Laminates for laminate tubes and laminate tubes

Abstract

To provide a laminate for laminate tubes that can produce a cylindrical sleeve with good roundness. [Solution] This disclosure relates to a laminate for a laminate tube, comprising a first heat seal layer, a base layer, and a second heat seal layer, wherein the first heat seal layer, the base layer, and the second heat seal layer contain polyolefin, and the first heat seal layer and the second heat seal layer are laminated with the base layer by a dry lamination method, the ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer is 0.9 to 1.1, and the thickness is 180 to 300 μm.

Description

TECHNICAL FIELD

[0001] The present invention relates to a laminate for a laminated tube and a laminated tube. BACKGROUND ART

[0002] A cylindrical sleeve that serves as the body of a laminated tube is formed by welding and joining the end portions (side seam portions) of the resin material of a raw sheet. The welded end portions are distorted due to rapid heating and rapid cooling during welding, so the resin in the peripheral portion of the weld (non-side seam portion) is pulled, the side seam portion becomes convex, and the cross section of the sleeve is distorted into an egg shape. In consideration of suitability for subsequent processes, it is preferable that the cross section of such a distorted sleeve be corrected to approximate a perfect circle.

[0003] As a countermeasure against this distortion, there has been proposed a method for manufacturing a tube container including a step of blowing water vapor onto the outer periphery of the sleeve, in a tube manufacturing method comprising a step of rolling a raw sheet and welding both end portions to form a sleeve, a step of cutting the sleeve at regular intervals, a step of welding a head molded body having a mouth portion and a shoulder portion to one end of the sleeve, and the like (see, for example, Patent Document 1). PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] PATENT DOCUMENT 1 Japanese Unexamined Patent Application Publication No. 2011-121342 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0005] In the method of Patent Document 1, although the distortion at the welded portions on both ends of the raw sheet can be corrected to some extent, it may be difficult to correct the change in cross-sectional shape accompanied by physical deformation of the welded portions caused by the laminated structure.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a laminate for laminate tubes that can produce a cylindrical sleeve having good roundness. The present invention also aims to provide a laminate tube formed from said laminate for laminate tubes. [Means for solving the problem]

[0007] A laminate for a laminate tube according to one aspect of the present invention comprises a first heat seal layer, a base layer, and a second heat seal layer, wherein the first heat seal layer, the base layer, and the second heat seal layer contain polyolefin, and the first heat seal layer, the second heat seal layer and the base layer are laminated by a dry lamination method, the ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer is 0.9 to 1.1, and the thickness is 180 to 300 μm.

[0008] The laminate for laminated tubes described above has a specific layer structure and thickness, and each layer is laminated using a specific lamination method. This allows for the production of a cylindrical sleeve with good roundness during the tube molding process. The good roundness of the sleeve suppresses filling defects during content filling, and results in a laminated tube with excellent self-supporting properties and extrusion characteristics. Furthermore, the laminate for laminated tubes described above, in which the first heat-seal layer, the base layer, and the second heat-seal layer all contain polyolefin, is said to have excellent recyclability.

[0009] Furthermore, good roundness refers to the small degree of distortion from a perfect circle in the cross-sectional shape of a sleeve when a cylindrical sleeve is fabricated using a laminate for laminate tubes.

[0010] In one embodiment, the laminate for the laminate tube may further comprise an inorganic oxide layer on the substrate layer.

[0011] In one embodiment, the inorganic oxide layer may contain aluminum oxide or silicon oxide.

[0012] In one embodiment, the polyolefin may be polypropylene.

[0013] In one embodiment, the polyolefin content may be 90% by mass or more based on the total amount of the laminate.

[0014] In one embodiment, the laminate for the laminate tube may further include an adhesive layer between the first heat seal layer and the second heat seal layer and the substrate layer. The Tg of the adhesive layer may be 20°C or higher.

