JP7711399B2 - Paper tube container - Google Patents

Description

The present invention relates to a paper tube-shaped container.

There is known a tubular container that can be filled and packaged with medicines, cosmetics, food, etc. The body of the tubular container is made of a paper sheet formed into a cylindrical shape.
For example, Patent Document 1 describes a body portion for a tubular container that has an outermost layer and an innermost layer made of a heat-sealable resin and a middle paper layer, and is formed into a cylindrical shape by side-sealing the outermost layer and the innermost layer using a high-frequency sealing method.
Patent Document 2 describes a tubular container having a body formed by overlapping both side ends of a blank, which is made of a laminate mainly made of paper and having thermoplastic resin layers as at least the outermost and innermost layers, with the innermost layers overlapping and then folding and heat-sealing the both side ends to form a body seal.

Publication number 7-45311 JP 2012-25471 A

The tube-shaped containers described in Patent Documents 1 and 2 use paper, which reduces the amount of plastic used, but there is a problem in that the opaque paper makes it impossible to check the internal state, such as the amount of content remaining. The advantage of paper is that it has improved light blocking properties compared to transparent laminate films, and the use of paper can suppress changes in the content caused by light.
Therefore, in order to be able to check the internal state such as the remaining amount of contents while using paper, for example, a method is conceivable in which a paper sheet 61 is rolled up and a pair of opposing edges of the sheet 61 are separated from each other, and a transparent tape material 62 is attached to the inner peripheral surface side of the body 60 of the sheet 61 so as to cover the pair of edges with the inner peripheral surface side of the body 60 and join the pair of edges (see Figs. 7(a) and (b)). However, the exposed part of the tape material 62 becomes a weak part, and there is a risk that the body 60 may be damaged by impact or dropping during distribution or use. In addition, since the transparent part is always exposed, only that part has no light blocking properties. Therefore, it could not be used as a paper tube-shaped container for contents that are sensitive to light or ultraviolet rays.

Therefore, the objective of the present invention is to provide a paper tube-shaped container that maintains the strength and light-blocking properties of the body and allows the user to check the internal condition, such as the amount of remaining contents, after the container has been used.

The invention described in claim 1 is a paper tubular container including a body portion having one end closed and capable of containing contents, and a spout portion attached to the other end of the body portion and capable of closing the other end of the body portion, wherein the body portion is laminated in the order of at least a paper layer, an adhesive layer, and a transparent laminate film layer from the outermost layer side, and has a release piece that is peeled off via the adhesive layer, the release piece being formed by a hinge portion provided in a portion that overlaps the edge of the spout portion and by cutting into the paper layer leaving the hinge portion, and the adhesive strength between the paper layer and the transparent laminate film layer is 1 N/15 mm or more and 3 N/15 mm or less.

The invention described in claim 2 is the paper tubular container described in claim 1, characterized in that the paper layer has a basis weight of 20 g/ ^m2 or more and 200 g/ ^m2 or less.

The invention described in claim 3 is a paper tubular container described in claim 1 or 2 , characterized in that the other end of the body is attached to the peripheral portion of the spout portion on the side opposite the one end side of the body of the spout portion.

The invention described in claim 4 is the paper tubular container described in claim 3, characterized in that the spout portion has a flat closure portion perpendicular to the height direction of the body portion, the peripheral portion is an edge of the closure portion, and the other end of the body portion is adhered to the surface of the closure portion opposite the one end side of the body portion at the peripheral portion.

The paper tube container of the present invention has a body in which the contents are accommodated, which is laminated from the outermost layer side with at least a paper layer, an adhesive layer, and a transparent laminate film layer in this order, and has a release piece that can be peeled off via the easily peelable layer. The release piece is formed by a hinge portion and a cut made in the paper layer leaving the hinge portion.
Therefore, by peeling back the peelable strip after starting use, the internal condition, such as the remaining amount of the contained contents, can be confirmed through the transparent laminate film layer. In addition, the peelable strip is not completely peeled off by the hinge portion, but can be peeled back while still connected by the hinge portion, and since the structure allows the body portion to be opened and closed by the adhesive layer, there is no risk of the peelable strip being peeled off during distribution or use, leaving the transparent laminate film layer exposed, and therefore it is possible to maintain the strength and light-shielding properties of the body portion.

