JP2016175697A - Paper container having volume reduction structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper container capable of reducing its volume according to discharge of a content without preventing the content from being discharged by a side face part folded during volume reduction, without using another component such as a ring and without requiring any labor.SOLUTION: The paper container having a volume reduction structure comprises vertical ruled lines 11 in each corner, has a polygon cross-section, comprises a flexible film layer 102 at least on all face in the container, and is formed of a base material containing paper. There are provided at right angle to the vertical ruled lines, as one pair, a ridge folding ruled line 12 arranged over the whole periphery and a valley folding ruled line 13 which is arranged in the bottom face side with a distance of the folding length 4 from the ridge folding ruled line in parallel with the ridge folding ruled line. There are also provided, with each vertical ruled lines as a center line, windows 5 which have an upper end contacting the ridge folding ruled line and exceed the valley folding ruled line on the base material layer, and inward folding ruled lines of U-shape in the lower side of the windows.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a paper container having a structure capable of reducing the capacity.

  Paper containers used for the contents of food and non-food liquids and powders and made of paper as the base material are liquid drinks such as fruit juice drinks, juice, tea, coffee, milk drinks, soups, sake, shochu Widely used in liquors such as These paper containers are provided with a sealant layer made of a thermoplastic resin on the inner surface of the paper layer, and the containers can be formed by fusing the partially matched inner surfaces. In order to prevent the container from becoming dirty or liquid from being lost, and in order to make it easier to cover the end face of the base material, there is also a film layer of a thermoplastic resin provided on the outer surface.

However, in order to preserve the contents for a long period of time, a layer having a barrier property such as an aluminum foil, an aluminum vapor deposition film, or an inorganic oxide vapor deposition film is provided between the paper layer and the sealant layer. However, once the container is opened and a part of the contents is discharged and the contents are reduced, if the volume of the container does not decrease, a large amount of oxygen or the like of the outside air enters the inside, and the oxidative deterioration tends to proceed.
In addition, since the size of the conventional paper container does not change even when the contents are reduced, there is a problem that other foods cannot be put in a refrigerator or the like while being bulky for storage.
Therefore, if there is a paper container that can reduce the volume as much as the content decreases, the amount of internal oxygen that causes deterioration can be reduced, and the storage property is improved.

  For example, in Patent Document 1, the container is formed by forming a fold number of folds that divide a folded portion of the container and a plurality of oblique fold lines that are located between the fold lines and connect diagonal edges. The volume reduction type deformable container is proposed in which the volume of the container can be reduced by rotating the upper and lower parts of the container in accordance with the direction in which the oblique folds are formed.

However, if it is finally discarded, there is no problem, but when the contents are still contained and deformed to reduce the capacity, the folded side faces are perpendicular to the contents discharge direction. The problem arises that it becomes a barrier to the discharge of contents.
Further, in a deformed state, it may be difficult to make the container stand stably, and when the container is opened and temporarily placed on a table, it tends to fall over and spill.
Further, when the contents are discharged in a deformed state, there is a problem that the spout fluctuates and is easily spilled.

  In Patent Document 2, a paper container that can be reduced in the height direction by providing a crease guide line on the side surface forming the height direction of the paper container, and folding the crease guide line in a mountain and a valley. The crease guide line is provided with a protruding portion formed only on a pair of opposing side surfaces forming the height direction of the paper container. .

  When the volume of the paper container is reduced, there is a problem that the side surface portion protrudes to the outside and the storage property is lowered, and the protruding portion of the folded side surface portion becomes a wall perpendicular to the discharge direction of the contents. There will be a problem that the contents will be discharged. On the other hand, it is proposed that a ring is prepared separately and the protrusion is pressed down to fit the ring, but this is very complicated and inconvenient.

In Patent Document 3, a pouring member serving as a spout on an inclined roof portion formed of a laminate including at least a base material layer made of a paper layer, an intermediate layer made of a gas barrier layer, and an inner layer made of a thermoadhesive resin layer Two notch portions in which only the base material layer is cut out so as to sandwich one side plate constituting the trunk portion of the gobeltop shape paper container, A gobel top type paper container has been proposed, characterized in that at least one ruled line connecting the two notches is provided on the side plate at the position connecting the two notches at the shortest.

  This gable-top type paper container has two notches, but it is not a mechanism that reduces the capacity, it is a container that is easily discharged by applying internal pressure so that the contents can be easily discharged. , Neither height nor width can be reduced.

