CA1109420A - Packaging container provided leak-proof tear-open perforations - Google Patents
Packaging container provided leak-proof tear-open perforationsInfo
- Publication number
- CA1109420A CA1109420A CA304,216A CA304216A CA1109420A CA 1109420 A CA1109420 A CA 1109420A CA 304216 A CA304216 A CA 304216A CA 1109420 A CA1109420 A CA 1109420A
- Authority
- CA
- Canada
- Prior art keywords
- perforation
- tearing
- packing container
- tearing strength
- tear
- 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
Links
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
- B65D5/065—Rectangular containers having a body with gusset-flaps folded outwardly or adhered to the side or the top of the container with supplemental means facilitating the opening, e.g. tear lines, tear tabs
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Cartons (AREA)
- Packages (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention provides a packaging container, provided with a tear-open perforation, of the kind which is produced from a laminate comprising a relatively stiff and unmalleable basic layer, at least one side of which being turned towards the inside of the package has a leakproof unbroken plastic coating, said tear perforation being so arranged that it substantially penetrates the basic layer but without penetrating the plastic layer turned towards the inside of the package, characterized in that said tear perforation along the region on the packaging container where, during the shaping of the package, the packaging material is exposed to folding or some other processing which intensely stresses the packaging material is sparsely perforated or not at all or it is made in such a way that the packaging material is not weakened to such an extent that the tear perforations breaks up but that the tear perforation along non-bent surfaces of the packaging container, or along surfaces stressed in some other way, have a more readily tearable perforation.
The invention provides a packaging container, provided with a tear-open perforation, of the kind which is produced from a laminate comprising a relatively stiff and unmalleable basic layer, at least one side of which being turned towards the inside of the package has a leakproof unbroken plastic coating, said tear perforation being so arranged that it substantially penetrates the basic layer but without penetrating the plastic layer turned towards the inside of the package, characterized in that said tear perforation along the region on the packaging container where, during the shaping of the package, the packaging material is exposed to folding or some other processing which intensely stresses the packaging material is sparsely perforated or not at all or it is made in such a way that the packaging material is not weakened to such an extent that the tear perforations breaks up but that the tear perforation along non-bent surfaces of the packaging container, or along surfaces stressed in some other way, have a more readily tearable perforation.
Description
The present invention relates to a packaging container provided with a leakproof tear-open perforation. Said packaging container is of the kind produced from a laminate comprising a relatively stiff and unmalleable basic layer, at least one side of said basic layer being turned towards the inside of the package has a leakproof unbroken plastic coating, said tear perforation being so arranged that it completely pierces or substantially penetrates the basic layer but without penetrating the plastic layer turned towards the inside of the package.
Modern packages for liquids for single use are often produced from a packaging laminate having a relatively stiff and unmalleable basic layer, for example, paper, and a leakproof homogeneous plastic layer arranged on either side around the basic layer. A frequently used method for producing packaging containers from this kind of packaging laminate lies in that the packaging material is formed by folding and sealing logether the sides turned towards each other by heat-sealing so that a closed packaging container with an unbroken inner leakproof plastic layer is obtained. Various shapes can be imparted to the packaging containers mentioned hereinbefore and tetrahedral as well as parallelepipedic packaging containers are thus found on the market. However, they have one thing in common, namely, the aim to provide them with an opening mechanism which can be easily broken and makes the goods in the packaging container readily accessible. This problem has been solved in a number of different ways. It is also known, that an opening which is covered with a cover strip is provided in the package wall and that said cover strip can be torn off, thus exposing said opening, or the packaging container can be provided with a tear perforation with the aid of which a portion of the packaging container can be torn open in order to expose an opening through which the content can be poured out.
The opening mechanisms with said cover strips which can be torn off function satisfactorily but unfortunately they have the drawback that they are relatively expensive to use in association with single-use packages for daily goods such as milk. The reason for this is that the manufacture of these opening mechanisms requires of course additional material and additional stages of operation. However, openlng mechanisms based on the principle of a tear perforation arranged in the wall of the packaging material have the drawback that the tear per-foration which must be installed in the packaging material priorto the latter's shaping cannot be rendered easily tearable through-out since the packaging material is exposed to great tensile stresses and compressive stresses in connection with the shaping and folding of the packaging container. This requires a com-promise, which means that the tear-open perforations are made in such a way that they withstand the stresses to which the packaging material is exposed while the package is formed but, on the other hand, they must be so readily tearable that they can be torn open without difficulty when the package is to be opened and the goods are to be made accessible.
This compromise of course implies that the tear-open perforations of the kind described hereinbefore cannot be rendered as easily tearable as desired and that, therefore, these tear-open perforations have a relatively unsatisfactory function.
