CA1156194A

CA1156194A - Package for aromatic contents and process for its production

Info

Publication number: CA1156194A
Application number: CA000358422A
Authority: CA
Inventors: Leif Sorensen
Original assignee: BRDR Schur International AS
Current assignee: BRDR Schur International AS
Priority date: 1979-08-28
Filing date: 1980-08-15
Publication date: 1983-11-01
Also published as: FI802711A; DK363880A; IE50467B1; DE3066976D1; FI69611B; ATE6617T1; FI69611C; DK150723B; NO154830B; NO154830C; EP0024596A1; DE2934673A1; JPS5632260A; NO802535L; AU6155380A; IE801804L; EP0024596B1; AU536317B2

Abstract

Abstract A package for aromatic contents comprising a bag including front and rear mutually facing portions formed of a common piece of laminate material, said portions joining at a material fold defining the bag bottom, side seam heat seals of high strength extending the length of and joining together corresponding longitudinal margins of facing surfaces of front said rear portions, a hand peelable heat seal seam of substantially lower strenth than said side seam heat seals, joining facing surfaces of said first and rear portions together, transverse to said side seals, longitudinally removed from said fold, wherein traverse extremities of said hand peelable seal overlap said respective side seam heat seals to provide seam crossing zones of great strength so that said hand peelable seal can be opened only between said seam crossing zones, wherein said laminate is a three layer lamination consisting of an outer layer of polypropylene, a central layer of paper and an inner layer of flexible thermo-plastic with said facing surfaces of said first and second portion being said flexible thermoplastic.

Description

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PACKAGE FOR AROMATIC CONTENTS
AND PROCESS FOR ITS PRODU TION

Back~round of the Invention Field of the Invention This invention pertains to a package for aromatic contents and/or contents to be maintained at a desired mois-ture level.

Description of the Prior Art A tobacco bag is known, from German Offenlegungs-schrift No. 2,518,229, in which the upper edge forming the opening of the bag is not closed. One of the two wall portions which forms the bag in its lower portion, namely the rear wall portion, is elongated into a fold-over flap, which lQ lies against the outæide of the bag portion when the bag is folded up. An adh~sive paralleling the bottom fold line is intended on the-one hand to close the upper wall at the top edge and on the other hand in the adjacent area to close the rear wall portion. However, in this manner an aroma and moisture sealing closure is not achieved. In addition, the tobacco bag is not advantageous in either manufacture or use.

1079-80 ~S6194 ~ tobacco bag is also known from'German Offenlegungs-schrift No. 2,840,223. There, the sealing seam paralleling the bottom fold is between wall parts or different plastic materials, so a breakable welded closure is achieved. If the bags are formed, as taught by these Offenlegungsschrifts, by folding an elongated piece of material along a transverse bottom fold, e.g., at about one-third from the end of the material strip, the inner layer of the bag consists of a first material type and the outer layer of a second material type. The upper edge of the front wall is folded inward and welded directly to the adjacent inside of the rear wall. In this manner two different material types face one another upon welding, and by appropriately adjusting the materials, their seam strength upon welding can be reduced to an extent that a peelable welded seam is attained. However, this reduction of seam strength also applies to the sealed seams of the two side edges of the bag, i.e. when so-welding two different materials, it has not been possible to form the seam seals of differing seal strength -- one of relatively low strength which can be peeled open and an adjacent one of high strength which resists opening when the neighboring low strength peelable seal is opened. Specifically, it has been found, disadvan-tageously, that the user, when opening the peelable closure seam at the outer edges, also pulls apart the upper areas of the lateral sealing means. These packages are then, disadvantageously, no longer firmly sealed along their sides with great sealing strength.

Packages are also known, e.g. folding tobacco pouches or flat bags, in which seam strength is reduced not by folding over, as in the example described above, but by strip-lacquering one surface. In this the disadvantage has been encountered that solvents evaporate into the bag contents and, upon bag opening by the ultimate consu~er, solvent residues in the form of solid crumbs drop into the bag contents.

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An additional disadvantage of known packages having breakable or peelable closure seams is damage caused to the package during the sealing process when the bag contents are first sealed into the bag. When heat for sealing the wall parts together is trans-mitted by heated jaws, an unattractive seam, visible to the finalcustomer, is formed on the rear side of the seal, i.e., on the outside of the finished tobacco bag. This can even destroy the decorative bag design in the case of less than careful production and in any event an unattractive appearance results.