JP 2006-248614 A Japanese Patent No. 5199402 Japanese Patent No. 5380850

  Therefore, according to the discharge of the contents, the side part that is folded when the volume is reduced does not prevent the discharge of the contents, does not use a separate part such as a ring, and a paper container that can be reduced without taking time and effort. Providing is a challenge.

The present invention has been made to solve the above problems, and the invention of claim 1 of the present invention provides:
A cross section having a vertical ruled line at each corner is a polygon, a flexible film layer is provided on at least the entire surface of the container, and a paper container formed by a substrate including paper,
A mountain fold ruled line that is perpendicular to the vertical ruled line
A valley fold ruled line parallel to the mountain fold ruled line is provided as a pair on the bottom side separated from the mountain fold ruled line by the distance of the folding length,
Each vertical ruled line is the center line, the upper end touches the mountain fold ruled line, and a window that penetrates the valley fold ruled line is provided in the base material layer.
A paper container having a volume reduction structure characterized in that a U-shaped inner crease line is provided on the lower side of a window.

  According to a second aspect of the present invention, there is provided the paper container having a volume reducing structure according to the first aspect, wherein the window has a lateral width that is substantially folded from the center line to the left and right.

  A third aspect of the present invention is the paper container having a volume reducing structure according to the first or second aspect, wherein the height of the window is less than twice the folding length.

  The invention according to claim 4 of the present invention is the volume-reducing structure according to any one of claims 1 to 3, wherein the U-shaped inner folded ruled line has a parallel part having the same width as the window at the upper part. A paper container.

  The invention according to claim 5 of the present invention is characterized in that the shape of the U-shaped inner folded ruled line has a height that is not less than the folded length from the valley folded ruled line. A paper container having a container structure.

  The invention according to claim 6 of the present invention is characterized in that the U-shaped inner folded ruled line has a parallel part having the same length as the folded length below the valley folded ruled line. A paper container having a container structure.

The invention according to claim 7 of the present invention is the mountain fold ruled line, the valley fold ruled line parallel thereto, a window, U
The paper container having a volume reducing structure according to any one of claims 1 to 6, wherein a plurality of volume reducing mechanisms each including a letter-shaped inner folding ruled line are provided in a height direction.

  The invention according to claim 8 of the present invention is a paper container having a volume reducing structure according to any one of claims 1 to 7, wherein the paper container has a rectangular cross section.

  The invention according to claim 9 of the present invention has the volume reducing structure according to any one of claims 1 to 8, wherein a convex base material notch is provided at an upper end of the window intersecting with the vertical ruled line. It is a paper container.

  The invention according to claim 10 of the present invention is characterized in that the convex base material notch tip provided at the upper end of the window is formed at the intersection of a quadratic curve. A paper container.

  Invention of Claim 11 of this invention provided the base-material notch of convex shape in the lower side at the window lower end which cross | intersects a vertical ruled line, The volume reduction in any one of Claims 1-10 characterized by the above-mentioned. A paper container having a structure.

  The invention according to claim 12 of the present invention is characterized in that the convex base material notch tip provided at the lower end of the window is formed at the intersection of a quadratic curve. A paper container.

  A thirteenth aspect of the present invention is the volume reducing structure according to any one of the first to twelfth aspects, wherein the flexible film layer provided on the window is made of a transparent film. A paper container.

The volume-reducible paper container of the present invention can be reduced in volume, not only when it is discarded, but also when the contents remain in use.
Moreover, even if no separate parts are used, the upper side of the container can be firmly fitted into the lower side simply by pushing the upper side downward, and the volume reduction state can be fixed and maintained, enabling stable dispensing. is there.
In addition, the folded side wall is formed upward, so that it does not interfere with the dispensing of the contents.
Furthermore, since the window can be seen through, there is an advantage that the remaining amount of contents can be visually confirmed.