A way of solving the above problem and avoiding the drawbacks of the known tear-open notches has been found according to the present invention, which is characterized in that along the region of the packaging container where the packaging material is exposed to folding or other processing which intensely stresses the packaging material said tear perforation is sparsely per-forated or not at all or it is made in such a way that the packaging material is not weakened to such an extent that the Z~
tear perforations break up but that that the tear perforation along non-bent surfaces of the packaging container or along surfaces stressed in some other way have a more readily tearable perforation.
An embodiment of the invention is described hereafter with reference to the attached drawings.
Figure 1 shows a parallelepipedic packaging container provided with a tear mechanism according to the invention;
Figure 2 shows the same packaging container after the tear perforation has been torn open.
Figure 3 shows a portion of a flat material for the packaging containers shown in Figure 1 and 2.
Figure 4 shows a diagram representing the relationship ~ between tensile strength and punched perforation length (in j percent) for different lengths of notching or punching.
The packaging container shown in Figure 1 has a parallel-epipedic shape and consists of side walls 1, an upper end wall 2 and a bottom portion (not shown). As mentioned in the intro-duction the package is produced from a relatively rigid, unmalle-able but foldable, web-like material. A rational method of - producing the packaging containers lies in that the web-like packaging material is so shaped that a tube is obtained and by pressing said tube flat and sealing it across the tube is closed in transverse narrow zones. If the tube is filled with the intended goods in advance, then the goods will be enclosed in the sealed packaging containers, which will obtain the intended parallelepipedic shape by folding. By repeatedly pressing the tube ; flat and sealing it across along zones disposed at intervals a sealing fin 3 is formed. In the subsequent shaping process said sealing fin is folded down towards the upper end wall 2 of the packaging container. During the shaping operation which is required for obtaining the parallelepipedic shape shown additional ZO
four triangular double-walled lugs 4 are formed, they are located in corner sections of the packaging container. Three of the four corner lugs 4 are folded in towards the bottom portion and the gable wall (not shown in the Figure, only a lug 4 is visible in Figure 1). This corner lug 4 is folded over about the straight edge 6 of the side wall and fixed by means of an easily breakable bond to one edge 6 belonging to the side wall 1. The sealing fin 3 extends over both the lug 4 and the end wall 2 as well as over the lug (not shown) folded down at the opposed side of this end wall. The packaging container shown as a practical example is also provided with curves 5, which extend from the ends of the side edges over the end wall 2 to a point of intersection at the base line 7 on the sealing fin 3.
In order to facilitate the opening of the package, it is provided with a tear perforation consisting of linear or curved perforation lines 8 only partially passing through the packaging material. Said perforations lines 8 originate from a common point _ located on the inside of the lug 4 at a distance from the base line 7 of the fin 3. They then pass through symmetric point _ on the free side edges of the lug and end at a point _ at the base line 7 somewhat within the lug 4.
The tear perforation described hereinbefore is attained simply because prior to the shaping of the package the packaging material is provided with a perforation to such an extent that the desired tear perforation 8 on the packaging container shown in Figure 1 is obtained. Figure 3 shows diagrammatically a piece of a packaging material web having an inverted perforation pattern, which, in the case described here, is formed by a slightly U-shaped perforation line 8 so located on the web of the packag-ing material that when the package is shaped said line 8 isfound at the intended place on the packaging container.
Figure 2 shows the packaging container according to 21~
Figure 1 in the open state, a discharge opening 9 being formed in that the portion of the sealing fin 3 which extends over the lug 4 is torn away along with an additional smaller portion of the fin, partly a portion of the material in the fin itself, i.e., the material between the tear perforation 8 and the fin 3.
As is evident from Figure 1 the tear perforation 8 has a plurality of cut-off points b, d at which the tear perforation is exposed to substantial stresses in connection with the shaping of the package. It can be seen easily that a leakage will be caused if the tear perforation along with its region is so easily tearable that it breaks on being exposed to said stresses.
In order to avoid this drawback without simultaneously rendering the tear perforation difficulty tearable, the tear perforation according to Figure 3 is designed with differentiated tear strength. The tear perforation shown in Figure 3 consists of two angle-positioned straight lines but if another tear , perforation is desired for the packaging container, then the shape of the tear perforation produced on the packaging material can of course be varied and adapted to the tear perforation on the finished packaging container. It is thus possible to design the tear perforation as a straight or curved line or also as a plurality of continuous straight or curved tear-perforation lines.
In the present case the tear perforations 8 is so designed that certain portions b and d which correspond to the parts of the tear perforation shown in Figure 1 and are located on parts of the packaging material which is exposed to folding. The per-foration line 8 shown in Figure 3 consists of a series of notches or punchings in the packaging material web 10, said notches or punchings 11 being separated from each other by a non-broken portion 12. The unbroken portions 12 can be advantageously made of the same size along the entire perforation line, whereas the length of the notches 13 along the regions b and d are made 94~0 substantially shorter than the notches 11 along the other portions of the tear perforation. Th s means that the tear perforation will be less readily tearable and that the strength within the regions b and d increases while the remaining region of the tear ~ perforation will be readily breakabie.
