US2596224A - Paper container - Google Patents

Description

May 13, 1952 w. A. EATON ET AL PAPER CONTAINER 5 Sheets-Sheet 1 Filed Jan. 51, 1946 INVENTORS Selig/0rd Roy S y \AZfraiA.Eabolz/,

y 13, 1952 w. A. EATON ET AL 2,596,224

PAPER CONTAINER Filed Jan. 51, 1946 5 SheetsSheet 2 INVENTORS Roy S Saqfiard BY WiyredAEaZ'ow.

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Glti'omzeys May 13, 1952 w. A. EATON ET AL PAPER CONTAINER 3 Sheets-Sheet 3 Filed Jan. 31, 1946 INVENTORS oy'S. Scugford BY Wig W 7 redA. E do/z/ attorneys Patented May 13, 1952 PAPER CONTAINER Wilfred A. Eaton and Roy S. Sanford, Oakville,

Conn, assignors, by mesne assignments, of onehalf to Ex-Cell-O Corporation, Detroit, Micln, a corporation of Michigan, and one-half to a group comprising Ace C. Fessenden, 111., and Ace Carton Corporation, a corporation of Illinois Chicago, Chicago, 111.,

Application January 31, 1946, SeriaI'No. 644,547

19 Claims;

This invention relates to containers of paperboard or other sheet material, and more particularly to novel means and methods for sealing the ends of such containers in order to provide a liquid-tight or sift-proof end closure for a container adapted to holdliquids or finely powdered materials.

Many attempts have previously been made to manufacture containers of the type wherein the and closure for the container comprises a plurality of foldable end flaps, preferably formed integrally with the walls of the container, but difliculty has been experienced in insuringpositive closingof all the cracks and pin holes occurring between the foldable flaps, and at the junction of the flaps with the walls of the container. In the copendin application of Wilfred A. Eaton, Serial No. 633,246, filed December 6, 1945, now U. S. Patent No. 2,521,208 issued on September 5, 1950, for Paper Container, owned by the same assignee as the present application, a novel arrangement is disclosed whereby during closing and sealing of the end flaps the flaps is caused to positively flow in such manner as to insure the complete sealing of all existing cracks and pin holes. Such highly desirable results are secured in the prior construction by providing one or more of the overlapped flaps with a novel recess or pocket arrangement which is designed to receive a slightly thicker coating of the adhesive, than the remaining por-- tion of the flaps. During pressure sealing of the flaps, the adhesive within the pocket is positively directed to the cracks and pin holes to thereby completely seal the same.

The present invention constitutes an improvement on the invention'of the prior application and one of the prime objects herein is to provide a novel arrangement for efficiently sealing all the cracks and pin holes without the necessity of providing one or more of the container flaps with pockets or recesses.

Another object of the invention is to provide in a-container of the above type, a novel arrangement for adhesively sealing the end flaps of a container, and for positively directing the adhesive outwardly towards the edges and corners of the container in order to provide for. positive closing of any openings with adhesive.

Yet another object of the invention is. to provide a containerhaving foldable endflaps so arranged as to prevent the flow of adhesive between-some .of the flaps in one direction and to insure ,the how of ,adhesivein other directions of a container, the adhesive on in order to close all openings between the flaps and the walls of the container.

A further object of the invention is to provide a novel container blank having adhesively coated end flaps so arranged and folded as to m sure the flow of adhesive outwardly toward the walls of the container to seal all openings between the flaps and container walls, and at the same time to provide a firmly bonded closure for the end of the container which will beof great strength.

Still another object of the invention is toprovide a novel means and method for completely closing the end of a container which insures a flow of adhesive toward the walls and corners thereof inside of the container.

Another object of the invention is to provide a container blankhaving container end closing flaps coated with relatively thin layers of adhesive, so constituted that on the application of pressure to theflaps, sufiicient adhesive will be positively directed toward the corners and edges of the container end to effectively seal all openings at said edges and corners, aswell as to securely bond the flaps together.

