US3249286A

US3249286A - Reinforced plastic bag

Info

Publication number: US3249286A
Application number: US399443A
Authority: US
Inventors: Charles E Palmer
Original assignee: Monsanto Co
Current assignee: Monsanto Co
Priority date: 1964-09-28
Filing date: 1964-09-28
Publication date: 1966-05-03
Anticipated expiration: 1983-05-03

Description

May 3, 1966 c. E. PALMER 3,249,286

REINFORCED PLASTIC BAG Filed sept. 2e, 1964 INVENTOR. C HARLES E. PALM ER 7%' Q/fm A 77' OFP/VE' Y Unid seres Parent O This invention relates to improvements in plastic bags and methods of fabricating such containers and, more particularly, a yreinforced plastic bag providing highly desirable qualities.

An important object of the present invention is to yprovide a plastic bag which uniquely embodies and cornbines the mostfdesirable qualities of semi-rigid plastic and flexible plastic film.

Another object of the present invention is to provide a plastic bag which has suflicient rigidity to stand up on a shelf for display purposes and to resist damage from normal impact or shock in handling and distribution. y Yet another object ofthe present invention is to provide an all-plastic bag which affords excellent visual display ofthe product within, yet is sufficiently rigid that a number of such containers may be stacked for display or for shipping purposes, without damage to the goods contained with the bag.

' Anotherr most important object of the present invention is'to prevent the semi-rigid element of a container from cutting through or damaging the plastic lm in which it is enclosed.

These and other featuresand objects of the present 'invention will be more readily understood from a reading ofthe description of several embodiments of the present invention which follows, taken together with the drawings in which: Y

FIGURE l is a perspective view of one embodiment of the present invention;

FIGURE 2, is a top elevational view of a blank used to forni the container illustrated in FIGURE 1; FIGURE 3 is. a. perspective view of an embodiment of the present invention including an inner containerjof flexible Vplastic film;

FIGURE 4 is a top elevational view of a bank used for for-ming the container shown in FIGURE 3;

bodiment of the present invention,

The Vall plastic bag or container of the present invention basically comprises an inner liner which is of semi- `rigid synthetic plastic sheet material and an outer container of flexible synthetic plastic film enclosing the inner liner and having portions which extend beyond the -top and bottom of the inner liner, which are adapted to 'be folded to form the bottom and the top closures of 'the bag. The outer container of flexible synthetic plastic lm has reinforcing strips elllxed to its inner side so as to overlap the top and bottom free edges of the innerliner ,which defines the sidewalls of the container. The inner liner is of semi-rigid synthetic plastic sheet material and is secured to the flexible filmt along common edges lying between the top and bottom reinforcing strips and the edges of the resulting assembly are bonded in a common overlapping closure leaving top and bottom extending portions of the flexible film. As mentioned previously, the bottom portion of the yflexible synthetic plastic film extending beyond the edges of the semirigid inner liner is approximately folded into a closure and bonded, and after the-bag has been lled with the 3,249,236 Patented May 3, 1 966 product to be contained therein, the top portion of the flexible synthetic plastic illlm is similarly folded and'secured .to complete the final closure of the bag.

In the method of fabricating the reinforced plastic bag of the present invention, the spaced reinforcing strips-are affixed to a substantially rectangular sheet. of flexible synthetic plastic film, the reinforcingstrips beingpositioned parallel to and inwardly from opposing edges. ofthe sheet. Then a vsubstantially rectangular sheet of semirigid plastic sheet material is placed in overlying relationship upon the sheet of flexible film with two ofits edges overlapping the reinforcing strips and its remaining two edges coincident with portions of two edges of the `flexible film. The two sheets of plastic are then secured along the latter coincident edges lying between the spaced, parallel reinforcing strips. This composite is then further assembled by b-onding the previously secured edges of the two sheets in overlapping relationship and securing the top and bottom extending portions of the flexible film to provide top and bottom enclosures for the container.

The reinforced plastic bag of the present invention may take the form of a number ofdifferent embodiments, including a substantially tubular container as is described above, or a container of substantially polygonal crosssection which may include sidewalls of substantially rectangular shape as defined by the semi-rigid synthetic plastic sheet material which for-ms the inner lining of the bag. In fabricating the latter embodiment of the present invention, the assembly of the inner liner and outer sheet undergo the further step of being folded substantially in accordance with the method `and means described in my vPatent No. 2,954,725, issued October 4, 1960, for Method and Apparatus for Folding Sheet Stock.