Thisinvention provides a bag of the initially mentioned type by providing a peelable closing seam created in place without the bag lateral permanent edge seals being even partially damaged, and wherein damage to the bag outer surfaces is also avoided.

The present invention provides a flexible container in the form of a pouch for use in packaging aromatic contents having a hand peelably openable seal, said container comprising a laminate comprising at least two distinct layers, at least one layer con~
sisting of polymer material capable of being sealed together with itself by applying high frequency electrical energy so as to form said peelably openable seal, said laminate being folded so that the fold line forms the bottom of said container and said polymer layer capable of forming a peelable seal forms at least a part of the inner portion of said container, the side edges forming said container being formed of heat seals of substantially higher strength than said peelable seal, and said peelable closing seal is formed in the area of the upper edge of said container between said high strength seals whereby said container is hermetically sealed.

By the invention, a package is produced which has high seam strength at the crossing points of the peelable closing seam at the top outer edge of ihe bag and the two side edge sealing seams. The consumer can open such a package without particular care along the peelable, openable closing seam by pulling the front wall portion away from the rear wall portion so that the closing seam is opened up from the center toward both sides.

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This opening process is brought to a stop at the crossing points with the side sealing seams as a result of the great strength of the side sealing seams. In this manner, a pleasant and very advantageously usable package is created, especially for use as a tobacco bag. The new arrangement of the closing seam also provides increased stability of the paekaged eontents sinee, before opening, the aroma and the moisture are retained within the paekage to a great extent beeause of the hermetie sealing provided by the high strength lateral side seals and the peelable elosure seal. An adhesive, sueh as a lacquer coating or the like as provided in conventional bags is not used. In accordance with the invention, the bag is elosed without aid of foreign materials, whieh eould mix with the paekaged material and affeet its taste and with other qualities. Material strips with plastic films are also usable with improved properties and, advantageously, while improving the stability of the tobacco, the tightness of closure of a tobacco bag can be improved, and the fold-over flap provided in the customary tobaceo bags ean even be eliminated without impairing the barrier properties.

It is also advantageous in accordance with this invention if the closing seam extends from one longitudinal side 115~4 edge of ~he bag to the other. In this way, production can be improved and production speed increased since the bags are produced by feeding the bag material in the longitu-dinal direction. The equipment used can also be made simpler, since the exact length of the closing seam is not very important.

Brief Description of The Drawin~s Figure 1 is a vertically sectioned schematic isometric view of the preferred embodiment of the bag of the inven-tion, with the section taken to show only the right-hand half of the bag;

Figure 2 is a broken section view taken as indicated by circle A in Figure l;

Figure 3 is a broken section view taken as indicated by circle B in Figure l;

Figure 4 is a broken front view of another embodi-ment of the bag of the invention.

1079-80 1~56~4 Description of the Preferred Embodiments The bag as shown in Figure 1 includes a laminated triple layered material strip 30, the outer plastic film 1 of ~hich is preferably composed of polypropylene with good optical transmission properties. The middle layer 2 is a paper insert. (The majority of final consumers, especially smokers, prefer a bag, especially a tobacco pouch, produced in the traditional manner with a decorative paper insert enclosed by transparent films.) The third layer 3 of the material strip is the interior plastic film which depending on its selected components absorbs high-frequency radiation in the desired manner. As a result, it is possible to produce seam 4 as an openable, peel-able sealing seam. The seam 4, along with the layer structure 1, 2 and 3 of the material strip 30, of which the bag is formed, is clearly shown in Figure 1 or on an en-larged scale in Figure 2. The structure of layers 1, 2 and 3 is visible in Figure 3. The reopenable sealing seam 4 preferably is perpendicular to the longitudinal direc-tion of the material strip 30 and is indicated by line x-x-x in Figures 1 to 4.