1A is a front perspective view of the paper tube container according to the first embodiment before the peel-off piece is turned over, and FIG. 1B is a front perspective view of the paper tube container according to the first embodiment after the peel-off piece is turned over. FIG. 11 is a front perspective view of a paper tubular container according to a second embodiment before the peel-off piece is peeled back. FIG. 11 is a front perspective view of a paper tubular container according to a third embodiment before the peel-off piece is peeled back. FIG. 2 is a side view of a paper tube-shaped container according to the first to third embodiments. 5 is an enlarged cross-sectional view of the vicinity of the spout portion of FIG. 4 taken along line AA. FIG. FIG. 2 is a cross-sectional view showing an example of the layer structure of a laminated sheet that constitutes the body of a paper tube-shaped container according to the first to third embodiments. 7(a) is a front perspective view of an example of a conventional paper tube container, and (b) is an enlarged cross-sectional view taken along line BB in FIG.

Below, we will explain examples of embodiments of the paper tube container according to the present invention, referring to the drawings as necessary.

<Paper tube container according to the first embodiment>
A paper tubular container 100 according to a first embodiment will be described with reference to Fig. 1 and Fig. 4 to Fig. 6. Fig. 1(a) is a front perspective view of the paper tubular container 100 according to the first embodiment before the peel-off piece 20 is turned over. Fig. 1(b) is a front perspective view of the paper tubular container 100 according to the first embodiment after the peel-off piece 20 is turned over. Fig. 5 is an enlarged cross-sectional view taken along line A-A in the vicinity of the spout 3 in Fig. 4. Fig. 6 is a cross-sectional view showing an example of the layer structure of the laminated sheet 50 constituting the body 10 of the paper tubular container 100 according to the first embodiment.

As shown in FIG. 1, the paper tube container 100 includes a body 10 capable of containing contents and a spout 3. The body 10 has a bottom 2 located at one end that is closed, and contains contents (not shown). The spout 3 is attached to the other end of the body 10, and as shown in FIG. 5, includes a flat closure 4 that is perpendicular to the height direction of the body 10 so that the other end of the body 10 can be closed. In FIG. 1, the height direction of the body 10 refers to the axial direction of the body 10 that connects the bottom 2 located at one end of the body 10 and the spout 3 attached to the other end of the body 10.

As an example, the body 10 is formed by forming a laminated sheet 50 having a pair of approximately parallel edges into a cylindrical shape, then gluing the bottom 2 and the inner surfaces of the edges of the laminated sheet 50, which are the edges along the height direction of the body 10, together in a palm-to-palm joint (not shown), and then laying the palm-to-palm joint to one side so that the paper layers 52 on the surface come into contact with each other and are bonded together with an adhesive or the like.

As shown in FIG. 6, the laminated sheet 50 is made up of an ink layer 51, a paper layer 52, an adhesive layer 53, and a transparent laminate film layer 54, layered in this order from the outermost layer side. Also, as shown in FIG. 1, the body 10 has a release piece 20 that is peeled off via the adhesive layer 53.

This release piece 20 is formed by the hinge portion 30 and a cut 40 made in the paper layer 52 leaving the hinge portion 30. The cut 40 is formed by a perforation that penetrates only the paper layer 52 or by a half cut in the paper layer 52 (FIG. 1 shows the cut as a perforation), and is formed leaving the hinge portion 30, so that the release piece 20 peeled off via the adhesive layer 53 is formed as a so-called window portion in the body portion 10 that can be opened and closed.

1(b), by flipping over the peel-off piece 20 after starting use, the internal condition, such as the remaining amount of the contained contents, can be confirmed through the transparent laminate film layer 54. Furthermore, the peel-off piece 20 is not completely peeled off by the hinge portion 30, but can be flipped over while still connected by the hinge portion 30, and since the body portion 10 has a structure that allows it to be opened and closed, there is no risk of the peel-off piece 20 being peeled off during distribution or use, leaving the transparent laminate film layer 54 exposed, and therefore the strength and light-blocking properties of the body portion 10 can be maintained.

In addition, it is preferable that the start of turning is indicated by printing or the like so that the start of turning can be seen, and that one or more of the following treatments are applied between the paper layer 52 and the adhesive layer 53: application of a weak adhesive, application of a release varnish, or application of a glue-killing treatment, to make it easier to turn the peel-off piece 20. Note that, even though it is called a perforation, it is preferable that the part where the start of turning is indicated by the above printing or the like is a straight cut 40, not a perforation, to a length that can be turned with a finger, so that the transparent laminate film layer 54 is exposed by turning along the cut 40. In addition, in the case of a half cut, it is preferable that the part where the start of turning is indicated by the above printing or the like is a cut 40 that penetrates the paper layer 52, not a half cut, to a length that can be turned with a finger, so that the transparent laminate film layer 54 is exposed by turning along the cut 40.

