Aluminum laminated paper tube and method for manufacturing the same

Abstract

To provide a cylindrical paper-made molded product excellent in durability, airtightness and noncombustibility in spite of being lightweight.SOLUTION: The aluminum laminated paper tube 1 comprises a cylindrical intermediate layer 10 including one or a plurality of paper layers, an inner layer 20 including an aluminum foil provided on the inner surface side of the intermediate layer 10, and an outer layer 30 including an aluminum foil provided on the outer surface side of the intermediate layer 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cylindrical paper tube laminated with aluminum foil and a method for manufacturing the same. [Background technology]

[0002] Conventionally, aluminum foil-laminated cardboard has been used as a building material for air conditioning ducts and the like (Patent Document 1, Patent Document 2). For example, Patent Document 1 discloses a non-flammable cardboard box in which the front or back of a corrugated cardboard box (core material) with a core portion made of a combustible material is covered with aluminum foil. This non-flammable cardboard box is delivered to the construction site in an unfolded plate-like state, and can then be folded along the creases to form it into a rectangular tube.

[0003] This type of aluminum-laminated cardboard is lightweight yet durable, airtight, and non-flammable, and can be assembled into a rectangular tube on-site and used as an air-conditioning duct, making it easy to install on-site. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-001095 [Patent Document 2] Japanese Patent Publication No. 2020-020530 Summary of the Invention [Problem to be solved by the invention]

[0005] While conventional aluminum-laminated cardboard is suitable for applications in which it is molded into cylindrical shapes such as square or other polygonal shapes, the nature of the cardboard makes it difficult to mold it into a cylindrical shape. On the other hand, for example, some air conditioning ducts are cylindrical, so there is a certain demand for cylindrical molded products laminated with aluminum foil.

[0006] Furthermore, conventional aluminum-laminated cardboard is first manufactured into a flat, unfolded sheet and then folded into a rectangular tube or other shape for use as a duct. Therefore, the length of the rectangular tube-shaped duct depends on the length of the unfolded cardboard. Since the length of the unfolded cardboard is limited by the capacity of the manufacturing equipment, the length of the rectangular tube-shaped duct is also naturally limited. Therefore, when a duct longer than the capacity of the cardboard manufacturing equipment is required, it is necessary to secure the desired length by connecting multiple ducts assembled from cardboard. However, connecting multiple ducts presents a problem: the airtightness, durability, and non-flammability of the duct are reduced at the joints.

[0007] Therefore, one of the objects of the present invention is to provide a cylindrical paper product that is excellent in durability, airtightness, and non-combustibility, and to provide a technique for manufacturing such a cylindrical paper product by a method that makes it easy to adjust its length. [Means for solving the problem]

[0008] The inventors of the present invention have intensively studied means for solving the problems of conventional inventions, and have discovered that by using a cylindrical paper tube as a core material instead of cardboard and covering both the front and back sides of this paper tube with aluminum foil, a cylindrical paper molded product with excellent durability, airtightness, and non-combustibility can be obtained. Based on this discovery, the inventors have come to the realization that the problems of the conventional technology can be solved, and have completed the present invention. Specifically, the present invention has the following configuration or steps.

[0009] A first aspect of the present invention relates to a paper tube 1 laminated with aluminum foil (also referred to as an "aluminum-laminated paper tube"). The aluminum-laminated paper tube 1 according to the present invention has a cylindrical middle layer 10 including one or more paper layers, an inner layer 20 including aluminum foil provided on the inner surface of the middle layer 10, and an outer layer 30 including aluminum foil provided on the outer surface of the middle layer 10. Note that the "cylindrical shape" referred to here is not limited to a hollow portion having a perfect circle in cross section, but also includes shapes in which the cross section of the hollow portion is approximate to a circle without corners, such as an ellipse, a rounded square, or an egg shape. As described above, the middle layer 10 (core portion) of the aluminum-laminated paper tube 1 employs a cylindrical paper tube formed from one or more cardboards. In the present invention, the front and back sides of this paper tube are covered with aluminum foil. By attaching aluminum foil to both sides of the paper tube in this way, a cylindrical molded product can be obtained that is lightweight yet has excellent durability, airtightness, and non-flammability. The aluminum laminated paper tube 1 according to the present invention can be suitably used as a building material, for example, an air conditioning duct.

[0010] In the aluminum laminated paper tube 1 according to the present invention, the inner layer 20 and the outer layer 30 preferably include overlapping portions 20a, 30a where aluminum foil is partially overlapped. By attaching the aluminum foil so that it is partially overlapped in this manner, the paper portion is less likely to be exposed on the front and back sides, thereby improving durability, airtightness, and non-flammability.