[0015] A laminate tube according to one aspect of the present invention comprises the laminate for laminate tube described above. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a laminate for laminate tubes that can produce a cylindrical sleeve having good roundness. Furthermore, according to the present invention, it is possible to provide a laminate tube formed from said laminate for laminate tubes. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic cross-sectional view showing a laminate for a laminate tube according to one embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing a laminate for a laminate tube according to another embodiment. [Figure 3] Figure 3 is a front view showing a laminate tube according to one embodiment. [Modes for carrying out the invention]

[0018] Preferred embodiments of this disclosure will be described in detail below, with reference to the drawings as appropriate. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted. Furthermore, the dimensional ratios in the drawings are not limited to those shown.

[0019] <Laminate for Laminated Tubes> Figure 1 is a schematic cross-sectional view showing a laminate for a laminated tube according to one embodiment. The laminate 10 for a laminated tube includes a first heat seal layer 1, a base material layer 2, and a second heat seal layer 3. The laminate for a laminated tube may be simply referred to as a laminate in some cases.

[0020] Figure 2 is a schematic cross-sectional view showing a laminate for a laminated tube according to another embodiment. The laminate 20 for a laminated tube includes a first heat seal layer 1, a base material layer 2, an inorganic oxide layer 4, and a second heat seal layer 3.

[0021] The thickness of the laminate is 180 to 300 μm, may be 200 to 280 μm, and may be 200 to 250 μm. When the thickness of the laminate for a laminated tube is not less than the above lower limit, good circularity can be maintained during sleeve forming, and good stiffness is easily obtained. On the other hand, when the thickness is not more than the above upper limit, a laminated tube that achieves both extrudability and self-standing property can be obtained.

[0022] The first heat seal layer and the second heat seal layer of the laminate, and the base material layer are laminated by a dry lamination method. The laminate is obtained by thermocompression bonding the first heat seal layer and the second heat seal layer via an adhesive layer formed on the base material layer. As described later, the laminate obtained by dry lamination can be said to include an adhesive layer between the first heat seal layer and the second heat seal layer, and the base material layer.

[0023] The adhesive layer is formed by applying an adhesive onto the base material layer by a coating method such as roll coating, gravure coating, kiss coating or a printing method, and then drying the adhesive. The amount of the adhesive used (the weight of the adhesive layer) is not particularly limited, but is 0.1 to 10 g / m in a dry state 2 and can be set, and 1 to 5 g / m 2 may be adopted.

[0024] From the standpoint of recyclability, the first heat-seal layer, the base layer, and the second heat-seal layer may all contain polyolefin, and may all contain polypropylene or polyethylene, or may all contain polypropylene. The polyolefin content may be 90% by mass or more, or 95% by mass or more, based on the total amount of the laminate. There is no particular upper limit on the polyolefin content, but from the standpoint of recyclability, it may be 98% by mass.

[0025] (base material layer) The base layer contains polyolefin. Uniaxially oriented or biaxially oriented polyolefin film can be used as the base layer. In this case, the base layer can be referred to as a stretched base material.

[0026] The polyolefin is not particularly limited and examples include polyethylene, polypropylene, polybutene, and cycloolefin polymers. From the viewpoint of recyclability and resistance to high temperature processing, polypropylene can be used as the polyolefin.

[0027] Polypropylene may be a homopolymer, a random copolymer, or a block copolymer. A polypropylene homopolymer is a single polymer of propylene; a polypropylene random copolymer is a random copolymer of propylene and other α-olefins other than propylene (e.g., ethylene, butene-1, 4-methyl-1-pentene, etc.); and a polypropylene block copolymer is a copolymer having polymer blocks made of propylene and polymer blocks made of the above-mentioned α-olefins other than propylene.

[0028] Among these polypropylenes, homopolymers or random copolymers can be used from the viewpoint of transparency. Homopolymers can be used when the rigidity and heat resistance of the laminate are important, while random copolymers can be used when impact resistance is important.

[0029] As polypropylene, biomass-derived polypropylene or mechanically or chemically recycled polypropylene may be used.

[0030] The base layer may consist of a single layer containing polyolefin, or it may consist of multiple layers containing polyolefin. If the base layer consists of multiple layers, the materials of each layer may be the same or different. If the base layer consists of multiple layers, each layer may be laminated by dry lamination. At least one of the layers constituting the base layer may be a support layer for the inorganic oxide layer (a layer for forming the inorganic oxide layer).

