US2244282A

US2244282A - Art of making liquid-tight containers

Info

Publication number: US2244282A
Application number: US246575A
Authority: US
Inventors: Bergstein Robert Morris
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-12-19
Filing date: 1938-12-19
Publication date: 1941-06-03
Anticipated expiration: 1958-06-03

Description

June R. M. BERGSTEIN 2,244,282

ART OF MAKING LIQUID-TIGHT CONTAINERS Filed Dec. -l9, 1938 5 Shets-Sheet 1 IN VENTOR. 1 80551 7 MAM/.5 file/gas rev/v.

ATTORNEYS- June 3,1941. R, BERGsTElN v 2,244,282

ART OF MAKING L IQUID-TIGHT CONTAINERS Filed Dec. 19, 1938 3 Sheets-Sheet 2 ATTORNEYS.

un 3, 1941. R. M. BERGSTEIN v 2,244,282

ART OF MAKING LIQUID-TIGHT CONTAINERS Filed Dec. 19, 1938 3 Sheets-Sheet 3 IN VEN TOR.

ATTORNEYS.

Patented June 3, 1941 UNITED STATES PATENT" OFFICE ART OF MAKING HQUlD-TIGHT CONT ' Robert Morris Bergstcin, Cincinnati, Ohio' Application December 19, 1938, Serial No. 246,575

8 Claims. (Cl. 93-594) 'In the past, liquid-tight containers, made of waxed or paraillne treated stock, and suitable for various liquids or wet food products, such as milk, cottage cheese, etc., have generally been handled inone of two ways. The most common of the two is that of supplying containers to users in erect form, such as for'example cylindrical spiral-wound containers that have been. paramned or waxed. The other way is Just by the provision of elaborate and expensive machinery which is installed in the user's plant, as for example in a dairy, which is designed to erect cartons made of untreated board, and carry these through a paraflln bath or spray, and finally through a chilling chamber and on through to the final stages of the operation. It is obvious that both of these methods have serious objections, in the first case, for example, the high cost of transporting, storing and handling of erect containers, and in the second case the investment, maintenance, and supervision required to install and operate a large. and complex assembling and treating machine at the point of use.

Up until the present time there has been no other practical manner of solving such a container problem, due to the absence of simple and effective ways of obtaining a liquid-tight closure in containers made of waxed or paraflin treated stocks. It is in this direction that my invention as herein disclosed is specifically directed, and it is an object of my invention to supply wax treated or otherwise waterproof containers in flat knock-down form, which may be simply and easily erected by the user into a sturdy, liquid-tight container. Another object of my invention is to supply flanged caps adaptable for end closure of carton bodies, which caps are precoated with a thermoplastic adhesive capable of being securely adhered to waxed surfaces in the presence of heat. A still other objects of myinvention will become ap-.

parent as the description proceeds, the nature and scope of my invention being set forth in the claims which form part of this specification.

In the drawings: I

Figure 1 illustrates a form of my closure cap, which is made of box'board or the like, treated on one surface with a coating of thermoplastic adhesive, as indicated by the shaded portions.

Fig.2 illustrates an alternative form of closure cap, having auxiliary flanges as indicated.

Fig. 3 illustrates the cap shown in. Fig. 2, somewhat in perspective, with the folds partially broken, in which semi-erect form the caps may be shipped, nested, if desired.

Fig. 4 illustrates the closure cap shown in Fig. l, with-the addition of an extra dab or globule of thermoplastic coating adjacent the comers, as indicated.

Fig. 5 illustrates a flat folded open-ended tubular body, which can be made of waxed or further object of my invention is to provide for the prefolding of said closure caps, if desired, to facilitate assembly of the container; to provide simple and effective means of inserting the said caps into container bodies in the presence of heat to secure said caps into position, in such a manner as to make a liquid-tight container; to provide special methods in connection with such closure whereby leaks at the corners are positively prevented, either through the use of the wax coating on the carton body, or thermoplastic coating on the closure cap, or both, or by the introduction of additional molten thermoplastic material into the comers. These and water-proof treated boxboard or the like.