In accordance with the concept of the present invention, the further step of folding the blank comprised of the Iassembled elements as described hereinbefore, includes supporting the assemblybetween a die pad underlying a plurality of parallel .lines which are normal to the free edges of the semi-rigid liner sheet, Jbut terminate short of v,the free edges. The spaced parallel lines are then folded with foldingV blades as described in mypreviously noted patent toestablish permanent Vfolds in the semi-rigid material so that the bag takes the shape of substantially rectangular sidewalls but the free edges defining rounded corners due to the fact .that the folds in the semi-rigid sheettliner terminateshort of. the freeedges of the semirigid materiak This rounded corner `configuration affords a particular advantage and desirable feature `of the present invention as will be explained more fully hereinaften` r.. 1

Referringnow to VFIGURE l, there is shown an em- -bodiment of the present invention having an outer container -lflof flexible synthetic plastic film enveloping an .inner liner 11 .of semi-rigidplastic sheet material which ,extends from its bottom edge .12 toits upper edge 13. Reinforcing strips 14 and 15 areafllxed to theinner surface of the outer container 10 of flexible synthetic plastic film andare positioned to overlap the respective bottom .and top

free edges

12 and 13 of the-inner liner 11'of semirigid plastic material. The outer container 10 is secured tothe inner sleeve 11 of semirigid material along the marginaledgesl between the top and

bottom edges

13 and 12 of the semi-rigid inner liner. The entire assembly Yis further secured in anoverlapping closure along the entire length 16 vof the edges of the composite structure, including the edges of the flexible synthetic plastic film extending lat the bottom and the'top'bey-onrl the liner 11 kof semi-rigid material. The portion of the flexible synthetic plastic film extending beyond the bottomk of the semi-rigid liner 11 is appropriately folded and secured as shown generally at 17 to form the bottom of the con- 'opposed and parallel edge. 'plastic sheet material 11 of substantially rectangular form tainer and the portionI 18 of the same plastic film extending beyond the top of the semi-rigid liner 11 affords a means of making a final closure of the package after itv has been filled with the product to be contained therein. The bag illustrated in FIGURE 1 is formed from a blank such as is illustrated in FIGURE 2 wherein like elements bear the same numerical designations as in FIGURE 1. A sheet of fiexible synthetic plastic sheet material of substantially rectangular shape has affixed to it two spaced, parallel reinforcing strips 14 and 15 which are positioned inwardly from one pair of opposed edges of the sheet 10 and extend from one of the other edges to the remaining A smaller sheet of semi-rigid and having a length equal to that of the reinforcing strips 14 and 15 is positioned over the film sheet 10 with parallel

free edges

12 and 13 partially overlapping the reinforcing strips 14 and 15, and the semi-rigid sheet 11 is secured to the film sheet 10 along the overlying coincident edges 19 lying between the parallel reinforcing strips 14 and 15. The blank assembly is further formed by closing the secured overlapping edges 19 upon themselves and bonding those edges in closure, including the edges lof the film sheet 10 extending beyond the free edges of the semirigid liner 11.

FIGURE 3 illustrates another embodiment of the present invention, including an outer container of flexible synthetic plastic film 20 and inner sleeve 21 of semi-rigid plastic sheet material which defines substantially rectan gular sidewalls of the bag, and an inner container 22 of flexible synthetic sheet material which may be added to the basic assembly as desired for the purpose of preventing a granular or powder-like product from tending to work between the outer film container 20 and the inner sleeve 21. As is the case of the embodiment illustrated in FIGURE l, the inner sleeve 21 extends to its free edges at the top 23 which partially overlap the upper reinforcing strip 24 affixed to the inner side of the film outer container 20 and similarly its bottom edges 25 partially overlap the lower reinforcing strip 26. The inner sleeve 21 of semi-rigid plastic material is permanently folded along spaced

parallel lines

27, 28, 29 and 30 to form the corners of the bag and define its sidewalls.

The particular manner in which the folds along lines `27, 28, 29 and 30 are made in the semi-rigid sheet 21 can perhaps be best seen in FIGURE 4 wherein like elements bear the same numerical designations as in FIG- UREv 3. In the top elevational view of FIGURE 4 there is shown a substantially rectangular sheet 20 of exible synthetic plastic film such as cellulose acetate, polyethylene, rubber hydro-chloride, polyvinylidene chloride, or polyvinyl-chloride-acetate copolymer, for example. Spaced

parallel reinforcing strips

24 and 26 are positioned inwardly from opposed edges of the iiexible sheet 20,

'which strip areas may be reinforced by adhesively secured tape, a deposited additional plastic coating, or a layer of heat sealed plastic, for instance. A semi-rigid sheet 21 of synthetic plastic material overlies the fiexible sheet material 20, two of its

edges

23 and 25 partially overlapping the reinforced strip areas 24 and 26., respectively, and the margins of its two remaining edges 31 and 32 being bonded to the exible sheet 20 along its coincident underlying edges. The semi-rigid sheet 21 may be any one of a number of suitable materials such as biaxially oriented polystyrene, polyethylene, polypropylene, cellulose acetate, cellulose acetate-butyrate or polyvinyl chlo'- ride-acetate copolymer.