[0011] In the aluminum-laminated paper tube 1 according to the present invention, the inner layer 20 and the outer layer 30 are preferably formed by spirally winding strip-shaped aluminum foil around the middle layer 10. By attaching the strip-shaped aluminum foil to the middle layer 10 (paper tube) by spiral winding in this way, the inner layer 20 and the outer layer 30 can each be formed without gaps using a single strip-shaped aluminum foil sheet, making it possible to efficiently manufacture the aluminum-laminated paper tube 1.

[0012] In the aluminum laminated paper tube 1 according to the present invention, the width (W2) of the aluminum foil forming the inner layer 20 may be shorter than the width (W3) of the aluminum foil forming the outer layer 30. In this way, making the width of the aluminum foil forming the inner layer 20 relatively narrow leads to improved strength of the entire aluminum laminated paper tube 1. On the other hand, keeping the width of the aluminum foil forming the outer layer 30 relatively wide reduces the number of seams when the aluminum laminated paper tube 1 is viewed externally, thereby improving the appearance of the aluminum laminated paper tube 1.

[0013] In the aluminum laminated paper tube 1 according to the present invention, conversely to the above, the width (W3) of the aluminum foil forming the outer layer 30 may be made shorter than the width (W2) of the aluminum foil forming the inner layer 20. By making the width of the aluminum foil forming the outer layer 30 relatively narrow in this way, it is possible to further improve the airtightness and non-flammability of the aluminum laminated paper tube 1. On the other hand, by maintaining the width of the aluminum foil forming the inner layer 20 relatively wide, it is possible to reduce the amount of aluminum foil material and the number of times the aluminum foil is wrapped, thereby reducing the manufacturing cost of the aluminum laminated paper tube 1.

[0014] A second aspect of the present invention relates to a method for manufacturing an aluminum-laminated paper tube 1. The manufacturing method according to the second aspect of the present invention is basically a method for efficiently manufacturing the aluminum-laminated paper tube 1 according to the first aspect described above. In the manufacturing method according to the present invention, first, an inner layer 20 is formed by spirally winding a strip of aluminum foil 20' around a winding rod 40 having a circular cross section (including a cylindrical cross section) (first step). Next, a middle layer 10 is formed by spirally winding one or more layers of strip-shaped cardboard 10' around the inner layer 20 while it is wound around the winding rod 40 (second step). Furthermore, an outer layer 30 is formed by spirally winding a strip of aluminum foil 30' around the middle layer 10 while it is wound around the winding rod 40 (third step). Then, the raw tube 1' including the inner layer 20, middle layer 10, and outer layer 30 is cut to a predetermined length (fourth step). This results in a cylindrical aluminum-laminated paper tube 1 of a predetermined length. In this way, by forming a cardboard middle layer 10 (paper tube), an aluminum inner layer 20, and an aluminum outer layer 30 by spirally winding the tube around the winding rod 40, it becomes easy to adjust the length of the aluminum laminated paper tube 1 from short to long.

[0015] In the manufacturing method according to the present invention, the step of forming the outer layer 30 (third step) preferably involves spirally winding a strip of aluminum foil onto the middle layer 10 so that the side edges of the paper that forms the middle layer 10 do not overlap with the side edges of the aluminum foil that forms the outer layer 30. If the boundary lines (side edges) between the cardboard that forms the middle layer 10 and the aluminum foil that forms the outer layer 30 overlap, gas or liquid may reach the middle layer 10 beyond the outer layer 30 and further affect the inner layer 20. For this reason, by intentionally preventing the seams between the middle layer 10 and the outer layer 30 from overlapping, the durability, airtightness, and non-flammability of the aluminum-laminated paper tube 1 can be maintained. [Effects of the Invention]

[0016] According to the present invention, a cylindrical paper molded product can be provided that is lightweight yet has excellent durability, airtightness, and non-combustibility. Furthermore, according to the present invention, a cylindrical paper molded product can be produced by a method that makes it easy to adjust its length. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view that schematically shows the appearance and internal structure of an aluminum-laminated paper tube. [Figure 2] FIG. 2 is a cross-sectional view showing the internal structure of the aluminum-laminated paper tube. [Figure 3] FIG. 3 is a schematic diagram showing an example of a manufacturing process for an aluminum-laminated paper tube. [Figure 4] FIG. 4 shows a schematic example of the width of each layer that constitutes an aluminum-laminated paper tube. [Figure 5] FIG. 5 shows a schematic example of the width of each layer constituting an aluminum-laminated paper tube. [Figure 6] FIG. 6 shows a schematic example of the width of each layer that constitutes an aluminum-laminated paper tube. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and includes appropriate modifications of the embodiments below within the scope obvious to those skilled in the art. In this specification, "A to B" means "A or more and B or less."