Fig. 6 illustrates, somewhat in perspective, the carton body shown in; Fig. 5, squared up, with the closure cap shown in Fig. ,2 inserted and secured in closing position, showing the appearance of the end closure at one end of the container.

Fig. '7 is a diagrammatical illustration of a machine adaptable for feeding out, folding and inserting, and thereafter sealing by means of heat the closure cap into position at one end of the carton body. I

Fig. 8 illustrates a detail of the male die used in connection with the machine illustrated in Fig. 7, showing the cut-away portions of same at the corners. I

Fig. 9 is a detail of an alternate form of die, which is expansible in four directions.

Fig. 9a is a section taken along line 9a-9a' of Fig. 9.

Fig. 10 illustrates a further alternative form of male die, showing a special flanged rim which upon expansion of the die, corresponds to a groove in the female die element.

Fig. 11 is a diagrammatic illustration of an alternate cap-inserting device, which provides for a shot of molten thermoplastic material into the corner portions, upon insertion of the cap.

Fig. 12- illustrates a form of my container wherein one end'has been closed by the cap previously referred to, and the other end closed by means of bringing two opposite walls of the container together, the remaining two opposite walls having definite folds to permit infolding, a

separate strip of thermoplastic coated board or paper having beensecured over the infolded walls, to provide a closure as illustrated.

Fig. 13 is a diagrammatic illustration of the mechanism for applying the closure strip illustrated in Fig. 12, which mechanism is adaptable to folding the strip, applying it, in the presence of heat to cause positive adhesion, simultaneously severing the strips to desired unit lengths.

Fig. 13a is a section taken along line l3a-|3a of Fig. 13.

Fig. 14 is an illustration, somewhat in perspective. of an erect, sealed container, made by 4 the mechanism illustrated in Fig. 11.

Before beginning a. detailed description of the drawings, a word might be in order regarding the thermoplastic coatings contemplated by my invention. I have found that paper, or board, or the like, pre-coated with certain materials, such as rubber-wax mixtures, or with isobutylene polymer sold under the trade name of Vistanex, possesses the property of adhering tenaciously to waxed or parailined surfaces when pressed against such surfaces in the presence of heat. Both of these materials can be coated by what is known as the hot melt method, which consists in the application of the coating in molten form to the paper, thereafter allowing the coating to cool, although there are other coatings such as synthetic resins which may be applied in solvent form, which, upon evaporation of the solvents, leave a film or coating on the surface of the paper which possesses the desired thermo-adhesive properties.

I prefer to have the flanges of closure cap prepared with such a thermo-adhesive coating on the surfaces which are brought into contact with the carton body upon assembly of the container, although if desired the entire surface of the cap can be so coated. However, I may also apply wax or parailin over the coated surface of the cap, in accordance with the disclosure in my copending application, Serial No. 43,570, filed October 4. 1935, which has now matured into U. S. Patent 2,154,083. issued April 11, 1939, wherein I have shown the principle of duplex thermoplastic coatings, such as a primary coating of latex and a secondary coating of wax, wherein the presence of heat causes the adhesive properties of the primary coating to take effect through the superimposed secondary wax-like coatings.

Fig. 1"illustrates my preferred form of closure cap, the shaded areas designating the coated portions as above described. The cap consists of a main body panel blank i, to which is articulated by the lines of fold 2, the side walls 3.

Fig. 2 illustrates an alternate form of closure cap, the same as illustrated in Fig. 1, except with the addition of auxiliary flanges t which are articulated to the flanges as shown by score lines 5.

Fig. 3 illustrates the closure cap'shown in Fig. 2 on which the folding has been partially carried out, leaving the cap in semi-erect condition as illustrated. It will be observed that the base flanges, that is the flanges 3 articulated to the main body panel, have been folded upwardly along thelines of fold number 2, and the auxiliary or secondary flanges 4 have been folded reversely along the fold lines-5. The device adapted to the partial erection of the closure cap into this form if it is pre-folded for shipment into the semierect form as illustrated.

