US3913825A - Leak proof bottom for a paperboard container - Google Patents

Leak proof bottom for a paperboard container Download PDF

Info

Publication number
US3913825A
US3913825A US378491A US37849173A US3913825A US 3913825 A US3913825 A US 3913825A US 378491 A US378491 A US 378491A US 37849173 A US37849173 A US 37849173A US 3913825 A US3913825 A US 3913825A
Authority
US
United States
Prior art keywords
blank
gusset
flap
thermoplastic material
tuck
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US378491A
Other languages
English (en)
Inventor
Milton A Brownlee
Robert L Lanham
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Paper Co
Original Assignee
International Paper Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Paper Co filed Critical International Paper Co
Priority to US378491A priority Critical patent/US3913825A/en
Priority to AU70814/74A priority patent/AU7081474A/en
Priority to GB29649/74A priority patent/GB1481844A/en
Priority to CA204,479A priority patent/CA997728A/en
Priority to NL7409405A priority patent/NL7409405A/xx
Priority to NO742532A priority patent/NO142164C/no
Priority to SE7409109A priority patent/SE406896B/xx
Priority to JP49080060A priority patent/JPS5810301B2/ja
Application granted granted Critical
Publication of US3913825A publication Critical patent/US3913825A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D5/00—Rigid or semi-rigid containers of polygonal cross-section, e.g. boxes, cartons or trays, formed by folding or erecting one or more blanks made of paper
    • B65D5/02—Rigid or semi-rigid containers of polygonal cross-section, e.g. boxes, cartons or trays, formed by folding or erecting one or more blanks made of paper by folding or erecting a single blank to form a tubular body with or without subsequent folding operations, or the addition of separate elements, to close the ends of the body
    • B65D5/06—Rigid or semi-rigid containers of polygonal cross-section, e.g. boxes, cartons or trays, formed by folding or erecting one or more blanks made of paper by folding or erecting a single blank to form a tubular body with or without subsequent folding operations, or the addition of separate elements, to close the ends of the body with end-closing or contents-supporting elements formed by folding inwardly a wall extending from, and continuously around, an end of the tubular body
    • B65D5/064—Rectangular containers having a body with gusset-flaps folded outwardly or adhered to the side or the top of the container
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S229/00—Envelopes, wrappers, and paperboard boxes
    • Y10S229/93—Fold detail