- Since in the finished packaging container the tearing of the tear perforation starts either at point c or at point a, i.e., points having readily breakable tear perforation it is merely a matter of initiating the tearing and when this has properly started the portions b and d in readily tearable tear perforations offer only a slight resistance, which is barely noticeable in most cases.
Said differentiated tear strength of the tear perfor-ation 8 is also illustrated in Figure 1, where the tear perfor-ation along the portions b and d have notches or punchings 11 of substantially smaller length than that of the notches or ` ~ punchings 12 along the other portions of the tear perforation 8.
,, ~ The packaging container 1 shown in Figure 1 and provided -- with tear perforation has double-walled triangul~ar lugs 4 as mentioned hereinbefore. Said tear perforation is arranged along one of these lugs 4. The tear perforation 8 in Figure 1 actually is concealed to a great extent since on passing the edge of the triangular lug 4 at b the perforation extends along the underside of the lug 4 to the region b', where the perforation 8' is visible again along the surface of the lug 4 along the portions not covered by the folded down sealing fin 3. However, large portions of the perforation 8' along the side of the lug 4 of the packaging container and the surface 2 against which the sealing fin 3 is folded down will be covered by the fin 3. In order to indicate the fact that certain portions of the tear perforation are concealed by the material layer overhead or by the superposed sealing fin 3, the concealed portions of the tear perforation 1~3420 have been marked with primes, i.e., 8', b', d'. At the same time said concealed portions of the tear perforation have been marked with thinner lines as compared with the visible portions.
As mentioned hereinbefore, it has been found that it is favourable to keep an unchanged interval 12 between the notches or punchings 11 or 13, since in that case an even tear resistance is obtained when the packaging container is opened.
At the same time a substantially strengthening of the tear per-foration can be obtained by shortening the notches or punchings 13 substantially. However it is of course also possible and absolutely in accordance with the idea of the invention that instead of varying the length of the notches and punchings 11 and 13 the interval between them is varied or the length of the notches or punchings 11 or 13 and the interval 12 are varied.
As indicated hereinbefore it is even possible to attain the differentiated tear strength by changing the depth of penetration i~ of the basic layer of the packaging material but this kind of tear perforation has been found to be more difficult to produce with sufficient accuracy in order to attain the intended aim and moreover it has been shown that no improvement of the tear function can be obtained.
Tear tests carried out with packaging material consist-ing of a basic layer of paper with thin surface coatings of polyethylene, wherein the perforations have completely broken through the basic layer, have surprisingly shown a tendency that the strength of the tear perforation is greater for small inter-vals between the perforations than with slightly greater inter-vals on the assumption that the ratio between the length of the punchings and the length of the intervals is the same. This rule possibly does not apply generally, but the diagram in Figure 4, which shows diagrammatically the relationship between the tear strength and the percentage of punch length per unit of length indicates that the rule is applicable for lengths of cut of approximately 0.5 to 1 mm. The diagram according to Figure 4 shows no tear strength in absolute values since this is relatively uninteresting in this connection and, for example, it varies with the paper quality, paper thickness and quality of plastic coating, etc., but the diagram shows the mutual relation-ship between tear strengths of different perforations, i.e., perforations made with perforating knives having different ' "toothings." Figure 4 also shows diagrammatically a section of a perforating knive, where the width of the knife blade is marked with A and the interval between the knife blades with B. As ' mentioned hereinbefore the horizontal axis of the diagram is divided into percent and illustrates the percentage of perforation which has been broken through, i.e., the graduation corresponds to a term for lOOA , referred to hereafter as breakthrough ratio.
A+B
For reasons explained hereinbefore the vertical axis is not graduated but is intended only to illustrate the tear strength with the increasing tear strength shown above and the tear strength 20 O in the origin. The diagram contains a dashed-line region which is intended to illustrate the easily torn region within which the unknown portions of the tear perforation can be assigned.
However, the portions of the tear perforation are not within this region of the'diagram since they then break spontaneously during the deformation. The diagram according to Figure 4 shows three curves representing B = 0.5 mm, B = 0.7 mm and B = 1.0 mm, wherein B is the interval between knife portions. For a break-through ratio of 50% (i.e., A = B) it can be seen that the tear strength is slightly higher for a perforation with B = 0.5 mm than for perforations with B = 0.7 mm and B = 1.0 mm. However, the curves for different values of B tend to converge as the break-through ratio increases. However, it does not seem that the value of the factor B has a somewhat greater influence when the break-through ratio has reached a value of 70 to 75~.