It is an example of the paper container which has a volume reduction structure of this invention, and is the external appearance perspective view and longitudinal cross-sectional view of the paper container in the stage before volume reduction. It is an expanded view which shows an example of the blank shape which manufactures the paper container which has a volume reduction structure of this invention. It is an example of the paper container which has the volume reduction structure of this invention, and is the external appearance perspective view and longitudinal cross-sectional view of the paper container in the stage which reduced the volume only in the lower stage. It is an example of the paper container which has the volume reduction structure of this invention, and is the external appearance perspective view and longitudinal cross-sectional view of the paper container in the state which folded the lower two steps and reduced the volume. It is an example of the paper container which has the volume reduction structure of this invention, and is the external appearance perspective view and longitudinal cross-sectional view of the paper container in the state which folded all the folding parts and reduced the volume. It is an example of the paper container which has the volume reduction structure of this invention, and is sectional drawing of the state which is discharging the contents by the paper container in the state which folded all the folding parts and reduced the volume.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1-1 is an example of a paper container having a volume reducing structure of the present invention, and is an external perspective view of the paper container in a stage before volume reduction.
In this embodiment, the bottom 3 is a square paperbell top paper container, and the spout 21 is fused to the top plate 2 of the top of the bell.

The trunk portion 1 has four vertical ruled lines 11, and mountain fold ruled lines 12 are provided over the entire circumference at right angles to the vertical ruled lines 11.
A valley fold ruled line 13 and a mountain fold ruled line 12 are provided as a pair on the bottom surface 3 side in parallel to the mountain fold ruled line 12 with a folding length of 4 apart.
Windows 4 are provided at four corners where the mountain fold ruled line 12 and the vertical ruled line 11 intersect.
The window 5, has become the vertical lines 11 into a shape bent shape centered line, near the top end is in contact with the mountain fold border 12, the lower the shape that penetrates the inwardly folded borders 13, remove the substrate Yes, the inner layer is a flexible film that separates the inside and outside of the container.
An inwardly creased line 14 is provided below the window 5. The inner folding ruled line 14 is U-shaped and has the same width as the width of the window 5.

Although the container cross section of FIG. 1-1 is a square, if it is a polygon, it may be a triangle, a rectangle, or a pentagon. However, if the number of polygons is larger than that of a pentagon, the container is likely to be distorted and difficult to pour when the container is held.
Moreover, even if the top plate side is not a gobeltop shape as shown in FIG. 1-1 but a flat top shape, if the same window, mountain fold ruled line, valley fold ruled line, inner fold ruled line, etc. are processed, Similarly, it can be reduced in volume.

FIG. 1-2 is an example of a paper container having a volume reducing structure of the present invention, which is a paper container in a stage before the volume reduction of the bottom surface is a square shape, and is a longitudinal sectional view cut along a plane A in FIG. The window 5 and the vicinity of the spout 21 are shown in an enlarged view.
The container has a paper base material layer 101 and forms a window 5 or a govel top shape. A flexible film layer 102 is provided on the entire inner surface of the base material layer. The flexible film 102 is also present in the window 5 portion and separates the inside and outside of the container, but since there is no base material, the window 5 portion is easily deformed.
The flexible film is made of a thermoplastic resin that can be fused at least on the innermost surface, so that the innermost layers can be bonded to each other. Of course, it is preferable to have a structure containing at least one layer of material that does not allow permeation / penetration of the contents.
The spout 21 is used by fusing the flange 211 of the spout to the inner surface of the flexible film layer 102 in a state where the front end of the spout protrudes from the inside of the opening provided in the top plate.

  FIG. 2 is a developed view showing a container having a square bottom surface as an example of a blank for producing a paper container having a volume reduction structure of the present invention.

  The side plate portion is connected to the front side plate 152, the right side plate 153, and the back side plate 154 in order from the left side plate 151 to the right. A left side fusing plate 155 and a folded side fusing plate 156 are connected to the left of the left side plate 151.

  The bottom surface 3 includes a left bottom plate 31 below the left side plate 151, a front bottom plate 32 below the front side plate 152, a right bottom plate 33 below the right side plate 153, a back bottom plate 34 below the back side plate 154, and side surfaces. The bottom side fusion plate 35 is connected to the lower side of the fusion plate 155, and the folded bottom fusion plate 36 is connected to the lower side of the folded side surface fusion plate 156, and the adjacent bottom surface plates are also connected to each other.

The upper surface plate portion includes a left upper surface plate 21 above the left side surface plate 151, a front upper surface plate 22 above the front surface plate 152, a right upper surface plate 23 above the right upper surface plate 153, a back upper surface plate 24 above the back upper surface plate 154, and a side fusion plate. The upper fusion plate 25 is connected to the upper side of 155, the upper fusion plate 26 is connected to the upper side of the folding side surface fusion plate 156, and the adjacent upper surface plates are also connected to each other.