Definitions

  • ABSTRACT Disclosed is an improved bottom closure for a paperboard container of the type commonly used to package milk.
  • the improvement specifically relates to the blank from which the container is formed.
  • a container is formed from a blank which embodies this improvement, leaks in the bottom closure thereof are substantially prevented.
  • a substantial quantity of fluids are packaged in paperboard containers which have been coated with a thermoplastic, e.g. polyethylene.
  • a thermoplastic e.g. polyethylene
  • the major proportion of containers of this type are used for packaging milk.
  • the container construction which is predominantly used is a so-called gable top container which is formed from a one piece blank.
  • milk carton blanks are typically manufactured by paper companies. More particularly, paperboard of the desired basis weight (pounds per three thousand square feet) is continuously manufactured on a paper machine and stored in large rolls. Subsequently, the paperboard thus manufactured is unrolled and fed through an extruder wherein polyethylene is extruded onto the surfaces of the paperboard to provide a coating. Thereafter, the thermoplastic coated paperboard is generally rerolled. The coated paperboard is fed into a press which cuts the continuous web of paperboard into the container blanks of the desired size. Additionally, the same press may be employed to provide appropriate score lines which facilitate the folding and erecting of the container as well as any printing or art work.
  • the product resulting at this point is a flat, thermoplastic coated paperboard blank which has been appropriately cut and scored.
  • the two longitudinal edges of the blank are joined so as to form a square tube.
  • the joining of the two longitudinal edges is achieved through a heat seal, i.e. the polyethylene coating adjacent to the two longitudinal edges is heat and the two heated edges are pressed together.
  • Tubes of the type thus formed are generally sold in a flat condition, by the manufacturing company, to a dairy.
  • the paperboard tubes When received by the dairy, the paperboard tubes are usually sequentially fed into a so-called form, fill and seal machine.
  • the paperboard tube which was shipped in a flat condition is formed into a square tube and deposited upon an upstanding, square mandrel.
  • the tube is placed on the mandrel so that the part of the tube which will form the bottom of the container extends past the exposed end of the mandrel.
  • the machine proceeds to position the carton under a heater which heats the polyethylene coating on the bottom forming flaps to a temperature at which the polyethylene coating will act as a bonding or adhesive agent.
  • the machine then proceeds to manipulate the flaps extending past the end of the mandrel so as to form a bottom closure.
  • the mandrel moves such that a series of cooled plates (pressre pads) are pressed against the formed bottom for a time sufficient to effect a heat seal between the bottom forming flaps. Thereafter, the open top container thus formed is stripped off the mandrel, filled with milk and the top is appropriately sealed.
  • the process steps of filling the container and sealing the top thereof are not particularly'significant because the instant invention relates to an improved, bottom closure.
  • an index of the difficulty of packaging liquids such as soft drink syrups is the fact that milk carton type containers are often provided with an interior metal foil laminate when such containers are used to package soft drink syrups.
  • a container and container blank employing H such a construction is disclosed in US. Pat. No. 3,365,111 which is incorporated herein by reference.
  • thermoplastic coated paperboard blank with an improved bottom closure.
  • a blank embodying the instant invention may be formed into a container on a standard form, fill and seal machine which is either unmodified or only slightly modified depending upon the particular embodiment of the invention which is used.
  • the container resulting from erecting a blank which embodies this-invention may be used to successfully package penetrative liquids such as soft drink diet syrups.
  • FIG. 1 shows the lower half of a paperboard blank of the type known to the prior art and which may be erected to form a container for packaging milk.
  • the upper part of the blank 12 shown in FIG. 1 has been omitted since that part of the blank is known to the prior art and does not particularly pertain to the instant invention.
  • the blank shown therein is comprised of two major portions, i.e. a body forming portion 13 and a bottom forming portion 14.
  • the body forming portion 13 is comprised of four side wall panels 16, 17, 18 and 19, each having an equal width and forming the side walls of the erected container.
  • the side walls 16, 17, 18 and 19 are connected by longitudinal fold lines 67, 78 and ,89 respectively.
  • the bottom forming portion 14 is comprised of four flaps 16a, 17a, 18a and 19a.
  • the aforementioned bottom forming flaps are connected to the side panels by transverse fold lines 26, 27, 28 and 29 respectively.
  • the four bottom flaps 16a, 17a, 18a and 19a are connected to each other by longitudinal fold lines 67, 78 and 89 respectively, i.e. the longitudinal fold lines which interconnect the bottom forming flaps are extensions of the fold lines which interconnect the side wall panels.
  • blanks of the type shown in FIG. 1 are provided with a so-called manufacturers joint which is'foldably connected to one of the side walls, e.g. 16.
  • the manufacturers joint is typically heated by an exposed flame and is then overlappingly bonded to the interir surface of the side wall panel 19 adjacent to its longitudinal edge 21.
  • bottom forming portion 14 it may be noted that certain of the bottom forming flaps which form this portion have a degree of symmetry.
  • the bottom forming flaps 16a and 18a which may be defined as gusset forming flaps
  • these flaps are spaced apart by the flap 17a but are otherwise symetrical.
  • their transverse edges 46a, 46b and 48a, 48b are transversely aligned.
  • each of the gusset forming flaps is provided with two diagonally disposed score lines which define sub-panels.
  • the diagonal score lines 31, 32 define sub-panels 16b, 16c and 16d.
  • diagonal score lines 33, 34 on the flap 18a define sub-panels 18b, 18c and 18d.