1, the position at which the peel-off piece 20 is formed is at a position on the front surface at the boundary between the spout 3 and the body 10 where it overlaps with the edge of the closure 4, and the portion that overlaps with the edge of the closure 4 serves as a hinge portion 30, with an inverted U-shaped cut 40 formed from that portion toward one end of the body 10. This portion that overlaps with the edge of the closure 4 at the boundary between the spout 3 and the body 10 is already folded when the paper tubular container 100 is formed, so there is no need to turn over the peel-off piece 20 and fold it at the hinge portion 30 after starting use.

The position and shape of the peel-off piece 20, i.e., the position and shape of the cut 40, are not particularly limited as long as the internal condition, such as the amount of remaining content, can be confirmed by flipping over the peel-off piece 20, and can be arbitrarily selected depending on the size and shape of the paper tube container 100.

As described above, as shown in FIG. 6, the laminated sheet 50 is formed by laminating an ink layer 51, a paper layer 52, an adhesive layer 53, and a transparent laminate film layer 54 in this order from the outermost layer side. The transparent laminate film layer 54 is formed by laminating, for example, a barrier layer 55, a base film layer 56, and a sealant layer 57 in this order from the outermost layer side.

Next, we will explain each layer that makes up the laminated sheet 50.

(paper layer)
The material used for the paper layer 52 is not particularly limited as long as it is opaque and has light-shielding properties, but it is possible to use Unryu paper for aesthetic purposes, thick craft paper for rigidity, etc. Furthermore, the paper layer 52 can be defined as containing cellulose fibers by containing 5% or more cellulose fibers, which distinguishes it from synthetic paper made by papermaking resin fibers.

The basis weight of the paper layer 52 is preferably 20 g/m ² or more and 200 g/m ² or less. Among them, it is more preferable that the basis weight is 50 g/m ² or more and 150 g/m ² or less. If the basis weight of the paper layer 52 is less than 20 g/m ² , the light blocking property is poor, and it becomes difficult to bond the paper layer 52 and the transparent laminate film layer 54. In addition, the paper layer 52 is too thin, and it becomes difficult to perform scratch processing, which is the incision 40 for forming the peeling piece 20. If the basis weight of the paper layer 52 exceeds 200 g/m ² , the paper layer 52 becomes hard, and it becomes difficult to fold the pleats when welding to the spout part 3.

The paper layer 52 has perforations 40 that run through it.

(Barrier Layer)
The barrier layer 55 is laminated to block oxygen, water vapor, and the like, and to improve the preservation properties of the contents.

The barrier layer 55 is transparent and may be composed of at least one of the following: a vapor deposition film of an inorganic compound such as nylon, silica, or alumina; a vapor deposition film of a metal such as aluminum; a metal foil such as aluminum; a coating of a barrier coating agent containing a plate-like mineral and/or a barrier resin. As the barrier resin used in the barrier coating agent, ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), etc. may be used, and a binder resin other than the barrier resin is appropriately blended in the barrier coating agent. The barrier layer 55 may be laminated in advance on the base film layer 56 to form a barrier film, or may be provided as a single layer film.

(Base Film Layer)
The material used for the base film layer 56 is not particularly limited as long as it has transparency, but from the viewpoints of heat resistance, toughness when heated, and physical strength, stretched films of polyolefin, polyester, polyamide such as nylon, etc. are preferred.

(Sealant Layer)
The sealant layer 57 is the innermost layer of the laminated sheet 50, and is a thermoplastic resin layer. The sealant layer 57 is a layer that is sealed when the laminated sheet 50 is formed into a cylindrical shape. In addition, since the sealant layer 57 is a layer that adheres the body 10 formed into a cylindrical shape to the spout 3, it is preferable that the sealant layer 57 is suitable for adhesion to the spout 3, and is preferably made of the same material as the thermoplastic resin used for the spout 3. By using the same thermoplastic resin for the sealant layer 57 as the thermoplastic resin layer used for the spout 3, the seal strength between the body 10 and the spout 3 can be improved.

