JPH0999935A - Liquid paper container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily open a top seal part in a liquid paper container of the gable-top type by forming a recess, which is formed by pressing a thermoplastic resin at a softening point, in either or both of a rib on the top end of a top folded side wall on the side of an opening and a rib in opposition to the rib. SOLUTION: A gable top carton is manufactured by a method wherein gable roof parts connected to a body are joined together by holding top end folded ribs of top folded side walls by means of top end ribs of top side walls and heat-sealing the joined part thereof. In that case, recess treatment patterns P are formed at predetermined positions of inner surfaces of ribs 1T-3T. The patterns P are formed by simultaneously conducting blanking of a blank or rule pressing, and, for example, a male die prepared according to a predetermined pattern is set and a die heated to a softening point of thermoplastic resin on both surfaces of a blank is used to form a recess. As a result, a pouring spout can be opened easily and cleanly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of easy opening of gobel top type liquid paper containers such as milk and fruit juice drinks.

[0002]

2. Description of the Related Art In a Gobel top carton (a gable roof carton) that has been established as a liquid paper container for milk, fruit juice drinks, dairy drinks, mineral water, etc., ribs (top panel) forming part of the spout (2) is generally coated with an anti-heat-seal agent to partially weaken the heat-sealing strength of the ribs to facilitate opening. In addition, a method has also been proposed in which a plastic spout prepared separately from the carton is pierced and fixed to the roof portion from the outside, and the liquid content is poured out from the spout. Further, a plastic spout with a cap is attached by heat sealing so as to cover the opening provided in the roof, and the fairness is 3-13.
In 80, there is also proposed an economy type one in which the spout is a one-piece plastic molded product, and when the integrally formed pull tab is pulled toward you, the molded product is broken and opened from the weakening line.

[0003]

However, when the anti-heat-sealing agent layer is provided on the rib portion, it takes time and effort to partially coat the rib on the inner surface of the carton with the anti-heat-sealing agent. There is a problem that not only the cost is required, but also the cost is increased, and if it is not accurately coated on a predetermined position, liquid leakage may occur. In addition, the method of sticking the spout prepared separately from the carton from the outside will reduce the total cost if the spout is used repeatedly, but there is the inconvenience that the spout must be present at the time of using the product containing the liquid paper container. However, when the same spout is continuously used for different liquid beverages as it is, there is a problem that the liquid content is mixed, and the repeated use without washing is also a hygienic problem. In addition, the plastic spout attached to the roof of each Goebel top carton has the problem of increasing costs even if it is an economy type, and it is difficult to separate and dispose of paper and plastic. There is also the problem of doing. Today, the retail industry tends to increase the pressure during heat-sealing in a molding and filling machine in order to reduce the liquid leakage at the distribution stage of the liquid carton. It is becoming difficult for users to open. On the one hand, the end users' demand for liquid paper containers that are clean and easy to open is only increasing. The industry has such a trade-off. The present invention has been made in view of such a problem, and provides a liquid paper container having an easy opening property only by physically processing a double-sided thermoplastic resin-coated paperboard used for a Gobel top carton. To aim.

[0004]

The gist of the present invention made to solve the above problems is as follows. (1) Using a paperboard coated on both sides with a thermoplastic resin or a laminate centered on the paperboard, a gabled body connected to the upper end of a quadrangular prism-shaped body composed of four body side wall panels via a fold line. Shaped roof part folds the opposite upper folded side walls inward along the diagonal fold lines, folds the remaining opposite upper folded side walls inward, and superimposes the upper folded ribs on the upper folded side walls by sandwiching the upper folded ribs. In the paper container formed by heat-sealing the overlapped portion, either the rib at the upper end of the upper folded side wall on the opening side and the rib facing the rib, or one of the ribs facing the rib is formed according to a predetermined pattern on the inner surface. A concave portion formed by being pressed at the softening temperature of the plastic resin is formed. (2) A pull tab is attached or formed on the upper folded side wall on the opening side or over the uppermost part of the body side wall panel connected to the upper folded side wall via a folding line.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a development view of a carton blank 10 for a liquid paper container according to the present invention. As shown in FIG. 1, first, the body of the liquid paper container according to the present invention is a side wall panel 1.
~ 4 and glue allowance 5 are connected via folding lines 15 to 17, and a roof portion 2 forming an upper side wall, that is, a gable roof on the upper part thereof.
G, 3G and gable (mountain-shaped walls on both ends of the gable roof)
The upper folding side walls 1G and 4G corresponding to are connected to each other via a folding line 11, and further, via a folding line 14, a folding rib 1
T, 4T and rib 2T that wraps it and seals the palm.
3T is extended. Also, the upper folded side walls 1G, 4G
Is provided with folding lines 12 and 18 that fold the side wall obliquely. The top sealing after filling the liquid paper container according to the present invention is all performed by heat sealing of ribs. Particularly important in the present invention are the ribs 1T on the upper part of the upper folded side wall 1G and the ribs 2T which are folded and face each other.
It is a part consisting of 3T. The bottom portion B is composed of a portion that is connected to the lower side of the body portion D via a fold line 19, and these are heat-sealed to form a flat bottom portion without liquid leakage.