  • Flap 19a may be referred to as a tuck-in flap and flap 17a may be referred to as a cover flap. It may be noted that in the prior art construction shown in FIG. 1, the transverse edge 49 of the tuck-in flap 19a and the transverse edge 47 of the cover flap 17a are substantially aligned.
  • a blank of the type shown in FIG. 1 When a blank of the type shown in FIG. 1 is to be erected to form a container, the blank is first formed into a tube as heretofore described. Thereafter, the gusset forming flaps 16a and 18a are urged downwardly into the container. As a result of this action, the triangular sub-panels 16b and 18b may be moved into a generally horizontal position. As a result of this action, the sub-panels 16c, 16d and 18c, 18d are folded back to horizontally overlie the sub-panels 16b, 18b respectively. Thus, a so-called gusset or triangular configuration is formed. The resulting triangular panels or gusset panels have an apex at the gusset points 40, 41.
  • the tuck-in flap 19a and the cover flap 17a will be moved into a horizontal position when the gusset forming flaps 16a, 180 are positioned as described above. More particularly, it may be noted that the longitudinal length of the tuck-in flap 19a and the cover flap 17a is greater than the longitudinal length of the gusset forming flaps. With regard to these dimensions, a number of factors should be pointed out. First, it may be noted that the adjacent transverse score lines are slightly displaced from each other. Thus, score lines 26, 28 are aligned with each other but are slightly longitudinally displaced from the aligned score lines 27, 29.
  • transverse score lines associated with the gusset forming flaps 16a, 18a are displaced slightly above the transverse score lines associated with the flaps 17a and 190 because the gusset forming flaps will be folded first and the flaps 17a and 19a will overlie the gusset forming flaps.
  • containers of the type erected from a blank shown in FIG. 1 are generally square.
  • the longitudinal height of the gusset forming flaps is generally equal to or slightly less than the width of the side wall panels so as to insure that when the gusset forming flaps are positioned within the container, the gusset points 40, 41 are almost touching.
  • the tuck-in flap 19a is horizontally positioned.
  • the cover flap 17a is also horizontally positioned so as to overlie the tuck-in flap 19a.
  • the work tuck-in accurately describes the flap 190 since, when the bottom is formed, the edge 49 of the tuck-in flap 19a is, in fact, tucked in between the cover flap 17a and the sub-panels 16c, 16d and 18c, 18d.
  • FIG. 2 there is shown a view which illustratese a container bottom which would result from erecting the blank shown in FIG. 1. More particularly, the view shown in FIG. 2 is that which would appear if one viewed the resulting bottom closure looking down into the tube or open ended container.
  • the resulting construction shown in FIG. 2 exemplifies the prior art and is representative of the bottom construction used on most paperboard milk cartons. Thus, it is instructive to consider this construction in some detail in order to obtain an understanding as to why this construction is deficient when one attempts to package certain liquids.
  • the gusset points 40, 41 disposed in the center of the container are almost touching and define what might be referred to as a central axis.
  • the tuck-in flap 19a is disposed between the gusset forming flaps and the cover flap 17a. This is particularly evident in FIG. 2 where it may be noted that the edge 49 of the tuck-in flap 19a is clearly visible.
  • the transverse edges associated with the gusset forming flaps are ultimately disposed in a channel forming relation.
  • the transverse edges 46a and 46b associated with the gusset forming flap are disposed parallel to each other and underneath the gusset panel 16b.
  • the transverse edges 48a and 48b associated with the gusset forming flap 18a are disposed parallel to each other and underneath the gusset panel 18b.
  • FIG. 3 wherein the interrelation between various overlying panels and flaps is shown.
  • the transverse edge of the tuck-in flap 1'9a causes a channel to form which is shown in cross section at 60 and may be referred to as the tuck-in flap channel.
  • the arrows 61 generally indicate paths of leakage along the exposed edge, 48a.
  • the arrows 61 terminate at the edges of the container where the final leakage may occur.
  • stakes are indentations (22, 23 FIG. 2) formed in the bottom of container blanks perpendicularly across a leakage path.
  • the stake or indentation is formed by providing a small, correspondingly shaped protuberance on the pressure pad on the form, fill and seal machine.
  • gusset channel Another leakage channel which is commonly formed and difficult to seal may be referred to as the gusset channel and is formed by the transverse edges of the gusset forming flaps.
  • a gusset channel shown in cross-section at 61, is formed between the two sub-panels 18d, 18c, the gusset panel 18b and the tuckin flap 19a. Entrance to the gusset channel is generally afforded at the gusset points 40, 41.
  • This leakage channel (which may be referred to as the side seam leakage channel) arises in essentially the same manner as the leakage channel associated with the exposed edge 49 of the tuck-in flap 19a, i.e. the exposed edge which is sandwiched between the other panels causes a channel to be formed adjacent thereto.
  • the prior art has attempted to seal this leakage channel by resorting to the use of stake points, e.g. stake point 24 as shown in FIG. 2.
  • FIG. 5 wherein the channel is shown, in cross section, at 65. Entrance to this channel is at the corner of the container as shown by the arrow 64 and the subsequent arrows which follow the path of the channel.
  • the fold line associated with the channel 65 (which may be called a corner channel) is fold line 67.
  • a total of four such corner channels may be formed, i.e. one such channel associated with each of the fold lines 56, 67, 78 and 89.
  • an improved bottom forming portion In combination with a thermoplastic coated paperboard blank of the type commonly used to form milk containers, an improved bottom forming portion is provided.