The material used for the sealant layer 57 is not particularly limited as long as it is a transparent thermoplastic resin, but examples thereof include polypropylene, polyethylene, cyclic polyolefin, and polyester. The softening temperature of the sealant layer 57 must be at least 20°C lower than the softening temperature of the base film layer 56, and is preferably at least 40°C lower. If the softening temperature of the base film layer 56 minus the softening temperature of the sealant layer 57 is less than 20°C, the base film layer 56 will soften when sealing the body 10 to form the laminated sheet 50 into a cylindrical shape, increasing the possibility of tiny holes (pinholes) occurring in the body 10.

(Adhesive Layer)
The adhesive layer 53 is a layer for enabling adhesion and peeling between the paper layer 52 and the transparent laminate film layer 54. In Fig. 6, the adhesive layer 53 is laminated between the paper layer 52 and the barrier layer 55 which is the outermost layer of the transparent laminate film layer 54.

The adhesive layer is made of a transparent thermoplastic resin, which contains one or more of various hot melt materials, such as polyolefin, polyacrylic acid, PE-based or PP-based. There are no particular limitations on the composition as long as it can be heat-sealed to the outermost layer (barrier layer 55 in FIG. 6) constituting the transparent laminate film layer 54, but it is preferable to use the same material as the outermost layer (barrier layer 55 in FIG. 6) constituting the transparent laminate film layer 54, as this will provide a higher adhesive strength.

The adhesive strength between the paper layer 52 and the transparent laminate film layer 54 is preferably 0.5 N/15 mm or more and 7 N/15 mm or less. Among them, an adhesive strength of 1 N/15 mm or more and 3 N/15 mm or less is more preferable. If the adhesive strength between the paper layer 52 and the transparent laminate film layer 54 is less than 0.5 N/15 mm, the strength is insufficient and the paper layer 52 and the transparent laminate film layer 54 will float. If the adhesive strength between the paper layer 52 and the transparent laminate film layer 54 exceeds 5 N/15 mm, the adhesive strength between the paper layer 52 and the transparent laminate film layer 54 becomes too strong, making it difficult to open and close the peelable piece 20 made of the paper layer 52. In addition, the adhesive strength of the adhesive layer 53 attached to the transparent laminate film layer 54 is set to be weaker than the adhesive state of the cured sealant layer 57.

In addition, to provide a location where the peeling (turning over) of the release piece 20 begins to occur via the adhesive layer 53, making it easier to turn over the release piece 20, one or more of the following may be applied between the paper layer 52 and the adhesive layer 53: application of a weak adhesive, application of a release varnish, or a glue-killing treatment.

The micro-adhesive and release varnish contain, for example, an acrylic resin, a silicone resin, or a garbage-based resin and a crosslinking agent. The adhesive-killing treatment is, for example, a method of printing ink or varnish.

(Ink layer)
The ink layer 51 is a layer applied by printing to provide various displays. In FIG. 6, the ink layer 51 is laminated only partially on the surface of the paper layer 52 opposite the adhesive layer 53, but the location where the ink layer 51 is laminated is not particularly limited.

The type of ink used in the ink layer 51 is not particularly limited, but it is preferable to select one that is suitable for the printing method and printing substrate. The printing method for the ink layer 51 is not particularly limited, but general printing methods such as gravure printing, offset printing, and flexographic printing can be used.

The body 10 of the paper tube container 100 of the present invention does not need to have an ink layer 51, and only needs to be laminated with at least the paper layer 52, the adhesive layer 53, and the transparent laminate film layer 54 in this order from the outermost layer side.

The laminate sheet 50 using the above layers is produced, for example, as follows.

An ink layer 51 is laminated (printed) on one side of the paper layer 52, and a perforated cut 40 is made in advance in the paper layer 52 using a die cutter or the like with a blade so that the peelable piece 20 is formed. When half-cut cuts 40 are made in the paper layer 52, they can be made with a blade or a laser device. In addition, a base film layer 56 and a barrier layer 55 are laminated in this order on the sealant layer 57, and then dry laminated with a dry lamination adhesive to produce a transparent laminate film layer 54.

An adhesive layer 53 is laminated on the surface of the barrier layer 55 opposite the base film layer 56, and a paper layer 52 printed with cuts 40 is supplied in a striped pattern with the printed side facing up and laminated on the surface of the adhesive layer 53 opposite the barrier layer 55. The paper layer 52 and the transparent laminate film layer 54 are bonded together by extruder lamination using the adhesive layer 53.