[0031] The substrate layer may contain antiblocking agents, antioxidants, UV absorbers, antistatic agents, flame retardants, inorganic fillers, organic fillers, dyes, pigments, etc., as long as the desired effect is achieved.

[0032] The polyolefin content in the base layer can be 85% by mass or more, and may be 95% by mass or more.

[0033] The substrate layer may be surface-treated. This can improve adhesion with adjacent layers. The surface treatment method is not particularly limited and includes physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0034] The thickness of the base layer (or the total thickness if multiple layers are present) can be 15 to 70 μm, 15 to 50 μm, or 20 to 40 μm. Having the base layer thickness within this range facilitates processing such as printing and lamination.

[0035] (First heat seal layer and second heat seal layer) The first and second heat-seal layers contain polyolefin. The first and second heat-seal layers are sometimes collectively referred to as the heat-seal layer. The heat-seal layer can be described as a surface substrate layer having heat-sealing properties.

[0036] There are no particular restrictions on the polyolefin used; examples include polyethylene and polypropylene. From the viewpoint of recyclability, polypropylene can be used as the polyolefin.

[0037] Examples of polyethylene include low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), medium-density polyethylene resin (MDPE), ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer.

[0038] Unstretched polypropylene (CPP) can be used as the polypropylene from the viewpoint of recyclability. Examples of polypropylene include propylene homopolymers, copolymers of propylene and unsaturated carboxylic acids, copolymers of propylene and unsaturated carboxylic acid esters, propylene-α-olefin copolymers, random copolymers or block copolymers of ethylene-propylene copolymers, etc. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic anhydride, and fumaric acid, and one or more of these can be copolymerized with propylene. Examples of unsaturated carboxylic acid esters include acrylic acid esters, methacrylic acid esters, maleic anhydride esters, and fumaric acid esters, and one or more of these can be copolymerized with propylene.

[0039] As the polyolefin, biomass-derived polyethylene or polypropylene, or mechanically recycled polyethylene or polypropylene may be used.

[0040] The heat seal layer may consist of a single layer containing polyolefin, or it may consist of multiple layers containing polyolefin. If the heat seal layer consists of multiple layers, each layer may be laminated by co-extrusion, and the materials of each layer may be the same or different.

[0041] The heat seal layer may contain antiblocking agents, antioxidants, UV absorbers, antistatic agents, flame retardants, inorganic fillers, organic fillers, dyes, pigments, etc., as long as the desired effect is achieved.

[0042] The polyolefin content in the heat seal layer can be 85% by mass or more, and may be 95% by mass or more.

[0043] The thickness of the heat seal layer can be 50 to 120 μm, or 70 to 110 μm. A heat seal layer thickness above the lower limit makes it easier to obtain sufficient seal strength and excellent self-supporting properties, while a thickness below the upper limit makes it easier to obtain excellent extrusion properties in the laminate tube.

[0044] From the viewpoint of obtaining a sleeve with good roundness, the ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer is 0.9 to 1.1, may be 0.95 to 1.05, or may be 1. By making the thickness of the first heat seal layer and the thickness of the second heat seal layer equal, that is, by making the front and back sides symmetrical with respect to the heat seal layer, good roundness can be maintained during sleeve formation.

[0045] (Inorganic oxide layer) The laminate may further include an inorganic oxide layer on top of the base layer. The inorganic oxide layer can be called a barrier layer, and because the inorganic oxide layer further suppresses the permeation of oxygen and water vapor, the storage stability of the contents is further improved. When forming the body of a laminate tube from the laminate, from the viewpoint of barrier properties, the inorganic oxide layer can be provided on the surface of the base layer opposite to the contents.

[0046] The inorganic oxide layer may contain aluminum oxide or silicon oxide. Compared to embodiments that use a metal layer such as aluminum foil or aluminum vapor-deposited film, metal foreign matter can be inspected using a metal detector after the contents have been filled and packaged.

[0047] The inorganic oxide layer may be a layer that sufficiently transmits visible light (transparent or semi-transparent). This makes it easy to see the color and transparency of the contents from the outside. A film having an inorganic oxide layer on a support layer as described above can be called a transparent barrier film.