  • a narrow band or bead of thermoplastic material is disposed upon the interior side of at least one of the bottom forming flaps so as to extend outwardly from the gusset points and along the gusset channel when a container is formed from the blank.
  • a band or bead of thermoplastic material is disposed upon at least the center portion of each of the bottom forming flaps and the beads are substantially aligned and the beads on the gusset forming flaps are adjacent to the exposed edges thereof.
  • At least the center portion of the transverse edge of the tuck-in flap is substantially aligned with the transverse edges of the gusset forming panels and the remainder of the edges of the tuck-in flap are disposed to underlie the gusset forming flaps when said blank is erected.
  • the thermoplastic material preferably has a melt index in the range of 3.0 to 300.
  • FIG. 1 is a view of a paperboard blank known to the prior art.
  • FIG. 2 is a plan view of a container bottom of the type resulting from erecting the blank of FIG. 1.
  • FIG. 3 is a fragmentary, sectional view taken along the section lines 33 of FIG. 2.
  • FIG. 4 is a fragmentary, sectional view taken along the section lines 44 of FIG. 2.
  • FIG. 5 is a fragmentary, sectional view taken along the section lines 55 of FIG. 2.
  • FIG. 6 is a view illustrating a preferred embodiment of my invention.
  • FIG. 7 is a plan view of a container bottom of the type resulting from erecting the blank of FIG. 6.
  • FIG. 8 is a fragmentary, sectional view taken along the section lines 88 of FIG. 7.
  • FIG. 9 is a fragmentary, sectional view taken along the section lines 88 of FIG. 7.
  • FIG. 10 is a view illustrating another embodiment of my invention.
  • FIGS. 11 and 12 are plan views of a container bottom and illustrate a structural requirement of this invention.
  • FIG. 6 a paperboard blank 12 is shown and represents a preferred embodiment of the instant invention. As may be noted, a major portion of the blank 12 shown in FIG. 6 is substantially identical to the blank 12' of FIG. 1. Thus, to the extent that these two blanks are the same, the same reference numbers have been employed.
  • the first structural difference between the blank 12 in FIG. 6 and the blank 12 of FIG. 1 comprises the cutout 80 in the tuck-in flap 19a.
  • the purpose of the notch or cut-out 80 is to alter the structure of the tuck-in flap 19a such that at least the center portion of the transverse edge thereof is aligned with the transverse edge of the gusset forming flaps 16a and 18 a.
  • a transverse edge 81 which is centrally located on the flap 19a and aligned with the transverse edges 46a, 46b and 48a, 48b of the gusset forming flaps.
  • the second structural difference between the prior art blank shown in FIG. 1 and the embodiment of this invention shown in FIG. 6 relates to the addition of a narrow band of thermoplastic material 92 which is disposed adjacent to the transverse edges of the flaps 16a and 18a on the interior side thereof and extends across the entire width of the blank 12.
  • FIGS. 7, 8 and 9 there is shown therein views of the bottom closure which results when the blank 12' of FIG. 6 is erected.
  • FIG. 7 there is shown a view of the resulting bottom structure as it would appear when viewed from within the container and prior to the heat sealing step.
  • the cutting of the tuck-in flap as hereinbefore described has the effect, when the blank is formed into a container, of aligning the edge 81 with the gusset points.
  • the tuck-in flap channels and the gusset channels are substantially coincident in the region that the band of adhesive 92 is visible between the gusset points.
  • FIG. 9 illustrates the same section shown in FIG. 8 except, unlike the view of FIG. 8, the view of FIG. 9 corresponds to how this section would appear after the heat sealing step.
  • the thermoplastic band 92 has been melted and, as a result of the pressure applied to the bottom of the container, the melted thermoplastic substantially fills the channel 60.
  • the portion of the thermoplastic band 92 which is visible in FIG.
  • thermoplastic band 92 extends across the width of the container from the side wall 16 to the side wall 18. This alignment of the thermoplastic band 92 such that portions thereof are adjacent to the side walls 16 and 19 is significant because, as a result, when the bottom closure is heat sealed, the so called comer leakage channels and the side seam leakage channel are sealed. That is to say, referring back to FIG. 2, it will be seen that the leakage path 63 associated with the side seam channel and the leakage path 64 associated with the comer leakage channels both terminate at the intersection of the side wall 16 with the adjacent gusset channel formed by the edges 46a and 46b.
  • thermoplastic band 92 is overlapped or juxtaposed at this point, when the bottom is heat sealed the termination of the leakage path 63 and the leakage path 64 is also sealed. Therefore, it will be appreciated that the blank construction shown in FIG. 6 effectively seals all of the leakage channels which have been discovered.
  • thermoplastic band 92 is a continuous band
  • the machines which form the blank from the thermoplastic coated paper roll stock may easily be adapted to continuously deposit the required thermoplastic band.
  • the adhesive band 92 may be deposited upon the blank before the blank is appropriately scored, i.e. it has been surprisingly determined that the adhesive band 92 does not interfere with the scoring operation.
  • thermoplastic band 92 With respect to the continuous nature of the thermoplastic band 92, it has been found that an acceptable bottom closure may be formed if the narrow thermoplastic band is deposited only upon the center portion of the bottom forming flaps. Such a construction, which is shown in FIG. 10, will seal the major leakage channels but will not seal the minor leakage channels because there will not be any thermoplastic material adjacent to the side walls 16 and 18 when the blank is erected. Thus, the bands 93, 94, 95 and 96 will seal the major leakage channels when the blank of FIG. is erected and heat sealed.
  • the thermoplastic material selected must meet certain criteria.
  • the material which comprises the thermoplastic band must be such that it will, upon melting and rehardening, adhere to the thermoplastic coating on the paperboard blank. Since the vast majority of such paperboard blanks are coated with polyethylene, the thermoplastic material must satisfy this requirement with respect to polyethylene.