As most clearly seen from FIGURE 5, a typical compositeblank as conceived by the present invention appears in cross-sectional view as a number of overlying elements. Exaggerated somewhat in relative proportions and actual dimensions for emphasis and clarity of illustration, FIG- URE 5 shows the large underlying thin sheet of plastic lm 20 with reinforcing

strip areas

24 and 26 overlying and affixed to the plastic film 20 inwardly from two of its opposed edges; the semi-rigid sheet 21, of synthetic plastic material in turn overlies both the larger sheet of plastic 'film 20 and the

reinforced strip areas

24 and 26, overlapping the latter only partially so that the

free edges

23 and 25 are positioned preferably near the middle of the reinforced

strips

24 and 26, respectively.

The

folds

27,28, 29 and 30 are made in the composite blank of FIGURE 4 by the method and means described in my Patent No. 2,954,725 and as can be seen most clearly in FIGURE 4 the folds along

lines

27, 28, 29 and 30 terminate inwardly of the

edges

23 and 25 of the semi-rigid sheet 21. Thus, when the composite blank is erected by securing the overlapping edges 31 and 32 to each other, the bag takes a substantially polygonal crosssectional formV along the permanentfolds and the top and bottom portions adjacent the

free edges

23 and 25 of the semi-rigid sheet 21 assume a round-cornered polygonal cross-sectional configuration as is best shown in the cross-sectional view of FIGURE 6. The

permanent folds

27,28, 29 and 30 in the inner liner 21 define the sidewalls of the container, but because the folds terminate inwardly of the free edges 23 `and 25 of the inner liner 21 there are no acutely angled corners, but rather the round cornered configuration shown in FIGURE 6. The advantage of this feature of the present invention is that the free edges of the semi-rigid innersheet to do not tend to tear or cut through the outer container of thin film. Additionally, the reinforced portions of the thin film outer container are permitted some movement with relation to the free edges of the inner sleeve preventing continuous wear in one place due to handling the container, filling it with the product which -it is to contain, shipping it, placing it on shelves for display, andthe like. Thus, the present invention Acombines the most desirable features of a transparent plastic film bag with the advantageous aspects of a transparent semi-rigid container of considerably heavier material.

The same features and advantages may be incorporated in many different shapes and configurations of the present invention, including, for instance, side walls which are tapered in a generally polygonal form and which preferably, though not necessarily, have two substantially parallel sets of edges at top and bottom of the sidewalls defining the basic shape of the container. FIGURE 7 illustrates a variant embodiment of the concept of the present invention in the form of a reinforced bag having a substantially triangular cross-section. An outer container 33 comprised of a sheet of flexible synthetic plastic lm encloses a smaller sheet of semi-rigid synthetic plastic material 34 having three folds 35, -36 and 37 which terminate inwardly of its free edges at top and

bottom

38 and 39, respectively, thus imparting a rounded co-rner configuration at theend sections of the semi-rigid inner liner 34. .The outer container 33 of fiexible synthetic plastic film has two reinforcing

strips

40 and 41 afiixed to its inner surface and partially overlapping the top and bottom

free edges

38 and 39, respectively, of the semi-rigid inner liner 34.

In appearance the bag of the lpresent container gives the visual impression of being fabricated of a single sheet inasmuch as the film sheet conforms closely to the configuration of the inner semi-rigid liner. Additionally, the liner imparts a degree of rigidity which resists rupture or damage to the bag from normal impact or shock. As will be appreciated by those skilled in the art, the present invention may take many different forms and configurations as may be desired to contain and display particular types of goods including generally rectangular lbu'ttapered side walls having top edges of its semi-rigid liner disposed in generally parallel relationship to the bottom edges of the liner.