Further, in my description, is illustrated a complete device adapted to take die-cut and coated closure caps, in flat form, feed these out and insert these in the presence of heat into the end of carton bodies. However, there are many users of treated liquid-tight containers, such as soda fountains, delicatessens, etc., where even the installation of this comparatively simple device might not be justifled ecenomically. It is for such smaller users that this partially folded closure cap with auxiliary flanges is particularly adapted, as it will be readily apparent to anyone skilled in the art that it is an extremely simple matter to insert by hand such a partially folded cap into the end of a squared up carton body. And since in this partially folded form the caps can be" shipped nested, the space required for shipping the caps i not much greater than in the flat form, and it is an extremely simple and easy matter to take the top cap off the nested stack, and insert it into the end of the carton body, the reversely folded auxiliary flanges serving as a convenient guide to insure the correct positioning of the cap within the carton body. After the cap has been so inserted, an extremely simple device consisting of a male heated die, as for example as shown in Fig. 8, with an outer supporting frame or female die, controlled by a simple lever action, is all that is necessary to seal the cap into position, as when the end of the container is brought into position over the male die, the outer or auxiliary flanges will thereby be folded downwardly along the outer surface of the carton body, and both the inner and outer flanges secured by a simple pressing operation in the presence of heat. In other words, such a device would not require any feeding or inserting mechanism for the closure cap, which is done by hand, the device merely consisting of the die elements controlled by one simple motion, to provide the actual adhesion.

Referring now to the closure cap shown in Fig. 4, there is an extra bead or globule of thermoplastic coating 6 placed adjacent the corner portions, as indicated in the drawings. If desired, instead of taking the form of a separate head at the corner, an extra heavy film could be provided along the entire line of fold or lines of fold connecting the flanges to the main body panel. Such continuous heavy band of coating at the desired areas can be provided by having grooves or recessions in the roll which applies the coating to the board, the grooves carrying and depositing on the paper a heavier film than the balance of the coating roll applies to the remaining surface of the sheet. By so treating the closure cap, a surplus amount of coating is provided, which will flow when turned into molten form by the heated die used in inserting the cap into closing position on a carton body, such surplus of material tending to plug the pinholes or crevices at the comers, and assure dependable liquid-tightness.

In Fig. 5, I have illustrated my preferred form of carton body, which is extremely simple in nature. It consists of four main body panels, I, 8, 9 and I0, there being a smaller panel or glue seam panel ll articulated to one of the outer main body panels. This carton body is preferably made of stock which has been waxed or similarly waterproofed on the inner surface at least, and it is shipped in the flat folded form indicated in the drawing, after having been folded along the score' lines To and 9a and the be turned down, at this time the members 2i glue seam secured to the edge of panel I as shown. I prefer to secure the glue seams to the outer surface rather than the inner surface of the panel 1 in providing the tubular structure, as in that way the glue seam is not interposed in the interior of the carton body when it is squared up, but an even unbroken interior of the carton body is provided, providing a better condition for theinsertion of the closure cap.

As can be seen in Fig. 6, the carton b'ody illustrated in Fig. above has been squared up, and one end is shown after my closure cap,as illustrated in Fig. 2, has been inserted and secured in position therein. As can be seen, the flanges of the closure cap numbers 3 have been secured to the inner surface of the ends of the carton body walls, while the auxiliary flanges 4 which are articulated to said first-mentioned flanges, have been folded down upon the outside of the end of the cartonbody walls, and are secured thereto. This provides a rigid and secure closure for the end of the container illustrated and after being fllled-the'other end of the container may be closed in the same manner or in any other manner desired.

