RECLOSEABLE CONTAINER
United States Patent 3618850
A recloseable container has a tubular body with a longitudinal flap extending along the length thereof, and a strip of nonresiliently deformable material extending about its inner periphery. The longitudinal flap is secured to the body, and the body is deformed by pleats extending through the secured area and generally parallel to the strip of deformable material to provide a tear channel. The strip of deformable material is capable of maintaining a folded configuration to render the container recloseable by folding it along the strip to engage opposed portions thereof.
US Patent References:
Closure means for containers
Koncak - July 1967 - 3330469
Plastic bags with metal foil laminated lips
Pickin - November 1967 - 3353662
BAG ENCLOSING RE-CLOSING FACILITY
Paxton - April 1969 - 3439867
Closure means for containers
Koncak - July 1967 - 3330469
Plastic bags with metal foil laminated lips
Pickin - November 1967 - 3353662
BAG ENCLOSING RE-CLOSING FACILITY
Paxton - April 1969 - 3439867
Application Number:
05/027835
Publication Date:
11/09/1971
Filing Date:
04/13/1970
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
383/905, 383/120, 383/89
International Classes:
B65D75/62; B65D33/30
Field of Search:
229/62,65,66,64 150/3
Primary Examiner:
Norton, Donald F.
Claims:
Having thus described the invention, I claim
1. A recloseable container comprising a generally tubular body having a recloseable end portion and a longitudinal flap extending along the length thereof, and a relatively thin, substantially continuous strip of nonresiliently deformable material extending about the inner periphery of said end portion and secured thereto at a location spaced from the end margin thereof, said container being formed of a length of sheet material with substantially parallel longitudinal edges, between and substantially perpendicular to which extends an elongated element of said material, said length of sheet material being bonded in face-to-face contact along said longitudinal edges to form said body and to provide said longitudinal flap with a portion of said elongated element thereon, said recloseable end portion being generally flattened with opposing surfaces between said end margin and said strip bonded together to close said container, said flap being secured to said body at least in an area about the edge of said elongated element portion adjacent to said end margin, at least said body being deformed by pleats extending through said secured area and generally parallel to said adjacent edge of said strip to provide a tear channel across said secured area, said deformable material being capable of maintaining a folded configuration to render said container recloseable by folding along said strip to interengage opposed portions thereof.
2. The container of claim 1 wherein said pleats are present in said strip.
3. The container of claim 1 wherein said body at said end portion is deformed by pleats extending generally longitudinally inwardly from said end margin to provide a tear channel for access to said parallel extending pleats.
4. The container of claim 1 wherein said sheet material has a sealable surface and wherein said tubular body is formed with said sealable surface inwardly thereof, said sealable surface providing said bonds along said longitudinal edges and between said opposing surfaces.
5. The container of claim 4 wherein said sealable surface is heat-sealable.
6. The container of claim 5 wherein said sealable surface is provided by a synthetic thermoplastic polymer.
7. The container of claim 6 wherein said sheet material is regenerated cellulose coated with said polymer.
8. The container of claim 1 wherein said deformable element comprises a wrought metal foil.
9. The container of claim 1 additionally including an article therewithin, the end of said tubular body spaced from said end portion being sealed to enclose said article within said container.
1. A recloseable container comprising a generally tubular body having a recloseable end portion and a longitudinal flap extending along the length thereof, and a relatively thin, substantially continuous strip of nonresiliently deformable material extending about the inner periphery of said end portion and secured thereto at a location spaced from the end margin thereof, said container being formed of a length of sheet material with substantially parallel longitudinal edges, between and substantially perpendicular to which extends an elongated element of said material, said length of sheet material being bonded in face-to-face contact along said longitudinal edges to form said body and to provide said longitudinal flap with a portion of said elongated element thereon, said recloseable end portion being generally flattened with opposing surfaces between said end margin and said strip bonded together to close said container, said flap being secured to said body at least in an area about the edge of said elongated element portion adjacent to said end margin, at least said body being deformed by pleats extending through said secured area and generally parallel to said adjacent edge of said strip to provide a tear channel across said secured area, said deformable material being capable of maintaining a folded configuration to render said container recloseable by folding along said strip to interengage opposed portions thereof.
2. The container of claim 1 wherein said pleats are present in said strip.
3. The container of claim 1 wherein said body at said end portion is deformed by pleats extending generally longitudinally inwardly from said end margin to provide a tear channel for access to said parallel extending pleats.
4. The container of claim 1 wherein said sheet material has a sealable surface and wherein said tubular body is formed with said sealable surface inwardly thereof, said sealable surface providing said bonds along said longitudinal edges and between said opposing surfaces.