In the embodiments of Figures 1 and 4, the bag generally designated 5 is formed by two opposing wall por-tions 6 and 7. If one views the partially opened bag according to Figures 1 and 4, 6 designates the front wall portion and 7 designates the rear wall portion. The rear wall portion is elongated upwardly in excess of the length of the front wall portion, to form a flap por~ion 8. In the embodiment of Figure 1, this flap portion is visibly longer than in the embodiment of Figure 4. By means of an adhe-sive strip 9 shown only in Figure 4, flap portion 8 is made 1 1S6~L9~

to adhere at the bottom or on the rear side of the ex-terior of the bag after filling the package and folding over. In the embodiment shown in Figure 1, the flap portion 8 is of longitudinal length exceeding that of front portion 6, so that when flap 8 is wrapped around the bag, downwardly over front portion 6, generous overlap of front portion 6 by flap 8 is provided; this furnishes redundancy to the seal provided by peelable seal 4.

The bottom edge of the bag portion 5 is defined by the bottom fold 10. The two side edges 11 and 12 extend transversely from the bottom fold 10 to the preferably sealed upper edge 13, which defines the opening of package 5.

While the peelable closing seam 4 preferably extend-ing parallel to traverse bottom fold 10 is shown in both the embodiments of Figures 1 to 3 and in Figure 4, the lateral sealing seam 14 is only shown on the right hand side in the embodiment of Figure 4, as a double broken line. There i8 also shown crossing point 15, at which reopenable peelable closing seam 4 crosses the lateral sealing seam 14. Therefore, Figure 4 shows in particular how the lateral sealing seams, with uniform and high seam strength, extend from the bottom fold 10 to the upper edge 13, so that the peelable sealing seam 4 has low seam strength only between crossing points 15, while at the crossing points 15 the seam strength i8 equal to that of the lateral sealing seams 14.

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For sales reasons, it is sometimes advantageous if metallized material strips are used to provide decoration and reinforcement of the bag exterior. A further develop-ment of the invention in this regard is then characterized by the fact that the closing seam is located on the non-metallized interior between two superimposed, external selectively metallized wall parts. In this manner, very attractive packages can be produced with the metallized film, and nevertheless the closing seam can be arranged by simple means for closing the bag opening in the manner that it can be opened, so that it can be peeled open only between the crossing points with the lateral sealing seams at the outer corners, so that the side edges, even in the case of bag material having selectively metallized surfaces, have a great seam strength all the way up to the top.

The term "metallization" as used herein denotes a partial, ribbon-like coating of selected areas of the laminate external surface film l with metal. In the high-frequency welding area, i.e. the area exterior of reopenable peelable seal 4, on the outside of the package and, naturally, also on the inside of the package, no metallization is present, in order, for example, to prevent an electrical short circuit. Since this area on the flattened-out bag laminate blank appears in ribbon-like from, the strip metallization likewise takes place, so to speak, "in ribbons" on the corresponding area. The ribbons of metal strengthen the package.

The invention furthermore pertains to a process for producing the bag described in the proceding, in which a laminated material strip including the plastic film 1 15~ 94 g is pulled longitudinally from rollers, folded around a bottom fold transverse to the feed direction to form the bag portion, and then welded parallel to the feed direction at the side edges of the bag and the formed bag is severed from the strip, after which the contents are packed in and the bag is thermally closed along the reopenable peelable closing seam connecting the side edges. The package with the characteristics presented in detail in the pre-c~ding is attained when, in accordance with the invention, the closing seam is produced while lightly pressing together the two parts of the material strip which are to be welded together and simultaneously applying high frequency energy to achieve welding.
Actually, high frequency welding with a frequency of 27 MHz is preferred in accordance with the invention. Naturally, however, the high frequency welding can also be performed under other conditions. In particular, by means of high frequency welding the unattractive distortion of the decorative pattern provided by the metallization ribbon due to pressing through the welding jaws along the closing seam can be avoided. By means of a suitably constructed material strip, especially the plastic film or films incorporated in it, it is possible to ensure that the material strip at its surfaces which are to be welded together more or less absorbs the energy of the high frequency radiation, so that a truly peelable welding closing seam can be attained without destroying the surfaces of the material strips.

In this process, it may be advantageous if, in accordance with the invention, the high frequency welding 115~9~t jaws are preheated to 40C. With this preparatory measure the high frequency welding can be used especially rapidly and with definitive effect.