  • Another requirement which such thermoplastic material must satisfy relates to the so-called melt index.
  • the melt index is a measure of the flowability or viscosity of a thermoplastic at an elevated temperature. In order for a thermoplastic material to perform satisfactorily, the thermoplastic must have a degree of flowability at the heat seal temperatures which are encounterd in order to insure that the heated thermoplastic material will seal the leakage channels.
  • thermoplastic with a melt index in the range of, approximately, 3.0 to 300 is acceptable.
  • the remainder of the exposed edges of the flap 19a extend longitudinally beyond the edge 81. This longitudinal extension of the remainder portion of the flap 19a is preferable because the portions of the flap 19a which extend beyond the edge 81 cooperate with the remainder of the flaps during erection of the blank in a manner which facilitates the forming of the bottom portion of the container.
  • the edges of the remainder portion of the tuck-in'flap must be disposed so as to underlie the gusset forming flaps when the blank is erected.
  • This latter requirement i.e. that the remainder of the edges underlie the gusset forming flaps when the blank is erected, is important in order to insure that the only entrances to the tuck-in flap channel are adjacent to and substantially aligned with the gusset points.
  • the edges of the tuck-in flap may be disposed as shown in FIG. 11 but not as shown in FIG.
  • the length of the narrow thermoplastic bands of material must be at least equal to the length of the aligned transverse edge 81. Such a minimum length is necessary in order to insure that the gusset points and the entrances to the tuck-in flap channels are effectively sealed as shown in FIG. 9.
  • the preferable minimum width of each band should be approximately 0.125 inches but preferably not greater than, approximatley, 0.5 inches. A width greater than 0.5 inches is economically disadvantageous. In any event, the width of the beads should not be greater than the longitudinal length of the bottom closing flaps.
  • the minimum length of the discontinuous bands of thermoplastic will depend upon the particular construction employed with respect to the tuck-in flap and the size of the container. Suffice it to say, therefore, that depending upon these factors, a minimum length will be selected which is at least sufficient to effect a sealing of the gusset points and the entrances to the tuck-in flap channel.
  • the notch should be at least, approxi mately, 0.5 inches wide and the bands of discontinuous thermoplastic should preferably be at least 0.5 inches long.
  • the thermoplastic material employed is a hot melt adhesive having a melt index in the range previously stated.
  • An acceptable hot melt is sold by Stein Hall Company under the designation LHM 597.
  • the minimum thickness for achieving a sealing of the various channels using the embodiments of the invention heretofore described is 5 mils.
  • a thickness of approximately 10 to 12 mils is employed.
  • an intrinsic advantage of these embodiments is the fact that they not only seal the major leakage channels but, as well, these embodiments insure that all exposed edges of the paperboard are protected.
  • the prior art has recognized that when certain liquids are packaged in thermoplastic coated paperboard containers, such liquids may penetrate or wick into the paperboard at points where cut edges of the paperboard are exposed to the packaged liquid. Such wicking occurs because any such exposed, cut edge, for example the edges 46a, 46b, 49a and 48b of the gusset flaps and the edge 49 of the tuck-in flap, are uncoated. Referring to FIG.
  • FIGS. 8 and 9 it will be seen that the plugging or sealing of the channel 60 results from providing the juxtaposed beads of thermoplastic 92 adjacent to the channel and having a thickness of at least mils and preferably in the range of 10-12 mils.
  • the configuration may be obtained by providing a bead of thermoplastic material on only the tuck-in flap 19a and the cover flap 17a.
  • a blank which would provide such a configuration would be a blank as shown in FIG. 10 wherein the beads 93 and 95 were omitted.
  • the major leakage channels may be substantially sealed if a bead is provided upon only one of the major flaps, for example, the cover flap. If a bead is provided only upon the cover flap, it may be found to be desirable to position the bead such that, prior to melting, the bead is aligned with the channel 60 shown in FIG. 9 so as to promote the plugging of the channel when the bead melts.
  • the thickness of the bead or beads which are provided must be greater than the 10-12 mil thickness previously recited, e.g. a thickness of approximatley 20 mils may be used.
  • the major leakage channel 60 is plugged by providing a thermoplastic bead or beads adjacent thereto.
  • sealing of the major leakage channels will generally be achieved if one employs a blank having a narrow band of thermoplastic material disposed upon at least one of the bottom forming flaps so as to extend outward from both of the gusset points when a container is formed from the blank.
  • the embodiments of our invention heretofore described provide this ultimate configuration although it may now be seen that still other blank constructions may be employed to provide the same ultimate configuration.
  • a thermoplastic bead on corresponding portions of the two gusset flaps will provide the required ultimate configuration, e.g. a bead positioned adjacent to the edge 46a and a bead positioned adjacent to the edge 48a or a bead positioned on the edge 46b and a bead positioned on the edge 48b.
  • thermoplastic beads are parallel, thus providing a bead of uniform width.
  • inner edge of the bead may be non-parallel with respect to the outer edge of the bead in order to provide a bead of varying width.
  • thermoplastic coated paperboard blank adapted to be erected to form a heat sealed container, said blank having a body forming portion and a bottom forming portion, said bottom forming portion including two spaced apart gusset forming flaps having substantially aligned transverse edges and forming gusset points and gusset channels when said blank is erected, a cover flap foldably connected by a longitudinal fold line to at least one of said gusset forming flaps, and a tuck-in flap foldably connected by a longitudinal fold line to at least one of said gusset forming flaps, the improvement which comprises;