[0019] FIG. 1 shows an aluminum-laminated paper tube 1 according to one embodiment of the present invention. FIG. 2 shows the cross-sectional structure of the aluminum-laminated paper tube 1 taken along line II-II in FIG. 1. As shown in FIG. 1, the aluminum-laminated paper tube 1 has a cylindrical shape overall, with a hollow 2 formed around its central axis L. The aluminum-laminated paper tube 1 is mainly composed of a middle layer 10, an inner layer 20 formed on the inner side of this middle layer 10, and an outer layer 30 formed on the outer side of this middle layer 10. Note that the ratio of the length to the diameter in the direction of the central axis L of this aluminum-laminated paper tube 1 shown in FIG. 1 is one example, and the ratio of the length to the diameter can be changed as appropriate depending on the application.

[0020] The middle layer 10 is a core layer and is formed of one or more layers of cardboard. A typical paper tube can be used for the middle layer 10. Examples of cardboard materials that can be used for the cardboard tube include one or more of the following: kraft paper, recycled paper, paperboard (coated cardboard), laminated paper, chipboard, straw board, and synthetic paper. Examples of cardboard materials for the cardboard tube include wood pulp such as kraft pulp and chemical pulp, recycled pulp such as waste paper pulp, non-wood pulp such as bagasse pulp and straw pulp, and synthetic resins such as polyethylene and polypropylene. To improve the strength and durability of the aluminum-laminated cardboard tube 1, the middle layer 10 is preferably formed by stacking multiple layers of cardboard. For example, in the example shown in FIG. 2, the middle layer 10 is formed by bonding four layers of cardboard, consisting of a first layer 11, a second layer 12, a third layer 13, and a fourth layer 14, with an adhesive. As described above, the middle layer 10 can have a four-layer structure, but is not limited thereto and may have a two-layer or three-layer structure, or may have five or more layers of cardboard stacked together. The overall thickness of the middle layer 10 can be, for example, 3 to 20 mm, preferably 5 mm or more, and particularly preferably 10 mm or more. The overall thickness of the middle layer 10 can be adjusted by adjusting the number of cardboard layers and the thickness of each layer.

[0021] The inner layer 20 is a layer for covering the inner surface of the middle layer 10, which serves as the core material, and is formed of one or more layers of aluminum foil. By covering the entire inner surface of the middle layer 10 with aluminum foil without any gaps, the durability, airtightness, and non-combustibility of the cardboard tube can be improved. Either pure aluminum foil or alloy aluminum foil may be used as the aluminum foil for the inner layer 20. The thickness of the aluminum foil for the inner layer 20 is preferably 10 μm or more, more preferably 50 μm or more, and particularly preferably 100 μm or more. Specifically, the thickness of the aluminum foil is preferably 50 to 300 μm, and particularly preferably 100 to 200 μm.

[0022] The outer layer 30 is a layer for covering the outer surface of the middle layer 10, which serves as the core material, and is formed of one or more layers of aluminum foil, similar to the inner layer 20. By covering the entire outer surface of the middle layer 10 without any gaps with aluminum foil, the durability, airtightness, and non-combustibility of the cardboard tube are further improved. As with the inner layer 20, either pure aluminum foil or alloy aluminum foil may be used as the aluminum foil for the outer layer 30. Similarly to the inner layer 20, the thickness of the aluminum foil for the outer layer 30 is preferably 10 μm or more, more preferably 50 μm or more, and particularly preferably 100 μm or more. Specifically, the thickness of the aluminum foil is preferably 50 to 300 μm, and particularly preferably 100 to 200 μm.

[0023] As described above, both the inner layer 20 and the outer layer 30 are formed of aluminum foil. These aluminum foils are attached to the middle layer 10, which is formed from a paper tube, using an adhesive. Examples of adhesives include epoxy resin adhesives, polyurethane adhesives, silicone adhesives, acrylic adhesives, hot melt adhesives, and contact cement. Among these, it is preferable to use an epoxy resin adhesive or a polyurethane adhesive to bond the aluminum foil to the paper tube, from the viewpoint of excellent durability, airtightness, non-flammability, water resistance, and moisture resistance.