In assembling the box, the folding side fusing plate 156 is folded outside the side fusing plate 155.
At the same time, the folded bottom fusion plate 36 is folded to the outside of the bottom side fusion plate 35, and the on-fold fusion plate 26 is folded to the outside of the upper side fusion plate 35.
Then, these fused plates are integrally bonded to the inner surface of the back side plate 154, the inner surface of the back upper surface plate 24, and the inner surface of the back bottom plate 34, thereby being edge protected and formed into a cylindrical shape. The side part becomes the barrel part of the container as it is.
After the body portion is formed, the right bottom plate 33 and the left bottom plate 31 are folded, and the front bottom plate 32 and the back bottom plate 34 are fused to each other and are fused while being folded flat so as to be integrated. A bottom surface is formed.
After the contents are filled, the upper left surface plate 21 and the right upper surface plate 23 are folded, and the upper surface is fused and closed by a fusion portion provided on the upper surface of each upper surface plate.

A side ruled plate 11 connects the side fusing plate 155, the left side plate 151, the front side plate 152, the right side plate 153, and the back side plate 154.
On the side plate, mountain fold ruled lines 12 run at right angles to the vertical ruled lines 11. In addition, a valley fold ruled line 13 and a mountain fold ruled line 12 are provided as a pair on the bottom surface 3 side in parallel to the mountain fold ruled line 12 with a folding length of 4 apart.
Windows 4 are provided at four corners where the mountain fold ruled line 12 and the vertical ruled line 11 intersect.

The window 5 has a line-symmetric shape with the vertical ruled line 11 as the center line, the upper end is in contact with the mountain-folded ruled line 12, and the lower part has a shape that protrudes through the valley-folded ruled line 13. The inner and outer flexible films separate the inside and outside of the container.
The window 5 has parallel portions parallel to the vertical ruled lines 11 on the left and right, and the window width 51 between the vertical ruled lines 11 and the parallel portions is approximately the length of the folding length 4. When the window width 51 is shorter than the folding length 4, when the folding is performed, the lower side plate is pushed inward, but the upper side plate is pushed out greatly and deformation is increased. In particular, if the window width 51 is extremely shorter than the folding length 4, a folding force is applied, and the container may be easily broken.
If the window width 51 is extremely longer than the folding length 4, the folding force is small and the folding is easy. However, on the contrary, there is a problem that it is easy to return to the original state from the state of being folded immediately.
Therefore, it is desirable to set the window width 51 to a width in the vicinity of the folding length 4.

The window height 52 is less than twice the folding length 4. This is because if the window height 52 is set to be twice or more the folding length 4, there is a problem that the folding force is small and it is easy to return to the original state when folding.
As for the shape of the window, it is desirable to fold the parallel part into a length of 4 or less.

An inwardly creased line 14 is provided below the window 5. The inner folding ruled line 14 is U-shaped and is provided with the same width as the width of the window 5.
The inner fold ruled line 14 has a function of reducing the cross section of the side plate below the valley creased ruled line 13 so as to easily enter the inside of the cross sectional shape of the mountain fold ruled line 12 when the container is folded. Yes.
At the same time, it is also a device that does not have the effect of deforming the cross section down to the bottom.
Therefore, the width of the window 5 is set to be the same as that of the window 5 so that it can be easily folded and is U-shaped so that the deformation can be accommodated only in the height range in which the inner folding ruled line 14 is provided. Therefore, the lower part may have a V shape and the upper part may rise in parallel.

The inward folding height 140 of the inner folding ruled line 14 from the valley folding ruled line 13 is set to a folding length of 4 or more.
When the inward fall height 140 is a folding length of 4 or less, when folding, the cross-section of the side plate below the valley fold ruled line 13 is reduced, and deformation is performed until both ends of the window intersecting the valley fold ruled line 13 touch each other. To do. At this time, the deformation of the side plate below the valley fold ruled line 13 is not settled, and there is a problem that the lower part is greatly deformed, and force is required, but the container is deformed and the space between the windows is changed. Problems such as unplanned folds occur. Therefore, the inward fall height 140 is set to a folding length of 4 or more.
If possible, if the parallel part length 141 parallel to the vertical ruled line is the same width as the window width 51 of the inwardly folded ruled line 14 and the folding length is 4 or more, the parallel part parallel to the vertical ruled line will not be forced. Can be deformed inward.