[0048] The inorganic oxide layer may be an inorganic oxide vapor-deposited layer. That is, an inorganic oxide layer may be formed on the surface of the substrate layer by a vapor deposition method such as physical vapor deposition or chemical vapor deposition. A barrier overcoat layer may be formed on the inorganic oxide layer by a coating method such as roll coating, gravure roll coating, or kiss coating, or by a printing method such as gravure printing, offset printing, or transfer printing.

[0049] The thickness of the inorganic oxide layer can be 10 to 100 nm, or 20 to 50 nm. A thickness of the inorganic oxide layer above the lower limit makes it easier to achieve sufficient barrier properties, while a thickness below the upper limit makes it easier to suppress deterioration of the barrier properties due to cracking.

[0050] (Adhesive layer) In the laminate, the first heat-seal layer and the second heat-seal layer are laminated to the base material layer by a dry lamination method. In other words, the laminate can be said to have an adhesive layer (dry lamination adhesive layer) between the first heat-seal layer, the second heat-seal layer and the base material layer.

[0051] Examples of adhesives included in the adhesive layer include polyvinyl acetate adhesives; polyacrylic acid ester adhesives consisting of homopolymers such as ethyl ester, butyl ester, and 2-ethylhexyl ester of acrylic acid, or copolymers thereof with methyl methacrylate, acrylonitrile, styrene, etc.; cyanoacrylate adhesives; ethylene copolymer adhesives consisting of copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, and methacrylic acid; cellulose adhesives; polyester adhesives; polyamide adhesives; polyimide adhesives; amino resin adhesives consisting of urea resin, melamine resin, etc.; phenolic resin adhesives; epoxy adhesives; polyurethane adhesives; and reactive (meth)acrylic acid adhesives.

[0052] From the viewpoint of creating an adhesive layer with excellent flexibility and bendability, polyurethane-based adhesives can be used as the adhesive. For example, adhesives mainly composed of polyether polyurethane resin, polyester polyurethane resin, or polyacrylate polyurethane resin can be used. Using polyurethane-based adhesives makes it easier to improve the suitability for processing such as lamination and printing.

[0053] Adhesives can take the form of aqueous, solution, emulsion, or dispersion types. Adhesives can take the form of film, sheet, powder, or solid. Adhesive reaction mechanisms can include chemical reaction, solvent evaporation, heat welding, or hot-pressure reactions. Non-solvent laminates, which do not contain organic solvent components, are preferred from an environmental perspective.

[0054] It is preferable that the adhesive layer has a certain degree of heat resistance. Polyolefin materials used in laminates tend to have difficulty maintaining their shape when subjected to heat, for example, around 40-50°C, during the manufacturing of the laminate. Therefore, by having a certain degree of heat resistance (resistance to softening) in the adhesive layer, the shape stability of the laminate containing polyolefin material can be further improved. From this viewpoint, the Tg of the adhesive layer can be 20°C or higher, may be 30°C or higher, or may be 40°C or higher. There is no particular upper limit to the Tg, but if the Tg of the adhesive layer is too high, the initial adhesion tends to be weak, so it can be set to around 100°C. Tg is a value measured in accordance with JIS K7121 Method for Measuring Glass Transition Temperature of Plastics.

[0055] (Printing layer) The laminate may further include a printed layer on the surface of the substrate layer. The printed layer may include images consisting of characters, patterns, symbols, and combinations thereof. The method for forming the printed layer is not particularly limited, and examples include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0056] When forming the body of a laminate tube from a laminate, from the viewpoint of design, the printed layer can be provided on the surface of the substrate layer facing the inorganic oxide layer.

[0057] <Laminated tube> The above laminate can be used for the body of a laminate tube. In other words, a laminate tube comprises the above laminate for laminate tubes. A laminate tube can also be called a tube container.