Referring now to Fig. 7, I have illustrated diagrammatically a mechanism capable of feeding out one closure cap at a time singly from a stack, folding the flanges thereof, inserting the cap into closing position at the end of the carton body, and applying heat and pressure to secure the adhesion of the caps to the carton body. Number l2 illustrates a hopper in which a stack of. flat closure caps are placed, represented by number is. At the base of the hopper, is located a rubber belt Hi, positioned around two pulleys l5 and It. In this manner the bottom cap of the stack in the hopper is resting directly upon the rubber belt M, audit will be apparent that as the rubber belt moves forward in the direction indicated by the arrow, it will carry with it the lowermost cap, clearance space ll being provided in the hopper to permit the passage of such a single cap at a time. The cap thus carried forward by the rubber belt is transferred onto a plate l8. Plate l8 has a rectangular or square opening l8a somewhat larger than the body panel I of the cap. Extending downward from the four corners of opening l8a are guide members i 9 which are so positioned as to engage the shoulders l9b of the cap member seen in Fig. 2. I

At the time when the cap is thus placed on top of the plate I8, the male die element 25 is positioned at the top of its stroke, that is above the upper surface of the cap. And after the cap has been so positioned however, as just described, the male die element begins its downward stroke, which brings the main body panel of the cap down through the opening l8a, simultaneously therewith the flanges of the cap are forced upwardly, the downward pressure of the male die tending to turn them upward against the edges of the opening.

As the die 25 descends further, the guides l9 engage the shoulders l9b retaining the cap in the position seen at A. As the cap enters at least partly into the carton body 20, the auxiliary flanges 4 are turned down and pressed against the carton walls by heated members II. The members2l have eccentric bearings 2la on shafts 2th and are urged to the relative posi-' tion therewith as shown by springs 2|c. Move-' ment of shafts 2th to rotate the members 2| downward will cause the auxiliary flanges 4 to strike the abutments 22 and further movement of shafts 2"), due to eccentrics Zia, will cause inward movement of heated members 2| to press the flanges 4 firmly against the carton walls.

Since both the male die element as well as the female die element or supporting frame, and the folding members for the auxiliary flanges may be heated by electric heating elements, it is apparent that in the maximum operative position or down stroke, the flanges of the cap will be pressed in the presence of heat securely against the ends of the carton body. As previously explained the thermoplastic adhesive coatings which are utilized, softener turn to a molten state rapidly in the presence of heat and by the down stroke or operative position of the mechanism, which only requires an'extremely short period of time, the end closure of the container will have been effected.

Since the illustration is merely diagrammatic,

I have not illustrated in detail the drive or timing mechanism used to coordinate the elements indicated, but these will be coordinated by simple mechanical means. It is understood, of course, that the entire operation istimed, the elements as described acting in succession, whereby, in order, a single cap is withdrawn from a stack and positioned over the forming element ,which is arranged above one end of the carton body, the plunger thereupon commencing its down stroke, and the auxiliary folders beginning at the proper time for infoldingifthe cap with auxiliary flanges is used, until the foldingxhas been completed and a point of depression reached ,thus completing the sealing of the capinto'closing position at the end of the cartonbody. Thereafter, of course, the auxiliaryfolders are lifted out of position, the male die element is withdrawn byan upward stroke, and the mechanism is thereupon ready to insert the succeeding cap in the same order of steps just given.

In connection with the mechanism just described it should be noted that the auxiliary flanges illustrated on the cap shown in Fig. 2

are offset or set back somewhat from the flangesto which they are articulated. This leaves an offset or shoulder I9b on the main flanges 3 so that if the guides or the female die element or retaining elements are positioned to this offset, the auxiliary flanges can readily be folded back between these guides, although if desired the auxiliary flanges may be the same length as the flanges to which they are articulated, or. smaller than the flanges to which they arearticulated, in any degree desired.

Fig. 8 illustrates a detail of the preferred male die element 25 used in connection with the machine described above. The over-all dimensions of this die' correspond approximately to the 7 length and width of the main body panel of the closure cap, and it will be noted that at the corners there are cut-away portions 26 as shown.