5. The container of claim 4 wherein said sealable surface is heat-sealable.
6. The container of claim 5 wherein said sealable surface is provided by a synthetic thermoplastic polymer.
7. The container of claim 6 wherein said sheet material is regenerated cellulose coated with said polymer.
8. The container of claim 1 wherein said deformable element comprises a wrought metal foil.
9. The container of claim 1 additionally including an article therewithin, the end of said tubular body spaced from said end portion being sealed to enclose said article within said container.
Description:
BACKGROUND OF THE INVENTION
Many types of closures and/or design modifications have heretofore been provided to enable a bag, container or overwrap to be closed and opened, or to be reclosed after an original seal has been removed or broken. Such packages are particularly useful when only a portion of the contents thereof are normally removed, and especially when the contents are subject to deterioration or spoilage due to atmospheric conditions after the package has been opened, e.g., when the package contains baked goods such as bread, cookies, etc. or when it contains other foodstuffs such as candy and the like.
Among the various methods which have been used to provide recloseable packages is the provision of pressure-sensitive adhesives on one or more portions of the package designed to permit repeated bonding and release. However, the use of adhesives in this manner has not been very successful for a number of reasons. As a fundamental matter, it is difficult to achieve a balance of properties in an adhesive whereby a desirable level of adhesion is coupled with relatively facile release characteristics for opening the package. In addition, there is a tendency for loss of tackiness to occur rapidly in such adhesives so that after relatively short periods of use they become relatively ineffectual due either to frequent opening and closing or to contamination of the adhesive with dirt particles and the like.
Other attempts to produce closeable packages have relied upon metal clasps and closures for bags, envelopes, etc. made of a variety of materials including paper and plastics. Such a closure is normally made of a nonresiliently deformable metal so that it can be bent upon itself or about a portion of the package to maintain a closed condition when desired. However, so far as is known the prior art constructions of this type do not permit convenient and complete sealing of the package initially, ready opening thereof without undue damage thereto, and repeated opening and closing of the package with substantially no loss of effectiveness after extensive use.
In Applicant's copending application Ser. No. 830,720 entitled RECLOSEABLE BAG MEMBER AND METHOD OF PRODUCING SAME, filed on June 5, 1969, now U.S. Pat. No. 3,554,436 he describes a bag member that is provided with a peripheral strip of nonresiliently deformable material adjacent its opening to render the bag member recloseable. Opposing portions of the bag member can be interengaged by folding it along the strip of deformable material to provide a closure therefor. Although the bag members produced in accordance with the invention of that application are very satisfactory in most instances, when the bag member is tubular and is secured in that configuration by a face-to-face (rather than overlapping) longitudinal seal that produces a flap, it has been found to be desirable to provide means to facilitate manual opening of the bag. More specifically, such means is desirably provided to reduce any tendency for the tear across the top of the bag to proceed along the seam and thereafter into the main body portion after it reaches the longitudinal flap. This tendency may be alleviated by securing the flap in the area of tearing, but such a practice is not entirely satisfactory because it results in the presence of a number of layers (i.e., at least four), which must be torn simultaneously. The resistance so presented makes it somewhat difficult to control the direction in which the tear proceeds.
Accordingly, it is an object of the present invention to provide a container that is of relatively simple construction, that may be conveniently and completely sealed initially, that may be readily opened without damage to the main portion thereof such as would render the container unsatisfactory for subsequent use, and that may thereafter be repeatedly closed and opened without loss of closing effectiveness. A more specific object is to provide such a container formed with a flap extending longitudinally along its length.
Another object of the invention is to provide such a container that is initially heat-sealable, i.e., sealed by the application of heat thereto.
Still another object is to provide such a container wherein effective reclosure is facilitated and wherein the cost of materials is minimized.
SUMMARY OF THE DISCLOSURE
It has now been found that the foregoing and related objects can be readily attained in a container comprising a generally tubular body having a recloseable end portion and a longitudinal flap extending along its length, and a strip of nonresiliently deformable material within the body. The strip of deformable material is relatively thin and substantially continuous and extends about the inner periphery of the end portion; it is secured thereto at a location spaced from the end margin thereof. The container is formed of a length of sheet material with substantially parallel longitudinal edges, between and substantially perpendicular to which extends an elongated element of the nonresiliently deformable material. The length of sheet material is bonded in face-to-face contact along its longitudinal edges to form the body and to provide the longitudinal flap with a portion of the elongated element thereon. The recloseable end portion of the body is generally flattened, with opposing surfaces between its end margin and the strip bonded together to close the container and with the flap secured to the body at least in an area about the edge of the elongated element portion that is adjacent to the end margin. At least the body of the container is deformed by pleats extending through the secured area and generally parallel to the adjacent edge of the strip, to provide a tear channel across the secured area. The deformable material is capable of maintaining a folded configuration to render the container recloseable by folding along the strip to interengage opposed portions thereof.