Other objects and novel features of the invention will appear more fully. hereinafter from the following detailed description. when considered in connection with theaccompanying drawings, wherein several embodiments of the invention are illustrated. It is to be expressly understood, however, that the ,drawings are utilized for purposes of illustration only,.and are not to be taken as a. definition of thelimits of theinvention, reference being bad for this purpose to the appended claims.

In the drawings, wherein similar reference characters refer to similar parts throughout the several views;

Fig. 1 is a partial perspective view of a ,blank adapted to be formed into a container of the above type;

Fig. 2 is a partial perspective view of a container partially assembled from the blank shown in Fig. 1;

Fig. 3 is a sectional'view of the container shown in Fig. 2- taken 'alongli-ne 3 3showing' the end flaps in assembled position;

Fig. 4 is a partial perspective viewofa container blank showing a modification of the invention;

Fig. 5 isa partial perspective view of -a partially assembled container utilizing the blankshown in Fig. 4;

Fig. 6 is asectional'lview taken along line 6-6 of Fig. 5, and showing the end flaps of the con.- tainer in folded position;

Fig. '7 is a partial perspective view of another modified form of container blank;

Fig. 8 is a partial perspective view of a container partially assembled from the blank shown in Fig. 7; and

Fig. 9 is a partial sectional view taken along line 9-9 of Fig. 8, showing the end flaps of the container in folded position.

The present invention is particularly directed to a means and method for sealing the open end of a paperboard or similar container of sheet material by means of adhesively bonded foldable overlapping end flaps, novel means having been provided for directing a foldable adhesive towards the corners and edges of the end of the container in order to insure positive closing of any cracks and pin holes by means of the adhesive which is applied to the end flaps.

To this end, one or more of the end flaps is coated, preferably on its inner side, with a flowable adhesive, and is folded along a scored folding line which divides the flap into two panels of substantially equal area and of substantially the same shape. The panels thus formed are folded with their adhesively' coated surfaces together, and the resulting flap of double thickness is folded at right angles to the adjacent container wall with the outer panel of the flap inside the container. When the panels are subjected to pressure, the adhesive flows toward the free edges of the panel which is inside the container, and the free edges are thus securely bonded to the container walls. Adhesive is prevented from escaping along the fold line of the panels, and consequently a substantial portion of the adhesive coating is forced out between the panels along the free edges of the outer panel. Since the fold line is so arranged that the free edges of the outer panelabut or substantially, abut the container Walls, it will be understood that the size of the openings between the free edges and the container walls is very small, and that the openings may be completely filled by a relatively small amount of adhesive exuded at the edges of the panels when the latter are pressed together. The relatively th n coating of adhesive on one of the panels is sufficient to bond the panels securely toget er, and the adhesive on the other panel is sufiicient to seal the openings bet een the free edges of the outer panel and the container walls.

Referring more particularly to Fig. l, the present invention is illustrated therein as including a container blank 4 which is separated by means of scored lines 5, into rectangular wall panels 8, l, 8 and 9, the wall panel 9 being provided with a flap Ii), having an adhesive coating 8 i, and adapted to be bonded to the left edge of the panel B to provide the usual side seam when the blank 4 is formed into a tubular container. The wall panels 6 and ii are preferably provided with integral half-flaps l2 and it, while the panels l and 9 are preferably provided with integral full-flaps i l and I5, the flaps l2, l3 and Hi, l thus being respectively in opposed relationship when the container is in assembled form as shown in Fig. 2. The flaps l2- and i3 are'provided with scored lines It and I! which divide the flaps respectively into separate panels i8 and i9 and 2d and 2! of the same shape and of substantially equal area, the inner surfaces of these flaps being provided with flowable adhesive coatings 22. The inner sur'ace of the flap i5 is provided with a similar adhesive coating 23, while flap is isprovided with narrow strips of adhesive coating 25 and 25 on either side as indicated, for purposes to be more fully described hereinafter.