Another advantage of the present invention is that the blank material comprising a continuous length of transparent synthetic plastic film material having reinforced strips may be combined with a continuous length of semirigid material in a single roll to form a multiplicity of blanks for fabricating the present invention as taught and described herein. Such a roll of blank material affords the convenience of being preassembled by a plastic material manufacturer and shipped to the user of the container where it may be cut into appropriate lengths in accordance with the size of the containers which are desired, permanently cold-folded as is taught by the concept of the present invention, assembled and erected, filled with the product to be contained therein and final closure made for shipment. Thus the concept of the present invention permits blank material to be shipped from a manufacturer in most convenient and economical `form at a minimum shipping cost. Moreover such rolls of lblank material may be easily and conveniently retained in inventory by the bag user 'because of its minimal space requirements in the roll form of blanks which is made possible within the concept and teaching of the present invention.

As well as being a practical and efficient ycontainer which, because of its rigidity, is capable of standing up -by itself for display and stocking purposes, the present invention, when embodied in transparent plastic materials, affords a most attractive, clear and virtually undistorted display of the goods or products contained therein. These features are due to the fact that the container of the present invention gives the appearance of a unitary, rigid, plastic material throughout these portions of the container through which the goods are usually viewed, i.e. the erect sidewalls of the container. The plastic film outer container of the bag of the present invention closely conforms to the flat, smooth configuration of the inner liner producing a minimum wrinkled or distortional effect in the display of the goods. The reinforcement strips which are aflixed to the inner side of the outer container in partially overlapping relation to the free edges of the semi-rigid inner sleeve, may be colored or carry a brand name thereon to attractively define the top and bottom of the container in its erected form. The portion of the outer container of flexible lm which extends beyond the top of the semi-rigid inner liner provides a convenient means of attaching an appropriate label for lbrand identilication, price, content or other information relating to the goods which the 4bag contains. Such identifying label may of course, as will be evident to those skilled in the art, perform `the equally important function of providing final closure of the bag after the goods have been placed therein.

Since many changes Icould be made in the above construction and many apparent widely different embodiments of the invention could be made without departing from the scope or spirit thereof, it is intended that all matter contained in the above description or the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, I claim:

1. A reinforced plastic bag `comprising a Itubular inner liner of semi-rigid synthetic plastic sheet material, said inner liner defining the sidewalls of said bag and having an open top and an open bottom, an outer 4container of flexible synthetic plastic film enclosing said inner liner and having portions extending beyond the top and bottom of said inner liner adapted to be folded to form top and bottom closures of said bag, and vertically spaced reinforcing strips of flexible material aflixed to the inside of said outer container and extending about the top and bottom edges of said inner liner in partial overlapping relationship to said top and bottom edges, said inner liner and outer container being secured to each other along both side edges lying between the top and bottom reinforcing s-trips and said side edges overlapping each other and being bonded to each other in a icommon overlapping closure .from top to bottom of said flexible film.

2. A reinforced plastic bag comprising a tubular inner liner of semi-rigid synthetic plastic sheet material having a curvilinear cross section, and outer container of flexible synthetic plastic film enclosing said tubular inner liner and having portions extending beyond the top and bottom of said inner liner adapted to be folded to form top and bottom closures of said bag, and vertically spaced reinforcing strips of flexible material aflixed to the inside of said outer container and extending about the top and bottom edges of said inner liner in partial overlapping relationship to said top and bottom edges, said inner liner and outer container being affixed to each other along Iboth side edges lying between the top and bottom reinforcing strips and said side edges overlapping each other and being bonded to each other in a commonv overlapping closure from top to bottom of said flexible film.

3. A reinforced plastic bag comprising a tubular inner liner of semi-rigid plastic sheet material, said inner liner having a plurality of panels defining the side walls of said bag and having an open top disposed in generally parallel relationship to an open bottom, an outer container of flexible synthetic plastic film enclosing said inner liner and having portions beyond the top and bottom of said liner adapted to be folded to form top and bottom closures of said bag, and vertically spaced reinforcing strips of flexible material affixed to the inside of said outer container and extending about the top and bottom edges of said inner liner in partial overlapping relationship to said top and bottom edges, said inner liner and outer container 'being affixed to each other along both side edges lying between the top and bottom reinforcing strips and said side edges overlapping each other and being bonded to each other in a common overlapping closure from top to bottom of said flexible film.

4. A reinforced plastic ba-g comprising a tubular inner liner of semi-rigid synthetic plastic sheet material, said inner liner having a plurality of substantially rectangular panels defining the side walls of lsaid bag and having an open top and an open bottom, an outer container of flexible synthetic plastic film enclosing said inner liner and having portions extending beyond the top and bottom of said inner liner adapted to be folded to form top and 'bottom closures of said bag, and vertically spaced reinforcing strips of flexible material afiixed to the inside of said outer container and extending about the top and bottom edges of said inner liner in partial overlapping relationship to said top and bottom edges, said inner liner and outer container being affixed to each other along both side edges lying between the top and bottom reinforcing strips and said side edges overlapping each other and being bonded to each other in a common overlapping closure from top to bottom of said flexible film.