In the preferred embodiments, the pleats are present in the strip of deformable material as well as in the body, and most desirably, the body is deformed at the end portion by pleats extending generally longitudinally inwardly from the end margin thereof, to provide a tear channel for access to the parallel-extending pleats. The sheet material employed may have a sealable surface, in which case the tubular body is formed with the sealable surface inwardly thereof to provide the bonds along the longitudinal edges and between the opposing surfaces of the end portion. Preferably the sealable surface is heat sealable, and most desirably it is provided by a synthetic thermoplastic polymer. It is particularly preferred that the sheet material utilized be regenerated cellulose coated with such a synthetic polymer, and that the deformable element comprise a wrought metal foil. The container may additionally include an article therewithin, in which case the end of the tubular body spaced from the recloseable end portion is sealed to enclose the article within the container.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary plan view of a blank utilized to produce a container embodying the present invention;
FIG. 2 is a perspective view of a container produced from the blank of FIG. 1 which has been partially opened by tearing away a portion of the body above the foil strip;
FIG. 3 is a fragmentary perspective view of the upper end of the container of FIG. 2, wherein the portion above the foil strip has been entirely removed and the plys of the end portion folded together to illustrate the recloseable feature of the containers of the invention;
FIG. 4 is a fragmentary sectional view, to an enlarged scale, of the reclosed container along the line 4-4 of FIG. 3; and
FIG. 5 is a fragmentary view, to an enlarged scale, of an area about the upper edge of the flap of the container of FIG. 2.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Turning now in detail to the appended drawing, therein illustrated (in FIGS. 2-5) is a recloseable container or bag embodying the present invention, which is produced from the blank shown in FIG. 1. The blank consists of a rectangular length or sheet 10 of transparent synthetic plastic sheet material and a nonresiliently deformable metal foil element 12 secured adjacent one edge, such as by heat seals extending along the length of the foil element 12. The ends of the foil element 12 are spaced slightly inwardly from the respective edges 20, 24 of the sheet 10 to provide spaces 16, 18 therebetween, for a purpose to be more fully described hereinafter.
The bag illustrated in FIGS. 2-5 is produced from the blank of FIG. 1 by positioning the edge portions in face-to-face contact to align the edges 20, 24 of the sheet 10, i.e., by curving the sheet 10 out of the page of the drawing and bonding the inside surfaces together along the edges 20, 24 thereof; a generally tubular body is thereby formed with a longitudinal flap 26 extending along its length. Thereafter, the opposing faces A, B of the sheet 10 are brought into contact and the upper end 34 of the bag sealed, such as by rolling a heated serrated spur or wheel thereacross to produce the longitudinally extending pleats 32. Similarly, the portion of the flap 26 within the area generally designated 22 is secured to the adjacent portion of the bag by the transverse pleats 30 extending therethrough generally parallel to the edge 14; the spaces 16, 18 between the ends of the strip 12 and the edges 20, 24 of the sheet 10 improve bonding of the flap 26 by providing foil-free areas thereon. After closure of the upper end 34 of the bag, the contents 28 may be placed therein and the opposite end of the bag sealed, such as with the heat-formed pleats 36. It will be appreciated that the lower end of the bag may be closed first and the upper end subsequently sealed after placing the contents 28 therewithin, if so desired.
To open the bag initially, the upper end 34 is torn longitudinally along one of the pleats 32, to a point adjacent the upper edge of the strip 12, and then along the strip 12 to the flap 26. At that point one of the transversely extending pleats 30 facilitates and guides the tear through the four plys of material present in the area 22. Tearing into the main portion of the bag is substantially prevented by the strip 12, and tearing along the intersection of the end portions of the strip 12 at the base of the flap 26 is similarly prevented by securing the flap 26 in the manner described.
Turning now in greater detail to FIGS. 3 and 4, therein illustrated is the manner in which the bag is reclosed after the portion 34 has been torn away to open it. In doing so, opposite faces A, B of the bag are brought together in face-to-face contact, and the element 12 is then folded longitudinally, preferably approximately midway between its upper and lower edges. Due to the nonresilient deformability of the foil element 12 and its consequent ability to maintain a folded configuration, the resultant interengagement of the opposing portions of the element 12 maintains the bag in the closed position shown in FIGS. 3 and 4.