Referring now to Figs. 2 and 3 it will be noted that the container blank has been folded to form a container of substantially rectangular cross section, and in order to effect a closure of the end of the container, flaps l2 and it are folded inwardly about the scored lines it and Il in order to bring the coated surfaces of the panels l8, l9 and 2D, 2! together, the flaps being folded thereafter bodily to positions substantially at right angles to the adjacent walls of the container, with the panels is and it inside the container. In order to complete the closure, flap it is folded inwardly over the folded flaps l2 and i3, and thereafter the flap i5 is folded over the other flaps, all the flaps then being subjected to a pressure sufhcient to cause the adhesive to eifect a bond between the flaps and at the same time to cause the adhesive between panels l8 and I9, and

261 and 2! of the flaps l2 and 3 to flow outwardly toward the free edges and corners of the panels 53 and 2b, the flow of adhesive toward the center of the container between these panels being prevented by the folding of the flaps around the scored lines it and El. It will thus be apparent that when the folded flaps l2 and it are subjected to sufficient pressure, the double coating of adhesive between the panels thereof will be positively forcedoutwardly in the directions above named in order to effectively seal any holes which might otherwise be present at the corners of the container end. At the same time, the flap i4 is bonded to the outer surfaces of the panels l9 and 2i of the flaps l2 and i3, and the panels l8 and i9 and 29 and 2! are also effectively bonded together.

Due to the fact that the panels l8, l8, and 26, 2 l, arefolded with their coated surfaces adjacent each other, a surplus of adhesive is provided which flows toward the corners and edges of the panels when the latter are pressed together, even though relatively thin coatings of adhesive are used, thus permitting the use of relatively thin coatings of uniform thickness on all of the end flaps. The end'flaps may be subjected to pressure to bond them together, and to flowrthe adhesive as above described, by placing the end of the container in a recessed support 26 and inserting a ram or plunger 2? in the open end of the container; as shown more particularly in Fig. 3. The ram is preferably provided at its lower end with an extended portion 28 adapted to fit between the folded flaps l2 and E3, the depth of the extended portion being substantially twice the thickness of the material forming the flaps, in order to insure substantially equal pressure over the entire surfaces of the end flaps when the ram is moved downwardly. The narrow strips of adhesive coating 24 and 25, being of substantially the same width as the panels ii) and 2 i, insures against contact of the lower end of the rain with any adhesively coated surfaces, thus facilitating the assembly operation. In the event a thermoplastic adhesive is employed, a suitable heating unit may be provided in the lower end of the ram, and suitable cooling means may be utilized to accelerate the setting of the adhesive a ter the operation of pressing the end flaps together has been completed. As shown, the support or base 28 is cupshaped and thus provides a support engaging the exterior surfaces of the side walls of the container adjacent the folded flaps. Hence, such side walls are prevented from moving outwardly in a direction at right angles to the vertical axis of the Figsl, 2 and 3 provides an end closurehaving satisfactorystrength characteristics, in the event an end closure of greater strength is desired, the latter may beconstructed and sealed in accordance with the modification shown in Figs. 4, 5, and'6. Thereimthe flaps l2, l3, l4 and l5 are all full flaps, and flaps l4 and I5 are each divided intotwo panels 2!], 38, and 3!, 32 Of the same shape and of substantially equal area by means of scored folding lines 33 and 34 which bisect the flaps and are formed parallel to the junction of the flaps with the corresponding container walls. The entire inner surfaces of all the end flap-s are provided with adhesive coatings 35, andthe end closure is formed by folding the panels 29 and 3! inwardly 180 degrees about the scored lines 33 and 34,- then folding the resulting flaps of double thickness bodily inwardly at right angles to the corresponding container walls with the panels 29 ands! within the container as shown in Figs. 5 and 6, and thereafter folding the flaps l2 and I3 inwardly in overlapping relation with the flaps l4 and [-5. The superposed flaps are then subjected to pressure suflicient to effect a bond between the flaps and to positively flow the adhesive coating on the panels 29, 38, 3| and 32 outwardly toward the edges and corners of the panels.