As a result of the tests performed a test was carried out to optimize the tear perforation and the result of this test , shows that;
a) for the easily torn region of the tear perforation, i.e., the region where it is shaped by folding the following values apply: B = 0.5 to 1.0 mm and A = 1.0 to 3.0 mm b) for the region within which the tear perforation will be shaped by folding the following values apply:
B = 0.3 to 0.7 mm and A = 0.3 to 1.0 mm.
j~ ~
As mentioned hereinbefore the perforation had to be dimensioned with regard to kind and quality of the basic layer and the strength of the external plastic layer, but the above values should be representative and a guide for the optimization of the perforation.
~- By producing tear-open perforations for packaging t. containers according to the invention it is possible to produce, r in a simple manner, functional and readily opening tear-open perforations without the risk of spontaneously breaking the tear perforations and without resulting in leakage when the package is -~
t. shaped. The embodiments described hereinbefore are intended only as examples. As mentioned hereinbefore it is possible to apply ~ the invention to any packaging container wherein the tear ,~ perforation will pass an edge or another break while the package is shaped when it is exposed to increased stresses. Thus, the application of the invention is not limited to the package construction or shape shown here but it can be generally applied to any form of packaging container which has the technical problem mentioned at the outset.
Modern packages for liquids for single use are often produced from a packaging laminate having a relatively stiff and unmalleable basic layer, for example, paper, and a leakproof homogeneous plastic layer arranged on either side around the basic layer. A frequently used method for producing packaging containers from this kind of packaging laminate lies in that the packaging material is formed by folding and sealing logether the sides turned towards each other by heat-sealing so that a closed packaging container with an unbroken inner leakproof plastic layer is obtained. Various shapes can be imparted to the packaging containers mentioned hereinbefore and tetrahedral as well as parallelepipedic packaging containers are thus found on the market. However, they have one thing in common, namely, the aim to provide them with an opening mechanism which can be easily broken and makes the goods in the packaging container readily accessible. This problem has been solved in a number of different ways. It is also known, that an opening which is covered with a cover strip is provided in the package wall and that said cover strip can be torn off, thus exposing said opening, or the packaging container can be provided with a tear perforation with the aid of which a portion of the packaging container can be torn open in order to expose an opening through which the content can be poured out.
The opening mechanisms with said cover strips which can be torn off function satisfactorily but unfortunately they have the drawback that they are relatively expensive to use in association with single-use packages for daily goods such as milk. The reason for this is that the manufacture of these opening mechanisms requires of course additional material and additional stages of operation. However, openlng mechanisms based on the principle of a tear perforation arranged in the wall of the packaging material have the drawback that the tear per-foration which must be installed in the packaging material priorto the latter's shaping cannot be rendered easily tearable through-out since the packaging material is exposed to great tensile stresses and compressive stresses in connection with the shaping and folding of the packaging container. This requires a com-promise, which means that the tear-open perforations are made in such a way that they withstand the stresses to which the packaging material is exposed while the package is formed but, on the other hand, they must be so readily tearable that they can be torn open without difficulty when the package is to be opened and the goods are to be made accessible.
This compromise of course implies that the tear-open perforations of the kind described hereinbefore cannot be rendered as easily tearable as desired and that, therefore, these tear-open perforations have a relatively unsatisfactory function.
A way of solving the above problem and avoiding the drawbacks of the known tear-open notches has been found according to the present invention, which is characterized in that along the region of the packaging container where the packaging material is exposed to folding or other processing which intensely stresses the packaging material said tear perforation is sparsely per-forated or not at all or it is made in such a way that the packaging material is not weakened to such an extent that the Z~
tear perforations break up but that that the tear perforation along non-bent surfaces of the packaging container or along surfaces stressed in some other way have a more readily tearable perforation.
An embodiment of the invention is described hereafter with reference to the attached drawings.
Figure 1 shows a parallelepipedic packaging container provided with a tear mechanism according to the invention;
Figure 2 shows the same packaging container after the tear perforation has been torn open.
Figure 3 shows a portion of a flat material for the packaging containers shown in Figure 1 and 2.
Figure 4 shows a diagram representing the relationship ~ between tensile strength and punched perforation length (in j percent) for different lengths of notching or punching.