[0024] Figure 3 shows an example of a method for industrially manufacturing an aluminum-laminated paper tube 1. As shown in Figure 3, the manufacturing equipment for the aluminum-laminated paper tube 1 includes a winding rod 40, a spiral winding machine 50, a support stand 60, and a cutter 70. In Figure 3, the winding rod 40 is arranged in the range indicated by the double-headed arrow.

[0025] As shown in Figure 3, first, a strip of aluminum foil 20' for forming the inner layer 20 is pulled out from a roll around which the strip of aluminum foil is wound, and this strip of aluminum foil 20' is then wound obliquely around a winding rod 40 having a circular cross section. During this process, tension is applied to the strip of aluminum foil 20' in its longitudinal direction. The diameter of this winding rod 40 corresponds to the diameter of the hollow 2 of the aluminum-laminated paper tube 1 that will ultimately be obtained. The cross-sectional shape of the winding rod 40 is not limited to a perfect circle, and may be an ellipse, a rounded square, an egg, or any other shape that approximates a circle without corners.

[0026] The winding rod 40 rotates in a fixed direction around its central axis as the axis of rotation. Therefore, by winding the strip-shaped aluminum foil 20' obliquely around the winding rod 40, the strip-shaped aluminum foil 20' is pulled out from the roll as the winding rod 40 rotates, and gradually stretches in a spiral shape in the direction of the outline arrow shown in Figure 3.

[0027] Furthermore, when winding the strip-shaped aluminum foil 20' around the winding rod 40, it is advisable to adjust the winding position and winding angle of the aluminum foil 20' around the winding rod 40 so that the aluminum foils 20' partially overlap each other to prevent gaps from forming. As a result, the inner layer 20 of the final aluminum-laminated paper tube 1 will have an overlapping portion 20a where the strip-shaped aluminum foil 20' is partially overlapped in two layers.

[0028] Furthermore, an adhesive such as an epoxy resin adhesive is applied to the entire surface of the front side (i.e., the side opposite to the side that comes into contact with the winding rod 40) of the strip-shaped aluminum foil 20' unwound from the roll. This adhesive not only serves to bond the partially overlapped aluminum foils 20' together, but also serves to bond the strip-shaped cardboard 10' to the aluminum foil 20' when it is placed on top of the aluminum foil 20'.

[0029] Next, as shown in FIG. 3, a strip-shaped cardboard 10' consisting of multiple layers to form the middle layer 10 (cardboard tube) is obliquely wound around the aluminum foil 20' spirally wound around the winding rod 40. At this time, tension is applied to the strip-shaped cardboard 10' in its longitudinal direction. In the example shown in FIG. 3, the strip-shaped cardboard 10' is composed of four layers, the first layer 11' to the fourth layer 14', as in the example shown in FIG. 2. In addition, adhesive is applied in advance between the layers 11' to 14' of the cardboard 10'. Therefore, by drying the adhesive after winding the cardboard 10' around the winding rod 40, the cardboard 10' solidifies in a spiral shape to match the shape of the winding rod 40, forming a cylindrical cardboard tube. As mentioned above, the aluminum foil 20' located on the inner surface of the cardboard 10' is pre-applied with adhesive, so by winding the cardboard 10' over the aluminum foil 20', the two are bonded to each other. This allows the inner surface of the cardboard tube to be covered with aluminum foil 20'.

[0030] 3, a strip of aluminum foil 30' for forming the outer layer 30 is pulled out from a roll around which the strip of aluminum foil is wound, and this strip of aluminum foil 30' is wound obliquely onto the cardboard 10' that is spirally wound around a winding rod 40. At this time, tension is applied to the strip of aluminum foil 30' in the longitudinal direction.

[0031] Furthermore, when winding the strip-shaped aluminum foil 30' around the winding rod 40, it is advisable to adjust the winding position and winding angle of the aluminum foil 30' around the winding rod 40 so that the aluminum foil 30' partially overlaps with itself to prevent gaps from forming. As a result, the outer layer 30 of the final aluminum-laminated paper tube 1 will have an overlapping portion 30a where the strip-shaped aluminum foil 30' is partially overlapped in two layers.