From the above blank 10 to the present liquid paper container 20
In order to mold the blank, first, the blank is vertically folded in three by the folding line 15 (right) and the folding line 17, and the glue allowance panel 5 and the body portion 4,
The upper folding side wall 4G and the rib 4T are heat-sealed and attached to a tube to form a flat folding carton. This is supplied to a molding and filling machine, raised in a prismatic shape, the bottom is molded first, the contents are filled, then a gable roof is molded, and finally the top rib is sealed by heat sealing. In this top seal, first, when the upper folded side walls 1G, 4G are folded inward along the diagonal folding lines 12, 18, and the folding line 11, the ribs 1T, 4T on the upper side are folded at the central folding lines 27, 2.
Folds in two at 8, and in conjunction with that, the remaining ribs 2T, 3T
Ribs that collapsed inward at the same time and double folded 1
The T and 4T are sandwiched between them to form a seal, and the top seal is completed, resulting in a gable top carton. In this case, the thermoplastic resin layer welds between the four ribs to be polymerized.

FIG. 2 is an explanatory view of opening the gable top carton. FIG. 2A is a perspective view showing a state before opening. When the roof parts 2G and 3G overlapping the upper folded side wall 1G on the carton opening side are strongly opened to the left and right with both hands, the ribs 1 to 4T which are quadruple heat-sealed are separated from the middle, as shown in FIG. 2 (b). Thus, the rib portion is T-shaped. When the left and right sides of the rib 1T are pulled toward you while pressing them with your fingers as shown by the arrows, peeling starts at the point where the five fold lines of the rib 1T intersect, and the peeling spreads to the left and right and upward, and finally shown in FIG. 2 (c). Thus, the spout M can be opened. Hereinafter, this point at which peeling starts will be referred to as K point. 2 (b)
2 (b) or 5, the pulling pull tab PU previously provided on the upper folding side wall 1G is peeled off in the half-opened state as shown in FIG. You may make it open like 2 (c). This method is particularly suitable for children, the elderly and handicapped people. Furthermore, if the above-mentioned methods are combined and opened, the pouring opening can be formed more effectively without touching the inside of the rib. The pull tab is formed by half-cutting the carton base material, and a peeling stop means may be provided on the top of the pull tab so as not to cause excessive peeling.
This pull tab can also be used when reopening a reclosed roof.

It takes a little force to open the T-shaped half-opened state shown in FIG. 2 (b), but anyone can easily open it.
How to easily open from this state without using an additional coating agent such as an anti-heat sealing agent or a separately prepared pull tab member is an object of the present invention, and the means will be described below. Before that, the conventional anti-heat sealant method will be described. The conventional anti-heat sealant is partially coated on the inner surface of the carton at three locations almost the same as the pattern shown in FIG. The rib 1T is folded at the center and thermocompression-bonded by the inner surfaces of the opposing ribs 2T and 3T. However, the rib 1T does not adhere when an anti-heat seal agent is interposed, and even if it adheres, it maintains a weakly adhered state. Therefore, the peel strength of this portion is small, and peeling is easily performed at the interface of the anti-heat seal agent layer.