At the upper end of the window 5 in contact with the vertical ruled line 11, a convex upper base material notch 53 protruding from the mountain fold ruled line is provided.
The upper end base material notch 53 is a notch for facilitating entry of the lower end of the window when folded, and is preferably formed at the intersection of a quadratic curve. In other words, since the corner is cut in an arc shape, it is easy to enter along the arc of the quadratic curve.
Similarly, a convex lower end base material notch 54 is provided at the lower end of the window 5 in contact with the vertical ruled line 11.
The lower end base material notch 54 is also a notch for facilitating the lower end of the window when folded, and is preferably formed at the intersection of the quadratic curves. That is, since the corner is cut in an arc shape, it is easy to enter inside along the arc of the quadratic curve.

In an example of the blank for producing the paper container having the volume reducing structure of the present invention shown in FIG. 2, the volume reducing mechanism including the mountain fold ruled line 12, the valley fold ruled line 13, the window 5, and the folded ruled line 14 is arranged in the height direction. Three are provided.
Thus, by providing a plurality of volume reduction mechanisms, the capacity can be further reduced, and each container can be made into a better volume reduction mechanism without overdoing one by one. The number of stages of the volume reducing mechanism may be three as shown in FIG. 1, but it may be one, two, or four or more.

FIG. 3A is an example of the paper container of the present invention in which the blank made in the developed view of FIG. 2 is assembled. In the assembled paper container of the present invention of FIG. 1, only the lower volume reduction mechanism is folded. FIG. 6 is a perspective view showing a reduced volume state.
The height is lowered by twice the folding height 4. Further, it can be seen that the lower fold ruled line 13 portion enters the inside, and the surface having the fold ruled line 14 below the valley fold ruled line 13 enters the inside.

FIG. 3-2 is a longitudinal section of FIG. 3-1.
Since the window 5 has no base material, it is easily folded, but it can be seen that the center of the side surface with the base material is folded and folded inward.
Thus, since the center of the side surface with the base material is folded inward, it is possible to have a firm strength in this state, and it is also easy to pour the contents in a reduced volume state.

FIG. 3C is a transverse cross section on the BB plane of FIG.
It is shown more clearly that the four corners of the window 5 are easily deformed because there is no substrate and that the center of the side with the substrate is folded and folded inward.

FIG. 4A is a perspective view of the paper container shown in FIG. 3 in which the lower volume reduction mechanism is folded and the middle volume reduction mechanism is also folded to reduce the volume.
FIG. 4B is a longitudinal section of FIG.
Although it is folded from the lower side, it can also be folded from the upper side. If the top is pressed and folded toward the bottom, the container may be deformed because it is not determined from which stage it is folded.
Therefore, although it is preferable to fold from the bottom side, it is possible to fold at any step by pressing the upper side of the mountain crease ruled line above it while pressing the center of the side surface in the vicinity of the fold ruled line of the step to be folded.

FIG. 4C is a cross section in a state where the surface of the mountain crease ruled line 12 and the surface of the valley crease ruled line 13 are horizontally aligned when folded.
At the position where this force is most applied, the left and right intersections of the folding ruled line 14 and the valley folding ruled line 13 approach each other, the center of the side of the mountain folding ruled line 12 bulges outward, and the center of the side of the valley folding ruled line 13 enters inside. Pressed with.
As a result, the position of the vertical ruled line 11 at the center of the folded ruled line 14 enters the inside, and the intersection of the mountain fold ruled line 12 and the vertical ruled line 11 bulges outward so that they are smoothly folded without hitting them.

5A and 5B, in the paper container of FIG. 4, the middle volume reduction mechanism is folded, the upper volume reduction mechanism is folded, and all volume reduction mechanism parts are folded. It is the perspective view and longitudinal cross-sectional view which show the state reduced to the capacity | capacitance.
As shown in the cross-sectional view of FIG. 5C, when the contents 7 are poured out in a state where the volume reducing mechanism portion is folded, the folded portion of the folded volume reducing mechanism portion is released toward the spout 21. Thus, the discharge of the contents 7 is not hindered.
Moreover, since the rigidity of the trunk portion increases in a reduced volume state, the container can be held and supported firmly from the outside.
Therefore, the contents can be stably poured out to the end even in a reduced volume state.