[0032] Furthermore, an adhesive such as an epoxy resin adhesive is applied to the entire back side of the strip-shaped aluminum foil 30' unwound from the roll (i.e., the surface that comes into contact with the cardboard 10' wound around the winding rod 40). This adhesive not only serves to bond the partially overlapped aluminum foils 30' together, but also to bond the aluminum foil 30' to the cardboard 10' that is overlapped underneath. In this way, the outer surface of the cardboard tube formed by the cardboard 10' can be covered with the aluminum foil 30'.

[0033] Next, with the raw tube 1' consisting of the aluminum foil 20' of the inner layer 20, the cardboard 10' of the middle layer 10, and the aluminum foil 30' of the outer layer 30 wound around the winding rod 40, the raw tube 1' is tightened using a spiral winding machine 50. This tightens the adhesion between the layers 10, 20, and 30 of the raw tube 1'. The spiral winding machine 50 is a well-known device that is also used in the manufacture of general cardboard tubes. That is, the spiral winding machine 50 has belts attached to two rollers, and by winding these belts around the winding rod 40 and the layers 10, 20, and 30, the two rollers rotate as the winding rod 40 rotates, and at the same time, a force is applied in a direction that tightens the adhesion between the layers 10, 20, and 30 and the raw tube 1'.

[0034] Next, at the end of the raw tube 1' that extends beyond the length of the winding rod 40, a support base 60 is provided to support the raw tube 1'. This support base 60 serves to support the raw tube 1' when the winding rod 40 is not yet inserted into the hollow. By supporting the raw tube 1' by the support base 60 even after it has passed the winding rod 40 in this way, the raw tube 1' continues to extend in the extension line of the winding rod 40 (in the direction of the white arrow in Figure 3).

[0035] As shown in Figure 3, a gap is provided in the support stand 60, and a cutter 70 is installed in this gap. This cutter 70 is a device for cutting the raw tube 1' to a predetermined length. By cutting the raw tube 1' with this cutter 70, individual aluminum-laminated paper tubes 1 are obtained. The position at which the raw tube 1' is cut by this cutter 70 can be freely adjusted. Therefore, according to the manufacturing method shown in Figure 3, the length of the aluminum-laminated paper tube 1 that is finally obtained can be adjusted relatively freely.

[0036] FIG. 4 shows the widths of the aluminum foil 20′ (inner layer 20), cardboard 10′ (middle layer 10), and aluminum foil 30′ (outer layer 30) that make up the raw pipe 1′. In FIG. 4, the width of the cardboard 10′ is indicated by the symbol W1, the width of the aluminum foil 20′ is indicated by the symbol W2, and the width of the aluminum foil 30′ is indicated by the symbol W3. In the example shown in FIG. 4, the widths W1, W2, and W3 of the materials 10′, 20′, and 30′ are substantially equal (note that "substantially equal" means that an error of ±5% or less is allowed). Furthermore, the cardboard 10′ is made up of four layers 11′ to 14′, and the widths of each layer are all W1, which is substantially equal. In this way, by making the aluminum foil 20' forming the inner layer 20, the cardboard 10' forming the middle layer 10, and the aluminum foil 30' forming the outer layer 30 each substantially the same width, it becomes easier to procure and process each material, thereby reducing the manufacturing cost of the aluminum laminated paper tube 1.

[0037] As an example, the widths W1, W2, and W3 of the materials 10', 20', and 30' can be set to 80 to 150 mm. More specifically, the widths W1, W2, and W3 are 100 to 110 mm. Note that the widths W1, W2, and W3 of the materials are not limited to those listed here and can be adjusted as appropriate.

[0038] Furthermore, as shown in Figure 4, when stacking the materials 10', 20', and 30', it is preferable that the side edges of one material do not overlap with the side edges of the material above it in the thickness direction (cross-sectional direction). Specifically, the aluminum foil 20' forming the inner layer 20 and the cardboard 10' stacked thereon are offset so that their side edges do not overlap. Similarly, the cardboard 10' forming the middle layer 10 and the aluminum foil 30' stacked thereon are offset so that their side edges do not overlap. If the side edges of materials placed above and below overlap, there is a concern that the airtightness and non-combustibility of the aluminum-laminated paper tube 1 may be reduced. Therefore, it is preferable to intentionally offset the side edges of each material placed above and below, as shown in Figure 4.

