrapper or liner 8 will stick to the rigid container 9 and cover 12 along the areas 13 which causes considerable difliculty in the opening of the package by the final consumer. This bleeding of the wax coating and migration or seepage of the wax through the seams of the wrapper during the heat sealing process is therefore highly objectionable, and regardless of whether the cheese flexible outer Wrapper, the wax bleed shown at 13 will invariably adhere to the outer container due to its of the base sheet is then coated in a suitable manner as at 16 with a thermoplastic material such as wax adapted to provide moisture-proofness and cling to the product to be wrapped. Next, one of the marginal edges of the base sheet is creased as at 17 along a line extending parallel to the adjacent edge to form a laterally extending tab or flange -18 which is thereafter folded along the crease 17 down against the adjacent coated surface 16 of the sheet to provide a marginal lip portion 19 which is devoid of coating. The coated sheet 15 is then folded along a line 20 intermediate the ends of the sheet so that two plies or folds are superimposed as shown in Fig. 3 with the coating 16 in face-to-face relation, the plies forming

side walls

21, 22. The opposite marginal edges of the

superimposed plies

21, 22 are then sealed to unite the same by applying sealing heat and pressure thereto along the

areas

23, 24 thereby providing a flexible pouchlike container 26 having an access mouth 27 of which one of the marginal edges is of double thickness. The pouch-like container thus described may then be provided with the commodity in the usual manner by placing the same in a more-or-less rigid open topped container and pouring the molten cheese as hereinabove described into the flexible pouch-like wrapper. The mouth of the pouch-like wrapper 26 is thereafter closed and sealed by first folding the free lip portion of the Wall 22 directly over the cheese loaf or other commodity 28 and thereafter bringing the free lip portion of the wall 21 over batch enclosed within the inner Wrap or liner 8 is thereafter enclosed in a rigid container as described or in a the outer surface of the adjoining lip portion of the wall 22 so that the folded marginal lip portion 19 lies directly against the exterior of the wall 22. The overlying mouth portions of the

walls

21, 22 are finally secured to each other by activating the coating material by application of heat and pressure adjacent to the folded marginal lip portion 19 along the area 39 as shown in Fig. 4 which activates the adjacent coating and causes sealing of the overlying wrapper portions. The end tabs 29 may thereafter be folded as shown in Fig. 4 and the package may be overwrapped either in a relatively rigid container as shown in Fig. 5 or with a suitable flexible outer wrapping sheet.

In some instances, it may be desired to close the wrapper mouth by means of a so-called fin type seal; and in such cases, the wrapper 15 is formed as shown in Fig. 5 with opposed inturned and wax-free lip portions. As shown in Fig. 5, the side wall or ply 22 is provided with an inwardly folded marginal portion or lip 25 which may be formed in the same manner as the lip 19, and the opposed

uncoated lips

19, 25 are then brought into face-to-face relation with sealing heat being applied to the adjacent coating as by heat sealing members 31 to seal the wrapper month. Also, it is sometimes desirable to strip or omit the wax from along the marginal inturned lip portions, as at 33 in Fig. 7, prior to creasing and folding the same to thereby eliminate some of the wax coating and reduce the thickness and bulkiness along the lips of the final package. In addition, it has been found that migration or seepage of the thermoplastic coating at the opposed sealed marginal edges can be minimized by eliminating coating from the transverse areas 32 immediately adjacent to the opposed marginal edges and outwardly of the

seals

23, 24. By providing the wax-free areas 32, the coating along the

seams

23, 24 upon activation during the heat sealing step can bleed or flow into the adjacent uncoated areas 32 and will be confined thereto rather than migrating from the seams to the exterior of the wrapper as in the case of prior wrappers ofthis general type.

In producing the improved wrapper thus described and as shown in the drawing, the wax coating may be conveniently applied in any suitable manner as by means of'a transfer roll 34 having a recessed area 35 periodically contacting the surface of the advancing sheet or web 15 to thereby provide the wax-free transverse areas 32. The coated sheet or web 15 may then be advanced about a suitable guide roll 37 having a peripheral shoulder 38 coacting with a creasing member 39 for forming the crease 17, and the laterally extending tab 18 formed by the coacting

elements

37, 38, 39 may then be folded inwardly upon the adjacent coated surface of the sheet 15, as by means of a split wire folder '40 as shown in Fig. 2. Finally, the web may be severed into sections in a wellknown manner along a line corresponding approximately to the dot-and-dash line extending through the medial portions of the uncoated transverse areas 32 to thereby provide wrapper sections which may subsequently be folded and formed into pouch-like containers already dmcribed.