The packaging container shown in Figure 1 has a parallel-epipedic shape and consists of side walls 1, an upper end wall 2 and a bottom portion (not shown). As mentioned in the intro-duction the package is produced from a relatively rigid, unmalle-able but foldable, web-like material. A rational method of - producing the packaging containers lies in that the web-like packaging material is so shaped that a tube is obtained and by pressing said tube flat and sealing it across the tube is closed in transverse narrow zones. If the tube is filled with the intended goods in advance, then the goods will be enclosed in the sealed packaging containers, which will obtain the intended parallelepipedic shape by folding. By repeatedly pressing the tube ; flat and sealing it across along zones disposed at intervals a sealing fin 3 is formed. In the subsequent shaping process said sealing fin is folded down towards the upper end wall 2 of the packaging container. During the shaping operation which is required for obtaining the parallelepipedic shape shown additional ZO
four triangular double-walled lugs 4 are formed, they are located in corner sections of the packaging container. Three of the four corner lugs 4 are folded in towards the bottom portion and the gable wall (not shown in the Figure, only a lug 4 is visible in Figure 1). This corner lug 4 is folded over about the straight edge 6 of the side wall and fixed by means of an easily breakable bond to one edge 6 belonging to the side wall 1. The sealing fin 3 extends over both the lug 4 and the end wall 2 as well as over the lug (not shown) folded down at the opposed side of this end wall. The packaging container shown as a practical example is also provided with curves 5, which extend from the ends of the side edges over the end wall 2 to a point of intersection at the base line 7 on the sealing fin 3.
In order to facilitate the opening of the package, it is provided with a tear perforation consisting of linear or curved perforation lines 8 only partially passing through the packaging material. Said perforations lines 8 originate from a common point _ located on the inside of the lug 4 at a distance from the base line 7 of the fin 3. They then pass through symmetric point _ on the free side edges of the lug and end at a point _ at the base line 7 somewhat within the lug 4.
The tear perforation described hereinbefore is attained simply because prior to the shaping of the package the packaging material is provided with a perforation to such an extent that the desired tear perforation 8 on the packaging container shown in Figure 1 is obtained. Figure 3 shows diagrammatically a piece of a packaging material web having an inverted perforation pattern, which, in the case described here, is formed by a slightly U-shaped perforation line 8 so located on the web of the packag-ing material that when the package is shaped said line 8 isfound at the intended place on the packaging container.
Figure 2 shows the packaging container according to 21~
Figure 1 in the open state, a discharge opening 9 being formed in that the portion of the sealing fin 3 which extends over the lug 4 is torn away along with an additional smaller portion of the fin, partly a portion of the material in the fin itself, i.e., the material between the tear perforation 8 and the fin 3.
As is evident from Figure 1 the tear perforation 8 has a plurality of cut-off points b, d at which the tear perforation is exposed to substantial stresses in connection with the shaping of the package. It can be seen easily that a leakage will be caused if the tear perforation along with its region is so easily tearable that it breaks on being exposed to said stresses.
In order to avoid this drawback without simultaneously rendering the tear perforation difficulty tearable, the tear perforation according to Figure 3 is designed with differentiated tear strength. The tear perforation shown in Figure 3 consists of two angle-positioned straight lines but if another tear , perforation is desired for the packaging container, then the shape of the tear perforation produced on the packaging material can of course be varied and adapted to the tear perforation on the finished packaging container. It is thus possible to design the tear perforation as a straight or curved line or also as a plurality of continuous straight or curved tear-perforation lines.
In the present case the tear perforations 8 is so designed that certain portions b and d which correspond to the parts of the tear perforation shown in Figure 1 and are located on parts of the packaging material which is exposed to folding. The per-foration line 8 shown in Figure 3 consists of a series of notches or punchings in the packaging material web 10, said notches or punchings 11 being separated from each other by a non-broken portion 12. The unbroken portions 12 can be advantageously made of the same size along the entire perforation line, whereas the length of the notches 13 along the regions b and d are made 94~0 substantially shorter than the notches 11 along the other portions of the tear perforation. Th s means that the tear perforation will be less readily tearable and that the strength within the regions b and d increases while the remaining region of the tear ~ perforation will be readily breakabie.
- Since in the finished packaging container the tearing of the tear perforation starts either at point c or at point a, i.e., points having readily breakable tear perforation it is merely a matter of initiating the tearing and when this has properly started the portions b and d in readily tearable tear perforations offer only a slight resistance, which is barely noticeable in most cases.
Said differentiated tear strength of the tear perfor-ation 8 is also illustrated in Figure 1, where the tear perfor-ation along the portions b and d have notches or punchings 11 of substantially smaller length than that of the notches or ` ~ punchings 12 along the other portions of the tear perforation 8.
,, ~ The packaging container 1 shown in Figure 1 and provided -- with tear perforation has double-walled triangul~ar lugs 4 as mentioned hereinbefore. Said tear perforation is arranged along one of these lugs 4. The tear perforation 8 in Figure 1 actually is concealed to a great extent since on passing the edge of the triangular lug 4 at b the perforation extends along the underside of the lug 4 to the region b', where the perforation 8' is visible again along the surface of the lug 4 along the portions not covered by the folded down sealing fin 3. However, large portions of the perforation 8' along the side of the lug 4 of the packaging container and the surface 2 against which the sealing fin 3 is folded down will be covered by the fin 3. In order to indicate the fact that certain portions of the tear perforation are concealed by the material layer overhead or by the superposed sealing fin 3, the concealed portions of the tear perforation 1~3420 have been marked with primes, i.e., 8', b', d'. At the same time said concealed portions of the tear perforation have been marked with thinner lines as compared with the visible portions.