Outstanding features of the novel containers disclosed herein include the convenience and effectiveness of sealing and the ease with which they may be opened initially and thereafter effectively closed and opened repeatedly during subsequent use. The strategically located pleats not only greatly facilitate initial opening of the container without damage to the main portion of the body thereof, but when they are also present in the strip of deformable material they may be relied upon to strengthen the strip and facilitate closure of the container. Thus, the pleats extending along the strip of deformable material stiffen it in the longitudinal direction and thereby permit a lighter gauge of material to be used; this, in turn, minimizes the cost thereof. The pleats in the strip also provide folding guides and may enhance the seal somewhat by affording a more positive interlock and by presenting a tortuous path for gas passage. Although the term "pleats" has been used with reference to the folds or ridges produced in the body and deformable material of the present containers, "corrugations" or "serrations" may be used synonymously as equally appropriate terms. It should be understood that the configuration so defined consists of a series of ridges and grooves wherein the apices are relatively sharp and well defined.
When the body of the container is made of a sealable material, placement of the element or strip of nonresiliently deformable material in a position partially blocking the sealable surface on the inside of the sheet material ensures that it can be opened without significant detriment to the portion of the body below the nonresiliently deformable strip, and yet exposes a portion of the sealable surface thereabove for initial sealing. Securing the deformable material to the outside surface of the article, on the other hand, necessitates very careful control and placement of equipment during the sealing step to avoid the creation of a seal under or between the plys of deformable material which would render the package virtually impossible to open without considerable inconvenience and without rendering it unsatisfactory for further use.
The method of effecting the seal to close the bag and to form the tubular body may vary widely and will depend primarily upon the characteristics of the sealable material involved. Although other techniques may be feasible, the most effective and convenient manner of producing the seals will usually be by use of an elevated temperature technique employing materials which are heat sealable, i.e., rendered adhesive or tacky by subjecting them to heat. Many different types of heat sealing apparatus may be used, such as the conventional heated jaws or rollers, and the heat source may involve infrared, dielectric, ultrasonic, or impulse heating effects; however when a pleated configuration is desired, a toothed roller or spur-type element may be most suitable.
The sealable surface or material may be provided by the inherent thermoplastic nature of the packaging sheet material of which the entire body of the bag member is constructed, or a heat activatable coating may be used on the inner surface, such as by laminating a film of greater heat-sealing characteristics to a film having less effective heat sealing characteristics. More particularly, the packaging material may be sheet material of a synthetic thermoplastic polymeric resin having inherent sealing characteristics such as the olefin and vinyl homopolymers and copolymers, the vinyl chloride/vinylidene chloride copolymers, the ethylene/vinyl acetate copolymers, etc.; in many instances laminated combinations of or with such polymers are particularly preferred. Both (or all) components of such a laminate may have sealing characteristics, or one of the components may provide other properties which are desired, such as a nonsticking surface or advantageous gas and liquid permeation characteristics, certain of which may be obtainable with layers of paper, cellophane, polyesters, and the like. The packaging material may be a normally nonsealing material such as paper treated with a sealable composition, and such treatment may involve coating the paper with a heat-activatable adhesive or dispersing a suitable polymer in the fiber slurry during its manufacture the inner surface of a sheet material component may be entirely coated with the heat-sealable material or coated in only limited areas thereof. The materials preferred for use herein are the regenerated cellulose films coated with synthetic thermoplastic polymers, such as the so-called "K-type" cellophane (polyvinylidene chloride-coated regenerated cellulose) sold by E. I. duPont de Nemours & Co.
The appropriate thickness of the packaging material will depend primarily upon the intended use of the bag member and is readily determinable by those skilled in the art. Polymeric sheet material will normally range from about 0.5 to 5.0, and will preferably be about 1.0 to 3.0 mils in thickness. In some instances the packaging material may be as much as 30 or more mils thick, but the design of an economically feasible process employing such heavy gauge materials will usually entail more complicated equipment and procedures, and the gauge of deformable material necessary to maintain such a package closed may be prohibitive.
As has been mentioned, the material most appropriate for use as the deformable material is foil of a relatively ductile metal such as aluminum. It may be possible to substitute other nonresiliently deformable structures such as can be produced with a wire framework or skeleton (which may or may not be attached to or imbedded within a matrix such as paper), but from the standpoint of economics and convenience of manufacture the metal foils will generally be preferable. Virtually any configuration may be employed for the deformable element which will provide a substantially continuous strip or loop within the article and a portion at least partially traversing the flap, when the sheet is formed to provide the tubular body. Accordingly, the length of the material should be somewhat longer than the peripheral dimension of the tubular body and it should be approximately equal to the width of the sheet from which the body is formed. It may be preferred that the ends of the strip terminate somewhat short of the longitudinal edges of the sheet so that a small area of the sheet material is fully exposed thereat for direct bonding to the body of the container, as has previously been described.