The laminated sheet 50 preferably has a thickness of 30 μm or more and 300 μm or less. This thickness makes it easy to squeeze out the contents with light force in a paper tube-shaped container 100 using a body 10 made of the laminated sheet 50. In addition, when squeezing out the contents, the body 10 can be crushed evenly all the way to the ends, reducing the radius of curvature at the widthwise ends of the body 10 and reducing the amount of content remaining.

The body 10 can be produced using the laminated sheet 50 as follows, for example.

The body 10 is formed, for example, by gluing together the inner faces of band-shaped portions including each of a pair of edges of a laminated sheet 50 having a pair of approximately parallel edges, then turning the gluing portions to one side and bringing the paper layers 52 on the surfaces into contact with each other and bonding them together with an adhesive or the like. The body 10 can be made using a bag making machine, a pillow stick packaging machine, or the like. The bottom 2 located at one end of the body 10 is closed, and the contents are then placed inside.

The method for bonding the laminated sheets 50 together in the bottom 2 is not particularly limited, but for example, a method can be used in which an adhesive layer containing polyethylene is provided between the innermost layers of the opposing laminated sheets 50 and they are heat-welded. In addition, the other end of the body 10 is sealed to the spout 3.

Next, we will explain the structure near the spout 3 of the paper tube container 100.

As shown in FIG. 1, FIG. 4, and FIG. 5, the spout 3 is disposed at the top 1 located at the other end of the body 10.
1 and is a member that can close the top 1 of the body 10. As described above, the spout 3 has a flat closure 4 that is perpendicular to the height direction of the body 10.

The closure 4 is, for example, disk-shaped, but the shape is not limited as long as it is flat, and may be elliptical, oval, polygonal, etc. The material of the outlet 3 is not particularly limited, but a resin material such as low-density polyethylene can be preferably used. In addition, by using a material with a barrier function for the outlet 3 as well as the body 10, the barrier function of the entire paper tube container 100 is improved, and the quality of the contents can be better protected. The outlet 3 with the closure 4 formed in a flat plate can reduce the material used compared to the outlet 3 according to the conventional technology, which is formed in a tapered shape.

As an example, the closure portion 4 has a circular half cut 6 in the approximate center, and a pull ring 7 inside the half cut 6. By providing the half cut 6 and the pull ring 7 in the closure portion 4, the user of the paper tube-shaped container 100 can form an opening in the closure portion 4 for removing the contents by pulling the pull ring 7 and removing a part of the closure portion 4 along the half cut 6. Note that an opening for removing the contents may be formed in advance in the closure portion 4 without providing the half cut 6 and pull ring 7.

The top 1 of the body 10 is attached to the surface of the outlet 3 opposite the bottom 2 of the body 10 at the peripheral portion 5 of the outlet 3. In FIG. 5, the top 1 of the body 10 is bonded to the surface of the closure 4 opposite the bottom 2 of the body 10 at the edge (peripheral portion 5) of the closure 4.

The method of welding the body 10 and the closure 4 is not particularly limited, but for example, a method can be used in which a sealant layer 57 containing polyethylene is provided on the innermost layer of the laminated sheet 50, and the spout 3 is formed from a material containing polyethylene, and then these are heat-welded. In addition, the body 10 and the closure 4 can be welded together while creating pleats that are equally spaced around the periphery of the closure 4 at the top 1 of the body 10.

In addition, the paper tube container 100 further includes, as an example, a hinge cap (not shown) that is attached to the spout portion 3.

The hinge cap is a member that is attached to the spout 3 and allows the opening formed in the spout 3 to be closed and opened.

The form for closing and opening the opening formed in the spout 3 is not limited to a hinge cap, and may include, for example, a cylindrical portion having an external thread provided in the spout 3 and a cap having an internal thread that can be screwed onto the external thread.

In the paper tube container 100, the spout 3 has a flat closure 4 that is perpendicular to the height direction of the body 10, and the top 1 of the body 10 is glued to the side of the closure 4 opposite the bottom 2 of the body 10 at the edge of the closure 4. Therefore, by bending the body 10 at the edge of the closure 4 with fingers or the like, the small amount of content remaining in the body 10 can be pushed out toward the periphery of the opening of the spout 3 by pinching it between the inner flat surface of the closure 4 and the inner surface of the body 10.