The aforementioned pressure step may be accomplished by placing the container in the recessed member 26 as shown in Fig. 6, and forcing the ram 21 downward to press the flaps together, provision being made. for alternately applying heat andcold as heretofore described in the event a fiowable adhesive of the thermoplastic type is employed. The adhesively bondedpanels 29, til and 3|, 32 form very strong reinforcing members for the container closure, and the adhesive which is forced outwardly between the panels toward the edges and corners thereof within the container .eifectively closes all openings between the end flaps and container walls. A coating of paraffin or other moisture-resisting substance may be applied to the container to render the material of the. latter, resistant to liquids or other substances, but need not be relied on to make the container leakproof, this latter function being performed by the flowable adhesive which is directed toward the openings between the flaps and container walls due to the novel arrangement of the folded-over flaps It and I5 which prevents the flow of adhesive between the folded panels thereof toward the center area of the end closure. This construction conserves adhesive and insures an adequate supply of adhesiveto seal .pin holes and other openings, even though a relatively thin coating of adhesive is applied to the end flaps.

A furthermodificationis shown in Figs. 7, 8 and 9, the container blank A therein, being provided preferably with full end flaps 12, I3, l4 and I5. Asshown, the container has a square cross section. with correspondingly square end flaps, although it will be understood that this form, as

well'astheothers heretofore described, is-adapt-.

able for use with polygonal. containers; having;

cross. sections which are not square. Referring more particularly to Fig. 7, the end flaps Hand 13 are provided along parallel diagonals with scored folding lines 36 and 37, and the inner surfaces of all theend flaps; are provided with coatings 35 0f a. flowable adhesive. The blank is folded into a'tubular form, the seamlfiap l0 being'adhesively bonded; tothe-wall panelt. The;

score lines 36 and 3'! divide the endflaps l2 and I3 into triangular panels 38, 39 and 40,. 4| and forming andsealing of the end closure is effected by folding the panels 33 and Gil inwardly "degreesabout the scored folding lineste and 31, then foldingthe flaps l2 and I3 bodily inwardly substantially atright angles to the. correspond ingcontainerwallswith thepanels wand 49 within the container, and thereafterfolding the flaps l4 and l5 inwardly-in overlapping relationship as shown in Fig. 8. The-overlapped flaps are.

then subjected to pressure-sufficient to eifecta bond betweenthe adhesively coated surfaces.

thereof and to positively flow adhesiveoutwardly between the panels 33, 39 and 48, 4| to seal all openings betweenthe flaps and between the flaps and side walls of the containers. Here again, the step of applying pressureto the flaps may be accomplished by placing the container end with" the superposed flaps, in the recessed member 26, shown in Fig. 9, and inserting the ram 21 into the open endof the'container to apply pressure to the flap assembly. Due to thelocation of the scored folding lines on the flaps I2 and I 3, the

diagonals of these flaps will substantially c0- incide when they are-folded, as shown in Figs. 3 and 9, and the edgesof the-panels .38 and 4t will substantially abut the walls of the container andwill also coincide with the edges of the panels 39 and 4!. Due to the folding of the panels about lines 36 and t1, the flow of adhesive will be directed toward the free edges of the panels 558 and 49 when the flaps are subjected to pressure, and the adhesivewill serve to effectively seal all openings between the flaps and the side walls of the container. The free edges of the panels 38, 39, 4G and 4! are bonded to the container walls by the adhesive which is'positively flowed toward the edges of the panels, and the panels, when bonded to each other and to the other flaps, form reinforcing members which materially strengthen the end closure of the container. It will be understood that the function of the recessed support 25, in connection with the formation of the end closure of Figs. i-Q-ina elusive, is the same as that previously'described in connection with Figs. 2 and 3.

While several modifications of the invention have been illustrated and described with considerable particularity, it will be understood, by those skilled in the art, that various changes maybe made therein without departing from the spirit of the invention. Reference will therefore be had to the appended claimsfor a definition of the limits of the invention.