The window 5 is a portion of the base material where there is no paper, and the innermost surface is made of a thermoplastic resin film. In addition, a barrier film or the like may be stacked.
In addition, by making the window 5 transparent, the amount of contents can be grasped and the volume can be reduced accordingly. Therefore, when the resin layer or the surface of the inner layer is laminated with a resin, it must be transparent. preferable. However, even if it is not transparent, there is no problem in providing a volume reduction mechanism.

The paper container having the volume reducing structure of the present invention is as described above. However, the laminate constituting the blank uses paper as the base material and seals a thermoplastic resin (sealant) as the innermost layer. If used, it can cope with any configuration.
From the table, the basic configuration may be a thermoplastic resin layer, a printing layer, a paper base material layer, an adhesive resin layer, or a sealant layer.
In the manufacture of the blank, the paper base is printed in advance, the window position and the like are set, and the window 5 is extracted. Thereafter, the outer layer film can be bonded to the entire surface of the paper substrate, the inner layer film can be bonded to the entire surface, and the outer shape and the hole for the spout can be removed with a ruled line.

It is preferable to provide a barrier layer between the innermost sealant layer and the base material layer in order to make a container having gas barrier properties against contents that are liable to be oxidized and deteriorated, such as liquor and coffee beverages. As a barrier layer, it can be set as the structure which provided vapor-deposited layers, such as metal oxides, such as metals, such as metals, such as aluminum, and a silicon oxide, in the outer surface of a biaxially stretched thermoplastic resin layer. The thickness of the vapor deposition layer is preferably 5 to 100 nm.
Moreover, metal foil etc. can also be used as a barrier layer.

  A thermoplastic resin such as a low density polyethylene resin or a linear low density polyethylene resin is preferred as the resin used for the outer thermoplastic resin layer constituting the laminate used in the paper container of the present invention.

  Using these thermoplastic resins, the outer surface of the paper substrate can be provided by extrusion lamination. The print layer provided on the outer surface of the thermoplastic resin layer is a layer containing a pattern, product information, or the like applied by a method such as gravure printing or offset printing using a known ink. It is preferable to perform easy adhesion treatment such as corona treatment to enhance adhesion with the printed layer. On the printed layer, an overcoat layer may be further provided on the printed layer in order to improve wear resistance.

As the paper substrate, usually, paperboard such as milk carton base paper is used. The basis weight and density are appropriately selected depending on the capacity and design of the container, but paper having a density of 0.6 to 1.1 g / cm ³ is preferably used in the range of the basis weight of 200 to 500 g / m ² .

  The adhesive resin layer is a layer made of a polyolefin-based resin used for extrusion lamination for bonding a paper base material to an inner layer or an outer layer thermoplastic resin layer. The thickness is usually in the range of 10 μm to 60 μm. If it is less than 10 μm, sufficient adhesive strength cannot be obtained.

  Specifically, ethylene-based resins such as low-density polyethylene and linear low-density polyethylene, polypropylene, and ethylene / α, β-unsaturated carboxylic acids such as ethylene / acrylic acid copolymers and ethylene / methacrylic acid copolymers. Acid copolymers, esterified products of ethylene / α, β unsaturated carboxylic acid copolymers such as ethylene / methyl acrylate, ethylene / ethyl acrylate, ethylene / methyl methacrylate, ethylene / ethyl methacrylate, Ionic cross-linked products of ethylene / α, β unsaturated carboxylic acid copolymer cross-linked with sodium ion or zinc ion, such as ethylene / maleic anhydride graft copolymer or ethylene / ethyl acrylate / maleic anhydride Anhydride-modified polyolefins such as terpolymers, ethylene glycy Epoxy compound-modified polyolefins, such as methacrylate copolymers, single resin selected from ethylene-vinyl acetate copolymer, or provided by such a mixture of two or more selected from these.

In order to increase the adhesive strength, the adhesive strength can be improved by preliminarily performing an easy adhesion treatment such as a corona discharge treatment, an ozone treatment, or an anchor coat on the surface of the paper base material or the thermoplastic resin layer.
When laminating a barrier layer in the middle to improve storage performance, as a laminating adhesive, urethane two-component curable dry laminating adhesive (including solvent-free adhesive) Can be used. The dry coating amount is preferably 0.5 to 7.0 g / m ³ .

  The thermoplastic resin layer that is fused when the innermost and outermost paper containers are molded includes low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ethylene / vinyl acetate copolymer. Although it can be used, it is preferable to use linear low density polyethylene. Further, in order to facilitate the opening of the seal portion, a blend resin of a polyethylene resin such as low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene and a thermoplastic elastomer may be used. Furthermore, the sealant layer may have a multilayer structure, and a cyclic polyolefin resin layer may be provided for the purpose of low adsorption of contents and low elution of adhesive components.