In addition, since the blocking portion 4 of the outlet 3 is flat, unlike the outlet 3 formed in a tapered shape as in the prior art, it does not have a space on the inside that would allow the contents to remain. Therefore, the contents pushed out toward the periphery of the opening of the outlet 3 can be squeezed out from the opening without remaining inside the body 10 and the outlet 3. As a result, it is possible to suppress the contents from remaining inside the container.

As described above, in the paper tube-shaped container 100, the contents can be squeezed out while bending the body 10, thereby preventing the contents from remaining. For this reason, it is preferable to form the body 10 from a laminated sheet 50 that has low rigidity (is not very stiff), which allows the body 10 to be easily bent.

As described above, by setting the thickness of the laminated sheet 50 constituting the body 10 to 30 μm or more and 300 μm or less, in the paper tube-shaped container 100 using the body 10 composed of the laminated sheet 50, the contents can be easily squeezed out with light force, and the amount of contents remaining can be reduced. In addition, the body 10 can be easily folded.

In addition, when the above-mentioned hinge cap is provided as the cap, the rigidity against twisting required for the body 10 that is grasped by hand when opening the cap can be reduced compared to the case where a cap is provided that screws onto the closure portion 4 and is opened by rotating it, so it is preferable to use a laminated sheet 50 with low rigidity.

<Paper tube container according to the second embodiment>
A paper tubular container 101 according to a second embodiment will be described with reference to Fig. 2 and Fig. 4 to Fig. 6. Fig. 2 is a front perspective view of the paper tubular container 101 according to the second embodiment before the peelable piece 21 is turned over. Fig. 4 is a side view of the paper tubular container 101 according to the second embodiment. Fig. 5 is an enlarged cross-sectional view taken along line A-A in the vicinity of the spout 3 in Fig. 4. Fig. 6 is a cross-sectional view showing an example of the layer structure of the laminated sheet 50 constituting the body 11 of the paper tubular container 101 according to the second embodiment.

The only difference between the paper tube container 101 of the second embodiment and the paper tube container 100 of the first embodiment is the position where the peel-off piece is formed. The rest of the two are the same, so a description of the rest will be omitted.

As shown in FIG. 2, the peeling piece 21 is formed at approximately the center of the body 11 on the front side, with the part from the center toward one end of the body 11 serving as the hinge part 31 and a U-shaped cut 41 formed from that part toward the other end of the body 11.

<Third embodiment of paper tube container>
A paper tubular container 102 according to a third embodiment will be described with reference to Fig. 3 and Fig. 4 to Fig. 6. Fig. 3 is a front perspective view of the paper tubular container 102 according to the third embodiment before the peelable piece 22 is turned over. Fig. 4 is a side view of the paper tubular container 102 according to the third embodiment. Fig. 5 is an enlarged cross-sectional view taken along line A-A in the vicinity of the spout 3 in Fig. 4. Fig. 6 is a cross-sectional view showing an example of the layer structure of the laminated sheet 50 constituting the body 12 of the paper tubular container 102 according to the third embodiment.

The only difference between the paper tube container 102 of the third embodiment and the paper tube container 100 of the first embodiment is the position where the peel-off piece is formed. Since the rest of the two are the same, a description of the rest will be omitted.

As shown in FIG. 3, the peel piece 22 is formed at a position on the front surface that overlaps with the edge of the other end of the body 12 of the bottom 2, and the part that overlaps with the edge of the other end of the body 12 is the hinge part 32, and an inverted U-shaped cut is formed from this part toward one end of the body 12.

The position at which the peeling piece is formed is not limited to the positions of the peeling pieces according to the first to fourth embodiments described above, but may be, for example, a combination of two or more of the positions of the peeling pieces according to the first to third embodiments.

The inventors of the present application conducted tests using the paper tube-shaped containers of Examples 1 to 3 and Comparative Examples 1 to 4 to confirm the ease of peeling off the peelable strip, the strength of the body (drop resistance, impact resistance), and the light-blocking properties.

Next, we will explain the body parts of Examples 1 to 3 and Comparative Examples 1 to 4.

Example 1
The laminated sheet constituting the trunk section in Example 1 used unbleached kraft paper (manufactured by Oji F-Tex Co., Ltd.) with a basis weight of 70 g/ ^m2 as the paper layer, and a transparent laminate film layer in which a 15 μm-thick nylon (manufactured by Unitika Ltd., product name: ONBC) and a 12 μm-thick transparent barrier film (manufactured by Toppan Printing Co., Ltd., product name: GL-ARH-F) were bonded in this order by dry lamination using an adhesive on a 50 μm-thick polyethylene (manufactured by Tamapoly Co., Ltd., product name: SE620A).