5. A reinforced plastic bag comprising a tubular inner liner of semi-rigid synthetic plastic sheet material, said inner liner having a plurality of rectangular panels defining three side walls of said bag and having an open top and an open bottom, an outer container of flexible synthetic plastic film enclosing said inner liner and having portions extending lbeyond the top and the bottom of said bag adapted to be folded to form top and bottom closures of said bag, and vertically spaced reinforcing strips of flexible material aflixed to the inside of said outer container and extending about the top and bottom edges of said inner liner in partial overlapping relationship to said top and bottom edges, said inner liner and outer container being affixed to each other along both side edges lying between the top and bottom reinforcing strips and said side edges overlapping each other and being bonded to each other in a common overlapping .closure from top to bottom of said flexible film.

6. A reinforced plastic 'bag comprising a tu-bular inner liner of semi-rigid synthetic plastic sheet material, said inner liner having a plurality of rectangular panels defining two pairs of substantially identical sidewalls and having an open top and an open bottom, an outer container of flexible synthetic plastic film enclosing said inner liner and having portions extending beyond the top and bottom of said inner liner adapted to be folded to form a top and bottom of said bag, and vertically spaced reinforcing strips affixed to the inside of said outer container and extending about the top and bottom edges of said inner liner in partial overlapping relationship to said top and bottom edges, said inner liner and outer container being affixed to each other along both side edges lying between the top and bottom reinforcing strips and said side edges overlapping each other and being bonded to each other in a common overlapping closure from top to bottom of said ilexible lm.

' 7. The reinforced plastic bag of claim 3 wherein said plurality of rectangular panels define two pairs of opposing sidewalls and the opposing sidewalls of each said pair of substantially identical dimensions.

8. A blank for a reinforced plastic bag comprising a substantially rectangular planar sheet of semi-rigid plastic sheet material, a substantially rectangular sheet of flexible synthetic plastic lm of the same width as said sheet to provide side edges in general alignment and of greater length than said sheet to provide portions extending beyond the other edges of said sheet, said sheets being bonded to each other along the generally aligned side margins, and spaced reinforcing strips of ilexible material affixed to said film sheet and extending along the other side edges of said semi-rigid sheet in partial overlapping relationship to said other edges of said semi-rigid sheet.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS Great Britain.

References Cited by the Applicant UNITED STATES PATENTS l2/1943 10/1956 12/1956 8/1957 10/1957 8/1959 l/l963 4/1964 Buttery. Thompson. Williams et al. Roper. Erekson. Scholle. Kindseth et al. Mack.

JOSEPH R. LECLAIR, Primary Examiner.

D. M. BOCKENEK, Assistant Examiner.

Claims

1. A REINFORCED PLASTIC BAG COMPRISING A TUBULAR INNER LINER OF SEMI-RIGID SYNTHETIC PLASTIC SHEET MATERIAL, SAID INNER LINER DEFINING THE SIDEWALLS OF SAID BAG AND HAVING AN OPEN TOP AND AN OPEN BOTTOM, AN OUTER CONTAINER OF FLEXIBLE SYNTHETIC PLASTIC FILM ENCLOSING SAID INNER LINER AND HAVING PORTIONS EXTENDING BEYOND THE TOP AND BOTTOM OF SAID INNER LINER ADAPTED TO BE FOLDED TO FORM TOP AND BOTTOM CLOSURES OF SAID BAG, AND VERTICALLY SPACED REINFORCING STRIPS OF FLEXIBLE MATERIAL AFFIXED TO THE INSIDE OF SAID OUTER CONTAINER AND EXTENDING ABOUT THE TOP AND BOTTOM EDGES OF SAID INNER LINER IN PARTIAL OVERLAPPING RELATIONSHIP TO SAID TOP AND BOTTOM EDGES, SAID INNER LINER AND OUTER CONTAINER BEING SECURED TO EACH OTHER ALONG BOTH SIDE EDGES LYING BETWEEN THE TOP AND BOTTOM REINFORCING STRIPS AND SAID SIDE EGES OVERLAPPING EACH OTHER AND BEING BONDED TO EACH OTHER IN A COMMON OVERLAPPING CLOSURE FROM TOP TO BOTTOM OF SAID FLEXIBLE FILM.