As regards the transverse or width dimension of the strip, it need only be wide enough to allow facile folding longitudinally thereof to provide adequate interengagement, and the same criterion is applicable to determine an appropriate thickness for the strip or deformable element. It should be appreciated that the use of metal foil is of particular advantage because the foil element also provides a cutting edge adjacent the upper end of the article for initial tearing away of the end portion above the foil element to effect opening, either by providing a sharp straight edge or one which is serrated to promote cutting of the packaging material. The positioning of the strip on the inside of the bag is also important in this respect since a strip located on the exterior surface would allow the material of the bag to be torn between the plys thereof, and would therefore render it ineffective as a cutting edge.
The packaging material will normally be employed initially in the form of individual rectangular lengths of sheet material or as a substantially continuous length having parallel longitudinal edges. When the packaging material is provided as a substantially continuous length to enable the production of a multiplicity of bags on a continuous or semicontinuous basis, the elements of deformable material are secured thereto by conventional means at a multiplicity of points spaced along the length thereof and substantially perpendicular to the longitudinal or parallel edges thereof. Thereafter, the length of packaging material may be formed into a generally cylindrical configuration, such as by rolling or folding it about a suitable mandrel, and the longitudinal edges thereof may then be bonded together continuously along the length of material as it passes over the mandrel. As the body thus formed passes from the mandrel, a second sealing mechanism may pinch or otherwise secure opposite sides together, simultaneously forming a lower end seal for one bag and an upper end seal for the preceding one. The mandrel in such a method may suitably be hollow for use in filling the packages with the desired contents prior to sealing of the end portions. The pleats will be formed at the desired locations by appropriate means, such as by rolling members, presses, or the like and, although this may be done subsequently, they will normally be most conveniently formed during a bonding or sealing operation, such as by use of heated members suitably configured to create the pleats.
Thus, it can be seen that the present invention provides a container that is of relatively simple construction, that may be conveniently and completely sealed initially, that may be readily opened without damage to the main portion thereof such as would render the container unsatisfactory for subsequent use, and that may thereafter be repeatedly closed and opened without loss of effectiveness of closure. More specifically, the invention provides such a container that is formed with a longitudinal flap, and the container may initially be heat sealable, i.e., sealable by the application of heat thereto. Effective reclosure may be facilitated and the cost of materials may be minimized in the container provided hereby.
Many types of closures and/or design modifications have heretofore been provided to enable a bag, container or overwrap to be closed and opened, or to be reclosed after an original seal has been removed or broken. Such packages are particularly useful when only a portion of the contents thereof are normally removed, and especially when the contents are subject to deterioration or spoilage due to atmospheric conditions after the package has been opened, e.g., when the package contains baked goods such as bread, cookies, etc. or when it contains other foodstuffs such as candy and the like.
Among the various methods which have been used to provide recloseable packages is the provision of pressure-sensitive adhesives on one or more portions of the package designed to permit repeated bonding and release. However, the use of adhesives in this manner has not been very successful for a number of reasons. As a fundamental matter, it is difficult to achieve a balance of properties in an adhesive whereby a desirable level of adhesion is coupled with relatively facile release characteristics for opening the package. In addition, there is a tendency for loss of tackiness to occur rapidly in such adhesives so that after relatively short periods of use they become relatively ineffectual due either to frequent opening and closing or to contamination of the adhesive with dirt particles and the like.
Other attempts to produce closeable packages have relied upon metal clasps and closures for bags, envelopes, etc. made of a variety of materials including paper and plastics. Such a closure is normally made of a nonresiliently deformable metal so that it can be bent upon itself or about a portion of the package to maintain a closed condition when desired. However, so far as is known the prior art constructions of this type do not permit convenient and complete sealing of the package initially, ready opening thereof without undue damage thereto, and repeated opening and closing of the package with substantially no loss of effectiveness after extensive use.