The first point of the present invention is to form a recess processing pattern P at predetermined positions as shown in FIG. 3 on the inner surfaces of the ribs 1 to 3T instead of the anti-heat seal agent. This recess processing pattern P is as shown in FIG.
As shown in (b), a pattern P having a predetermined shape is provided on either one of the inner surfaces of the facing ribs, or
As shown in (c), it may be provided on both opposing surfaces. This pattern shape does not necessarily have to be rectangular as shown in FIG. The above pattern is shown in FIG.
The whole may be formed of a concave portion as shown in the left diagram of FIG. 3 (d) showing the A and A cross section in FIG. 3, or may be formed of a concave portion and a convex portion as shown in the right diagram. The recess must have such a depth that the inner surfaces of the ribs facing each other can be kept in non-contact with each other during filling and sealing. From the gist of the present invention that produces easy-opening property, it is better that the entire pattern is made up of concave portions, but if it is made up of concaves and convexes, the moldability is better. However, as a matter of course, since the convex portion is finally heat-sealed with the facing surface, it is important to reduce the area ratio of the convex portion to the concave portion. By subjecting the ribs 1 to 3T to the above-described recess processing, the heat sealing strength between the opposing ribs 1T and 2T and 1T and 3T is weakened as in the case of applying the conventional anti-heat sealing agent. Therefore, it is possible to obtain the action and effect that the easy opening property is obtained and the spout can be easily formed. If you only want to give a chance to open the package, you can use Fig. 3 (a).
As shown by, the spot-like recess S is formed in the center of the rib 1T.
All that is required is to provide P. However, the total peeling resistance in this case becomes large.

The processing of the recess processing pattern P described above can be performed simultaneously with blanking and ruled stamping. That is, a male mold or a concavo-convex mold prepared according to a predetermined pattern is set on the upper tank, and the mold is heated to the softening temperature of the thermoplastic resin on both sides of the blank, for example, in the case of low density polyethylene, the temperature is in the range of 65 to 90 ° C. Then, by pressing the rib inner surface of the blank 1 at a pressure of 6 to 7 ton / cm ² for 0.5 seconds, a recess having a depth of 0.15 to 0.16 mm can be stably obtained. On the other hand, when the temperature is 65 ° C. or less, the depth remains at about 0.13 mm, and this value varies and it is difficult to obtain the desired depth. After filling the liquid paper container according to the present invention with the contents, the inner surfaces of the ribs are thermocompression-bonded with each other under a strong pressure. However, if the pressure at this time is too high, even the recesses in the recess processing pattern P aiming at non-contact are heated. Since the bonding is performed, it is meaningless to process the recess. Normally, the pressure applied when sealing the rib is about 1.2 ton / cm
It is about ² , but it is desirable to reduce the pressure as much as possible.

In the conventional partial coating method of the anti-heat-seal agent, the interval between the folding line 14 and the lower edge of the anti-heat-seal portion is not constant, and if this interval is too small, it causes liquid leakage. However, in the liquid paper container according to the present invention, the processing of the recess processing pattern P is performed at the same time as the ruled lines as described above, and thus the relative positional accuracy with respect to the recess processing pattern P and the folding line 14 and the like obtained is extremely excellent. It is possible to accurately maintain a space of 1 to 2 mm between the folding line 14 under each rib shown in FIG. 3 and the lower edge of the recess processing pattern P, and it is necessary to worry about liquid leakage as long as the entire rib is heat-sealed. There is no.