As a result of this, when the male die is in operative position, pressure is applied to the flanges of the closure cap, but due to the cut-away space there is no pressure at the corners, or contacts of the male plunger at the corners, causing thereby a tendency of the softened andrnolten material to flow into the corner portions, to plug up the pinholes or openings that may exist at these corner portions.

In Figs. 9 and 9a is illustratedan alternate also is designed to seform of male die, which cure tightness at the corners. In this form,

the die is composed of four

separate pieces

21, 28, 29 and 30 mounted on shaft 3! and urged to the position shown by springs 21a. Upon attaining its maximum downward stroke, the tapered portion 3M of the shaft extending into the central opening of the four pieces of the die as shown, causes an expansion of this die in all directions, throwing special stress at the corner portions. The pressure thus exerted directly at the corners by this expansible die is sufficient to partially flatten out the crease or fold lines at the corners of the carton body, providing intimate contact between the corners of the closure cap and the corner score lines of the carton body, and providing thereby a tight seal.

The die illustrated in Fig. is a. modification of the die shown in Fig. 9. The principle of expansion is the same, but in addition the outer periphery or edges 32a of the male die elements are provided with a raised rim as indicated by the number 331). In the female die or outer holder is a groove 33a which corresponds to this raised rim. Upon expansion of the die for sealing, this rim forces the flanges of the closure cap and the corresponding portion of the carton body partially into the groove, in the female die, which affect counteracts the fold lines of the corners of the carton body at the point where it crosses the fold lines, providing another means of assuring close and intimate contact between the cap and the carton body at the corner portions. If desired, instead of being a continuous raised bead or rim around the periphery of the male die, this bead or rim could extend only around each corner of the male die, with the remaining sides of the male die being left fiat, as it is the corner portions this is designed to affect particularly, setting up a stress, as explained, to counteract-the corner crease lines of the carton body.

The device illustrated in Fig. 11 differs from the devices shown previously, in that an arrangement is provided to fiow or inject molten thermoplastic material into the corners. As illustrated, the male die has pipe-like passages 32, these hollowed out openings or pipes leading to the four lower corners of the die as at 33. Indicated at 34 is a supply line leading to a reservoir of thermoplastic material, which is kept heated by any desired means. The normal gravitational downward flow of the molten thermoplastic material fills the chamber 35 which has a plunger 36 to force the flow of a small amount of the molten thermoplastic material into the corners of the closure cap. The dies here shown are carried by an arrangement of levers generally indicated at 37. The closure cap, formed as in Fig. 3, is placed on the carton body and the die assembly moved downward into operating relation therewith by manual actuation of the handle 38. When the inner die reaches its ex treme downward position, as determined by the depth of the cap, continued movement of the handle will cause the tapered portion 3la of shaft 3| to expand the die within the cap, and the plunger 36 fixed to shaft 3| will force the molten material from chamber into the corners of the cap. It will be understood that the various members will be provided with electrical heating elements as necessary for flow of the material. By this alternate process, the corner portions are container parts themselves. The use of this arrangement "may be desirable in certain cases where the container and the closure cap are formed of very heavy board, or for other reasons where the gap at the corner points will be larger than normal and where the other means previously mentioned would not provide a sufficient amount of surplus thermoplastic material to dependably close these corner openmgs.

Fig. 12 illustrates an alternate application of my principle of utilizing pre-coated thermoplastic surfaces to obtain liquid-tight container closures. Here the container illustrated has had one end closed as at 40 by means of the flanged cap previously shown, and which for the sake of convenience will be designated as the bottom end. In this case, however, two opposite panels or the top end of the container, have been scored to permit an infolding of the remaining two opposite walls, in a manner that is well known, to permit these two remaining opposite carton body walls to be broughttogether. A separate strip of paper or board 4| with a precoating of thermoplastic material onone surface, which surface is to contact the outer surfaces of the two folded together carton walls, has been placed over the two folded together carton walls in the vmanner shown, and secured thereto by means of heat and pressure.