In Applicant's copending application Ser. No. 830,720 entitled RECLOSEABLE BAG MEMBER AND METHOD OF PRODUCING SAME, filed on June 5, 1969, now U.S. Pat. No. 3,554,436 he describes a bag member that is provided with a peripheral strip of nonresiliently deformable material adjacent its opening to render the bag member recloseable. Opposing portions of the bag member can be interengaged by folding it along the strip of deformable material to provide a closure therefor. Although the bag members produced in accordance with the invention of that application are very satisfactory in most instances, when the bag member is tubular and is secured in that configuration by a face-to-face (rather than overlapping) longitudinal seal that produces a flap, it has been found to be desirable to provide means to facilitate manual opening of the bag. More specifically, such means is desirably provided to reduce any tendency for the tear across the top of the bag to proceed along the seam and thereafter into the main body portion after it reaches the longitudinal flap. This tendency may be alleviated by securing the flap in the area of tearing, but such a practice is not entirely satisfactory because it results in the presence of a number of layers (i.e., at least four), which must be torn simultaneously. The resistance so presented makes it somewhat difficult to control the direction in which the tear proceeds.
Accordingly, it is an object of the present invention to provide a container that is of relatively simple construction, that may be conveniently and completely sealed initially, that may be readily opened without damage to the main portion thereof such as would render the container unsatisfactory for subsequent use, and that may thereafter be repeatedly closed and opened without loss of closing effectiveness. A more specific object is to provide such a container formed with a flap extending longitudinally along its length.
Another object of the invention is to provide such a container that is initially heat-sealable, i.e., sealed by the application of heat thereto.
Still another object is to provide such a container wherein effective reclosure is facilitated and wherein the cost of materials is minimized.
SUMMARY OF THE DISCLOSURE
It has now been found that the foregoing and related objects can be readily attained in a container comprising a generally tubular body having a recloseable end portion and a longitudinal flap extending along its length, and a strip of nonresiliently deformable material within the body. The strip of deformable material is relatively thin and substantially continuous and extends about the inner periphery of the end portion; it is secured thereto at a location spaced from the end margin thereof. The container is formed of a length of sheet material with substantially parallel longitudinal edges, between and substantially perpendicular to which extends an elongated element of the nonresiliently deformable material. The length of sheet material is bonded in face-to-face contact along its longitudinal edges to form the body and to provide the longitudinal flap with a portion of the elongated element thereon. The recloseable end portion of the body is generally flattened, with opposing surfaces between its end margin and the strip bonded together to close the container and with the flap secured to the body at least in an area about the edge of the elongated element portion that is adjacent to the end margin. At least the body of the container is deformed by pleats extending through the secured area and generally parallel to the adjacent edge of the strip, to provide a tear channel across the secured area. The deformable material is capable of maintaining a folded configuration to render the container recloseable by folding along the strip to interengage opposed portions thereof.
In the preferred embodiments, the pleats are present in the strip of deformable material as well as in the body, and most desirably, the body is deformed at the end portion by pleats extending generally longitudinally inwardly from the end margin thereof, to provide a tear channel for access to the parallel-extending pleats. The sheet material employed may have a sealable surface, in which case the tubular body is formed with the sealable surface inwardly thereof to provide the bonds along the longitudinal edges and between the opposing surfaces of the end portion. Preferably the sealable surface is heat sealable, and most desirably it is provided by a synthetic thermoplastic polymer. It is particularly preferred that the sheet material utilized be regenerated cellulose coated with such a synthetic polymer, and that the deformable element comprise a wrought metal foil. The container may additionally include an article therewithin, in which case the end of the tubular body spaced from the recloseable end portion is sealed to enclose the article within the container.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary plan view of a blank utilized to produce a container embodying the present invention;
FIG. 2 is a perspective view of a container produced from the blank of FIG. 1 which has been partially opened by tearing away a portion of the body above the foil strip;
FIG. 3 is a fragmentary perspective view of the upper end of the container of FIG. 2, wherein the portion above the foil strip has been entirely removed and the plys of the end portion folded together to illustrate the recloseable feature of the containers of the invention;
FIG. 4 is a fragmentary sectional view, to an enlarged scale, of the reclosed container along the line 4-4 of FIG. 3; and
FIG. 5 is a fragmentary view, to an enlarged scale, of an area about the upper edge of the flap of the container of FIG. 2.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Turning now in detail to the appended drawing, therein illustrated (in FIGS. 2-5) is a recloseable container or bag embodying the present invention, which is produced from the blank shown in FIG. 1. The blank consists of a rectangular length or sheet 10 of transparent synthetic plastic sheet material and a nonresiliently deformable metal foil element 12 secured adjacent one edge, such as by heat seals extending along the length of the foil element 12. The ends of the foil element 12 are spaced slightly inwardly from the respective edges 20, 24 of the sheet 10 to provide spaces 16, 18 therebetween, for a purpose to be more fully described hereinafter.