In the paper layer, perforated cuts were made in advance using a die cutter with a blade so that a peelable piece would be formed. The position where the peelable piece was formed was the same as in the paper tubular container 101 according to the second embodiment described above, at approximately the center of the body on the front side, with the part on one end side of the body from the center serving as a hinge part, and a U-shaped cut was made from that part toward the other end of the body.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive with an adhesive strength of 0.5 N/15 mm between the paper layer and the transparent laminate film layer.

Example 2
The laminated sheet constituting the trunk portion in Example 2 used unbleached kraft paper (manufactured by Oji F-Tex Co., Ltd.) with a basis weight of 120 g/ ^m2 as the paper layer, and the same transparent laminate film layer as in Example 1 was used.

The paper layer was pre-cut with perforations so that the peelable pieces would be formed in the same position and shape as in Example 1.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive with an adhesive strength of 1.5 N/15 mm between the paper layer and the transparent laminate film layer.

Example 3
The laminated sheet constituting the body in Example 3 used unbleached kraft paper (manufactured by Oji F-Tex Co., Ltd.) with a basis weight of 80 g/ ^m2 as the paper layer, and the same transparent laminate film layer as in Example 1 was used.

The paper layer was pre-cut with perforations so that the peelable pieces would be formed in the same position and shape as in Example 1.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive having an adhesive strength of 2.8 N/15 mm between the paper layer and the transparent laminate film layer.

(Comparative Example 1)
The laminated sheet constituting the body in Comparative Example 1 was the same as that in Example 1, both in terms of the paper layer and the transparent laminate film layer.

The paper layer was pre-cut with perforations so that the peelable pieces would be formed in the same position and shape as in Example 1.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive with an adhesive strength of 0.1 N/15 mm between the paper layer and the transparent laminate film layer.

(Comparative Example 2)
The laminated sheet constituting the body in Comparative Example 2 was the same as that in Example 1, both in terms of the paper layer and the transparent laminate film layer.

The paper layer was pre-cut with perforations so that the peelable pieces would be formed in the same position and shape as in Example 1.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive with an adhesive strength of 10.0 N/15 mm between the paper layer and the transparent laminate film layer.

(Comparative Example 3)
In the laminated sheet constituting the trunk portion in Comparative Example 3, paper having a basis weight of 300 g/m ² was used as the paper layer, and the same transparent laminate film layer as in Example 1 was used.

The paper layer was pre-cut with perforations so that the peelable pieces would be formed in the same position and shape as in Example 1.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive with an adhesive strength of 1.8 N/15 mm between the paper layer and the transparent laminate film layer.

(Comparative Example 4)
The laminated sheet constituting the body in Comparative Example 4 was the same as that in Example 1, both in terms of the paper layer and the transparent laminate film layer.

In the case of Example 4, no cuts were made in the paper layers, and instead, as shown in FIG. 7, the laminated sheet was rolled up to separate a pair of opposing edges of the sheet, and a transparent tape material was attached to the inner periphery of the body of the sheet so as to cover the pair of edges with the inner periphery of the body while joining the pair of edges, thereby allowing the inside to be seen.

The paper layer and the transparent laminate film layer were bonded together by extruder lamination using an adhesive with an adhesive strength of 2.0 N/15 mm between the paper layer and the transparent laminate film layer.

(Evaluation items and test methods)
[Ease of peeling off the peeled piece]
The ease of peeling off the peel strip via the adhesive between the paper layer and the transparent laminate film layer was evaluated.
[Drop test]
Based on JIS Z0200, each paper tube-shaped container was placed in a cardboard box and packaged together, and a drop test was performed, measuring the drop height at 80 cm (level 1).
[Random vibration test]
Based on JIS Z0200, each paper tube-shaped container was placed in a cardboard box and packaged together, and a random instruction test was conducted to measure under level 1 conditions.
[Light blocking property]
The presence or absence of exposure of the transparent portion (the transparent laminate film layer or tape material) was visually evaluated.

(Test results and discussion)
The test results according to the above test methods are shown in Table 1.
In Table 1, the evaluation item "ease of peeling off" was evaluated as ◯ when the peeling off piece was particularly easy to peel off, ◯ when the peeling off piece was easy to peel off, and × otherwise. The evaluation items "drop test" and "vibration test" were evaluated as ◯ when the contents did not leak, and × when the contents leaked. The evaluation item "light blocking" was evaluated as ◯ when the transparent part (transparent laminate film layer or tape material) was not exposed and had light blocking properties, and × when the transparent part was completely exposed. In addition, the above evaluation items were evaluated comprehensively, and good was evaluated as ◯, close to poor was evaluated as △, and poor was evaluated as ×.