  As the linear low density polyethylene to be used, those having a density of 0.925 or less and MI of 4 or more are preferably used. The thickness of the sealant layer 5 is preferably 30 to 100 μm, and an unstretched film formed by a T-die method or an inflation method is preferable.

As described above, the paper container having the volume reducing structure of the present invention is provided with the volume reducing mechanism perpendicular to the vertical ruled line on the side surface of the container, and can be easily reduced in volume. In addition, even when the contents are poured out in a reduced volume, it is possible to pour out to the end because the folded fold does not prevent the contents from being discharged and the container has a firm waist. .
Further, if the front and back films are laminated after the window is removed from the base material, it is possible to use a normal production line for paper containers, so that productivity is high and the merit of the present invention is high.

DESCRIPTION OF SYMBOLS 1 ...... trunk | drum 101 ... paper base layer 102 ... flexible film layer 11 ... vertical ruled line 12 ... ··· Fold crease 13 ······ Valley crease 14 · · · Inner crease 140 · · · Inner fold height 141 · · · Parallel portion length 151 · · · ...... Left side plate 152... Front side plate 153... Right side plate 154... Back side plate 155. ··· Folding side surface fusion plate 2 ··········································································· ..... Front upper surface plate 23 ... Right upper surface plate 24 ... Back upper surface plate 25 ... Upper surface fusion plate 26 ... On folding Fusing plate 3 ... Bottom 31... Left bottom plate 32... Front bottom plate 33... Right bottom plate 34. ··· Fusion plate 36 ············································································· Width 52 ... Window height 53 ... Upper end base material notch 54 ... Lower end base material notch 7 ... Contents

Claims (13)

A cross section having a vertical ruled line at each corner is a polygon, a flexible film layer is provided on at least the entire surface of the container, and a paper container formed by a substrate including paper,
A mountain fold ruled line that is perpendicular to the vertical ruled line
A valley fold ruled line parallel to the mountain fold ruled line is provided as a pair on the bottom side separated from the mountain fold ruled line by the distance of the folding length,
Each vertical ruled line is the center line, the upper end touches the mountain fold ruled line, and a window that penetrates the valley fold ruled line is provided in the base material layer.
A paper container having a volume-reducing structure, wherein a U-shaped inner crease line is provided on a lower side of a window.   The paper container having a volume reducing structure according to claim 1, wherein the window has a lateral width that is substantially folded from the center line to the left and right.   The paper container having a volume reducing structure according to claim 1 or 2, wherein the height of the window is less than twice the folding length.   The paper container having a volume-reducing structure according to any one of claims 1 to 3, wherein the U-shaped inner folded ruled line has a parallel part having the same width as the window at an upper part.   The paper container having a volume-reducing structure according to claim 1, wherein the U-shaped inner crease ruled line has a height that is equal to or greater than a length folded from the valley crease ruled line.   The paper container having a volume-reducing structure according to claim 1, wherein the U-shaped inner crease ruled line has a parallel portion having a length equal to the folded length downward from the valley crease ruled line.   7. A volume reduction mechanism comprising the mountain fold ruled line, a valley fold ruled line parallel to the mountain fold ruled line, a window, and a U-shaped inner fold ruled line, and a plurality of volume reducing mechanisms are provided in a height direction. A paper container having a volume-reducing structure according to claim 1.   The paper container having a volume reducing structure according to any one of claims 1 to 7, wherein the paper container has a rectangular cross section.   The paper container having a volume reducing structure according to any one of claims 1 to 8, wherein a convex base material notch is provided at an upper end of the window intersecting the vertical ruled line.   The paper container having a volume reducing structure according to claim 9, wherein the tip of the convex base material notch provided at the upper end of the window is formed at the intersection of a quadratic curve.   The paper container having a volume-reducing structure according to any one of claims 1 to 10, wherein a convex base material notch is provided on a lower side at a lower end of the window intersecting with the vertical ruled line.   The paper container having a volume reducing structure according to claim 11, wherein the tip of the convex base material notch provided at the lower end of the window is formed at the intersection of a quadratic curve.   The paper container having a volume reducing structure according to any one of claims 1 to 12, wherein the flexible film layer provided on the window is made of a transparent film.