The improved wrappers thus provided have proven highly satisfactory in actual commercial use in the packaging of commodities such as processed cheese adapted to be introduced to the wrapper in hot flowable condition, and in which the wrapper coating is in the nature of a thermoplastic seal-ing material having a tacky wax-rubber base adapted to flow at a lower temperature than the commodity. The folded marginal lip portion 19 or the opposed

marginal lip portions

19, 25 which are devoid of coating provide an uncoated marginal area within which any displaced coating material is confined, thereby eliminating migration or seepage of the wax or other thermoplastic coating material beyond the sealed wrapfurthermore provides a convenient gripping tab or edge for aiding the consumer in opening the package for access to the product. It should, of course, be understood that the wax-free strips or areas 32 may or may not be provided, but in instances where wax bleed and seepage or migration of the coating past the opposed marginal edges adjacent to the

heat sealing zones

23, 24 is a problem, the problem can invariably be overcome by providing the free areas 32. Where the wax coating 16 is relatively heavy, it is also desirable to eliminate the coating from the marginal lip portion alongthe folded lip 19 as hereinabove described to thereby minimize bulkiness.

In fabricating the improved wrapper, a suitable base sheet of cellophane, Mylar, paper, foil to paper, foil to cellophane laminated sheeting or other films may be used, and the thermoplastic coating may be selected from various rubber-wax mixtures, waxes per se or low melting polymers of combinations thereof.

It is important, however, that in all cases the thermoplastic coating must have a melting temperature or a flow temperature which is somewhat below the ambient temperature of the packaged product and/or the temperature normally used for sealing the wrapper. It is also usual practice to apply an anti-blocking material to the thermoplastic coating, and the material selected for anti-blocking purposes may be any one of several known materials such as cornstarch, sorbic acid, silicones, lacquers, or the like.

One typical specific example of a cheese wrapper embodying the invention consists of a base sheet of 300 MAD-2 cellophane having a weight of 20-21 lbs. per ream and approximately 0.001 inch thick coated on one side with a blend of rubber and microcrystalline wax in amounts of 45-50 lbs. per ream, approximately 0.003 to 0.004 inch thick, the coating having cornstarch applied in amounts of 4 to lbs. per ream. It should be noted that the stock used must be flexible and must possess the desired properties with respect to moistureproofness and product protection, and the coating must have a melting point, fiow point or a pseudo melt point at or below the temperature of the product being packaged or the sealing heat utilized. As for the width of the inturned lip portion 19 or

portions

19, 25, this may vary from A of an inch to approximately /2 of an inch, and in most instances the optimum size has proven to be $1 to A of an inch. It has been found that the coating in the wrapper thus described when subjected to either the heat of the product being packaged or the sealing heat will not adversely bleed exteriorly of the seams of the final package.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise steps of the method herein shown and vdescribed, since various modifications may occur to persons skilled in the art to which this invention pertains.

We claim:

1. A commodity package comprising, superimposed pl-ies of flexible packaging material united along all but one of their marginal edges to provide a normally fiat pouch-like receptacle having an access mouth, a commodity confined within said receptacle, the inner surfaces of said plies being coated with a thermoplastic sealing material adapted to flow upon application of heat and the exterior exposed surfaces being devoid of such thermoplastic coating, at least one of said plies along the marginal edge of said access mouth being folded inwardly upon its coated surface and toward the interior of said receptacle thus forming an uncoated lip, said lip overlying an uncoated surface of the other ply and the mouth being closed and sealed by heat applied directly adjacent the marginal edge of the mouth and to said lip, whereby outward flow of the thermoplastic coating material is retarded and migration thereof to the exterior of the package is prevented.

2. A commodity package comprising, superimposed plies of flexible packaging material united along all but one of their marginal edges to provide a normally flat pouch-like receptacle having an access mouth, a commodity confined within said receptacle, the inner surfaces of said plies being coated with a thermoplastic sealing material adapted to flow upon application of heat and the exterior exposed surfaces being devoid of such thermoplastic coating, at least one of said plies along the marginal edge of said access mouth being devoid of coating and being folded inwardly upon its coated surface adjacent to the uncoated area and toward the interior of said receptacle thus forming an uncoated lip,

said lip overlying an uncoated surface of the other ply and the mouth being closed and sealed by heat applied directly adjacent the marginal edge of the mouth and to said lip, whereby outward flow of the thermoplastic coating material is retarded and migration thereof to the exterior of the package is prevented.