What is claimed is:

l. A flat blank-of foldablematerial adapted-to be formed intoa container having asquare cross section and a closed end, said blankccmprising other of said wall panels, one of said square flaps 7 .being, provided withascoredline'along one;-of=.its

diagonals and the other of said square flaps being provided with a scored line along the diagonal thereof parallel to the first named diagonal.

2. The method of sealing an open end of a polygonal tubular container having side walls, foldable end flaps connected with the side walls, and a scored folding line on at least one of said end flaps dividing the latter into inner and outer panels of the same shape and of substantially equal area, which comprises providing a coating of flowable adhesive on the inner surface of each flap, folding the outer panel of said one flap inwardly about said scored line, folding the entire flap inwardly about the junction thereof with the corresponding side wall with said outer panel inside of the container, folding said other flaps inwardly in overlapping relationship with said one flap, and subjecting said flaps and the adhesive therebetween to sufiicient pressure to effect a bond between all of said flaps and between the coated surfaces of said panels and to positively flow adhesive toward the free edges and corners of said outer panel to seal all openings in the corners of said container adjacent the outer corners of said outer panel.

3. A container of paperboard or the like made in accordance with the method set forth in claim 2.

4. The method of sealing an open end of a container of rectangular cross section having side walls, a pair of opposed end flaps integral with one pair of side walls, and another pair of opposed end flaps integral with the other side walls and'provided with scored folding lines dividing said flaps into inner and outer panels or" the same shape and of substantially the same area, which comprises providing a coating of flowable adhesive on the inner surface of each flap, folding the outer panels of each of said another pair of flaps inwardly about said scored lines with the coatings thereof in engagement with the coatings on said inner panels, thereafter folding said another pair of flaps bodily inwardly with said outer panels thereof within the container, folding the first pair of fiaps inwardly in overlapping relationship with said another pair of flaps, and subjecting said flaps and the adhesive to sufficient pressure to eifect a bond between said flaps and between said panels of said another pair of flaps and to positively fiow the adhesive between said panels outwardly toward the free edges and corners of said outer panels to seal all the corners of said container and to seal all the openings along said free edges.

5. The method of closing and sealing an open end of a tubular container of rectangular cross section provided with foldable end flaps formed integrally with the side walls of the container and of directing and flowing an adhesive outwardly toward the edges and corners of said container end, which comprises providing a coating of flowable adhesive on the inner surface of each end flap, folding two opposing flaps inwardly about median lines dividing each of said two flaps into inner and outer panels with the adhesive coatings of the panels of each flap adjacent each other, folding each of said flaps inwardly substantially at right angles to the corresponding side wall with the outer panels of said flaps within the container, folding the other end flaps inwardly substantially at right angles to the cor responding side walls, and subjecting all of said flaps to pressure to effect a bond therebetween and to positively flow a portion of the adhesive coating on said two opposing flaps outwardly between the folded panels thereof toward the free edges and corners of the said outer panels.

6. A container of paperboard or the like made in accordance with the method set forth in claim 5.

7. The method of closing an open end of a tubular, four-sided container provided with foldable end flaps integral with the side walls of the container and of directing and flowing an adhesive outwardly toward the edges and corners of the container end to seal openings therein, which comprises providing a coating of fiowable adhesive on the inner surface of each end flap, folding each of two opposing flaps inwardly about lines dividing said flaps into inner and outer panels of the same shape and of substantially equal areas with the edges and corners of the inner and outer panels of each of said two flaps substantially coinciding with each other and with the coated surfaces thereof adjacent each other, folding said two flaps bodily inwardly substantially at right angles to the corresponding side walls with the outer panels of the flaps within the container, folding the other flaps inwardly in overlapping relationship with said two flaps, and subjecting said naps to pressure sufficient to effect an adhesive bond between the adjacent surfaces thereof and to positively flow a portion of the adhesive on said panels outwardly toward the free edges and corners of the outer panels to seal all openings between the side walls and end flaps of said container.