[0039] FIG. 5 shows a modification of the example shown in FIG. 4. In the example shown in FIG. 5, the width W2 of the aluminum foil 20' forming the inner layer 20 is shorter than the width W1 of the cardboard 10' forming the middle layer 10 and the width W3 of the aluminum foil 30' forming the outer layer 30. Specifically, the width W2 of the aluminum foil 20' can be 20 to 70% or 30 to 60% of the width W3 (100%) of the aluminum foil 30'. In this way, shortening the width W2 of the aluminum foil 20' of the inner layer 20 compared to the other layers improves the overall strength of the aluminum-laminated paper tube 1. On the other hand, maintaining the width of the aluminum foil 30' of the outer layer 30 wide reduces the number of seams visible when the aluminum-laminated paper tube 1 is viewed externally, improving the appearance of the aluminum-laminated paper tube 1. In the example shown in FIG. 5, the width W1 of the cardboard 10' and the width W3 of the aluminum foil 30' are substantially equal.

[0040] FIG. 6 shows another modified example of the example shown in FIG. 4. In the example shown in FIG. 6, the width W3 of the aluminum foil 30' forming the outer layer 30 is shorter than the width W1 of the cardboard 10' forming the middle layer 10 and the width W2 of the aluminum foil 20' forming the inner layer 20. Specifically, the width W3 of the aluminum foil 30' can be 20 to 70% or 30 to 60% of the width W2 (100%) of the aluminum foil 20'. By shortening the width W3 of the aluminum foil 30' of the outer layer 30 compared to the other layers, the airtightness and non-combustibility of the aluminum-laminated paper tube 1 can be further improved. On the other hand, by maintaining the width W2 of the aluminum foil 20' forming the inner layer 20 relatively wide, the amount of aluminum foil material and the number of times the aluminum foil is wrapped can be reduced, thereby reducing the overall manufacturing cost of the aluminum-laminated paper tube 1. Furthermore, the aluminum foil 20' forming the inner layer 20 is the first to be wound around the winding rod 40 as shown in FIG. 3, and serves as a base for other materials. If the width of this aluminum foil 20' is short, overlapping portions 20a of the aluminum foil 20' will be formed frequently, increasing unevenness, which may cause distortion or wrinkles when other materials are wound on top of it. From this perspective, it is preferable to maintain the width of the aluminum foil 20' forming the inner layer 20 relatively wide. In the example shown in FIG. 6, the width W1 of the cardboard 10' and the width W2 of the aluminum foil 20' are substantially equal.

[0041] In the above description of the present invention, the embodiments of the present invention have been described with reference to the drawings in order to express the contents of the present invention. However, the present invention is not limited to the above embodiments, and includes modifications and improvements that are obvious to those skilled in the art based on the matters described in the present specification. [Explanation of symbols]

[0042] 1...Aluminum laminated paper tube 1´...Original tube 2…Hollow 10…Medium layer 10´…Cardboard 11…1st layer 12...Second layer 13...Third layer 14...4th layer 20...inner layer 20´...Aluminum foil 20a...Overlapped portion 30...Outer layer 30'...Aluminum foil 30a...Overlapped portion 40...Winding rod 50...Spiral winding machine 60...Support stand 70...Cutter

Claims

1. a cylindrical middle layer including one or more paper layers; An inner layer including an aluminum foil provided on the inner surface side of the middle layer; An outer layer including aluminum foil provided on the outer surface side of the intermediate layer Aluminum laminated paper tube.

2. The inner layer and the outer layer include overlapping portions where aluminum foils are partially overlapped. The aluminum laminated paper tube according to claim 1.

3. The inner layer and the outer layer are made of strip-shaped aluminum foil spirally wound around the middle layer. The aluminum laminated paper tube according to claim 1 or 2.

4. The width of the aluminum foil forming the inner layer is shorter than the width of the aluminum foil forming the outer layer. The aluminum laminated paper tube according to claim 3.

5. The width of the aluminum foil forming the outer layer is shorter than the width of the aluminum foil forming the inner layer. The aluminum laminated paper tube according to claim 3.

6. A method for manufacturing an aluminum laminated paper tube, comprising: forming an inner layer by spirally winding a strip of aluminum foil around a winding rod having a circular cross section; forming a middle layer by spirally winding one or more layers of paper strips onto the inner layer wound around the winding rod; forming an outer layer by spirally winding a strip of aluminum foil onto the middle layer wound around the winding rod; cutting the original pipe including the inner layer, the middle layer, and the outer layer to a predetermined length. Manufacturing method for aluminum laminated paper tubes.

7. The step of forming the outer layer includes spirally winding a strip of aluminum foil around the intermediate layer so that the side edges of the paper forming the intermediate layer do not overlap with the side edges of the aluminum foil forming the outer layer. The method for manufacturing the aluminum laminated paper tube according to claim 5.

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