As mentioned hereinbefore, it has been found that it is favourable to keep an unchanged interval 12 between the notches or punchings 11 or 13, since in that case an even tear resistance is obtained when the packaging container is opened.
At the same time a substantially strengthening of the tear per-foration can be obtained by shortening the notches or punchings 13 substantially. However it is of course also possible and absolutely in accordance with the idea of the invention that instead of varying the length of the notches and punchings 11 and 13 the interval between them is varied or the length of the notches or punchings 11 or 13 and the interval 12 are varied.
As indicated hereinbefore it is even possible to attain the differentiated tear strength by changing the depth of penetration i~ of the basic layer of the packaging material but this kind of tear perforation has been found to be more difficult to produce with sufficient accuracy in order to attain the intended aim and moreover it has been shown that no improvement of the tear function can be obtained.
Tear tests carried out with packaging material consist-ing of a basic layer of paper with thin surface coatings of polyethylene, wherein the perforations have completely broken through the basic layer, have surprisingly shown a tendency that the strength of the tear perforation is greater for small inter-vals between the perforations than with slightly greater inter-vals on the assumption that the ratio between the length of the punchings and the length of the intervals is the same. This rule possibly does not apply generally, but the diagram in Figure 4, which shows diagrammatically the relationship between the tear strength and the percentage of punch length per unit of length indicates that the rule is applicable for lengths of cut of approximately 0.5 to 1 mm. The diagram according to Figure 4 shows no tear strength in absolute values since this is relatively uninteresting in this connection and, for example, it varies with the paper quality, paper thickness and quality of plastic coating, etc., but the diagram shows the mutual relation-ship between tear strengths of different perforations, i.e., perforations made with perforating knives having different ' "toothings." Figure 4 also shows diagrammatically a section of a perforating knive, where the width of the knife blade is marked with A and the interval between the knife blades with B. As ' mentioned hereinbefore the horizontal axis of the diagram is divided into percent and illustrates the percentage of perforation which has been broken through, i.e., the graduation corresponds to a term for lOOA , referred to hereafter as breakthrough ratio.
A+B
For reasons explained hereinbefore the vertical axis is not graduated but is intended only to illustrate the tear strength with the increasing tear strength shown above and the tear strength 20 O in the origin. The diagram contains a dashed-line region which is intended to illustrate the easily torn region within which the unknown portions of the tear perforation can be assigned.
However, the portions of the tear perforation are not within this region of the'diagram since they then break spontaneously during the deformation. The diagram according to Figure 4 shows three curves representing B = 0.5 mm, B = 0.7 mm and B = 1.0 mm, wherein B is the interval between knife portions. For a break-through ratio of 50% (i.e., A = B) it can be seen that the tear strength is slightly higher for a perforation with B = 0.5 mm than for perforations with B = 0.7 mm and B = 1.0 mm. However, the curves for different values of B tend to converge as the break-through ratio increases. However, it does not seem that the value of the factor B has a somewhat greater influence when the break-through ratio has reached a value of 70 to 75~.
As a result of the tests performed a test was carried out to optimize the tear perforation and the result of this test , shows that;
a) for the easily torn region of the tear perforation, i.e., the region where it is shaped by folding the following values apply: B = 0.5 to 1.0 mm and A = 1.0 to 3.0 mm b) for the region within which the tear perforation will be shaped by folding the following values apply:
B = 0.3 to 0.7 mm and A = 0.3 to 1.0 mm.
j~ ~
As mentioned hereinbefore the perforation had to be dimensioned with regard to kind and quality of the basic layer and the strength of the external plastic layer, but the above values should be representative and a guide for the optimization of the perforation.
~- By producing tear-open perforations for packaging t. containers according to the invention it is possible to produce, r in a simple manner, functional and readily opening tear-open perforations without the risk of spontaneously breaking the tear perforations and without resulting in leakage when the package is -~
t. shaped. The embodiments described hereinbefore are intended only as examples. As mentioned hereinbefore it is possible to apply ~ the invention to any packaging container wherein the tear ,~ perforation will pass an edge or another break while the package is shaped when it is exposed to increased stresses. Thus, the application of the invention is not limited to the package construction or shape shown here but it can be generally applied to any form of packaging container which has the technical problem mentioned at the outset.