8. The method of closing an open end of a tubular container of rectangular cross section provided with foldable rectangular end flaps integral with the side walls of the container and ofdirecting and flowing an adhesive outwardly toward the edges and corners of the container and to seal all openings therein, which comprises coating the inner surfaces of said flaps with a flowable adhesive, folding the outer portions of an opposed pair of flaps inwardly about lines midway between the junction of the flaps with the corresponding side walls and the outer edges of the flaps and parallel thereto, folding said pair of flaps bodily inwardly about the junction thereof with the corresponding side walls and at substantially right angles thereto with the outer portions thereof inside the container, folding the other flaps inwardly in overlapping relationship with said pair of flaps, and subjecting said flaps to pressure sufficient to efiect an adhesive bond between the adjacent surfaces thereof and to positively flow a portion of the adhesive coating on said pair of flaps outwardly toward the corners and free edges of the outer portions thereof.

9. The method of closing an open end of a tubular container of square crosssecticn provided with a pair of opposed end flaps integral with the corresponding walls of the container and a pair of square end flaps integral with the other walls of the container and of directing and nowing an adhesive outwardly toward the corners of the container to seal all openings therein, which comprises coating the inner surfaces of all of said flaps with a flow-able adhesive, folding a portion of each of said square flaps inwardly about one of its diagonals and folding the resulting flaps of double thickness inwardly substantially at right angles to the corresponding walls, with said diagonals substantially coinciding with each other and extending between two opposite corners of the container, folding the first named pair of flaps inwardly in overlapping relationship with the second named pair of flaps,

andsubjecting all of saidflaps topressure suffithe corners and edges of said container.

16. The method of closing an open end of a tubular container of rectangular cross section provided with f ldable end flaps integral with the walls'of the container and of directing and flowing an adhesive toward the corners and edges of the container end to seal all openings therein, which comprises providing a coating of adhesive on the inner surface of each flap, folding the outer portions of two opposed flaps inwardly with the edges substantially coinciding with the edges of the inner portions of said flaps to form flaps of two superposed layers having two layers of said'adhesive coating therebetween, folding the other flaps inwardly in overlapping relationship with said two liens, and subjecting all of said flaps to pressure sufficient to effect an adhesive bond between the adjacent surfaces of said flaps and to positively flow a portion of the adhesive coatings on said two flaps outwardly toward the free edges of the outer portions of said two 11. The method of closing an open end of a four sided container provided with end flaps formed integrally with the walls of the container and of directing and flowing adhesive outwardly toward the edges and corners of said end to seal all openings therein, which comprises coating the inner surfaces of said flaps with a flowable adhesive, folding the outer portions of two opposed flaps inwardly with the coated surfaces thereof adjacent the coated surfaces of the remaining inner portions and with the free edges of both portions substantially abutting the walls of the container, folding the remaining end flaps inwardly in overlapping relationship with said two flaps, and forcing all of said flaps together with a force sufficient to effect an adhesive bond therebetween and to positively flow a portion of the adhesive between the inner and outer portions of said two flaps outwardly toward said walls and corners.

12. A container of paperboard or the like made in accordance with the method set forth in claim 11.

13. A container of sheet material comprising a tubular body portion of substantially polygonal cross section having side walls and a fiat end closure for said body portion, said end closure including at least one adhesively coated end closure flap joined with one of the side walls and provided with inner and outer panels of substantially the same Shape and area, the entire flap being positioned substantially at right angles to the corresponding side wall and the inner and outer panels being folded with their adhesively coated surfaces in engagement and with the outer panel on the inside of the container with the free edges thereof substantially abutting the container walls, and flaps connected with the other side walls arranged in overlapping relationship with the first named flap, all of said flaps being compressed to bond said flaps together and to positively flow the adhesive between said panels to said side walls to seal all pin holes and openings in said end closure.