  • the longitudinal length of at least the center portion of said tuck-in flap being approximately equal to one half the width of one of said gusset forming flaps and the remainder of said tuck-in flap disposed to entirely underlie said gusset forming flaps when said blank is erected;
  • thermoplastic material disposed upon the interior side of at least one of said bottom forming flaps so as to extend outwardly from said gusset points and along said gusset channel when a container is formed from said blank, said band of thermoplastic material having a thickness of at least approximately 5 mils and a longitudinal dimension less than the longitudinal length of said bottom forming flaps, the thickness and area of said band being such that, when a container is formed from said blank and said thermoplastic material is melted, it will not cover the entire area defined by said bottom forming flaps, whereby, when said blank is formed into a container, said thermoplastic material will seal at least the center portion of said gusset channels and at least the center portion of the tuck-in flap channel which is formed when said container is formed.
  • the paperboard blank of claim 3 which further includes a band of thermoplastic material disposed upon said tuck-in flap.
  • thermoplastic coated paperboard blank adapted to be erected to form a square head sealed container, said blank having a body forming portion and a bottom forming portion, said bottom forming portion including two spaced apart gusset forming flaps having substantially aligned transverse edges and forming gusset points when said blank is erected, a cover flap foldably connected by a longitudinal fold line to at least one of said gusset forming flaps, said cover flap extending longitudinally beyond the transverse edges of said gusset forming flaps and a tuck-in flap foldably connected by a longitudinal fold line to at least one of said gusset forming flaps, the improvement which comprises:
  • thermoplastic material disposed upon the interior side of at least the center portion of each of said bottom forming flaps, the outer edge of all of said bands being substantially transversely aligned, the outer edge of said bands disposed upon said gusset forming flaps being adjacent to the exposed transverse edge of said gusset forming flaps and the transverse length of each of said narrow bands of thermoplastic material being sufficient to heat seal said gusset points and the center portion of the transverse edge of the tuck-in flap when said blank is formed and sealed, said bands of thermoplastic material having a thickness of at least approximately 5 mils and having a longitudinal dimension less than the longitudinal length of said bottom forming flaps, the thickness and area of said bands being such that, when a container is formed from said blank and said thermoplastic material is melted, it will not cover the entire area defined by said bottom forming flaps, whereby, when said blank is formed into a container, said thermoplastic material will seal at least the center portion of said gusset channels and at least the center portion
  • thermoplastic is in the range of 3.0 to 300.
  • thermoplastic coated paperboard blank adapted to be erected to form a square heat sealed container, said blank having a body forming portion and a bottom forming portion, said bottom forming portion including two spaced apart gusset forming flaps having substantially aligned transverse edges and forming gusset points and gusset channels when said blank is erected, a cover flap foldably connected by a longitudinal fold line to at least one of said gusset forming flaps, said cover extending longitudinally beyond the transverse edges of said gusset flaps and a tuck-in flap foldably connected by a longitudinal fold line to at least one of said gusset forming flaps, the improvement which comprises:
  • transverse edge of said tuck-in flap being substantially aligned with the transverse edges of said gusset forming flaps with the outer transverse edges of the tuck-in flap underlying said gusset forming flaps when said blank is erected;
  • thermoplastic material disposed upon at least the center portion of each of said bottom flaps, all of said bands being substantially transversely aligned, the outer edge of said bands disposed upon said gusset forming flaps being adja-v cent to the exposed transverse edge of said gusset forming flaps and the transverse length of each of said narrow bands of thermoplastic material being sufficient to heat seal said gusset points and the center portion of the transverse edge of the tuck-in flap when said blank is formed and sealed, said band of thermoplastic material having a thickness of at least approximately 5 mils and a longitudinal dimension less than the longitudinal length of said bottom forming flaps, the thickness and area of said band being such that, when a container is formed from said blank and said thermoplastic material is melted, it will not cover the entire area defined by said bottom forming flaps, whereby, when said blank is formed into a container, said thermoplastic material will seal at least the center portion of said gusset channels and at least the center portion of the tuck-in
  • thermoplastic material has a melt index in the range of, approximately, 3.0 to 300.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Cartons (AREA)
  • Laminated Bodies (AREA)
US378491A 1973-07-12 1973-07-12 Leak proof bottom for a paperboard container Expired - Lifetime US3913825A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US378491A US3913825A (en) 1973-07-12 1973-07-12 Leak proof bottom for a paperboard container
AU70814/74A AU7081474A (en) 1973-07-12 1974-07-03 Container
GB29649/74A GB1481844A (en) 1973-07-12 1974-07-04 Leak proof bottom for a paperboard container
CA204,479A CA997728A (en) 1973-07-12 1974-07-10 Leak proof bottom for a paperboard container
NL7409405A NL7409405A (nl) 1973-07-12 1974-07-11 Lekvrije bodem voor een kartonnen reservoir.
NO742532A NO142164C (no) 1973-07-12 1974-07-11 Emne av termoplastbelagt kartong.
SE7409109A SE406896B (sv) 1973-07-12 1974-07-11 Emne av termoplastbelagd pappersboard for framstellning av en behallare med leckagefri botten
JP49080060A JPS5810301B2 (ja) 1973-07-12 1974-07-12 熱可塑性物被覆ボ−ル紙容器ブランク