In Fig. 13 is diagrammatically illustrated a mechanism adaptable to form the closure shown on the container in Fig. 12. Indicated by number 42 is a roll of paper or board, pre-coated on one side, as at 43, with a film of thermoplastic adhesive. After running over the rollers 44 and 45, the edges of the strip are turned downward to form an inverted U by any desired means, such as forming plate indicated at 45. At about this point the upper ends of the cartons. which have had their mouths brought together as described in reference to Fig. 12, are introduced into the inverted U formation of the strip. As the strip and carton progress in the direction indicated by the arrow, 2. pair of heated pressure rolls 41 are arranged to complete the seal. With the arrangement shown, the cartons are carried by conveyor 48, and a pair of knives 49 operate transversely to sever the strip thus completing the formation as illustrated in Fig. 12. It is understood of course that this operation is carried out in timed relation, by any suitable drive mechanism, whereby successive containers could be rapidly and easily sealed by the repetition dependably plugged by the introduction of thermoplastic material in "heat-softened form taken from a separate reservoir, rather than depending upon the softened material or coating on the of the operations just described.

Fig. 14 illustrates, in perspective, an erect container 50 assembled by the die illustrated in Fig.

11. Numbers 5| indicate the extra gobs of adhesive which have been applied to the four corner portions, securely plugging up any crevices which might exist at the corners of the containers.

The mechanisms have been illustrated diagrammatically throughout, to show the principles involved, and it will be apparent that many variations therein are possible, such as the use of the contracting and expanding dies, without departing from the spirit or scope of my invention.

By the use of the term pre-coating" I refer to any surface which has been coated and dried, that is a surface which has been so coated as to be untacky at ordinary temperatures up to about 50 centigrade. I have used the term "themno adhesive to designate that in the presence of mal temperaturea'a permanent and durable bond is formed between the surfaces.

Either the surfaces of the flanges which are to come in contact with the carton. body may be so pre-coated, or the entire surface of the closure cap may be so pre-coated; or if desired a portion of the carton body may be so treated; in any event at least one of the surfaces which are to be so adhered to each other in the presence of heat will be so pro-coated. If desired, a secondary coating of suitable material may be applied over the pre-coating just referred to, as for example if it is desired to protect the edges of the closure cap, the caps may have a primary coating of thermo adhesive material applied to the flanges, and thereafter the entire caps run through a bath of molten .paraiiin, according to the principle of primary and secondary thermoplastic coatings mentioned in my copending application previously referred to.

It is also obvious that variations can be made in the constructions herein disclosed, without departing from the spirit or scope of my invention. For example, the container can be made in one piece by having the edge of one flange of the closure cap articulated to a wall of the carton body. And if desired the carton .body and the .closure cap could be triangular instead of rectangular as illustrated, as any multiple-wall construction is adaptable to the principles outline herein.

Among the important features of my invention are the methods of assuring dependable liquid-tightnessin the closure, by plugging up the corner portions thereof with a molten thermoplastic adhesive. I have illustrated several alternative methods of accomplishing this important objective. One of these is through the use of special dies which either provide pressure adjacent the corners, .by a clearance space at the corners, force the molten thermo-adhesive material into the corners themselves, or which cause a 'positive pressure atthe corner itself, to assure positive contact therein. Another method is by the useof a heavier pre-coating at, or adjacent to, the corner portions, such as beads or gobs of pre-coated thermoplastic material on the closure caps. It is obvious that if desired these beads or extra thicknesses of pre-coated thermoplastic material might be applied to the comer folds or adjoining areas of the carton body, and my invention contemplates any such variations wherein an additional amount of thermoplastic material is so Pre-coated that upon the action of heat it will serve to provide a surplus of molten material which acts as a plug for the corners of the container. As also described, still another method of accomplishing this same objective contemplated by my invention is by the introduction or injection of separate thermoplastic material in molten form at the corners of the container, that is through the use of thermoplastic material other than that pre-coated on the surface of the closure cap or carton body.