An important feature of this invention is provided by the peelable sealing seam construction and the high strength side seam construction whereby two laminate surfaces are sealed to form the bag, where the laminate consists of three distinct and different layers, with the seal formed between facing surfaces of a common layer ?` ln of material, namely inner film 3. Thus, there is no - need to effect a seal between dissimilar materials. The rugged outer plastic film remains intact to form the exterior of the package, providing protection against package rupture.

Bag 5 has mutually facing front and rear portions ~ and 7 formed from a common piece of laminate material with the portions joining at a fold 10 defining the bag bottom. The lateral sealing seams 14, which are of high strength and noted in Figure 4, extend the longitudinal length of and join together corresponding longitudinal margins 12 of the bag. The peelable heat seal 4 is hand-openable and accordingly is of substantially lower strength than the side seam seals 14. The peelable seal joins the front and rear portions ~ and 7 of the bag together, extends transversely to side seals 14 and is longitudinally removed from fold 10 defining the 1 1 56 ~1 94 bag bottom. The transverse extremities of the hand peelable seal 4 overlap the respective side seam seals 14 as shown at 15 in Figure 4 to thereby provide seam crossing zones of great strength so that hand peelable seal 4 can be opened only between the seam crossing zones. The rear portion of the bag extends longitudinally from peelable seal 4, oppositely from fold 10 beyond front portion 6, a distance at least equal to longitudinal length of front portion 6. This facilitates folding of the thereby created extension portion 8 of rear portion 7 over front portion 6 and over the hand peelable seal 4 to thereby provide greater isolation of the bag contents when the bag is reclosed after opening seam 4.

An important feature of this invention is the con-struction whereby the bag is folded from a single piece of laminated material in such manner that all seals are made between facing surfaces of a common material, in this instance interior plastic film 3. This contruction allows all exterior surfaces of the bag to be made of a common material, namely outer plastic film 1.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A flexible container in the form of a pouch for use in packaging aromatic contents having a hand peelably openable seal, said container comprising a laminate comprising at least two dis-tinct layers, at least one layer consisting of polymer material capable of being sealed together with itself by applying high frequency electrical energy so as to form said peelably openable seal, said laminate being folded so that the fold line forms the bottom of said container and said polymer layer capable of forming a peelable seal forms at least a part of the inner portion of said container, the side edges forming said container being formed of heat seals of substantially higher strength than said peelable seal, and said peelable closing seal is formed in the area of the upper edge of said container between said high strength seals whereby said container is hermetically sealed.

2. The container of Claim 1 wherein said polymer layer capable of forming a peelable seal forms the entire inner portion of said container.

3. The container of Claim 1 wherein said polymer layer capable of forming a peelable seal forms only the upper edge portion of said container.

4. The container of Claim 1 wherein the outer portion of said container is metallized and said peelable seal is arranged on a non-metallized inner portion between two superimposed, externally metallized wall parts.

5. The container of Claim 1 wherein said laminate is a three layer lamination consisting of an outer layer of polypropylene, a central layer of paper and an inner layer of flexible thermo-plastic with said facing surfaces of said first and second portion being said flexible thermoplastic.

6. The container of Claim 1 wherein said outer layer of said laminate forming the outer portion of said container is poly-propylene.

7. The container of Claim 6 wherein said polypropylene surface of said container is metallized in the area above said side heat seals.

8. The container of Claim 1 wherein said rear portion extends longitudinally from said peelable seal oppositely from said fold, and beyond said front portion a distance at least equal to longitudinal length of said front portion so as to facilitate folding of said extension of said rear portion over said front portion, over said peelable seal and over said fold.

9. A flexible container in the form of a pouch for use in pack-aging aromatic contents having a hand peelably openable seal, said container comprising a laminate consisting of three distinct layers, one outer layer of said laminate consisting of flexible thermoplastic material capable of being sealed together with itself by applying high frequncy electrical energy so as to form said peelably openable seal, the other outer layer being poly-propylene and the inner layer being paper, said laminate being folded so that the fold line forms the bottom of said container and said thermoplastic layer capable of forming said peelable seal forms the inner portion of said container, the side edges forming said container being formed of heat seals of substan-tially higher strength than said peelable seal, and said peelable closing seal is formed in the area of the upper edge of said container between said high strength seals, whereby said container is hermetically sealed.