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US378491A US3913825A (en) 1973-07-12 1973-07-12 Leak proof bottom for a paperboard container

Publications (1)

Publication Number Publication Date
US3913825A true US3913825A (en) 1975-10-21

Family

ID=23493323

Family Applications (1)

Application Number Title Priority Date Filing Date
US378491A Expired - Lifetime US3913825A (en) 1973-07-12 1973-07-12 Leak proof bottom for a paperboard container

Country Status (8)

Country Link
US (1) US3913825A (no)
JP (1) JPS5810301B2 (no)
AU (1) AU7081474A (no)
CA (1) CA997728A (no)
GB (1) GB1481844A (no)
NL (1) NL7409405A (no)
NO (1) NO142164C (no)
SE (1) SE406896B (no)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0089033A1 (en) * 1982-03-12 1983-09-21 International Paper Company Container with raw edge protection
US4586643A (en) * 1984-06-01 1986-05-06 Weyerhaeuser Company Reinforced container
US4690835A (en) * 1984-06-01 1987-09-01 Weyerhaeuser Company Reinforced container
US4728024A (en) * 1981-04-01 1988-03-01 PKL Papier-und Kunstoff Liquid packaging container with filmed-over notches
US4730766A (en) * 1985-12-20 1988-03-15 Continental Bondware, Inc. Sealing of void area at the top of cup bead of hot melt
US5021040A (en) * 1987-05-21 1991-06-04 Phillips Robert D Paperboard container having leak preventative raised sealing scores
EP0748749A1 (en) * 1995-06-16 1996-12-18 Sankemikal Kabushikigaisha Medical waste collection container and blank for forming said container
US5711475A (en) * 1996-01-25 1998-01-27 International Paper Company Container fixant applicator and method for production and application therefor
US20030207039A1 (en) * 1999-03-05 2003-11-06 Sumitomo Rubber Industries, Ltd. Method of manufacturing golf ball

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4754917A (en) * 1986-07-29 1988-07-05 International Paper Company End closure construction for liquid containers

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2362862A (en) * 1942-07-15 1944-11-14 Harlow M Russell Paper container for fluid
US2440664A (en) * 1945-07-28 1948-04-27 Dow Chemical Co Making lap-welded articles from thermoplastic films
US2496043A (en) * 1946-07-26 1950-01-31 Marathon Corp Leakproof package and method of making same
US2926777A (en) * 1957-03-28 1960-03-01 Gibraltar Corrugated Paper Com Combined shipping and display cases
US3120335A (en) * 1961-09-07 1964-02-04 Ex Cell O Corp Container with infolded bottom closure
US3194473A (en) * 1961-08-23 1965-07-13 Kvp Sutherland Paper Co Sealable overlap carton
US3365111A (en) * 1966-03-21 1968-01-23 Int Paper Co Laminated container
US3412922A (en) * 1966-09-06 1968-11-26 Ex Cell O Corp Paperboard container closure
US3421678A (en) * 1967-10-09 1969-01-14 Us Plywood Champ Papers Inc Profile coated carton
US3455496A (en) * 1964-03-27 1969-07-15 Procter & Gamble Seal end carton
US3474951A (en) * 1968-07-19 1969-10-28 Ex Cell O Corp Container closure

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ZA723597B (en) * 1971-10-07 1973-02-28 Ex Cell O Corp Flat end closure container with reclosable pour spout