The bag illustrated in FIGS. 2-5 is produced from the blank of FIG. 1 by positioning the edge portions in face-to-face contact to align the edges 20, 24 of the sheet 10, i.e., by curving the sheet 10 out of the page of the drawing and bonding the inside surfaces together along the edges 20, 24 thereof; a generally tubular body is thereby formed with a longitudinal flap 26 extending along its length. Thereafter, the opposing faces A, B of the sheet 10 are brought into contact and the upper end 34 of the bag sealed, such as by rolling a heated serrated spur or wheel thereacross to produce the longitudinally extending pleats 32. Similarly, the portion of the flap 26 within the area generally designated 22 is secured to the adjacent portion of the bag by the transverse pleats 30 extending therethrough generally parallel to the edge 14; the spaces 16, 18 between the ends of the strip 12 and the edges 20, 24 of the sheet 10 improve bonding of the flap 26 by providing foil-free areas thereon. After closure of the upper end 34 of the bag, the contents 28 may be placed therein and the opposite end of the bag sealed, such as with the heat-formed pleats 36. It will be appreciated that the lower end of the bag may be closed first and the upper end subsequently sealed after placing the contents 28 therewithin, if so desired.
To open the bag initially, the upper end 34 is torn longitudinally along one of the pleats 32, to a point adjacent the upper edge of the strip 12, and then along the strip 12 to the flap 26. At that point one of the transversely extending pleats 30 facilitates and guides the tear through the four plys of material present in the area 22. Tearing into the main portion of the bag is substantially prevented by the strip 12, and tearing along the intersection of the end portions of the strip 12 at the base of the flap 26 is similarly prevented by securing the flap 26 in the manner described.
Turning now in greater detail to FIGS. 3 and 4, therein illustrated is the manner in which the bag is reclosed after the portion 34 has been torn away to open it. In doing so, opposite faces A, B of the bag are brought together in face-to-face contact, and the element 12 is then folded longitudinally, preferably approximately midway between its upper and lower edges. Due to the nonresilient deformability of the foil element 12 and its consequent ability to maintain a folded configuration, the resultant interengagement of the opposing portions of the element 12 maintains the bag in the closed position shown in FIGS. 3 and 4.
Outstanding features of the novel containers disclosed herein include the convenience and effectiveness of sealing and the ease with which they may be opened initially and thereafter effectively closed and opened repeatedly during subsequent use. The strategically located pleats not only greatly facilitate initial opening of the container without damage to the main portion of the body thereof, but when they are also present in the strip of deformable material they may be relied upon to strengthen the strip and facilitate closure of the container. Thus, the pleats extending along the strip of deformable material stiffen it in the longitudinal direction and thereby permit a lighter gauge of material to be used; this, in turn, minimizes the cost thereof. The pleats in the strip also provide folding guides and may enhance the seal somewhat by affording a more positive interlock and by presenting a tortuous path for gas passage. Although the term "pleats" has been used with reference to the folds or ridges produced in the body and deformable material of the present containers, "corrugations" or "serrations" may be used synonymously as equally appropriate terms. It should be understood that the configuration so defined consists of a series of ridges and grooves wherein the apices are relatively sharp and well defined.
When the body of the container is made of a sealable material, placement of the element or strip of nonresiliently deformable material in a position partially blocking the sealable surface on the inside of the sheet material ensures that it can be opened without significant detriment to the portion of the body below the nonresiliently deformable strip, and yet exposes a portion of the sealable surface thereabove for initial sealing. Securing the deformable material to the outside surface of the article, on the other hand, necessitates very careful control and placement of equipment during the sealing step to avoid the creation of a seal under or between the plys of deformable material which would render the package virtually impossible to open without considerable inconvenience and without rendering it unsatisfactory for further use.
The method of effecting the seal to close the bag and to form the tubular body may vary widely and will depend primarily upon the characteristics of the sealable material involved. Although other techniques may be feasible, the most effective and convenient manner of producing the seals will usually be by use of an elevated temperature technique employing materials which are heat sealable, i.e., rendered adhesive or tacky by subjecting them to heat. Many different types of heat sealing apparatus may be used, such as the conventional heated jaws or rollers, and the heat source may involve infrared, dielectric, ultrasonic, or impulse heating effects; however when a pleated configuration is desired, a toothed roller or spur-type element may be most suitable.