When the rib 1T which is further heat-sealed by the above-mentioned opening operation is to be pulled away from the semi-opened state shown in FIG. 2B, the shear stress concentrates at the point K due to the structure of the container. Therefore, it is important to provide a region where peeling easily occurs at least near the point K. FIG. 4 is a schematic horizontal cross-sectional view of a rib showing a peeled state, and FIG.
The peeling situation that occurs from the vicinity of the point K and propagates in the horizontal direction when the concave portion processing pattern P shown in FIG. In FIG. 4, the diagonal lines indicate the paperboard layer or the laminated body layer 21 having the paperboard layer inside, and the transparent portion indicates the thermoplastic resin layer 22. As shown in FIG. 4A, in the state before peeling, the recessed surface 23, which is the bottom surface of the recessed portion, is in a state of non-contact with the facing rib near the point K. Next, FIG.
As shown in (b), the force in the arrow direction acting on the point K can easily separate the rib 1T from the inner surface of the facing rib in the region of the recess processing surface 23, but when entering the left and right non-processing surface portions, Are separated while causing delamination.
Although not shown in FIG. 4B, this delamination occurs from the beginning in the portion sandwiched between the folding line 14 and the recess processing pattern P. The ribs 1T and 2T and the ribs 1T and 3T are peeled off without any resistance on the recessed surface 23, but as described above, the thermoplastic resins are completely welded and integrated with each other, so that they face each other. It must be peeled off by delamination in the paperboard layer on either side of the rib. Therefore,
At the stage where the peeling moves from the concave portion to the non-concave portion, it is necessary that one of the opposing ribs of the thermoplastic resin layer be destroyed.
The peel resistance for that purpose is also added, and the overall peel resistance temporarily increases. However, finally the ribs 1T, 2T and 1
As compared with the case where the recessed surface 23 is not provided at all, the total force required in the process until all the T and 3T are separated and the spout is fully opened as shown in FIG. Extremely low.

The second point of the present invention is to provide a means for easily and cleanly opening not only the first opening of the Goebel top carton but also the second and subsequent reopening, as shown in FIG.
(C) and providing a pull tab PU as shown in FIG. The pull tab PU is preferably provided so as to pull outward near the point K or over the central portion of the upper folded side wall 1G or over the upper folded side wall 1G and the upper end of the body portion 1. The pull tab PU is a piece of paper separate from the liquid paper container according to the present invention, a cutout sheet, a punched piece, or a cut piece of tape such as a plastic film,
A part of it may be attached to the upper folded side wall, and the paperboard of the portion where the pull tab PU is formed may be surrounded by a half cut line, and that portion may be peeled off with a paper layer to form the pull tab PU. The pull tab PU may have any shape such as an I-shape, a T-shape, a U-shape, and a string shape as long as it has a pulling function as shown in FIG. The half cut method will be described below. As an example, the pull tab PU has a closed lower part,
As shown in FIG. 5, a half cut 24 is added from the surface of the paper container laminate so as to partition the pull tab region into a shape with an open upper part, and it is easy to open from the lower end at the time of the first opening. The delaminated paper and the thin film made of a thermoplastic resin can be peeled off, and the purpose can be achieved only by pulling it toward you. As a stopper means for stopping peeling at the upper part of the pull tab PU, FIG.
As shown in Fig. 5
As shown in (b), the peeling stop portion 26 having a rounded shape may be provided on the upper portion of the half cut 24. The half cut 24 of the pull tab PU may have such a depth that the paperboard is delaminated from the intermediate layer. The processing of the half cut 24 can be performed at the same time when the carton blank is punched. Further, a half cut device may be attached to the molding and filling machine, and the half cut 24 may be processed for each of the liquid paper containers.

The laminated constitution of the base material of the liquid paper container of the present invention is preferably a paperboard layer which has been conventionally used, coated on both sides with a polyolefin-based resin, and the polyolefin-based resin may be low-density polyethylene or wire. Low density polyethylene, medium density polyethylene, polypropylene, ionomer, ethylene vinyl acetate copolymer, ethylene
Acrylic acid copolymer, ethylene / acrylic acid ester,
It may be selected from ethylene / vinyl alcohol copolymers and the like. Further, instead of the paperboard alone, a laminate of paper / polyethylene / aluminum foil, paper / ethylene / acrylic acid copolymer / aluminum foil, paper / polyethylene / aluminum foil / biaxially stretched polyester, etc. may be used.