Claims (11)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A packing container comprising a laminate including a relatively stiff and inextensible base layer, at least one side of which faces towards the inside of the packing container and has a liquid-tight homogeneous plastic covering also facing towards the inside of the packing container, the laminate having a tearing perforation which substantially penetrates the base layer without penetrating the plastic layer facing towards the inside of the package, wherein a portion of the tearing perforation along an area of the packing container where the laminate is folded and substantially stressed during manufacture has a relatively greater tearing strength and a portion of the tearing per-foration along an area of the packing container where the laminate is not folded and is substantially unstressed during manufacture of the packing container has a relatively lesser tearing strength, whereby the tearing perforation along the area of the laminate which is folded and substan-tially stressed during manufacture of the packing container is not spontaneously torn by said folding and stressing.
2. The packing container according to claim 1, wherein the tearing perforation includes at least one perfor-ation line weakening the tearing strength of the packing material, the at least one line including individual perfor-ations in the packing material spaced apart from one another which substantially penetrate the base layer of the packing material with the combined length of the individual perfora-tions along the at least one tearing perforation line varied to provide the relatively greater and lesser tearing strength along the tearing perforation.
3. The packing container, according to claim 1, wherein a depth of penetration of individual perforations in the base layer is varied to provide the relatively greater and lesser tearing strength.
4. The packing container according to claim 1, wherein the distance between successive individual perfora-tions forming the tearing perforation in the packing container is constant along the whole tearing perforation and the length of the individual perforations is varied to provide the relatively greater and lesser tearing strength.
5. The packing container according to claim 1, including triangular, double-walled lugs formed during manu-facture which are disposed at corner portions of the packing container, one of said corner lugs being provided with the tearing perforation extending over both the lug and an edge portion thereof, the tearing perforation forming an opening indication for the packing container, wherein the tearing perforation has a differentiated tearing strength so that the tearing strength is relatively greater in the portion of the tearing perforation provided over edge lines of the triangular lugs while the remaining portions of the tearing perforation have a relatively lesser tearing strength.
6. A packing container comprising a laminate of a relatively stiff and inextensible base layer and a liquid impervious layer which forms the interior wall of the packing container and a tear-off opening having a perforated line which is subjected to folding and substantial stress during manufacture, and which perforated line is formed by a plural-ity of individual perforations which substantially penetrate the base layer without penetrating the liquid impervious layer, the perforated line including a first region of a first tearing strength and a second region of a second tearing strength, the first tearing strength being relatively greater than the second tearing strength so as to provide a differentiated tearing strength along the perforated line, only said first region of said first and second regions being folded and substantially stressed during manufacture.
7. The packing container according to claim 6 wherein the plurality of individual perforations are uniformly spaced with respect to one another and the combined length of the individual perforations in the first region is dif-ferent from the combined length of the perforations in the second region of the perforated line to provide the dif-ferentiated tearing strength.
8. The packing container according to claim 6 wherein the depth of the individual perforations in the base layer is varied to provide the differentiated tearing strength.
9. The packing container according to claim 6 wherein the length of the individual perforations in the base layer is varied to provide the differentiated tearing strength.
10. The packing container according to claim 7 wherein the lengths of the individual perforations in the first region are different from the lengths of the individual perforations in the second region to provide the differen-tiated tearing strength.
11. The packing container according to claim 6 wherein triangular, double-walled lugs having edge portions are disposed at corner portions of the container, and the perforated line is partially disposed across both the lug and the edge portions of the lug, so that the perforated line is of a relatively greater tearing strength at the edge portions of the lug with respect to the tearing strength at the remaining portions of the lug.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE77.06163-8 | 1977-05-26 | ||