[0058] Figure 3 is a front view showing a laminated tube according to one embodiment. The laminated tube 500 shown in Figure 3 comprises a body portion 510 made of the laminate, a spout portion 520 attached to one end of the body portion 510, and a cap 530 attached to the spout portion 520. The body portion 510 is a cylindrical member formed so as to be able to contain contents by sealing portions 513 which bond the heat-sealed layers of the laminate together, and closing the bottom portion 511 located at the other end opposite to the end to which the spout portion 520 is attached. The spout portion 520 consists of a stopper portion 522 for discharging the contents and a shoulder portion 521 which is held by the body portion 510 and guides the contents to the stopper portion 522. The cap 530 is a member that enables the opening of the stopper portion 522 to be closed and opened.

[0059] Regarding the shape of the laminate tube, the shoulder can be positioned perpendicular to the body without a taper, allowing the contents to be squeezed out completely. The material of the spout and cap of the laminate tube is not particularly limited, but using the same resin as the base layer and heat seal layer can further improve recyclability.

[0060] <Summary of this embodiment> [Invention 1] It comprises a first heat seal layer, a base layer, and a second heat seal layer. The first heat seal layer, the base layer, and the second heat seal layer each contain polyolefin. The first heat seal layer and the second heat seal layer and the substrate layer are laminated by a dry lamination method. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer is 0.9 to 1.1. A laminate for laminate tubes with a thickness of 180-300 μm. [Invention 2] The laminate for a laminate tube according to Invention 1, further comprising an inorganic oxide layer on the aforementioned base material layer. [Invention 3] The laminate for a laminate tube according to Invention 2, wherein the inorganic oxide layer contains aluminum oxide or silicon oxide. [Invention 4] A laminate for a laminate tube according to any one of Inventions 1 to 3, wherein the polyolefin is polypropylene. [Invention 5] A laminate for a laminate tube according to any one of Inventions 1 to 4, wherein the polyolefin content is 90% by mass or more based on the total amount of the laminate. [Invention 6] A laminate for a laminate tube according to any one of Inventions 1 to 5, further comprising an adhesive layer between the first heat seal layer and the second heat seal layer and the base material layer, wherein the Tg of the adhesive layer is 20°C or higher. [Invention 7] A laminate tube comprising a laminate for laminate tubes according to any one of inventions 1 to 6. [Examples]

[0061] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0062] <Fabrication of laminated structures for laminated tubes> (Example 1) A 20 μm thick OPP film (U-1, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) and an 18 μm thick OPP film (manufactured by Toppan Printing Co., Ltd.) with a 50 nm thick silicon dioxide vapor-deposited layer were laminated together via dry lamination using an adhesive. On both sides of this laminate, a 100 μm thick CPP film (UT100, manufactured by Okamoto Co., Ltd.) was laminated as a heat-seal layer, also via dry lamination using an adhesive. A two-component reactive polyester polyurethane resin (A626 / A50, manufactured by Mitsui Chemicals, Inc., Tg after adhesive layer formation: 26℃) was used as the adhesive, and the amount of adhesive used was 3.5 g / m². 2 The material was left in a dry state. This resulted in obtaining a laminate for a laminate tube. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer was 1.

[0063] (Example 2) A laminate was obtained in the same manner as in Example 1, except that an 18 μm thick OPP film (manufactured by Max Specialty Films, TI) was used instead of a 20 μm thick OPP film, and an 80 μm thick CPP film (manufactured by Toray Industries, Inc., ZK99S) was used instead of a 100 μm thick CPP film. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer was 1.

[0064] (Example 3) A laminate was obtained in the same manner as in Example 1, except that a 20 μm thick OPP film was not used, and a 120 μm thick CPP film (Toray Industries, Inc., ZK99S) was used instead of a 100 μm thick CPP film. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer was 1.

[0065] (Comparative Example 1) A laminate was obtained in the same manner as in Example 1, except that a 60 μm thick CPP film (manufactured by Toray Industries, Inc., ZK99S) was used instead of a 100 μm thick CPP film. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer was 1.

[0066] (Comparative Example 2) A laminate was obtained in the same manner as in Example 3, except that a 60 μm thick CPP film (Toray Industries, Inc., ZK207) and a 200 μm thick CPP film (Okamoto Co., Ltd., AT40S) were used instead of a 120 μm thick CPP film. The ratio of the second heat-seal layer thickness to the first heat-seal layer thickness was approximately 3.3.