3. A commodity package comprising, a base sheet of flexible packaging material having one surface coated over substantially its entire area with a thermoplastic sealing material adapted to flow upon application of heat, the sheet being folded about a commodity to form a receptacle with the coating disposed interiorly, opposed marginal edge portions and the exterior of said sheet being devoid of said coating with the folds being secured to each other along said opposed marginal edges by heat'sealing within the coated area immediately adjacent to the uncoated edges, at least one of said folds along the marginal edge of said access mouth being folded inwardly upon its coated surface and toward the interior of said receptacle thus forming an uncoated lip, said lip overlying an uncoated surface of the other fold and the mouth being closed and sealed by heat applied directly adjacent the marginal edge of the mouth and to said lip, whereby outward flow of the thermoplastic coating material is retarded and migration thereof to the exterior of the package is prevented.

4. A commodity package comprising, superimposed plies of flexible packaging material united along all but one of their marginal edges to provide a normally fiat pouch-like receptacle having an access mouth, a commodity confined within said receptacle, the inner surfaces of said plies being coated With a thermoplastic sealing material adapted to flow upon application of heat and the exterior exposed surfaces being devoid of such thermoplastic coating, at least one of said plies along the marginal edge of said access mouth being folded inwardly upon its coated surface and toward the interior of said receptacle thus forming an uncoated lip, said lip overlying the exterior uncoated surface of the other ply and the mouth being closed and sealed by heat applied directly adjacent the marginal edge of the overlying ply and said lip, whereby outward flow of the thermoplastic coating material is retarded and migration thereof to the exterior of the package is prevented.

5. A commodity package comprising, superimposed plies of flexible packaging material united along all but one of their marginal edges to provide a normally flat pouch-like receptacle having an access mouth, a commodity confined within said receptacle, the inner surfaces of said plies being coated with a thermoplastic sealing material adapted to flow upon application of heat and the exterior exposed surfaces being devoid of such thermoplastic coating, both of said plies along the marginal edge of said access mouth being folded inwardly upon their coated surfaces and toward the interior of said receptacle thus forming uncoated opposed lips, the mouth being closed and sealed by heat applied directly adjacent the marginal edge of the mouth and to said lips, whereby outward flow of the thermoplastic coating material is retarded and migration thereof to the exterior of the package is prevented.

6. A commodity package comprising, superimposed 7 plies of flexible packaging material united along all but one of their marginal edges to provide a normally flat pouch-like receptacle having an access mouth, a commodity which is flowable at high temperatures confined within said receptacle, the inner surfaces of said plies being coated with a thermoplastic sealing material having a tacky wax rubber base adapted to flow at a lower temperature than the commodity upon application of heat and the exterior exposed surfaces being devoid of such thermoplastic coating, at least one of said plies along the marginal edge of said access mouth being folded inwardly ,upon its coated surface and toward the interior of said receptacle thus forming an uncoated lip, said lip overlying an uncoated surface of the other ply and the mouth being closed and sealed by heat applied directly adjacent the marginal edge of the mouth and to said lip, whereby out- 8 ward flow of the thermoplastic coating material is retarded and'migration thereof to the exterior of the package is prevented.

References Cited in the file of this patent UNITED STATES PATENTS Nicol Jan. 8, 1957

Claims

1. A COMMODITY PACKAGE COMPRISING, SUPERIMPOSED PILES OF FLEXIBLE PACKAGING MATERIAL UNITED ALONG ALL BUT ONE OF THEIR MARGINAL EDGES TO PROVIDE A NORMALLY FLAT POUCH-LIKE RECEPTACLE HAVING AN ACCESS MOUTH, A COMMODITY CONFINED WITHIN SAID RECEPTACLE, THE INNER SURFACES OF SAID PILES BEING COATED WITH A THERMOPLASTIC SEALING MATERIAL ADAPTED TO FLOW UPON APPLICATION OF HEAT AND THE EXTERIOR EXPOSED SURFACES BEING DEVOID OF SUCH THERMOPLASTIC COATING, AT LEAST ONE OF SAID PILES ALONG THE MARGINAL EDGE OF SAID ACCESS MOUTH BEING FOLDED INWARDLY UPON ITS COATED SURFACE AND TOWARD THE INTERIOR OF SAID RECEPTACLE THUS FORMING AN UNCOATED LIP, SAID LIP OVERLYING AN UNCOATED SURFACE OF THE OTHER PLY AND THE MOUTH BEING CLOSED AND SEALED BY HEAT APPLIED DIRECTLY ADJACENT THE MARGINAL EDGE OF THE MOUTH AND TO SAID LIP, WHEREBY OUTWARD FLOW OF THE THERMOPLASTIC COATING MATERIAL IS RETARDED AND MIGRATION THEREOF TO THE EXTERIOR OF THE PACKAGE IS PREVENTED.