For Examples 2 and 3, the "ease of peeling off the peelable piece" was rated as ◎, while all other evaluation items for Examples 1 to 3 were rated as 〇, and therefore the overall evaluation for Examples 1 to 3 was 〇.

On the other hand, in Comparative Example 1, the adhesive strength between the paper layer and the transparent laminate film layer was too weak, so the paper layer and the transparent laminate film layer remained peeled off. In Comparative Example 2, on the other hand, the adhesive strength between the paper layer and the transparent laminate film layer was too strong, so the peeled piece was difficult to peel off. In Comparative Example 3, the paper was too thick and hard, and the pleats could not be folded when welding to the spout, so the body could not be attached to the spout and it was not possible to form a paper tube-shaped container, so it was not possible to evaluate. In Comparative Example 4, a part of the transparent tape material was always completely exposed, so there was no light-blocking property.

From the above test results, it can be seen that when the basis weight of the paper layer is 20 g/ ^m2 or more and 200 g/m2 or ^less , the adhesive strength between the paper layer and the transparent laminate film layer is 0.5 N/15 mm or more and 7 N/15 mm or less, and further, there is a hinge portion and a peel-off piece formed by cutting into the paper layer leaving the hinge portion, the peel-off piece can be easily peeled back to allow the internal condition to be confirmed, and the strength and light-blocking properties of the body can be maintained.

As described above, the paper tube container of the present invention has a body in which the contents are accommodated, which is laminated from the outermost layer side with at least a paper layer, an adhesive layer, and a transparent laminate film layer in that order, and has a release piece that can be peeled off via the easily peelable layer. The release piece is also formed by a hinge portion and a cut made in the paper layer leaving the hinge portion.
Therefore, by peeling back the peelable strip after starting use, the internal condition, such as the remaining amount of the contained contents, can be confirmed through the transparent laminate film layer. In addition, the peelable strip is not completely peeled off by the hinge portion, but can be peeled back while still connected by the hinge portion, and since the structure allows the body portion to be opened and closed by the adhesive layer, there is no risk of the peelable strip being peeled off during distribution or use, leaving the transparent laminate film layer exposed, and therefore it is possible to maintain the strength and light-shielding properties of the body portion.

1: Top portion 2: Bottom portion 3: Spout portion 4: Closure portion 5: Periphery portion (edge of the closure portion)
6: Annular half cut 7: Pull ring 10, 11, 12: Body 20, 21, 22: Release pieces 30, 31, 32: Hinge section 40, 41, 42: Cuts 100, 101, 102: Paper tube container 50: Laminated sheet 51: Ink layer 52: Paper layer 53: Adhesive layer 54: Transparent laminate film layer 55: Barrier layer 56: Base film layer 57: Sealant layer 60: Body of conventional paper tube container 61: Paper sheet 62: Transparent tape material

Claims (4)

A paper tube-shaped container including a body portion having one end closed and capable of accommodating a content, and a spout portion attached to the other end of the body portion and capable of closing the other end of the body portion,
the body portion has at least a paper layer, a pressure-sensitive adhesive layer, and a transparent laminate film layer laminated in this order from the outermost layer side, and has a release piece that is peeled off via the pressure-sensitive adhesive layer;
The peelable piece is formed by a hinge portion provided at a portion that overlaps an edge of the spout portion and a cut made in the paper layer leaving the hinge portion,
A paper tube-shaped container, characterized in that the adhesive strength between the paper layer and the transparent laminate film layer is 1 N/15 mm or more and 3 N/15 mm or less. The paper tube container according to claim 1, wherein the paper layer has a basis weight of 20 g/m2 or ^more and 200 g/ ^m2 or less. The paper tube container according to claim 1 or 2, characterized in that the other end of the body is attached to the surface of the spout portion opposite the one end of the body, at the periphery of the spout portion. The paper tube container according to claim 3, characterized in that the spout portion has a flat closure portion perpendicular to the height direction of the body portion, the peripheral portion is an edge of the closure portion, and the other end of the body portion is bonded to the surface of the closure portion opposite the one end side of the body portion at the peripheral portion.