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2362862A (en) * 1942-07-15 1944-11-14 Harlow M Russell Paper container for fluid
US2440664A (en) * 1945-07-28 1948-04-27 Dow Chemical Co Making lap-welded articles from thermoplastic films
US2496043A (en) * 1946-07-26 1950-01-31 Marathon Corp Leakproof package and method of making same
US2926777A (en) * 1957-03-28 1960-03-01 Gibraltar Corrugated Paper Com Combined shipping and display cases
US3194473A (en) * 1961-08-23 1965-07-13 Kvp Sutherland Paper Co Sealable overlap carton
US3120335A (en) * 1961-09-07 1964-02-04 Ex Cell O Corp Container with infolded bottom closure
US3455496A (en) * 1964-03-27 1969-07-15 Procter & Gamble Seal end carton
US3365111A (en) * 1966-03-21 1968-01-23 Int Paper Co Laminated container
US3412922A (en) * 1966-09-06 1968-11-26 Ex Cell O Corp Paperboard container closure
US3421678A (en) * 1967-10-09 1969-01-14 Us Plywood Champ Papers Inc Profile coated carton
US3474951A (en) * 1968-07-19 1969-10-28 Ex Cell O Corp Container closure

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4728024A (en) * 1981-04-01 1988-03-01 PKL Papier-und Kunstoff Liquid packaging container with filmed-over notches
US4801073A (en) * 1981-04-01 1989-01-31 Pkl Papier- Und Kunstoff Werke Linnich Gmbh Liquid packaging container with a filmed-over notch
EP0089033A1 (en) * 1982-03-12 1983-09-21 International Paper Company Container with raw edge protection
US4586643A (en) * 1984-06-01 1986-05-06 Weyerhaeuser Company Reinforced container
US4690835A (en) * 1984-06-01 1987-09-01 Weyerhaeuser Company Reinforced container
US4730766A (en) * 1985-12-20 1988-03-15 Continental Bondware, Inc. Sealing of void area at the top of cup bead of hot melt
US5021040A (en) * 1987-05-21 1991-06-04 Phillips Robert D Paperboard container having leak preventative raised sealing scores
EP0748749A1 (en) * 1995-06-16 1996-12-18 Sankemikal Kabushikigaisha Medical waste collection container and blank for forming said container
US5711475A (en) * 1996-01-25 1998-01-27 International Paper Company Container fixant applicator and method for production and application therefor
US20030207039A1 (en) * 1999-03-05 2003-11-06 Sumitomo Rubber Industries, Ltd. Method of manufacturing golf ball

Also Published As

Publication number Publication date
NO142164C (no) 1980-07-09
NL7409405A (nl) 1975-01-14
GB1481844A (en) 1977-08-03
NO742532L (no) 1975-02-10
SE406896B (sv) 1979-03-05
JPS5049070A (no) 1975-05-01
AU7081474A (en) 1976-01-08
JPS5810301B2 (ja) 1983-02-25
CA997728A (en) 1976-09-28
SE7409109L (sv) 1975-01-13
NO142164B (no) 1980-03-31

Similar Documents

Publication Publication Date Title
US2341845A (en) Container and method of making the same
US3120335A (en) Container with infolded bottom closure
DE69313533T2 (de) Verfahren zum Heisssiegeln einer, nur an einer Seite mit einer Polymerschicht versehenen Faltschachtel sowie das Produkt
US4730766A (en) Sealing of void area at the top of cup bead of hot melt
US4287247A (en) Packing laminate provided with crease lines
US4702410A (en) Bottom design of packing containers
US4441648A (en) Single piece packaging container
US3913825A (en) Leak proof bottom for a paperboard container
US5501394A (en) Gable top carton having a U-shaped stake seal and method and apparatus for forming
US3389849A (en) Plastic gable top container
US3913826A (en) Leak proof bottom for a paperboard container
US3421678A (en) Profile coated carton
EP0249180B2 (de) Giebelpackung
US4785993A (en) Low stress flat end closure arrangement for thermoplastic coated paperboard carton
US4546884A (en) Tear strip end closure on liquid tight carton
US4601425A (en) Nonwicking bottom closure for a liquid-tight container
US4453270A (en) Pasted valve stepped end bag
DK153455B (da) Emne for en beholder af foldeligt banemateriale og beholder fremstillet af dette emne
US3474951A (en) Container closure
US5851630A (en) Container and blank for "duckbill" elimination
US5021040A (en) Paperboard container having leak preventative raised sealing scores
NZ197196A (en) Container and blank therefor; at least two bottom panels connected by vertical score lines
US5018660A (en) Container and blank for constructing same
NZ196920A (en) Paperboard container;opening for straw less than the width of the inner overlapped panel
US3294310A (en) Paperboard container and method of eliminating edge wicking in the container