[0067] (Comparative Example 3) A laminate was obtained in the same manner as in Example 3, except that a 160 μm thick CPP film (manufactured by Toray Industries, Inc., ZK207) was used instead of a 120 μm thick CPP film. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer was 1.

[0068] (Comparative Example 4) A 150 μm thick PE film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., FC-S), a 12 μm thick PET film, and a 12 μm thick PET film with a 50 nm thick silicon dioxide vapor-deposited layer (manufactured by Toppan Printing Co., Ltd.) were laminated by extrusion lamination using a 40 μm thick LDPE (manufactured by Nippon Polyethylene Co., Ltd., LC600A) between each layer. A 12 μm thick PE film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., FC-S) was laminated onto a 12 μm thick PET film with a silicon oxide vapor deposition layer by dry lamination via an adhesive, in the same manner as in Example 1. A laminate was obtained as a result.

[0069] <Various evaluations> The following evaluations were performed on the laminates obtained in each example. The results are shown in Table 1. In the "Composition" column of Table 1, " / / " indicates the location of the inorganic oxide layer.

[0070] (lower back strength) From each example, strips of film measuring 15 mm in width and 50 mm in length were cut from both the MD and TD directions of the laminate. The cut strips of film were placed in a loop stiffness tester manufactured by Toyo Seiki Seisakusho Co., Ltd., and the rebound force was measured at room temperature (25°C) with a compression depth of 10 mm. This measurement was performed five times with different samples. The average value of the rebound force (mN) obtained from the measurements was defined as the loop stiffness.

[0071] (Ellipticity (increase in inner diameter)) Ten cylindrical sleeves were fabricated using the laminates obtained in each example. The laminates were used so that the layers listed on the left side of the "Composition" column in Table 1 formed the outer surface of the sleeves. The sleeves were designed so that the inner diameter (diameter) of the sleeve when the cross-section was a perfect circle was 35 mm. The overlap width of the laminates was set to 2 mm. The maximum inner diameter (along the major axis of the ellipse) of the sleeve cross-section (A mm) was measured at room temperature (25°C), and the percentage increase in inner diameter compared to the inner diameter of 35 mm when the sleeve cross-section is perfectly round was calculated. This process was repeated 10 times with different sleeves. The average of the calculated percentage increases was then defined as the ellipticity (%). This was used to evaluate the roundness. Ellipticity (%) = 100 × (A - 35) / 35

[0072] [Table 1] [Explanation of symbols]

[0073] 1...First heat seal layer, 2...Base layer, 3...Second heat seal layer, 4...Inorganic oxide layer, 10,20...Laminate for laminate tube, 510...Body, 511...Bottom, 513...Seal part, 520...Outlet part, 521...Shoulder part, 522...Stop part, 530...Cap, 500...Laminate tube.

Claims

1. It comprises a first heat seal layer, a base layer, and a second heat seal layer. The first heat seal layer, the base layer, and the second heat seal layer each contain polyolefin. The first heat seal layer and the second heat seal layer and the substrate layer are laminated by a dry lamination method. The ratio of the thickness of the second heat seal layer to the thickness of the first heat seal layer is 0.9 to 1.

1. A laminate for laminate tubes with a thickness of 180 to 300 μm.

2. The laminate for a laminate tube according to claim 1, further comprising an inorganic oxide layer on the base material layer.

3. The laminate for a laminate tube according to claim 2, wherein the inorganic oxide layer comprises aluminum oxide or silicon oxide.

4. The laminate for a laminate tube according to claim 1 or 2, wherein the polyolefin is polypropylene.

5. The laminate for laminate tube according to claim 1 or 2, wherein the polyolefin content is 90% by mass or more based on the total amount of the laminate.

6. The laminate for a laminate tube according to claim 1 or 2, further comprising an adhesive layer between the first heat seal layer and the second heat seal layer and the base material layer, wherein the Tg of the adhesive layer is 20°C or higher.

7. A laminate tube comprising a laminate for laminate tubes according to claim 1 or 2.

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