[0015]

EXAMPLE A liquid paper container according to the present invention was applied to milk to prepare a carton blank having an internal volume of 1000 ml. As the carton base material, the one having the following laminated structure manufactured by Weyerhaeuser Co., which is currently used for milk, was used as it was. That is, polyethylene 16 g /
m ² / bleached kraft paper 313 g / m ² / polyethylene 27
It has a layer structure of g / m ² and the total basis weight is 356.
g / m ² . A mold surface temperature of 90 ° C. and a pressure of 6.5 ton / in order to form a concave portion processing pattern P as shown in FIG. 3C on the back surface of the rib 1T of the carton blank made of this laminated material.
It was pressure-molded at a pressure of 0.5 cm for ² cm ² . as a result,
A recess having a depth of 0.15 to 0.16 mm was stably obtained. The blank 10 according to the present invention obtained by performing the above processing was tube-adhered by the same tube-adhering machine as the conventional one, and then molded, filled and sealed under the same conditions with a milk molding-filling machine. Twenty samples were randomly selected from the products obtained in this way, and the opening test was conducted by five panelists. It was uncomfortable with the products using conventional anti-heat sealant. It turned out to be easy to open. Further, a peeling resistance value at the time of opening was tested with a push-pull scale (made by Imada Seisakusho Co., Ltd.) by adding a comparative example sample in which no rib portion was processed, and the following results were obtained. Carton using anti-heat sealing agent 1.4 Kg Carton with recess processing (invention) 1.3 Kg Comparative example (carton without processing) 1.9 Kg As can be seen from the above results, the liquid paper according to the present invention The container has an easy-open property comparable to the case where an anti-heat sealing agent is used. It should be noted that, although there is a slight difference in the initial resistance value and the resistance value in the middle, depending on the position of the other concave portion processing pattern P shown in FIG.

The liquid paper container according to the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the gist of the present invention. For example, the blank of the Gobel top carton of this embodiment is drawn in a pure pack type, but it is also effective for other types of Gobel top carton. The liquid paper container according to the present invention has a square horizontal cross section, but may have a rectangular cross section.

[0017]

According to the present invention, it is possible to easily and cleanly open a spout by processing only a double-sided thermoplastic resin-coated paperboard that is a base material of a Gobel top carton or a laminated body centered on the paperboard. As compared with the conventional anti-heat seal agent method, the material cost and the manufacturing cost can be reduced by omitting the anti-heat seal agent and its partial coating process, and the position accuracy of the recess processing pattern P can be improved. By increasing it, the anxiety factor of liquid leakage can be reduced. Since the processing of the depression processing pattern P by pressing is performed at the softening temperature of the thermoplastic resin, the efficiency of forming the depression is improved. further,
The base material coated with polyethylene on both sides of the paperboard is
It can be incinerated and discarded as burning garbage and can be recycled, thus reducing the environmental load.

[Brief description of drawings]

[Figure 1] Carton blank development view

[Fig.2] Illustration of opening procedure of spout

FIG. 3 is an explanatory view of a recess processing pattern.

FIG. 4 is a schematic horizontal sectional view of a rib showing a peeled state.

FIG. 5 is an explanatory diagram of a pull tab.

[Explanation of symbols]

 1-4 Carton body side wall 5 Cylinder gluing margin 1G, 4G Upper folding side wall 2G, 3G Roof part 1T-4T Rib (top panel) 11 Fold line 12, 13 Diagonal fold line 14-17 Fold line 18 Diagonal fold line 19 Fold line 20 Liquid paper container according to the invention 21 Paper layer 22 Thermoplastic resin layer 23 Recessed surface 24 Half cut 25 Poly tape 26 Peeling stop portion 27, 28 Fold line 29 Interlayer peeling portion in paper layer B Bottom molding portion K Peeling start point M Opening P Recessed portion Processing pattern PU pull tab SP spot concave

Claims (2)

[Claims] 1. A board, which is coated on both sides with a thermoplastic resin, or a laminated body centered on the board, is connected to the upper end of a quadrangular prism-shaped body composed of four body side wall panels through fold lines. The gabled roof part folds the opposite upper folded side walls inward along the diagonal folding lines, bends the remaining opposite upper folded side walls inward, and sandwiches the upper folded side ribs of the upper folded side wall with the upper end ribs. In a paper container formed by polymerizing and heat-sealing this polymerized portion, both of the ribs at the upper end of the upper folding side wall on the opening side and the ribs facing them, or either one of them, according to a predetermined pattern on the inner surface. A liquid paper container characterized in that a concave portion formed by being pressed at a softening temperature of the thermoplastic resin is formed. 2. A pull tab is attached or formed on the upper folded side wall on the opening side or across the uppermost portion of the body side wall panel connected to the upper folded side wall via a fold line. The liquid paper container according to claim 1.