The sealable surface or material may be provided by the inherent thermoplastic nature of the packaging sheet material of which the entire body of the bag member is constructed, or a heat activatable coating may be used on the inner surface, such as by laminating a film of greater heat-sealing characteristics to a film having less effective heat sealing characteristics. More particularly, the packaging material may be sheet material of a synthetic thermoplastic polymeric resin having inherent sealing characteristics such as the olefin and vinyl homopolymers and copolymers, the vinyl chloride/vinylidene chloride copolymers, the ethylene/vinyl acetate copolymers, etc.; in many instances laminated combinations of or with such polymers are particularly preferred. Both (or all) components of such a laminate may have sealing characteristics, or one of the components may provide other properties which are desired, such as a nonsticking surface or advantageous gas and liquid permeation characteristics, certain of which may be obtainable with layers of paper, cellophane, polyesters, and the like. The packaging material may be a normally nonsealing material such as paper treated with a sealable composition, and such treatment may involve coating the paper with a heat-activatable adhesive or dispersing a suitable polymer in the fiber slurry during its manufacture the inner surface of a sheet material component may be entirely coated with the heat-sealable material or coated in only limited areas thereof. The materials preferred for use herein are the regenerated cellulose films coated with synthetic thermoplastic polymers, such as the so-called "K-type" cellophane (polyvinylidene chloride-coated regenerated cellulose) sold by E. I. duPont de Nemours & Co.
The appropriate thickness of the packaging material will depend primarily upon the intended use of the bag member and is readily determinable by those skilled in the art. Polymeric sheet material will normally range from about 0.5 to 5.0, and will preferably be about 1.0 to 3.0 mils in thickness. In some instances the packaging material may be as much as 30 or more mils thick, but the design of an economically feasible process employing such heavy gauge materials will usually entail more complicated equipment and procedures, and the gauge of deformable material necessary to maintain such a package closed may be prohibitive.
As has been mentioned, the material most appropriate for use as the deformable material is foil of a relatively ductile metal such as aluminum. It may be possible to substitute other nonresiliently deformable structures such as can be produced with a wire framework or skeleton (which may or may not be attached to or imbedded within a matrix such as paper), but from the standpoint of economics and convenience of manufacture the metal foils will generally be preferable. Virtually any configuration may be employed for the deformable element which will provide a substantially continuous strip or loop within the article and a portion at least partially traversing the flap, when the sheet is formed to provide the tubular body. Accordingly, the length of the material should be somewhat longer than the peripheral dimension of the tubular body and it should be approximately equal to the width of the sheet from which the body is formed. It may be preferred that the ends of the strip terminate somewhat short of the longitudinal edges of the sheet so that a small area of the sheet material is fully exposed thereat for direct bonding to the body of the container, as has previously been described.
As regards the transverse or width dimension of the strip, it need only be wide enough to allow facile folding longitudinally thereof to provide adequate interengagement, and the same criterion is applicable to determine an appropriate thickness for the strip or deformable element. It should be appreciated that the use of metal foil is of particular advantage because the foil element also provides a cutting edge adjacent the upper end of the article for initial tearing away of the end portion above the foil element to effect opening, either by providing a sharp straight edge or one which is serrated to promote cutting of the packaging material. The positioning of the strip on the inside of the bag is also important in this respect since a strip located on the exterior surface would allow the material of the bag to be torn between the plys thereof, and would therefore render it ineffective as a cutting edge.
The packaging material will normally be employed initially in the form of individual rectangular lengths of sheet material or as a substantially continuous length having parallel longitudinal edges. When the packaging material is provided as a substantially continuous length to enable the production of a multiplicity of bags on a continuous or semicontinuous basis, the elements of deformable material are secured thereto by conventional means at a multiplicity of points spaced along the length thereof and substantially perpendicular to the longitudinal or parallel edges thereof. Thereafter, the length of packaging material may be formed into a generally cylindrical configuration, such as by rolling or folding it about a suitable mandrel, and the longitudinal edges thereof may then be bonded together continuously along the length of material as it passes over the mandrel. As the body thus formed passes from the mandrel, a second sealing mechanism may pinch or otherwise secure opposite sides together, simultaneously forming a lower end seal for one bag and an upper end seal for the preceding one. The mandrel in such a method may suitably be hollow for use in filling the packages with the desired contents prior to sealing of the end portions. The pleats will be formed at the desired locations by appropriate means, such as by rolling members, presses, or the like and, although this may be done subsequently, they will normally be most conveniently formed during a bonding or sealing operation, such as by use of heated members suitably configured to create the pleats.
Thus, it can be seen that the present invention provides a container that is of relatively simple construction, that may be conveniently and completely sealed initially, that may be readily opened without damage to the main portion thereof such as would render the container unsatisfactory for subsequent use, and that may thereafter be repeatedly closed and opened without loss of effectiveness of closure. More specifically, the invention provides such a container that is formed with a longitudinal flap, and the container may initially be heat sealable, i.e., sealable by the application of heat thereto. Effective reclosure may be facilitated and the cost of materials may be minimized in the container provided hereby.