It is apparent that many different embodiments of this invention may be made without departing from the spirit and scope thereof;

therefore it is not intended to be limited except as indicated in the appended claims.

I claim:

1. In a packaging machine, means for inserting a closure cap into an open end of a waterproof multi-walled tubular carton body, and sequentially related means for injecting a sumcient amount of molten thermoplastic material into the corner portions of said closure cap to fill any crevices at'said corner portions.

2. A process of constructing a liquid-tight carton which includes the steps of providing a paperboard tube the inner surfaces at least of which are coated with wax, providing a closure member, the inner surface of. which at least is coated with a'thermoplastic rubbery substance of similar appearanceto wax but forming a strong bond therewith when heated, assembling the closure to thetube while the coatings on both are in non-adhesive condition, and thereafter producing adhesion of the contacting parts by the application thereto of heat and pressure.

3. The process of claim 2 wherein the coating on the tube is a coating of paraflin wax and the coating on the closure is a coating of isobutylene polymer.

4. The process of claim 2 wherein the tube is a tube of polygonal cross section and the closure is a closure having a base of the same cross section and flaps attached thereto, said closure being inserted in said tube with said flaps lying toward the end of said tube into which said closure is inserted and paralleling said walls.

5. The process of claim 22 wherein the tube is a tube of polygonal cross section and the closure is a closure having a base of the same cross section and flaps attached thereto, said closure being inserted in said tube with said flaps lying toward the end of said tube into which said closure is inserted and paralleling said walls, and in which said coating is so applied to said closure member as to be substantially thicker adjacent corner portions of said base whereby to provide an excess of the coating for corner seal ing purposesat said corners without impairing the general surface coating of said closure memher.

6. The process of claim 2 wherein the tube is a tube of polygonal cross section and the r-iosure is a closure having a base of the same crt ss section and flaps attached thereto, said closu'e being inserted in said tube with said flaps lying toward the end of said tube into which said closure is inserted and paralleling said walls, and in which the 'heat and pressure is applied by means of dies having cut-away portions at the corners thereof and so shaped as to compress softened portions of the coating on said closure member at least into the comers of the said closure.

7. A process of constructing a liquid-tight carton which includes the steps of providing a paperboard tube the inner surfaces at least of which are coated with wax, providing a closure member, the inner surface of which at least is coated with a thermoplastic rubbery substance of similar appearance to wax but forming a strong bond therewith when heated, assembling the closure to the tube while the coatings on both are in non-adhesive condition; and thereafter producing adhesion of the contacting parts by the application thereto of heat and pressure, said tube being a flat walled tube of polygonal cross section, said closure member comprising a base oi the same cross section and flanges articulated to said base and independent of each other, said A flanges, when said closure member is inserted in. said tube, adapted to parallel the walls therot, the coating on said closure member being suificiently thick to provide an excess when soitened during the application of heat and pressure, a portion of which excess will flow into the con ners of said closure member and seai said corners and meeting portions of said flanges to said tube.

8. A process of making a liquid-tight container which comprises providing a flat walled paper= board tube of polygonal cross section and having its inner surfaces at least coated with wax, proaaeaoea viding a closure member to fit in said tube, said closure member being of paperboard and comprising a base of the same shape as the cross section 01' the tube. flanges articulated to said base but independent of each other, said flanges being adapted upon the insertion of said closure member into said tube to parallel the walls of said tube, and a coating on at least one side of said closure member of a thermoplastic rubbery substance of similar appearance to a wax coating but having the property 02 forming a strong bond therewith under heat and pressure, insertins said closure into said tube, sealing said flanges to the walls of said tube by the application of heat and pressure and separately supplying a molten thermoplastic material to the cormore of said closure member to fill any crevices at said corner portions.

enema MORRIS Emmi.