14. A container of sheet material comprising a tubular body portion having four side walls and a flat end closure for said body portion, said end closure comprising a pair of end closure flaps integral with two opposed side walls adhesively coated on their inner surfaces and divided "by'scored folding lines into inner and outer panels, said pair of flaps being positioned substantially at right angles to the corresponding side walls and the inner and outer panels of each of said pair of flaps being folded with their adhesively coated surfaces in engagement and with the outer panels of said flaps on the inside of the body portion with the free edges thereof substantially abutting the side walls, and flaps integral with the other side walls folded in overlapping relationship over the first named pair of flaps, all of said flaps being compressed to bond the flaps together and to positively flow the adhesive between the panels of the first named pair or" flaps outwardly to said side walls to seal all pin holes and openings in said end closure.

15. The method of making a container having an open-end and a plurality of side walls arranged to provide a rectangular cross section from a flat paper board blank having four side wall panels, two of said panels being provided with integral end closing full flaps, and the other two panels being provided with integral end closing half flaps which comprises coating selected areas of all of said flaps with a thermoplastic adhesive capable of flowing under the application of heat and pressure, folding said flaps to bring some of said adhesively coated areas into contact and to overlap said flaps to bring some of the free edges of some of the flaps closely adjacent the inner surfaces of the container side walls, supporting the exterior walls of the container adjacent the flaps against movement outwardly in a direction at right angles to the vertical axis of the container while positively applying heat and pressure to the opposite faces of the overlapped flaps to positively flow the adhesive outwardly to directly contact the inner surfaces of the supported container walls to seal all openings and cracks between said free edges and said inner surfaces of the container side walls to firmly bond said free edges directly to said inner surfaces and to firmly bond the flaps together, and thereafter coating said container with wax to render the same moisture proof.

16. The method of making a container having an open end and a plurality of side walls arranged to provide a rectangular cross section from a flat paper board blank having four side wall panels, two of said panels being provided with integral end closing full flaps, and the other two panels being provided with integral end closing half flaps which comprises coating selected areas of all of said flaps on one side of the blank only with a thermoplastic adhesive capable of flowing under the application of heat and pressure, folding each flap of a pair of flaps to bring adhesively coated areas thereof into contact to provide a double thickness coating between the folded portions of each flap of said pair, overlapping said folded flaps and the other flaps to bring some of the free edges of some of the flaps closely adjacent the inner surfaces of the container side walls, supporting the exterior walls of the container adjacent the flaps against movement outwardly in a direction at right angles to the vertical axis of the container while positively applying heat and pressure to the opposite faces of the overlapped flaps to positively flow the ad h sive outwardly to directly contact the inner surfaces of the supported container walls to seal all openings and cracks between said free edges and said inner surfaces of the container side walls to firmly bond said free edges directly to said inner surfaces and to firmly bond the flaps together, and thereafter coating said container and end closure flaps at one end of the blank comprising a pair of long flaps of similar length integral with alternate wall panels and a pair of shorter flaps of substantially half the length of the long flaps integral with the other wall panels and provided with median score lines defining relatively foldable narrow inner and outer panels having the same shape and area, and an adhesive coating on the inner surfaces only of said end flaps, the coating on one of said long flaps being confined to areas along the two opposite free edges thereof corresponding in width to the width ofsaid narrow inner panels of said foldable short flaps, and the coatings on all the other flaps being coextensive with the areas thereof.

18. The method of forming a carton end sealing element comprised of a pair of registering therebetween and with a fold of said material connecting said panels along said one side, and

subjecting said panels and the adhesive film therebetween to sufiicient pressure to bond said panels together and to flow a portion of said adsuperposed adhesively bonded together polygonal hesive outwardly to form said adhesive band alon all of said sides except said one side. 1

19.'In a paperboard container of the type having a plurality of flaps adapted to be folded together to close an end of the container, said flaps having free edges, the method which comprises coating said flaps with an adhesive capable of flowing under the application of pressure, folding at least one of said flaps along a median line to provide a fold and to bring the adhesively coated areas thereof into contact, arranging said flaps in overlapping relation, and subjecting all of said flaps to pressure to bond the flaps together, the fold of said one fiap insuring that a portion of theadhesive on said areas will be exuded around the free edges of said one flap.

WILFRED A. EATON. ROY S. SANFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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