| SE7706163A SE404005B (en) | 1977-05-26 | 1977-05-26 | PACKAGING WITH LIQUID RIP OPENING PERFORATION |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1109420A true CA1109420A (en) | 1981-09-22 |
Family
ID=20331435
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA304,216A Expired CA1109420A (en) | 1977-05-26 | 1978-05-26 | Packaging container provided leak-proof tear-open perforations |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5434981A (en) |
| AU (1) | AU524021B2 (en) |
| CA (1) | CA1109420A (en) |
| CH (1) | CH630309A5 (en) |
| DE (1) | DE2823015C2 (en) |
| FR (1) | FR2391919A1 (en) |
| GB (1) | GB1589127A (en) |
| IT (1) | IT1094850B (en) |
| NL (1) | NL188083C (en) |
| SE (1) | SE404005B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE451317B (en) * | 1982-03-18 | 1987-09-28 | Tetra Pak Ab | pACKING |
| SE451320B (en) * | 1983-02-07 | 1987-09-28 | Tetra Pak Ab | PACKAGING DEVICE |
| GB2190658B (en) * | 1986-03-24 | 1989-12-13 | Hans Rausing | Packing containers and blanks therefor |
| JP5086168B2 (en) * | 2008-05-08 | 2012-11-28 | レンゴー株式会社 | Packaging display box |
| JP6630421B1 (en) * | 2018-10-10 | 2020-01-15 | 株式会社マリア・デュオ | Kimono |
| EP3722218A1 (en) * | 2019-04-09 | 2020-10-14 | FRoSTA Aktiengesellschaft | Cardboard package with a perforation, in particular for a resealable deep-freeze packaging |
| CN111099106A (en) * | 2020-01-06 | 2020-05-05 | 纷美(北京)贸易有限公司 | Packaging sheet set |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE7126829U (en) * | 1900-01-01 | Delkeskamp Kg | Cardboard blank for a collapsible container | |
| DE671344C (en) * | 1937-10-21 | 1939-02-06 | Jagenberg Werke Ag | Cut of cardboard or the like for boxes or the like, as well as a method and device for its production |
| US2270617A (en) * | 1938-03-15 | 1942-01-20 | American Paper Bottle Co | Container |
| US2360439A (en) * | 1941-03-10 | 1944-10-17 | American Paper Bottle Co | Container |
| DE944927C (en) * | 1952-09-07 | 1956-06-28 | Heinrich Hermann Fa | Tear device for opening packs or the like. |
| CH429571A (en) * | 1965-01-29 | 1967-01-31 | Tepar Ag | A parallelepiped package made from a flexible, relatively stiff, sheet material shaped into a tube |
-
1977
- 1977-05-26 SE SE7706163A patent/SE404005B/en not_active IP Right Cessation
-
1978
- 1978-05-25 FR FR7815516A patent/FR2391919A1/en active Granted
- 1978-05-25 GB GB22758/78A patent/GB1589127A/en not_active Expired
- 1978-05-26 IT IT23914/78A patent/IT1094850B/en active
- 1978-05-26 NL NLAANVRAGE7805771,A patent/NL188083C/en not_active IP Right Cessation
- 1978-05-26 DE DE2823015A patent/DE2823015C2/en not_active Expired
- 1978-05-26 AU AU36544/78A patent/AU524021B2/en not_active Expired
- 1978-05-26 CH CH578578A patent/CH630309A5/en not_active IP Right Cessation
- 1978-05-26 JP JP6318778A patent/JPS5434981A/en active Granted
- 1978-05-26 CA CA304,216A patent/CA1109420A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU524021B2 (en) | 1982-08-26 |
| FR2391919A1 (en) | 1978-12-22 |
| NL188083B (en) | 1991-11-01 |
| FR2391919B3 (en) | 1981-02-06 |
| CH630309A5 (en) | 1982-06-15 |
| AU3654478A (en) | 1979-11-29 |
| JPS6340744B2 (en) | 1988-08-12 |
| NL188083C (en) | 1992-04-01 |
| DE2823015C2 (en) | 1982-09-16 |
| NL7805771A (en) | 1978-11-28 |
| SE404005B (en) | 1978-09-18 |
| DE2823015A1 (en) | 1978-11-30 |
| JPS5434981A (en) | 1979-03-14 |
| GB1589127A (en) | 1981-05-07 |
| IT7823914A0 (en) | 1978-05-26 |
| IT1094850B (en) | 1985-08-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| FI65202C (en) | VAETSKETAET KARTONGFOERPACKNING SOM BESTAOR AV KARTONGMATERIALPAO VARS BAODA SIDOR AER FAESTA KONSTAEMNESFILMER | |
| EP0267526B1 (en) | A packing container for liquid contents | |
| US3900155A (en) | Package | |
| CA1073832A (en) | Packing container provided with opening arrangement | |
| US6343876B2 (en) | Easy-to-open package having seal opening notch | |
| US5620550A (en) | Packaging material with an opening arrangement and a method of producing same | |
| US3797726A (en) | Container for liquids with an openable pouring spout | |
| EP0008545A2 (en) | Disposable portion package | |
| CA1146498A (en) | Packing container with pouring spout | |
| US4113103A (en) | Opening arrangement for packing containers | |
| US3379364A (en) | Package means | |
| CN111712441B (en) | Method for manufacturing a sealed, breakable package and corresponding sealed, breakable package | |
| US4740163A (en) | Channel opening feature for cartons | |
| EP0558946A1 (en) | An opening arrangement and a method of producing same | |
| US5188285A (en) | Opening device for packaging containers | |
| CA1109420A (en) | Packaging container provided leak-proof tear-open perforations | |
| US3094269A (en) | Container with a butt seam | |
| EP0521618A2 (en) | Pouch having means to facilitate tear initiation | |
| EP0317334A1 (en) | A container of flexible material | |
| GB2283007A (en) | Boil-in-bag sachet with tear-off strip | |
| US4666044A (en) | Tear-open flap orifice on packs consisting of plastic-coated laminated material with a folded-round fillet-seam closure and a process for producing the tear-open flap orifice | |
| US5884837A (en) | Opening arrangement | |
| US3507087A (en) | Article-separating packages for flat articles such as surgical supplies | |
| SU810073A3 (en) | Packing for liquids | |
| JPH035576Y2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |