Laminate for tube and laminate tube

Abstract

This laminate for a tube comprises a first sealant layer, a base material layer, a barrier layer, an adhesive layer, and a second sealant layer in this order. The barrier layer includes an inorganic oxide vapor deposition layer. The base material layer, the first sealant layer, and the second sealant layer each include polyethylene. The tensile elastic modulus in the flow (MD) direction of the base material layer is 500-2000 MPa at 23°C, and the tensile elastic modulus of the adhesive layer is 500 MPa or more at 23°C.

Description

Laminated tubes and laminated tubes

[0001] The present disclosure relates to a laminate for a tube and a laminate tube using this laminate. Note that the "laminate for a tube" may also be referred to as a "laminate for a tube container." Furthermore, the "laminate tube" may also be referred to as a "tube container."

[0002] A laminated tube made from a laminate having, in this order, a first sealant layer, a vapor-deposited film, a substrate, and a second sealant layer is known as a packaging container for semi-solid foods, cosmetics, pharmaceuticals, etc. (See, for example, Patent Document 1). The laminated tube is manufactured through a process of forming a cylindrical body tube made of the laminate and a process of molding a head member onto the body tube. In the cylindrical body tube forming process, a single tube laminate is fed and rolled into a cylindrical shape with the circumferential direction perpendicular to the machine direction (MD). The overlapping portions of the outermost and innermost sealant layers at both edges of the laminate are welded to form a cylindrical tube. Because laminated tubes are characterized by being repeatedly folded during use, they are required to have both rigidity (puncture resistance, barrier properties, and inversion resistance) and flexibility (resistance to repeated squeezing and bag drop). In conventional technologies, designs that laminate different materials (multi-materials) such as metal foils and resin films have been widely adopted to achieve these properties. However, containers with such a laminated structure are not easy to separate into individual materials after use, which makes recycling difficult. To solve this problem, in recent years, measures have been considered to significantly improve recyclability by producing and using packaging materials composed of as single material (mono-material) as possible. Patent Document 2 discloses a mono-material laminate tube.

[0003] JP 2021-160270 A JP 2021-160267 A

[0004] The laminate disclosed in Patent Document 1 has a base material and a sealant layer both comprising a polyethylene resin layer, and is said to have excellent recyclability. However, when a tube container made from the laminate is repeatedly crushed (squeezed) to squeeze out the contents, there is a risk that the barrier properties of the tube container will gradually deteriorate.

[0005] A first aspect of the present disclosure aims to provide a laminate for a tube that is excellent in recyclability and that can be used to produce a tube container whose barrier properties are unlikely to deteriorate even after repeated squeezing operations.

[0006] In Patent Document 2, a stretched polyethylene substrate is used, and the density of the polyethylene is set to 0.943 g / m ３ However, the use of a stretched polyethylene base material makes the laminate hard, and the repeated squeezing action that is characteristic of laminated tubes makes the vapor-deposited film susceptible to damage, which remains a problem.

[0007] The second to fourth aspects of the present disclosure aim to provide a laminate for a tube that is highly recyclable and in which the vapor-deposited film is less likely to be damaged even when the laminate is made into a tube and repeatedly squeezed.

[0008] The inventors investigated the effect of a squeeze action on each constituent layer of a laminate for a tube mainly composed of polyethylene, and found that the barrier layer is susceptible to damage by the squeeze action, and that it is important to appropriately protect the barrier layer in order to prevent a decrease in barrier properties, which led to the first aspect of the present disclosure.

[0009] A laminate for a tube according to a first aspect of the present disclosure comprises a first sealant layer, a substrate layer, a barrier layer, an adhesive layer, and a second sealant layer in this order, wherein the barrier layer comprises an inorganic oxide vapor-deposited layer, the substrate layer, the first sealant layer, and the second sealant layer each comprise polyethylene, and the substrate layer has a tensile modulus in the machine direction (MD) of 500 to 2000 MPa at 23°C, and the adhesive layer has a tensile modulus of 500 MPa or more at 23°C.

[0010] In such a laminate, the barrier layer is protected by the substrate layer and adhesive layer, which have a predetermined tensile modulus. Therefore, even if the tube container is repeatedly squeezed, the barrier layer is less likely to be damaged and good barrier properties are easily maintained. Furthermore, since the main constituent layers, the first sealant layer, the substrate layer, and the second sealant layer, all contain polyethylene, the laminate can be said to have excellent recyclability.

[0011] In the first aspect, the adhesive layer may be formed from an epoxy adhesive. The adhesive layer may have a thickness of 0.1 to 20 μm. The substrate layer may be an unstretched film. The first sealant layer and the second sealant layer may contain linear low-density polyethylene. The first sealant layer and the second sealant layer may have a thickness of 20 to 200 μm. The laminate may further include an underlayer on the barrier layer side of the substrate layer. The inorganic oxide vapor-deposited layer may contain silicon oxide or aluminum oxide. The polyethylene may contain recycled polyethylene.

[0012] A laminate for a tube according to a second aspect of the present disclosure includes a substrate having a substrate layer made of an unstretched polyethylene film and a barrier layer formed by vapor deposition on one surface of the substrate layer, a first sealant layer made of a polyethylene film and provided on one side of the substrate, and a second sealant layer made of a polyethylene film and provided on the opposite side of the substrate from the first sealant layer, wherein the MD elongation of the substrate layer is 2.5% or more and 6.5% or less.

[0013] A laminate for a tube according to a third aspect of the present disclosure includes a substrate portion having a substrate layer made of a polyethylene film, a primer layer composed primarily of ethylene vinyl alcohol and formed on a first surface of the substrate layer, and a barrier layer formed on the primer layer, a barrier coat layer disposed between the primer layer and the barrier coat layer, a first sealant layer made of a polyethylene film and formed on a second surface of the substrate layer opposite the first surface, and a second sealant layer made of a polyethylene film and formed on the barrier coat layer. The primer layer has a cross-sectional indentation hardness of 0.05 to 0.1 gigapascals. The barrier coat layer contains a polyvinyl alcohol-based resin and has a cross-sectional indentation hardness of 0.5 gigapascals or less.

[0014] A laminate for a tube according to a fourth aspect of the present disclosure includes a substrate portion having a substrate layer made of a polyethylene film and a barrier layer made of a vapor-deposited film of metal aluminum formed on a first surface side of the substrate layer, a barrier coat layer disposed so as to cover the barrier layer, a first sealant layer made of a polyethylene film and provided on a second surface side of the substrate layer opposite the first surface, and a second sealant layer made of a polyethylene film and provided on the barrier coat layer. The cross-sectional indentation hardness of the barrier coat layer is 0.75 gigapascals or less.

[0015] The laminated tube according to the present disclosure is formed into a cylindrical shape using the laminate for a tube according to any one of the first to fourth aspects, and has a body portion with one end sealed and a shoulder portion attached to the other end of the body portion.

[0016] According to a first aspect of the present disclosure, a laminate for a tube is provided, which is capable of producing a tube container that has excellent recyclability and whose barrier property is resistant to deterioration even when repeatedly squeezed. According to second to fourth aspects of the present disclosure, a laminate for a tube is provided, which is highly recyclable and whose vapor-deposited film is resistant to damage even when repeatedly squeezed after being made into a laminate tube.

[0017] Here, "repeated squeezing" means repeatedly squeezing the tube container to squeeze out the contents. Also, "barrier properties" means oxygen barrier properties and water vapor barrier properties, and primarily refers to oxygen barrier properties.

[0018] FIG. 1 is a schematic cross-sectional view showing one embodiment of a laminate for tube containers according to the first aspect. FIG. 2 is a schematic cross-sectional view showing another embodiment of a laminate for tube containers according to the first aspect. FIG. 3 is a front view showing one embodiment of a laminate tube. FIG. 4 is a schematic cross-sectional view showing a first embodiment of a laminate for tubes according to the second aspect. FIG. 5 is a schematic cross-sectional view showing a second embodiment of a laminate for tubes according to the second aspect. FIG. 6 is a schematic cross-sectional view showing a third embodiment of a laminate for tubes according to the second aspect. FIG. 7 is a schematic cross-sectional view showing a first embodiment of a laminate for tubes according to the third aspect. FIG. 8 is a schematic cross-sectional view showing a second embodiment of a laminate for tubes according to the third aspect. FIG. 9 is a schematic cross-sectional view showing a first embodiment of a laminate for tubes according to the fourth aspect. FIG. 10 is a schematic cross-sectional view showing a second embodiment of a laminate for tubes according to the fourth aspect.

[0019] Hereinafter, embodiments of the present disclosure will be described in detail, but the present invention is not limited to the following embodiments.

[0020] [First Aspect] <Laminate for Tube Containers> Fig. 1 is a schematic cross-sectional view showing a laminate for tube containers according to one embodiment. The laminate for tube containers 50 includes a first sealant layer 51a, a substrate layer 52, a barrier layer 53, an adhesive layer 54, and a second sealant layer 51b. The body of a tube container can be produced from the laminate for tube containers.

[0021] The laminate for a tube container can also be called a laminate for a laminate tube. The laminate for a tube container may also be simply called a laminate. The laminate can be used with the first sealant layer 61a facing the outer surface of the tube container (with the second sealant layer 61b facing the contents).

[0022] 2 is a schematic cross-sectional view showing a laminate for a tube container according to another embodiment. The laminate for a tube container 60 includes a first sealant layer 51a, a first extruded polyethylene layer 65a, a printing layer 66a, a printing substrate layer 66b, a second extruded polyethylene layer 65b, a substrate layer 52, a primer layer 67, a barrier layer 53, an overcoat layer 68, an adhesive layer 54, and a second sealant layer 51b.

[0023] The thickness of the laminate can be 150 to 500 μm, or alternatively, 200 to 450 μm, or 300 to 400 μm. When the thickness of the laminate for a tubular container is equal to or greater than the above-mentioned lower limit, the strength of the tubular container is likely to be improved, while when the thickness is equal to or less than the above-mentioned upper limit, the tube body does not become too thick and is easy to squeeze.

[0024] From the viewpoint of recyclability, the first sealant layer, the base layer, and the second sealant layer all contain polyethylene, and the polyethylene content may be 80 mass % or more, 90 mass % or more, and more preferably 95 mass % or more, based on the total amount of the laminate.

[0025] (Base Layer) The base layer contains polyethylene. Examples of polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). The base layer can contain one or more of these polyethylenes. The polyethylene may be derived from petroleum or plants, or a mixture thereof. The polyethylene may be recycled polyethylene obtained by mechanical recycling, chemical recycling, or the like. The base layer may contain, in addition to polyethylene, a polyolefin other than polyethylene.

[0026] The substrate layer may be a polyethylene film. The substrate layer may be an unstretched film or a stretched (uniaxially stretched or biaxially stretched) film. Since the tube container is subjected to repeated squeezing operations, the substrate layer is preferably made of at least an HDPE film (density: 0.945 g / cm 3 ) from the viewpoint of ensuring both rigidity and flexibility.３ The substrate layer having a barrier layer can be referred to as a barrier substrate.

[0027] The substrate layer may be composed of a single film containing polyethylene, or may be composed of multiple films containing polyethylene. When the substrate layer is composed of multiple films, the materials of the films may be the same or different, but it is preferable that the polyethylene content is 80 mass% or more based on the total amount of the laminate. When the substrate layer is composed of multiple films, the substrate layer may be a multilayer polyethylene film extruded by coextrusion.

[0028] The content of polyethylene in the base layer can be 70% by mass or more, 80% by mass or more, 90% by mass or more, or even substantially 100% by mass.

[0029] The substrate layer may be subjected to a surface treatment, which can improve adhesion to adjacent layers. The method of the surface treatment is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

[0030] The thickness of the base layer (total thickness when multiple layers are provided) can be 10 to 50 μm, or alternatively 12 to 35 μm, or 20 to 30 μm. When the thickness of the base layer is equal to or greater than the lower limit, the strength of the laminate is likely to be improved, and when the thickness is equal to or less than the upper limit, the processability of the laminate is likely to be improved.

[0031] The tensile modulus of elasticity in the machine direction (MD) of the base material layer at 23°C is 500 to 2000 MPa, but can be 550 to 1500 MPa, or even 600 to 1500 MPa. Having this modulus of elasticity at or above the lower limit allows the base material layer to have a certain hardness and be less likely to stretch. This prevents the base material layer from being overstretched by repeated squeezing operations, allowing the barrier layer to be properly protected. Furthermore, having this modulus of elasticity at or below the upper limit allows the base material layer to have a certain softness and be more likely to disperse external stress. This prevents stress generated by repeated squeezing operations from concentrating in specific locations, allowing the barrier layer to be properly protected.

[0032] The tensile modulus in the machine direction of the base material layer can be adjusted by, for example, adjusting the film forming method or stretching method of the polyethylene film, adjusting the type of polyethylene contained in the polyethylene film (molecular weight or density), or using a polyethylene film with a multilayer structure, but the method for adjusting the tensile modulus is not limited to these.

[0033] The tensile modulus of the base layer in the machine direction is measured as follows. Sample: The base layer is cut into a size of 15 mm width x 5 cm length (width in TD, length in MD, conforming to JIS K-7161). Measuring device: Tensilon universal testing machine. Measurement method: A tensile test is performed at 23°C with a chuck distance of 5 cm and a tensile speed of 200 mm / min. The slope of the stress / strain curve corresponding to the two strain points between 0.05% and 0.25% tensile elongation is taken as the tensile modulus of the film.

[0034] (Barrier Layer) The barrier layer can include a vapor-deposited layer of an inorganic oxide such as silicon oxide, aluminum oxide, magnesium oxide, or tin oxide. Of these, the inorganic oxide vapor-deposited layer can include silicon oxide or aluminum oxide, particularly from the viewpoint of a balance between vapor deposition processability and high barrier properties. The barrier layer may also include a vapor-deposited layer of a metal such as aluminum.

[0035] The barrier layer prevents oxygen and water vapor from passing through, improving the storage stability of the contents. When forming the body of a tubular container from the laminate, the barrier layer can be provided on the surface of the base layer facing the contents, from the viewpoint of barrier properties.

[0036] The barrier layer (deposited layer) can be formed by a deposition method such as physical vapor deposition or chemical vapor deposition.

[0037] The thickness of the barrier layer can be 5 to 100 nm, or may be 10 to 85 nm. When the thickness of the barrier layer is equal to or greater than the lower limit, sufficient barrier properties are easily exhibited, and when the thickness is equal to or less than the upper limit, deterioration of the barrier properties due to cracks is easily suppressed.

[0038] (Overcoat Layer) A gas barrier overcoat layer (gas barrier coat layer) may be formed on the barrier layer by applying an overcoat agent by a coating method such as roll coating, gravure roll coating, or kiss coating, or a printing method such as gravure printing, offset printing, or transfer printing.

[0039] The overcoat agent may contain, for example, at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolyzate of a metal alkoxide, and a water-soluble polymer compound.

[0040] In addition to the above components, the overcoat agent may contain at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0041] In the overcoat agent, examples of the aqueous polymer compound include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate.

[0042] In the overcoat agent, the metal alkoxide is tetraethoxysilane [Si(OC ２ H ５ ) ４], triisopropoxyaluminum [Al(OC ３ H ７ ) ３ ], etc., of the general formula M(OR) ｎ (M: metal such as Si, Ti, Al, Zr, etc., R: CH ３ , C ２ H ５ Examples include those represented by the following alkyl groups:

[0043] In the overcoat agent, examples of the silane coupling agent include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate.

[0044] The thickness of the overcoat layer (after drying) can be set to 0.01 to 50 μm from the viewpoint of suppressing cracks, and may be 0.01 to 20 μm.

[0045] (Underlayer) An underlayer may be formed on the barrier layer side of the substrate layer, that is, the substrate layer and the barrier layer in the laminate may be laminated via the underlayer.

[0046] The underlayer may be an anchor coat layer formed using an anchor coat agent, or may be an extruded resin layer formed using a polyvinyl alcohol-based resin.

[0047] Anchor Coat Layer: Resins used in the anchor coating agent include acrylic resins, epoxy resins, acrylic polyol resins, acrylic urethane resins, polyester polyurethane resins, and polyether urethane resins.

[0048] Extruded resin layer: The polyvinyl alcohol-based resin may be any resin having a vinyl alcohol unit formed by saponifying a vinyl ester unit, such as polyvinyl alcohol (PVA), copolymer-modified or post-modified modified PVA, or ethylene-vinyl alcohol copolymer (EVOH). EVOH is preferred from the viewpoints of heat resistance and gas barrier properties. The extruded resin layer is formed by extrusion together with the substrate layer.

[0049] The thickness of the underlayer can be 0.01 to 5 μm, or alternatively 0.03 to 3 μm, or alternatively 0.05 to 2 μm. When the thickness of the underlayer is equal to or greater than the lower limit, the interlayer adhesion strength is more likely to be improved, and when the thickness is equal to or less than the upper limit, the desired barrier properties are more likely to be obtained.

[0050] (Printed Layer and Printed Substrate Layer) The laminate may include one or more printed layers between any of the layers. The printed layer is provided in a position visible from the outside of the laminate for the purposes of displaying information about the contents, identifying the contents, improving concealment, or improving the design of the packaging bag. The printed layer may be provided in any position as long as it is visible from the outside of the laminate. For example, the printed layer and printed substrate layer may be provided between the substrate layer and the first sealant layer. Note that FIG. 2 illustrates a layer configuration in which the printed layer 66a and the first extruded polyethylene layer 65a are in contact, and the printed substrate layer 66b and the second extruded polyethylene layer 65b are in contact, but the printed layer 66a and the printed substrate layer 66b may also be arranged so that the printed substrate layer 66b and the first extruded polyethylene layer 65a are in contact, and the printed layer 66a and the second extruded polyethylene layer 65b are in contact.

[0051] A printed layer may be formed on the outside of the first sealant layer. In this case, a transparent protective layer may be provided on the printed layer to prevent the printed layer from being rubbed by external contact. Alternatively, a printed layer may be formed on the outside of the second sealant layer. In this case, the printed layer is formed between the second sealant layer and the adhesive layer. In these cases, the printed layer may be formed on the first sealant layer or the second sealant layer by the printing method described below, and a printed substrate layer may not be used.

[0052] The printing ink for forming the printed layer is not particularly limited, and is appropriately selected in consideration of printability, design such as color tone, adhesion, safety, and the like.

[0053] The printing substrate layer may contain polyethylene from the viewpoint of recyclability. Examples of polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). The printing substrate layer may be a film containing these polyethylenes. Since the tube container is subjected to repeated squeezing operations, the printing substrate layer may be made of an unstretched LDPE film (density: 0.900 g / cm 3 ) from the viewpoint of ensuring flexibility. ３ 0.925g / cm or more ３ (less than)

[0054] From the viewpoint of light-blocking properties and concealing properties, the printing substrate layer may contain milky white polyethylene obtained by adding a white pigment or an extender pigment, such as titanium oxide, zinc oxide, calcium carbonate, barium sulfate, etc. In this case, from the viewpoint of visibility of the printed content, it is preferable that the printing layer be provided on the surface of the printing substrate layer facing the first sealant layer.

[0055] The thickness of the printing substrate layer can be 50 to 200 μm, or alternatively 70 to 150 μm, or 80 to 120 μm. When the thickness of the printing substrate layer is equal to or greater than the lower limit, the squeeze resistance is likely to be improved, and when the thickness is equal to or less than the upper limit, the processing suitability is likely to be improved.

[0056] The method for printing the printing layer onto the printing substrate layer is not particularly limited and may be appropriately selected from known printing methods. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Among these, aqueous flexographic printing is preferred from the viewpoint of environmental impact.

[0057] A printed layer may be formed by offset printing using an active energy ray-curable ink. Active energy rays are energy rays that can generate radically active species, and examples of such rays include electromagnetic waves such as X-rays and gamma rays, particle rays such as electron beams (EB), proton beams and alpha rays, and non-ionizing radiation such as microwaves and ultraviolet rays. The active energy ray-curable ink contains an active energy ray-curable resin. After offset printing is performed on a printing surface using such ink, the ink is irradiated with active energy rays, thereby curing the ink and forming a printed layer.

[0058] (First sealant layer and second sealant layer) The first sealant layer and the second sealant layer contain polyethylene. The first sealant layer and the second sealant layer may be collectively referred to as the sealant layer.

[0059] Examples of polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE). The sealant layer may contain one or more of these polyethylenes, and may particularly contain LLDPE. The polyethylene may be derived from petroleum or plants, or may be a mixture thereof. The polyethylene may be recycled polyethylene obtained by mechanical recycling, chemical recycling, or the like.

[0060] From the viewpoint of light-blocking properties and concealing properties, the sealant layer may contain milky white polyethylene obtained by adding a white pigment or an extender pigment such as titanium oxide, zinc oxide, calcium carbonate, or barium sulfate to the above polyethylene.

[0061] The sealant layer may be a polyethylene film. From the viewpoint of heat sealing properties, the sealant layer may be an unstretched polyethylene film, and an unstretched LLDPE film (density: 0.900 g / cm ３ 0.925g / cm or more ３ (less than)

[0062] The sealant layer may be composed of a single film containing polyethylene, or may be composed of multiple films containing polyethylene. The first sealant layer and the second sealant layer may contain the same material and have the same layer structure.

[0063] The thickness of the sealant layer can be 20 to 200 μm, or may be 50 to 120 μm. When the thickness of the sealant layer is equal to or greater than the lower limit, sufficient sealing strength can be easily obtained, and when the thickness is equal to or less than the upper limit, the processability of the laminate can be easily obtained.

[0064] (Adhesive Layer) The adhesive layer is a layer formed between the barrier layer (or overcoat layer) and the second sealant layer. Both layers are laminated via an adhesive by a dry lamination method or a non-solvent lamination method.

[0065] Examples of adhesives include epoxy adhesives, polyester / polyurethane adhesives, and polyamine adhesives. Of these, epoxy adhesives are preferred from the viewpoint of rigidity. Adhesives having a certain degree of heat resistance can be used.

[0066] The adhesive is preferably an adhesive (barrier adhesive) that exhibits gas barrier properties when cured to form an adhesive layer. In other words, the adhesive layer may be formed from a barrier adhesive, and may be said to be a cured product of the barrier adhesive. In particular, when an adhesive layer that comes into contact with the barrier layer is formed from an adhesive that exhibits barrier properties, it is possible to suppress a decrease in barrier properties due to the occurrence of cracks in the barrier layer. This can further improve the barrier properties of the laminate. Note that "exhibiting gas barrier properties" means that the oxygen permeability and water vapor permeability are as follows: Oxygen permeability: 3 cc mm / m ２ / day / atm or less, preferably 1 cc mm / m ２ / day / atm or less, more preferably 0.1 cc mm / m ２ / day / atm or less. Water vapor permeability: 3g・mm / m ２ / day or less, preferably 1 g mm / m ２ / day or less, more preferably 0.1 g mm / m ２ / day or less. Specific examples of the barrier adhesive include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation.

[0067] The thickness of the adhesive layer can be 0.1 to 20 μm, or alternatively 0.5 to 10 μm, or 1 to 5 μm. When the thickness of the adhesive layer is equal to or greater than the above-mentioned lower limit, cracking of the barrier layer is more easily suppressed, and the barrier properties of the laminate are more easily improved. Furthermore, when the thickness of the adhesive layer is equal to or greater than the above-mentioned lower limit, cushioning properties that absorb external impacts are more easily obtained, and cracking of the barrier layer due to impacts is more easily prevented. On the other hand, when the thickness of the adhesive layer is equal to or less than the above-mentioned upper limit, the flexibility of the laminate is more easily maintained.

[0068] The tensile modulus of the adhesive layer at 23°C is 500 MPa or more, but can be 800 MPa or more, or even 2000 MPa or more. When the tensile modulus is equal to or greater than the lower limit, the adhesive layer can be given a certain hardness and made less likely to stretch. This prevents the adhesive layer from being overstretched by repeated squeezing operations, and allows the barrier layer to be adequately protected.

[0069] Since the adhesive layer is thinner than the base layer, the adhesive layer can maintain a certain level of softness even if the tensile modulus is relatively high. Therefore, the upper limit of the tensile modulus of the adhesive layer is not particularly limited, but from the viewpoint of protecting the barrier layer, it can be set to, for example, 2500 MPa.

[0070] The tensile modulus of elasticity of the adhesive layer can be adjusted by the thickness of the adhesive layer, the molecular weight of the adhesive resin used, and the like.

[0071] The tensile modulus of the adhesive layer is measured as follows. Sample: A 30-40 μm thick adhesive layer cut into a size of 15 mm wide x 5 cm long. Measuring device: Tensilon universal testing machine. Measurement method: A tensile test was performed at 23°C with a chuck distance of 5 cm and a tensile speed of 200 mm / min. The slope of the stress / strain curve corresponding to the two strain points between 0.05% and 0.25% tensile elongation was taken as the tensile modulus of the film.

[0072] (Extruded Polyethylene Layer) The laminate may have one or more extruded polyethylene layers between any of the layers. The extruded polyethylene layer may be, for example, a first extruded polyethylene layer between the first sealant layer and the printing layer, or a second extruded polyethylene layer between the printing substrate layer and the substrate layer.

[0073] Examples of polyethylene contained in the extruded polyethylene layer include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), etc. Among these, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene are preferred from the viewpoint of interlayer adhesion.

[0074] The polyethylene may be biomass-derived polyethylene. The concentration of biomass-derived ethylene in the polyethylene contained in the extruded polyethylene layer is preferably 10% by mass or more.

[0075] The polyethylene may be recycled polyethylene obtained by mechanical recycling, chemical recycling, or the like.

[0076] The thickness of the extruded polyethylene layer can be 5 to 50 μm, or may be 10 to 30 μm. By setting the thickness of the extruded polyethylene layer to the above lower limit or more, the adhesion between the layers can be further improved. By setting the thickness of the extruded polyethylene layer to the above upper limit or less, the production cost of the laminate can be reduced and the productivity can be improved.

[0077] The extruded polyethylene layer is made from a resin composition containing polyethylene and can be bonded to the target layer by extruder lamination using a tandem machine. Examples of adhesives used for bonding include urethane-based, epoxy-based, and silicone-based adhesives.

[0078] <Tube container> The tube container has a body portion formed by rolling the laminate for a tube container into a cylindrical shape with its ends overlapping, and then heat-sealing the first sealant layer and the second sealant layer to each other at the ends. The tube container can also be called a laminate tube. The body portion can be formed with the first sealant layer on the outside.

[0079] Fig. 3 is a front view showing a tube container according to one embodiment. The tube container 100 shown in Fig. 3 includes a body 110 made of the laminate, a spout 120 attached to one end of the body 110, and a cap 130 attached to the spout 120.

[0080] Body 110 is a tubular member formed so as to be able to contain the contents by heat-sealing (sticking together) the sealant layers of the laminate at seal 113 and closing bottom (end) 111 located at the other end opposite to the end where spout 120 is attached. The heat seal width at seal 113 can be 1.5 to 8 mm.

[0081] The spout 120 made of a molded product is composed of a spout 122 for discharging the contents, and a shoulder 121 that is held by the body 110 and guides the contents to the spout 122.

[0082] The cap 130 is a member that allows the opening of the spout portion 122 to be closed and opened.

[0083] The shape of the tube container can be such that the shoulder is not tapered but is perpendicular to the body so that the contents can be squeezed out to the last drop. The materials for the spout and cap of the tube container are not particularly limited, but using the same polyethylene as the base layer and sealant layer can further improve recyclability.

[0084] [Second Aspect] The second aspect will be described below with reference to Fig. 4. As will be described in detail later, a laminate tube (hereinafter, sometimes simply referred to as a "tube") is produced by joining tube laminates into a cylindrical shape. Therefore, the configuration of the tube laminate will be described first.

[0085] 4 is a schematic cross-sectional view showing the layer structure of a laminate for a tube 1A according to this embodiment. The laminate for a tube 1A has a substrate 10A having a barrier function, and a first sealant layer 20 and a second sealant layer 30 bonded to the substrate 10A. The proportion of polyethylene in the total mass of the laminate for a tube 1A is 90 mass% or more, and the laminate for a tube has a mono-material structure.

[0086] The substrate portion 10A has a resin substrate layer 11 and a barrier layer 12 formed on the substrate layer 11. The substrate layer 11 is mainly composed of polyethylene. That is, polyethylene is the largest component of the resin component. The substrate layer 11 can also be made of a polyethylene film. The polyethylene film may be a film containing 70% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more of polyethylene, or a film containing 100% by mass of polyethylene. The polyethylene of the substrate layer 11 has a density of 0.940 g / cm ３ It is preferable that the main component be high density polyethylene (HDPE) of 0.925 g / cm or more. ３ 0.940g / cm or more ３ Medium density polyethylene (MDPE), density less than 0.900 g / cm ３ 0.925g / cm or more ３ Low density polyethylene (LDPE), density less than 0.900 g / cm ３ 0.925g / cm or more ３ Linear low density polyethylene (LLDPE), density less than 0.900 g / cm ３ When the base layer 11 contains a plurality of polyethylenes, the base layer 11 may have a single layer structure in which the polyethylenes are mixed, or a multi-layer structure in which some of the polyethylenes are layered.

[0087] When the base layer 11 has a multi-layer structure, it can be produced by film-forming polyethylene using a T-die method, an inflation method, or the like. When producing the base layer 11 using the T-die method, the melt flow rate (MFR) of the polyethylene is preferably 3 g / 10 min or more and 20 g / 10 min or less. By setting the MFR to 3 g / 10 min or more, the processability of the laminate can be improved. Furthermore, by setting the MFR to 20 g / 10 min or less, the produced base layer 11 can be prevented from breaking. When producing the base layer 11 using an inflation method, the MFR of the polyethylene is preferably 0.5 g / 10 min or more and 5 g / 10 min or less. By setting the MFR to 0.5 g / 10 min or more, the processability can be improved. Furthermore, by setting the MFR to 5 g / 10 min or less, the film-forming properties can be improved.

[0088] When the base layer 11 has a multi-layer structure, it can be a polyethylene film with a multilayer structure in which polyethylenes of different densities are extruded by a co-extrusion method (for example, a polyethylene other than high-density polyethylene / high-density polyethylene / polyethylene other than high-density polyethylene structure), or a polyethylene film with a multilayer structure in which polyethylene and a polyolefin other than polyethylene are extruded by a co-extrusion method (for example, a polypropylene / polyethylene / polypropylene structure).

[0089] The barrier layer 12 is formed on one surface of the substrate layer 11. Examples of materials for the barrier layer 12 include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoints of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of cost, it is selected from aluminum oxide and silicon oxide. Furthermore, from the viewpoint of excellent tensile elongation during processing, a layer using silicon oxide is more preferable. By using a barrier film made of a metal oxide as the barrier layer 12, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the tube laminate 1A. A vapor-deposited layer made of a metal oxide has the advantage of being transparent, and therefore less likely to cause a user who handles a packaging material made of the laminate to mistakenly believe that a metal foil is used, compared to a vapor-deposited layer made of a metal.

[0090] When the barrier layer 12 is formed of aluminum oxide, the thickness is preferably 5 nm or more and 30 nm or less. A film thickness of 5 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 30 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 30 nm is undesirable from an economic standpoint, as it increases the amount of material used and the film formation time, which tends to increase costs. From the same viewpoint as above, the film thickness of the vapor deposition layer is more preferably 7 nm or more and 15 nm or less.

[0091] When the barrier layer 12 is formed of silicon oxide, the thickness is preferably 10 nm or more and 50 nm or less. A film thickness of 10 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 50 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 50 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the film thickness of the vapor deposition layer is more preferably 20 nm or more and 40 nm or less.

[0092] If it is desired to impart light-blocking or concealing properties to the tube, the barrier layer 12 can also be formed using metallic aluminum. When the barrier layer 12 is formed using aluminum, the thickness is preferably 30 nm or more and 100 nm or less. A film thickness of 30 nm or more can provide sufficient light-blocking and gas barrier properties. Furthermore, a film thickness of 85 nm or less can suppress the occurrence of cracks due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. From the same viewpoint as above, the film thickness of the vapor deposition layer is more preferably 40 nm or more and 80 nm or less.

[0093] The barrier layer 12 can be formed by, for example, vacuum film formation. Vacuum film formation can use physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD, plasma CVD, and photo-CVD. Resistance heating vacuum deposition, electron beam (EB) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma enhanced chemical vapor deposition (PECVD) are particularly preferred for vacuum film formation. However, considering productivity, vacuum deposition is currently the most advantageous. The heating means for vacuum deposition is preferably an electron beam heating method, a resistance heating method, or an induction heating method.

[0094] The surface of the base material layer 11 on which the barrier layer 12 is to be formed may be subjected to an adhesion-facilitating treatment by dry surface treatment such as corona treatment or atmospheric pressure plasma treatment. In this way, the adhesion between the base material layer and the barrier layer 12 can be improved.

[0095] The first sealant layer 20 and the second sealant layer 30 are heat-sealable resin layers, and the first sealant layer 20 and the second sealant layer 30 can be joined by heat fusion. The first sealant layer 20 and the second sealant layer 30 are primarily composed of polyethylene. As with the base layer 11, various polyethylenes can be used, but from the perspective of heat sealing properties, LDPE, LLDPE, VLDPE, etc. are preferred as the primary component. The density of the polyethylene can be measured, for example, using a density measuring device BELPYCNO manufactured by Microtrack Bell Corporation.

[0096] Like the substrate layer 11, the first sealant layer 20 and the second sealant layer 30 can be configured as either a single layer or multiple layers, but from the viewpoint of processability, it is preferable to use an unstretched film. The first sealant layer 20 and the second sealant layer 30 may have the same configuration or different configurations. The thickness of the first sealant layer 20 and the second sealant layer 30 can be changed appropriately depending on the weight of the contents to be filled in the tube, and is, for example, approximately 50 μm to 250 μm. From the viewpoint of processability, a thickness of approximately 60 μm to 150 μm is preferable.

[0097] The substrate 10A is bonded to the first sealant layer 20 and the second sealant layer 30 by adhesive layers 2 and 3, respectively. Examples of materials for the adhesive layers 2 and 3 include one-component curing and two-component curing urethane adhesives, and both solvent-based and solventless adhesives can be used. These adhesives may contain a layered inorganic compound to further enhance the barrier properties.

[0098] The two-component curing urethane-based solventless adhesive contains a polyol component as a base component and a polyisocyanate component as a curing agent. The polyol component may be one or a mixture of two or more selected from the group consisting of polyester polyols, polyether polyols, polyether ester polyols, and polyurethane polyols. The polyester polyol may be, for example, an ester reaction product of a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a glycol-based solvent. The polycarboxylic acid may be, for example, succinic acid, glutaric acid, isophthalic acid, terephthalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, or dimer acid. The glycol-based solvent may be, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, neopentyl glycol, or 1,6-hexanediol. The polyether polyol may be, for example, a polymer of an oxirane compound and a low-molecular-weight polyol. The oxirane compound may be, for example, ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran. The low-molecular-weight polyol may be water, ethylene glycol, propylene glycol, trimethylolpropane, or glycerin. The polyetherester polyol may be, for example, one obtained by reacting a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a polyether polyol. The polyurethane polyol may be, for example, a reaction product of a polyester polyol, a polyether polyol, or a polyetherester polyol with a polyisocyanate monomer. The polyisocyanate component may be an aliphatic polyisocyanate, an aromatic polyisocyanate, or a mixture thereof. The aliphatic polyisocyanate may be, for example, a polyisocyanate monomer, a polyisocyanate derivative, or a polyisocyanate-terminated prepolymer.Examples of the polyisocyanate monomer include tetramethylene diisocyanate, isopropylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Examples of the polyisocyanate derivative include 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, lysine diisocyanate, and isophorone diisocyanate. Examples of the aromatic polyisocyanate include polyisocyanate monomers, polyisocyanate derivatives, and polyisocyanate-terminated prepolymers. Examples of the polyisocyanate monomer include tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. The polyisocyanate derivative may be, for example, an isocyanurate derived from a polyisocyanate monomer. The polyisocyanate-terminated prepolymer may be a bifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a bifunctional polyol compound such as polypropylene glycol. The polyisocyanate-terminated prepolymer may be a multifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a trifunctional or higher polyol compound such as trimethylolpropane.

[0099] Examples of solvent-based adhesives include urethane-based adhesives, epoxy-based adhesives, and silicone-based adhesives, but from the viewpoint of impact resistance, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are particularly preferred. The solvent used in the solvent-based adhesive is not particularly limited, but examples thereof include ethyl acetate, methanol, isopropyl alcohol, methyl ethyl ketone, and ethanol.

[0100] The coating weight (weight per unit area) of each adhesive layer after drying was 0.5 g / m ２ 3.0g / m or more ２ Preferably, 1.0 g / m or less ２ 2.0g / m or more ２The coating weight of the adhesive layer is more preferably 0.5 g / m or less. ２ If the coating weight of the adhesive layer is 3.0 g / m or more, the effect of suppressing delamination between layers can be improved. ２ If the thickness is below this range, it is possible to prevent the occurrence of winding slippage during processing of the laminate, to improve the appearance quality of the laminate, and in addition, to obtain appropriate lamination strength. As the coating method, various known methods can be selected and used, such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0101] The adhesive may be an adhesive (gas barrier adhesive) that exhibits gas barrier properties after curing. In other words, the adhesive layer may contain a gas barrier adhesive and may be said to be a cured product of the gas barrier adhesive. In particular, forming an adhesive layer that contacts the vapor deposition layer with an adhesive that exhibits gas barrier properties can further suppress deterioration of the gas barrier properties due to cracking of the vapor deposition layer. This further improves the gas barrier performance of the tube laminate 1A. Examples of gas barrier adhesives include epoxy-based adhesives, polyester / polyurethane-based adhesives, and polyamine-based adhesives. Specific examples include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation. The adhesive layers 2 and 3 may have the same composition or different compositions. Furthermore, their thicknesses may be the same or different. The thickness can be, for example, 0.5 μm to 6 μm, preferably 0.8 μm to 5 μm, and more preferably 1.0 μm to 4.5 μm. The adhesive layer 2 and the adhesive layer 3 can be formed by various known methods such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0102] The inventors conducted various studies to improve the resistance of a mono-material tube laminate to repeated squeezing. The inventors discovered that sufficient resistance to repeated squeezing can be achieved by using an unstretched film for the base layer 11. Because unstretched films have superior flexibility compared to stretched films such as uniaxially stretched and biaxially stretched films, portions bent during squeezing easily return to their pre-folded state. This means that the portion bent during the next squeezing operation is unlikely to be the same as the previous portion. As a result, the bent portion is less likely to become fixed, and bending loads are less likely to accumulate in specific local areas. Finally, repeated bending loads are also suppressed in specific local areas of the barrier layer 12, thereby suppressing damage such as cracks in the vapor-deposited barrier layer 12. On the other hand, while stretched films have higher rigidity than unstretched films, once bent during squeezing, the portion is less likely to return to its pre-folded state. As a result, it was found that the bent portions are likely to be fixed by repeated squeezing operations, and the barrier layer 12 is likely to be damaged.

[0103] The inventors' studies have confirmed that the above-mentioned effects can be sufficiently achieved when the MD elongation of the base layer 11 is 2.5% or more and 6.5% or less when a tension of 50 N / m is applied at 70°C. The MD elongation is more preferably 2.8% or more and 5.0% or less, even more preferably 2.8% or more and 5.0% or less, and extremely preferably 3.0% or more and 3.5% or less. An MD elongation within this range can be relatively easily achieved by using an unstretched film primarily composed of HDPE. The high-density polyethylene film may be derived from petroleum or plants, or a mixture thereof. The MD direction is one direction present in industrially produced resin films and is perpendicular to the other TD direction. Generally, in resin films distributed in roll form, the longitudinal direction is the MD direction and the width direction is the TD direction. In many cases of resin films distributed in rectangular or square shapes, the direction in which one side extends is the MD direction, and the direction in which another side perpendicular to this side extends is the TD direction.

[0104] The MD elongation can be measured by thermomechanical analysis (TMA). TMA is a technique for measuring the deformation of a sample with respect to temperature while applying a non-oscillating load (constant load (tension)) to the sample. The MD elongation is specifically defined as follows: MD elongation (%) = ((film length in the MD direction when a predetermined tension is applied at a predetermined temperature) - (film length in the MD direction when no tension is applied at room temperature)) / (film length in the MD direction when no tension is applied at room temperature). In the present invention, the load deflection temperature (heat distortion temperature) of polyethylene is around 70°C, and from the viewpoint that the flexibility of the film can be evaluated, the MD elongation is defined as the predetermined temperature of 70°C. Furthermore, from the viewpoint of the tension acting during vapor deposition on the base layer 11 and lamination processing of the base layer 11, the predetermined tension is set to 50 N / m.

[0105] As explained above, in the laminate for tube 1A according to this embodiment, by setting the MD elongation percentage within a predetermined range, the deposited film is less likely to be damaged even when the laminate is formed into a tube and repeatedly squeezed. As long as the MD elongation percentage is satisfied, there is no problem even if the base layer 11 is not a non-stretched film. However, stretched films, whether uniaxially or biaxially stretched, are always stretched in the MD direction and therefore are less likely to stretch in the MD direction. Therefore, it is practically impossible to set the MD elongation percentage of the base layer 11 within the above range using a stretched film.

[0106] When the base material layer 11 has a multi-layer structure, the above-mentioned MD elongation rate can be easily satisfied by configuring the base material layer 11 to have a flexible skin layer on the surface of the core layer, which is the main layer. For example, the mass ratio of the core layer in the base material layer 11 may be 70 mass% or more and 95 mass% or less. The thickness ratio of the core layer in the base material layer 11 may be 70 mass% or more and 95 mass% or less.

[0107] An example of a procedure for producing a laminated tube using the tube laminate 1A will be described. The tube laminate 1A is rolled so that the TD direction, which is perpendicular to the MD direction, is the circumferential direction, and the first sealant layer 20 and the second sealant layer 30 are joined by heat fusion at the opposing portions, resulting in a tubular member. One end of this tubular member is closed by heat fusion to form a body portion 110 that can be filled with contents. A shoulder portion 121, fabricated by resin molding, is attached to the open end of this body portion 110 by heat fusion to complete the laminated tube 100. The body portion 110 may be filled with contents either before or after the shoulder portion 121 is attached. In the example shown in Figure 3, the spout portion 122 of the spout portion 120 is sealed with a screw cap 130, so the spout portion 122 is provided with a thread, but instead of the screw cap 130, a fitting cap or the like may be used for sealing, in which case it is of course not necessary to provide a thread.

[0108] The second embodiment will be described with reference to Fig. 5. In the following description, components common to those already described will be assigned the same reference numerals, and redundant description will be omitted. Fig. 5 is a schematic cross-sectional view showing the layer structure of a laminate for a tube 1B according to this embodiment. The substrate portion 10B of the laminate for a tube 1B has a barrier coat layer 15 and a second substrate layer 16 in addition to a substrate layer 11 and a barrier layer 12 formed by vapor deposition.

[0109] An underlayer 13 is provided between the substrate layer 11 and the barrier layer 12 to enhance adhesion between the substrate layer 11 and the barrier layer 12. The underlayer 13 can be formed using an anchor coating agent, and examples of anchor coating agents include polyester-based polyurethane resins, polyether-based polyurethane resins, and acrylic urethane resins. From the viewpoints of heat resistance and interlayer adhesive strength, polyester-based polyurethane resins are preferred. The underlayer 13 can also be formed using a polyvinyl alcohol-based resin. Any polyvinyl alcohol-based resin may be used as long as it has vinyl alcohol units formed by saponifying vinyl ester units, such as polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH). When a polyvinyl alcohol-based resin is used for the underlayer 13, examples of the formation method include coating using a polyvinyl alcohol-based resin solution and multilayer extrusion. In the case of multilayer extrusion, lamination may be performed via an adhesive resin such as maleic anhydride-grafted modified polyethylene.

[0110] The barrier coat layer 15 is located on the barrier layer 12 on the opposite side to the substrate layer 11, and together with the barrier layer 12, the barrier coat layer 15 improves the barrier properties of the tube laminate and prevents a decrease or breakdown of the barrier properties by covering any minute defects that may occur in the barrier layer 12. The barrier coat layer 15 may contain a hydroxyl group-containing polymer compound, and specifically may be a heat-dried product of a composition containing at least one of a hydroxyl group-containing polymer compound and a hydrolysate thereof, and at least one selected from the group consisting of a metal alkoxide, a silane coupling agent, and a hydrolysate thereof.

[0111] The barrier coat layer 15 can be formed using a composition (hereinafter referred to as an overcoat agent) obtained by adding a hydroxyl-containing polymer compound and a metal alkoxide and / or a silane coupling agent to water or a water / alcohol mixture. The overcoat agent can be prepared by mixing, for example, a solution of a hydroxyl-containing polymer compound, which is a water-soluble polymer, in an aqueous (water or water / alcohol) solvent with a metal alkoxide and / or a silane coupling agent, either directly or after being previously treated by hydrolysis or the like.

[0112] Examples of hydroxyl group-containing polymer compounds include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, etc. Among these, polyvinyl alcohol (PVA) is preferred when used as the overcoat agent because it has particularly excellent gas barrier properties.

[0113] Examples of metal alkoxides include compounds represented by the following general formula (I): M(OR1) ｍ (R2) ｎ－ｍ ... (I) In the above general formula (I), R1 and R2 are each independently a monovalent organic group having 1 to 8 carbon atoms, and are preferably alkyl groups such as methyl and ethyl groups. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. When a plurality of R1 or R2 are present, the R1s or R2s may be the same or different. Specific examples of metal alkoxides include tetraethoxysilane [Si(OC ２ H ５ ) ４ ], triisopropoxyaluminum [Al(O-2'-C ３ H ７ ) ３ Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0114] Examples of the silane coupling agent include compounds represented by the following general formula (II): Si(OR11) ｐ(R12) ３－ｐR13...(II) In the above general formula (II), R11 represents an alkyl group such as a methyl group or an ethyl group, R12 represents a monovalent organic group such as an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkyl group substituted with an acryloxy group, or an alkyl group substituted with a methacryloxy group, R13 represents a monovalent organic functional group, and p represents an integer of 1 to 3. When multiple R11 or R12 are present, the R11s or R12s may be the same or different. Examples of the monovalent organic functional group represented by R13 include a glycidyloxy group, an epoxy group, a mercapto group, a hydroxyl group, an amino group, an alkyl group substituted with a halogen atom, or a monovalent organic functional group containing an isocyanate group. Specific examples of silane coupling agents include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. Furthermore, the silane coupling agent may be a polymer formed by polymerization of the compound represented by the general formula (II) above. A trimer is preferred as the polymer, and 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is more preferred. This is a condensation polymer of 3-isocyanate alkylalkoxysilane. It is known that while the isocyanate moiety of this 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate loses chemical reactivity, reactivity is maintained due to the polarity of the nurate moiety. It is generally added to adhesives, etc., in the same manner as 3-isocyanate alkylalkoxysilane, and is known as an adhesion improver. Therefore, by adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a hydroxyl group-containing polymer compound, hydrogen bonding can be used to improve the water resistance of the barrier coat layer 15. While 3-isocyanate alkylalkoxysilanes are highly reactive and have low liquid stability, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is not water-soluble due to the polarity of the nurate moiety, but is easily dispersed in aqueous solutions and can maintain a stable liquid viscosity.Furthermore, the water resistance performance of 3-isocyanate alkyl alkoxysilane and 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate is equivalent. 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate is sometimes produced by thermal condensation of 3-isocyanate propyl alkoxysilane, and may contain the raw material 3-isocyanate propyl alkoxysilane, but this does not pose any particular problems. 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate is more preferred, and 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate is even more preferred. Because the methoxy group has a fast hydrolysis rate and those containing a propyl group are relatively inexpensive, 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate is practically advantageous.

[0115] The amount of metal alkoxide in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound, from the viewpoints of maintaining adhesion to the vapor deposition layer and gas barrier properties. Similarly, the amount of silane coupling agent can be 0.01 to 1 part by mass, or may be 0.1 to 0.5 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound. When a silane compound (alkoxysilane) is used as the metal alkoxide, the amount of the silane compound (metal alkoxide and silane coupling agent) in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound.

[0116] The overcoating agent may contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, or a colorant, as needed, within a range that does not impair the gas barrier property. The overcoating agent can be applied by, for example, dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, or the like. The coating film obtained by applying the overcoating agent can be dried by, for example, hot air drying, heat roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0117] The temperature at which the coating film is dried can be, for example, 50 to 150°C, preferably 70 to 100°C. By maintaining the drying temperature within the above range, cracking in the barrier layer 12 and the barrier coat layer 15 can be further suppressed, resulting in excellent barrier properties. The barrier coat layer 15 may be formed using an overcoat agent containing a hydroxyl group-containing polymer compound (e.g., a polyvinyl alcohol-based resin) and a silane compound. The overcoat agent may contain an acid catalyst, an alkali catalyst, a photopolymerization initiator, or the like, as needed. Examples of silane compounds include silane coupling agents, polysilazanes, and siloxanes. Specific examples include tetramethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and hexamethyldisilazane. The thickness of the barrier coat layer 15 is preferably 50 to 1,000 nm, and more preferably 100 to 500 nm. If the thickness of the barrier coat layer 15 is 50 nm or more, more sufficient gas barrier properties tend to be obtained, and if it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0118] Since the second substrate layer 16 is a polyethylene film, the tube laminate 1B maintains a mono-material structure. The second substrate layer 16 may have the same composition as the substrate layer 11, or it may be a polyethylene film with a different composition. If light-blocking or opaque properties are desired for the laminated tube to be produced, the second substrate layer 16 may be a colored, opaque polyethylene film containing a white pigment or extender pigment, such as titanium oxide, zinc oxide, calcium carbonate, or barium sulfate. The second substrate layer 16 has a printing layer 17 on one side, located between the substrate layer 11 and the first sealant layer 20. The printing layer 17 can be formed by known methods such as gravure printing or flexographic printing. Depending on the method used, solvent-based inks or water-based inks can be selected, but water-based inks are preferred from an environmental perspective. Furthermore, the surface of the second substrate layer 16 on which the printing is to be formed may be subjected to surface treatments such as corona treatment or plasma treatment to improve the adhesion of the printing layer 17.

[0119] The second substrate layer 16 and the substrate layer 11 are joined by an adhesive layer 4. The adhesive layer 4 can be the same as the adhesive layers 2 and 3. The printing layer 17 may be located on either the substrate layer 11 side or the first sealant layer 20 side, but of the adhesive layers 2 and 4, the one in contact with the printing layer 17 is preferably a solvent-free adhesive from the viewpoint of suppressing dimensional changes in the printed image during lamination. Examples of solvent-free adhesives include urethane-based adhesives, epoxy-based adhesives, and silicone-based adhesives. From the viewpoint of impact resistance, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are particularly preferred.

[0120] The printed layer 17 may be provided at any position as long as it is visible from the outside of the laminate for a tube. Although Fig. 5 illustrates a layer configuration in which the printed layer 17 and the adhesive layer 2 are in contact with each other and the second base material layer 16 and the adhesive layer 4 are in contact with each other, the printed layer 17 and the second base material layer 16 may also be arranged so that the second base material layer 16 and the adhesive layer 2 are in contact with each other and the printed layer 17 and the adhesive layer 4 are in contact with each other.

[0121] A printed layer may be formed on the outside of the first sealant layer 20. In this case, a transparent protective layer may be provided on the printed layer to prevent the printed layer from being rubbed by external contact. Alternatively, a printed layer may be formed on the outside of the second sealant layer 30. In this case, the printed layer is formed between the second sealant layer 30 and the adhesive layer 3. In these cases, it is sufficient to form a printed layer on the surface of the first sealant layer 20 or the second sealant layer 30 by the above-mentioned printing method, and the second base material layer 16 does not need to be used.

[0122] A printed layer may be formed by offset printing using an active energy ray-curable ink. Active energy rays are energy rays that can generate radically active species, and examples of such rays include electromagnetic waves such as X-rays and gamma rays, particle rays such as electron beams (EB), proton beams and alpha rays, and non-ionizing radiation such as microwaves and ultraviolet rays. The active energy ray-curable ink contains an active energy ray-curable resin. After offset printing is performed on a printing surface using such ink, the ink is irradiated with active energy rays, thereby curing the ink and forming a printed layer.

[0123] The laminate for tube 1B having the above configuration achieves the same effects as the first embodiment. Furthermore, the inclusion of the second substrate layer 16 in the substrate portion 10B also provides the advantage of improved puncture resistance after repeated squeezing. In the laminate for tube 1B, it is preferable that the MD elongation percentages of both the substrate layer 11 and the second substrate layer 16 are within the above-mentioned ranges. This prevents the accumulation of bending loads in specific areas not only in the substrate layer but also in the second substrate layer during repeated squeezing, which is expected to prevent the display of the printed layer from becoming blurred.

[0124] The barrier coating layer 15 and the underlayer 13 described in this embodiment are not specific to this embodiment, and may also be provided in the first embodiment. When provided in the first embodiment, both may be provided, or only one of them may be provided.

[0125] The third embodiment will be described with reference to Fig. 6. Fig. 6 is a schematic cross-sectional view showing the layer structure of a laminate for a tube 1C according to this embodiment. The laminate for a tube 1C differs from the laminate for a tube 1B according to the second embodiment only in that the adhesive layers 2 and 4 are replaced with adhesive layers 2A and 4A, respectively.

[0126] The adhesive layer 2A includes an anchor coat layer 2a and an extruded resin layer 2b. Similarly, the adhesive layer 4A includes an anchor coat layer 4a and an extruded resin layer 4b. The anchor coat layers 2a and 4a can be formed by applying and drying an anchor coat agent. Examples of anchor coat agents include any resin with a heat resistance temperature of 135°C or higher, such as vinyl-modified resin, epoxy resin, urethane resin, polyester resin, and polyethyleneimine. In particular, anchor coat agents that are cured products of polyacrylic or polymethacrylic resins (polyols) containing two or more hydroxyl groups in their structure and an isocyanate compound as a curing agent are preferred. A silane coupling agent may also be used as an additive, and soluble nitrocellulose may also be used to enhance heat resistance. The thickness of the anchor coat layers 2a and 4a after drying can be 0.1 μm to 1 μm, preferably 0.3 μm to 0.5 μm.

[0127] The extruded resin layers 2b and 4b may be made of polyethylene, polypropylene, or cyclic polyolefin resins, or copolymers, modified resins, or mixtures (including alloys) containing these resins as the main components. Examples of polyolefin resins include the above-mentioned polyethylene, polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, ethylene-polypropylene random or block copolymers, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. To improve interlayer adhesion, acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid may also be used. In addition, resins obtained by graft polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers with polyolefin resins can be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more. The thickness of the extruded resin layers 2b and 4b can be 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

[0128] The anchor coat layers 2a and 4a may be the same or different, and the extruded resin layers 2b and 4b may be the same or different.

[0129] As described above, the tube laminate 1C differs from the tube laminate 1B in that it employs extrusion lamination for bonding. This has the advantage of improving the flexibility of the laminate compared to bonding using only dry lamination or non-solvent lamination. In this embodiment, instead of adhesive layer 2A or 4A, adhesive layer 3 may be configured to include an anchor coat layer and an extruded resin layer, or all adhesive layers may be configured to include an anchor coat layer and an extruded resin layer. When two or more adhesive layers each having an anchor coat layer and an extruded resin layer are provided, lamination using a tandem extrusion laminator is preferred from the standpoints of productivity and cost.

[0130] [Third Aspect] The third aspect will be described below with reference to Fig. 7. As will be described in detail later, the laminate tube according to this embodiment (hereinafter, sometimes simply referred to as "tube") is produced by joining laminates for tubes into a cylindrical shape. Therefore, the configuration of the laminate for tube will be described first.

[0131] 7 is a schematic cross-sectional view showing the layer structure of a laminate for a tube 1D according to this embodiment. The laminate for a tube 1D has a substrate portion 10C having a barrier function, and a first sealant layer 20 and a second sealant layer 30 bonded to the substrate portion 10C. The proportion of polyethylene in the total mass of the laminate for a tube 1D is 90 mass% or more, and the laminate for a tube 1D has a mono-material structure.

[0132] The substrate portion 10C has a resin substrate layer 11 and a barrier layer 12 formed on the substrate layer 11. The substrate layer 11 is mainly composed of polyethylene. That is, it contains polyethylene in the largest amount as a resin component. The substrate layer 11 can also be made of a polyethylene film. The polyethylene film may be a film containing 70% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more of polyethylene, or a film containing 100% by mass of polyethylene. If polyethylene is the main component, a resin component other than polyethylene, such as a polyolefin resin other than polyethylene, may also be contained. The polyethylene of the substrate layer 11 has a density of 0.940 g / cm３ It is preferable that the main component be high density polyethylene (HDPE) of 0.925 g / cm or more. ３ 0.940g / cm or more ３ Medium density polyethylene (MDPE), density less than 0.900 g / cm ３ 0.925g / cm or more ３ Low density polyethylene (LDPE), density less than 0.900 g / cm ３ 0.925g / cm or more ３ Linear low density polyethylene (LLDPE), density less than 0.900 g / cm ３ The substrate layer 11 may contain an ultra-low density polyethylene film (VLDPE) of less than 1000 MPa. When the substrate layer 11 contains multiple polyethylenes, it may be a single layer in which the polyethylenes are mixed, or a multi-layer structure in which some of the polyethylenes are layered. The thickness of the substrate layer 11 can be set appropriately. From the viewpoint of imparting excellent impact resistance and excellent gas barrier properties to the laminated tube to be produced, a thickness of 3 to 250 μm is preferable, and from the viewpoint of improving processability, rigidity, and flexibility, a thickness of 15 to 40 μm is preferable.

[0133] When the base layer 11 has a multi-layer structure, it can be produced by film-forming polyethylene using a T-die method, an inflation method, or the like. When producing the base layer 11 using the T-die method, the melt flow rate (MFR) of the polyethylene is preferably 3 g / 10 min or more and 20 g / 10 min or less. By setting the MFR to 3 g / 10 min or more, the processability of the laminate can be improved. Furthermore, by setting the MFR to 20 g / 10 min or less, the produced base layer 11 can be prevented from breaking. When producing the base layer 11 using an inflation method, the MFR of the polyethylene is preferably 0.5 g / 10 min or more and 5 g / 10 min or less. By setting the MFR to 0.5 g / 10 min or more, the processability can be improved. Furthermore, by setting the MFR to 5 g / 10 min or less, the film-forming properties can be improved.

[0134] When the base layer 11 has a multi-layer structure, it can be a polyethylene film with a multilayer structure in which polyethylenes of different densities are extruded by a co-extrusion method (for example, a layer structure such as polyethylene other than high-density polyethylene / high-density polyethylene / polyethylene other than high-density polyethylene), or a polyethylene film with a multilayer structure in which polyethylene and a polyolefin other than polyethylene are extruded by a co-extrusion method (for example, a layer structure such as polypropylene / polyethylene / polypropylene).

[0135] There is no particular limitation on whether the substrate layer 11 is stretched or not, and it may be uniaxially stretched, biaxially stretched, or unstretched. There is also no particular limitation on the stretching method. An unstretched substrate is likely to achieve higher adhesion strength with the barrier layer 12. It also has the advantage of being able to achieve both rigidity and flexibility, making stress concentration less likely, and making it less likely for the vapor-deposited film to crack due to repeated squeezing of the laminate tube. A stretched substrate has the advantage of being excellent in impact resistance, heat resistance, water resistance, dimensional stability, etc.

[0136] The barrier layer 12 is formed on one surface (first surface) of the substrate layer 11. Examples of materials for the barrier layer 12 include metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoints of transparency and barrier properties, the metal oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, from the viewpoint of cost, it is selected from aluminum oxide and silicon oxide. Furthermore, from the viewpoint of excellent tensile elongation during processing, a layer using silicon oxide is more preferable. By using a barrier film made of a metal oxide as the barrier layer 12, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the tube laminate 1D. A vapor-deposited layer made of a metal oxide has the advantage of being transparent, and therefore less likely to cause a user who handles a packaging material made of the laminate to mistakenly believe that a metal foil is used, compared to a vapor-deposited layer made of a metal.

[0137] When the barrier layer 12 is formed of aluminum oxide, the thickness is preferably 5 nm or more and 30 nm or less. A film thickness of 5 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 30 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 30 nm is undesirable from an economic standpoint, as it increases the amount of material used and the film formation time, which tends to increase costs. From the same viewpoint as above, the film thickness of the vapor deposition layer is more preferably 7 nm or more and 15 nm or less.

[0138] When the barrier layer 12 is formed of silicon oxide, the thickness is preferably 10 nm or more and 50 nm or less. A film thickness of 10 nm or more can provide sufficient gas barrier properties. Furthermore, a film thickness of 50 nm or less can prevent cracks from occurring due to deformation caused by internal stress in the thin film, thereby preventing a decrease in gas barrier properties. Note that a film thickness exceeding 50 nm is undesirable from an economic standpoint, as it increases costs due to an increase in the amount of material used and a longer film formation time. From the same viewpoint as above, the film thickness of the vapor deposition layer is more preferably 20 nm or more and 40 nm or less.

[0139] If it is desired to impart light-blocking or concealing properties to the tube, the barrier layer 12 can also be formed from a vapor-deposited layer made of metallic aluminum. When the barrier layer 12 is formed from aluminum, it is preferably 30 nm or more and 100 nm or less. A film thickness of 30 nm or more can provide sufficient light-blocking and gas barrier properties. Furthermore, a film thickness of 85 nm or less can suppress the occurrence of cracks due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. From the same viewpoint as above, the film thickness of the vapor-deposited layer is more preferably 40 nm or more and 80 nm or less.

[0140] The barrier layer 12 can be formed by, for example, vacuum film formation. Vacuum film formation can use physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD, plasma CVD, and photo-CVD. Resistance heating vacuum deposition, electron beam (EB) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma enhanced chemical vapor deposition (PECVD) are particularly preferred for vacuum film formation. However, considering productivity, vacuum deposition is currently the most advantageous. The heating means for vacuum deposition is preferably an electron beam heating method, a resistance heating method, or an induction heating method.

[0141] The surface of the base material layer 11 on which the barrier layer 12 is to be formed may be subjected to an adhesion-facilitating treatment by dry surface treatment such as corona treatment or atmospheric pressure plasma treatment. In this way, the adhesion between the base material layer and the barrier layer 12 can be improved.

[0142] An underlayer 13 is provided between the substrate layer 11 and the barrier layer 12, and a barrier coat layer 15 is provided on the side of the barrier layer 12 opposite to the side on which the underlayer 13 is provided. In other words, the barrier layer 12 is sandwiched between the underlayer 13 and the barrier coat layer 15.

[0143] The underlayer 13 is a resin layer whose main component is ethylene-vinyl alcohol copolymer (EVOH). That is, EVOH has the highest mass ratio among the resins constituting the underlayer 13. Examples of methods for forming the underlayer 13 include applying and drying a coating liquid containing EVOH, and co-extrusion of the resin that will become the base layer 11 with EVOH. In the case of co-extrusion, an adhesive resin such as maleic anhydride-grafted modified polyethylene may be sandwiched between the layers. The thickness of the underlayer 13 can be set appropriately taking into consideration productivity, flexibility (described below), and the like, and is, for example, approximately 0.2 to 10 μm.

[0144] The barrier coat layer 15 improves the barrier properties of the tube laminate together with the barrier layer 12, and prevents a decrease or breakdown in the barrier properties by covering any minute defects that may occur in the barrier layer 12. The barrier coat layer 15 according to this embodiment contains a polyvinyl alcohol-based resin and at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide.

[0145] The barrier coat layer 15 can be formed using a composition (hereinafter referred to as an overcoat agent) obtained by adding a hydroxyl group-containing polymer compound (e.g., a polyvinyl alcohol-based resin) and a metal alkoxide or the like to water or a water / alcohol mixed solution. The overcoat agent can be prepared, for example, by mixing a solution in which a polyvinyl alcohol-based resin is dissolved in an aqueous solvent (water or a water / alcohol mixed) with a metal alkoxide or the like directly, or with a solution that has been previously treated, such as by hydrolysis.

[0146] Examples of metal alkoxides include compounds represented by the following general formula (I): M(OR1) ｍ (R2) ｎ－ｍ ...(I) In the above general formula (I), R1 and R2 each independently represent a monovalent organic group having 1 to 8 carbon atoms, and are preferably alkyl groups such as methyl and ethyl groups. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. When a plurality of R1 or R2 are present, the R1s or R2s may be the same or different. Specific examples of metal alkoxides include tetraethoxysilane [Si(OC ２ H ５ ) ４ ], triisopropoxyaluminum [Al(O-2'-C ３ H ７ ) ３ Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0147] The barrier coat layer 15 may contain at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, and a reaction product of the silane coupling agent or the hydrolyzate of the silane coupling agent. Such a barrier coat layer 15 can be formed by further adding a silane coupling agent or the like to the above-mentioned overcoat agent.

[0148] Examples of the silane coupling agent include compounds represented by the following general formula (II): Si(OR11) ｐ (R12) ３－ｐR13...(II) In the above general formula (II), R11 represents an alkyl group such as a methyl group or an ethyl group, R12 represents a monovalent organic group such as an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkyl group substituted with an acryloxy group, or an alkyl group substituted with a methacryloxy group, R13 represents a monovalent organic functional group, and p represents an integer of 1 to 3. When multiple R11 or R12 are present, the R11s or R12s may be the same or different. Examples of the monovalent organic functional group represented by R13 include a glycidyloxy group, an epoxy group, a mercapto group, a hydroxyl group, an amino group, an alkyl group substituted with a halogen atom, or a monovalent organic functional group containing an isocyanate group. Specific examples of silane coupling agents include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. Furthermore, the silane coupling agent may be a polymer formed by polymerization of the compound represented by the general formula (II) above. A trimer is preferred as the polymer, and 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is more preferred. This is a condensation polymer of 3-isocyanate alkylalkoxysilane. It is known that while the isocyanate moiety of this 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate loses chemical reactivity, reactivity is maintained due to the polarity of the nurate moiety. It is generally added to adhesives, etc., in the same manner as 3-isocyanate alkylalkoxysilane, and is known as an adhesion improver. Therefore, by adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a hydroxyl group-containing polymer compound, hydrogen bonding can be used to improve the water resistance of the barrier coat layer 15. While 3-isocyanate alkylalkoxysilanes are highly reactive and have low liquid stability, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is not water-soluble due to the polarity of the nurate moiety, but is easily dispersed in aqueous solutions and can maintain a stable liquid viscosity.Furthermore, the water resistance performance of 3-isocyanate alkyl alkoxysilane and 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate is equivalent. 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate is sometimes produced by thermal condensation of 3-isocyanate propyl alkoxysilane, and may contain the raw material 3-isocyanate propyl alkoxysilane, but this does not pose any particular problems. 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate is more preferred, and 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate is even more preferred. Because the methoxy group has a fast hydrolysis rate and those containing a propyl group are relatively inexpensive, 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate is practically advantageous.

[0149] The amount of metal alkoxide in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound, from the viewpoints of maintaining adhesion to the vapor deposition layer and gas barrier properties. Similarly, the amount of silane coupling agent can be 0.01 to 1 part by mass, or may be 0.1 to 0.5 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound. When a silane compound (alkoxysilane) is used as the metal alkoxide, the amount of the silane compound (metal alkoxide and silane coupling agent) in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound.

[0150] The overcoating agent may contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, or a colorant, as needed, within a range that does not impair the gas barrier property. The overcoating agent can be applied by, for example, dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, or the like. The coating film obtained by applying the overcoating agent can be dried by, for example, hot air drying, heat roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0151] The temperature at which the coating film is dried can be, for example, 50 to 150°C, preferably 70 to 100°C. By maintaining the drying temperature within the above range, cracking in the barrier layer 12 and the barrier coat layer 15 can be further suppressed, resulting in excellent barrier properties. The barrier coat layer 15 may be formed using an overcoat agent containing a hydroxyl group-containing polymer compound (e.g., a polyvinyl alcohol-based resin) and a silane compound. The overcoat agent may contain an acid catalyst, an alkali catalyst, a photopolymerization initiator, or the like, as needed. Examples of silane compounds include silane coupling agents, polysilazanes, and siloxanes. Specific examples include tetramethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and hexamethyldisilazane. In one example, the thickness of the barrier coat layer 15 is approximately 0.2 to 10 μm.

[0152] The first sealant layer 20 and the second sealant layer 30 are heat-sealable resin layers, and the first sealant layer 20 and the second sealant layer 30 can be joined by heat fusion. The first sealant layer 20 according to this embodiment is located on the second surface of the base layer 11, opposite the first surface on which the barrier layer is provided. The first sealant layer 20 and the second sealant layer 30 are primarily composed of polyethylene. As with the base layer 11, various polyethylenes can be used, but from the viewpoint of heat sealing properties, LDPE, LLDPE, VLDPE, etc. are preferred as the primary component. The density of polyethylene can be measured, for example, using a density measuring device BELPYCNO manufactured by Microtrac-Bell Corporation.

[0153] Like the substrate layer 11, the first sealant layer 20 and the second sealant layer 30 can be configured as either a single layer or multiple layers, but from the viewpoint of processability, it is preferable to use an unstretched film. The first sealant layer 20 and the second sealant layer 30 may have the same configuration or different configurations. The thickness of the first sealant layer 20 and the second sealant layer 30 can be changed appropriately depending on the weight of the contents to be filled in the tube, and is, for example, approximately 20 μm or more and 250 μm or less. From the viewpoint of processability, a thickness of approximately 50 μm or more and 150 μm or less is preferable.

[0154] The substrate portion 10C is bonded to the first sealant layer 20 and the second sealant layer 30 by adhesive layers 2 and 3, respectively. Examples of materials for the adhesive layers 2 and 3 include one-component curing and two-component curing urethane adhesives, and both solvent-based and solventless adhesives can be used. These adhesives may contain a layered inorganic compound to further enhance the barrier properties.

[0155] The two-component curing urethane-based solventless adhesive contains a polyol component as a base component and a polyisocyanate component as a curing agent. The polyol component may be one or a mixture of two or more selected from the group consisting of polyester polyols, polyether polyols, polyether ester polyols, and polyurethane polyols. The polyester polyol may be, for example, an ester reaction product of a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a glycol-based solvent. The polycarboxylic acid may be, for example, succinic acid, glutaric acid, isophthalic acid, terephthalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, or dimer acid. The glycol-based solvent may be, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, neopentyl glycol, or 1,6-hexanediol. The polyether polyol may be, for example, a polymer of an oxirane compound and a low-molecular-weight polyol. The oxirane compound may be, for example, ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran. The low-molecular-weight polyol may be water, ethylene glycol, propylene glycol, trimethylolpropane, or glycerin. The polyetherester polyol may be, for example, one obtained by reacting a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a polyether polyol. The polyurethane polyol may be, for example, a reaction product of a polyester polyol, a polyether polyol, or a polyetherester polyol with a polyisocyanate monomer. The polyisocyanate component may be an aliphatic polyisocyanate, an aromatic polyisocyanate, or a mixture thereof. The aliphatic polyisocyanate may be, for example, a polyisocyanate monomer, a polyisocyanate derivative, or a polyisocyanate-terminated prepolymer.Examples of the polyisocyanate monomer include tetramethylene diisocyanate, isopropylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Examples of the polyisocyanate derivative include 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, lysine diisocyanate, and isophorone diisocyanate. Examples of the aromatic polyisocyanate include polyisocyanate monomers, polyisocyanate derivatives, and polyisocyanate-terminated prepolymers. Examples of the polyisocyanate monomer include tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. The polyisocyanate derivative may be, for example, an isocyanurate derived from a polyisocyanate monomer. The polyisocyanate-terminated prepolymer may be a bifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a bifunctional polyol compound such as polypropylene glycol. Alternatively, the polyisocyanate-terminated prepolymer may be a multifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a trifunctional or higher polyol compound such as trimethylolpropane.

[0156] Examples of solvent-based adhesives include urethane-based adhesives, epoxy-based adhesives, and silicone-based adhesives, but from the viewpoint of impact resistance, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are particularly preferred. The solvent used in the solvent-based adhesive is not particularly limited, but examples thereof include ethyl acetate, methanol, isopropyl alcohol, methyl ethyl ketone, and ethanol.

[0157] The coating weight (weight per unit area) of each adhesive layer after drying was 0.5 g / m ２ 3.0g / m or more ２ Preferably, 1.0 g / m or less ２ 2.0g / m or more ２The coating weight of the adhesive layer is more preferably 0.5 g / m or less. ２ If the coating weight of the adhesive layer is 3.0 g / m or more, the effect of suppressing delamination between layers can be improved. ２ If the thickness is below this range, it is possible to prevent the occurrence of winding slippage during processing of the laminate, to improve the appearance quality of the laminate, and in addition, to obtain appropriate lamination strength. As the coating method, various known methods can be selected and used, such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0158] The adhesive may be an adhesive (gas barrier adhesive) that exhibits gas barrier properties after curing. In other words, the adhesive layer may contain a gas barrier adhesive and may be said to be a cured product of the gas barrier adhesive. In particular, forming an adhesive layer that contacts the vapor deposition layer using an adhesive that exhibits gas barrier properties can further suppress deterioration of the gas barrier properties due to cracking of the vapor deposition layer. This further improves the gas barrier performance of the laminate 1. Examples of gas barrier adhesives include epoxy-based adhesives, polyester / polyurethane-based adhesives, and polyamine-based adhesives. Specific examples include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation. The adhesive layers 2 and 3 may have the same composition or different compositions. Furthermore, their thicknesses may be the same or different. The thickness can be, for example, 0.5 μm to 6 μm, preferably 0.8 μm to 5 μm, and more preferably 1.0 μm to 4.5 μm. The adhesive layer 2 and the adhesive layer 3 can be formed by various known methods such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0159] The inventors conducted various studies to improve the durability of a mono-material tube laminate against repeated squeezing. In the process, they discovered that sandwiching the hard and relatively fragile barrier layer 12 between a flexible base layer 13 and a barrier coat layer 15 can improve the durability of the barrier layer 12 against repeated squeezing. This is presumably because deformation during bending is absorbed to some extent by the base layer 13 and the barrier coat layer 15 before it reaches the barrier layer 12. Furthermore, because the base layer 13 is primarily composed of ethylene vinyl alcohol, the base layer 13 itself exhibits a certain level of barrier property. This allows the barrier property to be supplemented, preventing a rapid deterioration of barrier performance, even if fine cracks occur in the barrier layer 12.

[0160] As will be shown in the Examples in more detail, the inventors' investigations have revealed that sufficient barrier layer protection can be achieved when the indentation hardness of the underlayer 13 is within the range of 0.05 to 0.1 gigapascals (GPa) and the indentation hardness of the barrier coat layer 15 is 0.5 GPa or less. These layers are located in the middle of the laminate 1D for a tube in the thickness direction, and the indentation hardness can be measured by measuring the exposed portion in the cross section with a nanoindenter. The indentation hardness of the barrier coat layer 15 can be controlled, for example, by the compounding ratio of polyvinyl alcohol resin and metal alkoxide. Increasing the amount of polyvinyl alcohol resin softens the barrier coat layer 15, while increasing the amount of metal alkoxide hardens the barrier coat layer 15.

[0161] Furthermore, it was found that a more favorable barrier layer protection effect can be obtained when the barrier coat layer 15 is harder than the base layer 13 while maintaining a certain level of flexibility. Specifically, it was found that a ratio (S2 / S1) of the indentation hardness S1 of the base layer 13 to the indentation hardness S2 of the barrier coat layer 15 is more preferable when it is in the range of 3 to 10. While the detailed mechanism behind this has not been fully elucidated, it is thought to be as follows. While the substrate layer 11 is present between the base layer 13 and the first sealant layer 20, the second sealant layer 30 is located relatively close to the barrier coat layer 15 via the adhesive layer 3. For this reason, the barrier coat layer 15 is more susceptible to the effects of elongation deformation of the sealant layer than the base layer 13. Therefore, it is thought that making the barrier coat layer 15 harder within a range that maintains a certain level of flexibility contributes to suppressing the effects of large elongation of the second sealant layer 30.

[0162] As described above, in the tube laminate 1D according to this embodiment, the barrier layer 12 is sandwiched between the flexible base layer 13 and the barrier coat layer 15. This makes it possible to make the barrier layer less susceptible to damage even when the laminated tube is repeatedly squeezed, even in the case of a mono-material configuration. As a result, it is possible to achieve both high recyclability and resistance to deterioration of the barrier properties.

[0163] An example of a procedure for producing a laminated tube using the tube laminate 1D will be described. The tube laminate 1D is rolled so that the TD direction, which is perpendicular to the MD direction, is the circumferential direction, and the opposing portions of the first sealant layer 20 and the second sealant layer 30 are joined by heat fusion, resulting in a tubular member. One end of this tubular member is closed by heat fusion to form a body portion 110 that can be filled with contents. A shoulder portion 121, fabricated by resin molding, is attached to the open end of the body portion 110 by heat fusion to complete the laminated tube 100. The body portion 110 may be filled with contents either before or after the shoulder portion 121 is attached. When fabricating the body portion 110, either the first sealant layer 20 or the second sealant layer 30 may be on the outside. This changes the position of the barrier coat layer 15 in the completed laminated tube. When the barrier coat layer 15 is closer to the outer surface of the laminate tube, the laminate tube has an excellent barrier effect against oxygen and water vapor from the external environment. When the barrier coat layer 15 is closer to the inner surface of the laminate tube, the laminate tube has an excellent barrier effect against permeable components contained in the contents. In the example shown in Figure 3, the spout 122 of the spout 120 is sealed with a screw cap 130, so the spout 122 is provided with a thread, but instead of the screw cap 130, a fitting cap or the like may be used for sealing, in which case, of course, a thread is not required.

[0164] The second embodiment will be described with reference to Fig. 8. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted. Fig. 8 is a schematic cross-sectional view showing the layer structure of a tube laminate 1E according to this embodiment. The substrate portion 10C of the tube laminate 1E further includes a second substrate layer 16.

[0165] Since the second substrate layer 16 is a polyethylene film, the tube laminate 1E maintains a mono-material structure. The second substrate layer 16 may have the same composition as the substrate layer 11, or may be a polyethylene film with a different composition. As with the substrate layer 11, if the second substrate layer 16 is primarily composed of polyethylene, it may also contain non-polyethylene resin components, such as polyolefin resins other than polyethylene. The thickness of the second substrate layer 16 can be appropriately set. From the viewpoint of imparting excellent impact resistance and excellent gas barrier properties to the laminated tube to be produced, a thickness of 3 to 250 μm is preferred. Furthermore, from the viewpoint of improving processability, rigidity, and flexibility, a thickness of 15 to 40 μm is preferred. To impart light-blocking or concealing properties to the laminated tube to be produced, the second substrate layer 16 may be a colored, opaque polyethylene film containing a white pigment or extender pigment, such as titanium oxide, zinc oxide, calcium carbonate, or barium sulfate. The second substrate layer 16 has a printed layer 17 on one side and is located between the substrate layer 11 and the first sealant layer 20. The printed layer 17 can be formed by a known method such as gravure printing or flexographic printing. The ink used can be selected from solvent-based inks, water-based inks, etc. depending on the method used, but water-based inks are preferred from an environmental perspective. Furthermore, the surface of the second substrate layer 16 on which the print is to be formed may be subjected to a surface treatment such as a corona treatment or a plasma treatment to improve the adhesion of the printed layer 17.

[0166] The second substrate layer 16 and the substrate layer 11 are bonded by an adhesive layer 4. The adhesive layer 4 can be the same as the adhesive layers 2 and 3. The printing layer 17 may be located on either the substrate layer 11 side or the first sealant layer 20 side. However, of the adhesive layers 2 and 4, the one in contact with the printing layer 17 is preferably a solvent-free adhesive from the viewpoint of suppressing dimensional change of the printed image during lamination. Examples of solvent-free adhesives include urethane-based adhesives, epoxy-based adhesives, and silicone-based adhesives. However, from the viewpoint of impact resistance, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are particularly preferred. The adhesive layer 4, like the adhesive layers 2 and 3, may be formed from an adhesive that exhibits gas barrier properties after curing.

[0167] The printed layer 17 may be provided at any position as long as it is visible from the outside of the laminate for a tube. Although Fig. 8 illustrates a layer configuration in which the printed layer 17 and the adhesive layer 2 are in contact with each other and the second base material layer 16 and the adhesive layer 4 are in contact with each other, the printed layer 17 and the second base material layer 16 may also be arranged so that the second base material layer 16 and the adhesive layer 2 are in contact with each other and the printed layer 17 and the adhesive layer 4 are in contact with each other.

[0168] A printed layer may be formed on the outside of the first sealant layer 20. In this case, a transparent protective layer may be provided on the printed layer to prevent the printed layer from being rubbed by external contact. Alternatively, a printed layer may be formed on the outside of the second sealant layer 30. In this case, the printed layer is formed between the second sealant layer 30 and the adhesive layer 3. In these cases, it is sufficient to form a printed layer on the surface of the first sealant layer 20 or the second sealant layer 30 by the above-mentioned printing method, and the second base material layer 16 does not need to be used.

[0169] A printed layer may be formed by offset printing using an active energy ray-curable ink. Active energy rays are energy rays that can generate radically active species, and examples of such rays include electromagnetic waves such as X-rays and gamma rays, particle rays such as electron beams (EB), proton beams and alpha rays, and non-ionizing radiation such as microwaves and ultraviolet rays. The active energy ray-curable ink contains an active energy ray-curable resin. After offset printing is performed on a printing surface using such ink, the ink is irradiated with active energy rays, thereby curing the ink and forming a printed layer.

[0170] The laminate for a tube 1E having the above configuration has the same effects as those of the first embodiment. Furthermore, since the substrate portion 10C has the second substrate layer 16, there is also an advantage that the puncture resistance after repeated squeezing operations is improved.

[0171] The adhesive layer 4 according to this embodiment may be an extruded resin layer. Examples of materials for the extruded resin layer include polyethylene resins, polypropylene resins, and cyclic polyolefin resins, as well as copolymer resins, modified resins, and mixtures (including alloys) containing these resins as their main components. Examples of polyolefin resins include the above-mentioned polyethylene, polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. Furthermore, to improve interlayer adhesion, acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. In addition, resins obtained by graft polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers with polyolefin resins can be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more. The thickness of the extruded resin layer can be 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

[0172] [Fourth Aspect] The fourth aspect will be described below with reference to Fig. 9. As will be described in detail later, the laminate tube according to this embodiment (hereinafter, sometimes simply referred to as "tube") is produced by joining laminates for tubes into a cylindrical shape. Therefore, the configuration of the laminate for tube will be described first.

[0173] 9 is a schematic cross-sectional view showing the layer structure of a laminate for a tube 1F according to this embodiment. The laminate for a tube 1F has a substrate portion 10D having a barrier function, and a first sealant layer 20 and a second sealant layer 30 bonded to the substrate portion 10D. The proportion of polyethylene in the total mass of the laminate for a tube 1F is 90 mass% or more, and the laminate for a tube has a mono-material structure.

[0174] The substrate portion 10D has a resin substrate layer 11 and a barrier layer 12 formed on the substrate layer 11. The substrate layer 11 is mainly composed of polyethylene. That is, it contains polyethylene in the largest amount as a resin component. The substrate layer 11 can also be made of a polyethylene film. The polyethylene film may be a film containing 70% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more of polyethylene, or a film containing 100% by mass of polyethylene. If polyethylene is the main component, a resin component other than polyethylene, such as a polyolefin resin other than polyethylene, may also be contained. The polyethylene of the substrate layer 11 has a density of 0.940 g / cm ３ It is preferable that the main component be high density polyethylene (HDPE) of 0.925 g / cm or more. ３ 0.940g / cm or more ３ Medium density polyethylene (MDPE), density less than 0.900 g / cm ３ 0.925g / cm or more ３ Low density polyethylene (LDPE), density less than 0.900 g / cm ３ 0.925g / cm or more ３ Linear low density polyethylene (LLDPE), density less than 0.900 g / cm ３The substrate layer 11 may contain an ultra-low density polyethylene film (VLDPE) of less than 1000 MPa. When the substrate layer 11 contains multiple polyethylenes, it may be a single layer in which the polyethylenes are mixed, or a multi-layer structure in which some of the polyethylenes are layered. The thickness of the substrate layer 11 can be set appropriately. From the viewpoint of imparting excellent impact resistance and excellent gas barrier properties to the laminated tube to be produced, a thickness of 3 to 250 μm is preferable, and from the viewpoint of improving processability, rigidity, and flexibility, a thickness of 15 to 40 μm is preferable.

[0175] When the base layer 11 has a multi-layer structure, it can be produced by film-forming polyethylene using a T-die method, an inflation method, or the like. When producing the base layer 11 using the T-die method, the melt flow rate (MFR) of the polyethylene is preferably 3 g / 10 min or more and 20 g / 10 min or less. By setting the MFR to 3 g / 10 min or more, the processability of the laminate can be improved. Furthermore, by setting the MFR to 20 g / 10 min or less, the produced base layer 11 can be prevented from breaking. When producing the base layer 11 using an inflation method, the MFR of the polyethylene is preferably 0.5 g / 10 min or more and 5 g / 10 min or less. By setting the MFR to 0.5 g / 10 min or more, the processability can be improved. Furthermore, by setting the MFR to 5 g / 10 min or less, the film-forming properties can be improved.

[0176] When the base layer 11 has a multi-layer structure, it can be a polyethylene film with a multilayer structure in which polyethylenes of different densities are extruded by a co-extrusion method (for example, a layer structure such as polyethylene other than high-density polyethylene / high-density polyethylene / polyethylene other than high-density polyethylene), or a polyethylene film with a multilayer structure in which polyethylene and a polyolefin other than polyethylene are extruded by a co-extrusion method (for example, a layer structure such as polypropylene / polyethylene / polypropylene).

[0177] There is no particular limitation on whether the substrate layer 11 is stretched or not, and it may be uniaxially stretched, biaxially stretched, or unstretched. There is also no particular limitation on the stretching method. An unstretched substrate is likely to achieve higher adhesion strength with the barrier layer 12. It also has the advantage of being able to achieve both rigidity and flexibility, making stress concentration less likely, and making it less likely for the vapor-deposited film to crack due to repeated squeezing of the laminate tube. A stretched substrate has the advantage of being excellent in impact resistance, heat resistance, water resistance, dimensional stability, etc.

[0178] The barrier layer 12 is formed on one surface (first surface) of the base layer 11. The barrier layer 12 according to this embodiment is a vapor-deposited film made of metallic aluminum. By forming the barrier layer 12 as a vapor-deposited film made of metallic aluminum, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the tube laminate 1F.

[0179] When the barrier layer 12 is made of aluminum, the thickness is preferably 30 nm or more and 100 nm or less. A film thickness of 30 nm or more can provide sufficient light-shielding and gas barrier properties. Furthermore, a film thickness of 100 nm or less can suppress the occurrence of cracks due to deformation caused by internal stress in the thin film, thereby suppressing a decrease in gas barrier properties. From the viewpoint of further improving gas barrier properties, the film thickness of the vapor deposition layer is more preferably 50 nm or more and 90 nm or less.

[0180] The barrier layer 12 can be formed by, for example, vacuum film formation. Vacuum film formation can use physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include, but are not limited to, vacuum deposition, sputtering, and ion plating. Examples of chemical vapor deposition include, but are not limited to, thermal CVD, plasma CVD, and photo-CVD. Resistance heating vacuum deposition, electron beam (EB) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma enhanced chemical vapor deposition (PECVD) are particularly preferred for vacuum film formation. However, considering productivity, vacuum deposition is currently the most advantageous. The heating means for vacuum deposition is preferably an electron beam heating method, a resistance heating method, or an induction heating method.

[0181] The surface of the base material layer 11 on which the barrier layer 12 is to be formed may be subjected to an adhesion-facilitating treatment by dry surface treatment such as corona treatment or atmospheric pressure plasma treatment. In this way, the adhesion between the base material layer and the barrier layer 12 can be improved.

[0182] An underlayer 13 is provided between the substrate layer 11 and the barrier layer 12, and a barrier coat layer 15 is provided on the side of the barrier layer 12 opposite to the side on which the underlayer 13 is provided. In other words, the barrier layer 12 is sandwiched between the underlayer 13 and the barrier coat layer 15.

[0183] The primary component of the underlayer 13 may be an acrylic polyol resin, an ethylene-vinyl alcohol copolymer (EVOH), or the like. Examples of methods for forming the underlayer 13 include applying and drying a coating liquid containing an acrylic polyol resin or EVOH, or co-extrusion of the resin that will become the base layer 11 with the above material. In the case of co-extrusion, an adhesive resin such as maleic anhydride-grafted modified polyethylene may be sandwiched between the two. The thickness of the underlayer 13 can be set appropriately taking into consideration productivity, flexibility (described below), and the like, and is, for example, approximately 0.01 to 10 μm.

[0184] The barrier coat layer 15 improves the barrier properties of the tube laminate together with the barrier layer 12, and prevents a decrease or breakdown in the barrier properties by covering any minute defects that may occur in the barrier layer 12. The barrier coat layer 15 according to this embodiment contains a polyvinyl alcohol-based resin and at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide.

[0185] The barrier coat layer 15 can be formed using a composition (hereinafter referred to as an overcoat agent) obtained by adding a hydroxyl group-containing polymer compound (e.g., a polyvinyl alcohol-based resin) and a metal alkoxide or the like to water or a water / alcohol mixed solution. The overcoat agent can be prepared, for example, by mixing a solution in which a polyvinyl alcohol-based resin is dissolved in an aqueous solvent (water or a water / alcohol mixed) with a metal alkoxide or the like directly, or with a solution that has been previously treated, such as by hydrolysis.

[0186] Examples of metal alkoxides include compounds represented by the following general formula (I): M(OR1) ｍ (R2) ｎ－ｍ ...(I) In the above general formula (I), R1 and R2 each independently represent a monovalent organic group having 1 to 8 carbon atoms, and are preferably alkyl groups such as methyl and ethyl groups. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. When a plurality of R1 or R2 are present, the R1s or R2s may be the same or different. Specific examples of metal alkoxides include tetraethoxysilane [Si(OC ２ H ５ ) ４ ], triisopropoxyaluminum [Al(O-2'-C ３ H ７ ) ３ Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0187] The barrier coat layer 15 may contain at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, and a reaction product of the silane coupling agent or the hydrolyzate of the silane coupling agent. Such a barrier coat layer 15 can be formed by further adding a silane coupling agent or the like to the above-mentioned overcoat agent.

[0188] Examples of the silane coupling agent include compounds represented by the following general formula (II): Si(OR11) ｐ (R12) ３－ｐR13...(II) In the above general formula (II), R11 represents an alkyl group such as a methyl group or an ethyl group, R12 represents a monovalent organic group such as an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkyl group substituted with an acryloxy group, or an alkyl group substituted with a methacryloxy group, R13 represents a monovalent organic functional group, and p represents an integer of 1 to 3. When multiple R11 or R12 are present, the R11s or R12s may be the same or different. Examples of the monovalent organic functional group represented by R13 include a glycidyloxy group, an epoxy group, a mercapto group, a hydroxyl group, an amino group, an alkyl group substituted with a halogen atom, or a monovalent organic functional group containing an isocyanate group. Specific examples of silane coupling agents include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane. Furthermore, the silane coupling agent may be a polymer formed by polymerization of the compound represented by the general formula (II) above. A trimer is preferred as the polymer, and 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is more preferred. This is a condensation polymer of 3-isocyanate alkylalkoxysilane. It is known that while the isocyanate moiety of this 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate loses chemical reactivity, reactivity is maintained due to the polarity of the nurate moiety. It is generally added to adhesives, etc., in the same manner as 3-isocyanate alkylalkoxysilane, and is known as an adhesion improver. Therefore, by adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a hydroxyl group-containing polymer compound, hydrogen bonding can be used to improve the water resistance of the barrier coat layer 15. While 3-isocyanate alkylalkoxysilanes are highly reactive and have low liquid stability, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is not water-soluble due to the polarity of the nurate moiety, but is easily dispersed in aqueous solutions and can maintain a stable liquid viscosity.Furthermore, the water resistance performance of 3-isocyanate alkyl alkoxysilane and 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate is equivalent. 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate is sometimes produced by thermal condensation of 3-isocyanate propyl alkoxysilane, and may contain the raw material 3-isocyanate propyl alkoxysilane, but this does not pose any particular problems. 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate is more preferred, and 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate is even more preferred. Because the methoxy group has a fast hydrolysis rate and those containing a propyl group are relatively inexpensive, 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate is practically advantageous.

[0189] The amount of metal alkoxide in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound, from the viewpoints of maintaining adhesion to the vapor deposition layer and gas barrier properties. Similarly, the amount of silane coupling agent can be 0.01 to 1 part by mass, or may be 0.1 to 0.5 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound. When a silane compound (alkoxysilane) is used as the metal alkoxide, the amount of the silane compound (metal alkoxide and silane coupling agent) in the overcoating agent can be 1 to 4 parts by mass, or may be 2 to 3 parts by mass, per part by mass of the hydroxyl group-containing polymeric compound.

[0190] The overcoating agent may contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, or a colorant, as needed, within a range that does not impair the gas barrier property. The overcoating agent can be applied by, for example, dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset, or the like. The coating film obtained by applying the overcoating agent can be dried by, for example, hot air drying, heat roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0191] The temperature at which the coating film is dried can be, for example, 50 to 150°C, preferably 70 to 100°C. By maintaining the drying temperature within the above range, cracking in the barrier layer 12 and the barrier coat layer 15 can be further suppressed, resulting in excellent barrier properties. The barrier coat layer 15 may be formed using an overcoat agent containing a hydroxyl group-containing polymer compound (e.g., a polyvinyl alcohol-based resin) and a silane compound. The overcoat agent may contain an acid catalyst, an alkali catalyst, a photopolymerization initiator, or the like, as needed. Examples of silane compounds include silane coupling agents, polysilazanes, and siloxanes. Specific examples include tetramethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and hexamethyldisilazane. In one example, the thickness of the barrier coat layer 15 is approximately 0.2 to 10 μm.

[0192] The barrier coat layer 15 may be formed using a polyolefin-based aqueous coating material. A suitable example is an aqueous medium coating liquid containing an acid-modified polyolefin resin. By applying and drying this, a barrier coat layer primarily composed of the acid-modified polyolefin resin can be formed. The acid-modified polyolefin resin is primarily composed of an olefin component and is acid-modified with an unsaturated carboxylic acid component. Examples of acid-modified polyolefin resins include ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid-maleic anhydride copolymers, ethylene-acrylic acid ester-maleic anhydride copolymers, acid anhydride-modified polyethylene, acid anhydride-modified polypropylene, acid anhydride-modified ethylene-propylene resins, acid anhydride-modified ethylene-butene resins, acid anhydride-modified propylene-butene resins, acid anhydride-modified ethylene-propylene-butene resins, and these acid-modified resins further acrylic-modified with acrylic esters or the like. Furthermore, the acid-modified polyolefin resin may be chlorinated in a range of 5% by mass to 40% by mass. The amount of the aqueous coating material applied was 0.05 g / m2 in terms of weight after drying. ２ 2.0g / m or more ２ The coating method can be appropriately selected from known coating methods such as dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, and spray coating, and various known printing methods such as offset printing, gravure printing, and silk screen printing.

[0193] The first sealant layer 20 and the second sealant layer 30 are heat-sealable resin layers, and the first sealant layer 20 and the second sealant layer 30 can be joined by heat fusion. The first sealant layer 20 according to this embodiment is located on the second surface of the base layer 11, opposite the first surface on which the barrier layer is provided. The first sealant layer 20 and the second sealant layer 30 are primarily composed of polyethylene. As with the base layer 11, various polyethylenes can be used, but from the viewpoint of heat sealing properties, LDPE, LLDPE, VLDPE, etc. are preferred as the primary component. The density of polyethylene can be measured, for example, using a density measuring device BELPYCNO manufactured by Microtrac-Bell Corporation.

[0194] Like the substrate layer 11, the first sealant layer 20 and the second sealant layer 30 can be configured as either a single layer or multiple layers, but from the viewpoint of processability, it is preferable to use an unstretched film. The first sealant layer 20 and the second sealant layer 30 may have the same configuration or different configurations. The thickness of the first sealant layer 20 and the second sealant layer 30 can be changed appropriately depending on the weight of the contents to be filled in the tube, and is, for example, approximately 20 μm or more and 250 μm or less. From the viewpoint of processability, a thickness of approximately 50 μm or more and 150 μm or less is preferable.

[0195] The substrate portion 10D is bonded to the first sealant layer 20 and the second sealant layer 30 by adhesive layers 2 and 3, respectively. Examples of materials for the adhesive layers 2 and 3 include one-component curing and two-component curing urethane adhesives, and both solvent-based and solventless adhesives can be used. These adhesives may contain a layered inorganic compound to further enhance the barrier properties.

[0196] The two-component curing urethane-based solventless adhesive contains a polyol component as a base component and a polyisocyanate component as a curing agent. The polyol component may be one or a mixture of two or more selected from the group consisting of polyester polyols, polyether polyols, polyether ester polyols, and polyurethane polyols. The polyester polyol may be, for example, an ester reaction product of a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a glycol-based solvent. The polycarboxylic acid may be, for example, succinic acid, glutaric acid, isophthalic acid, terephthalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, or dimer acid. The glycol-based solvent may be, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, neopentyl glycol, or 1,6-hexanediol. The polyether polyol may be, for example, a polymer of an oxirane compound and a low-molecular-weight polyol. The oxirane compound may be, for example, ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran. The low-molecular-weight polyol may be water, ethylene glycol, propylene glycol, trimethylolpropane, or glycerin. The polyetherester polyol may be, for example, one obtained by reacting a polycarboxylic acid, a dialkyl ester of a polycarboxylic acid, or a mixture thereof with a polyether polyol. The polyurethane polyol may be, for example, a reaction product of a polyester polyol, a polyether polyol, or a polyetherester polyol with a polyisocyanate monomer. The polyisocyanate component may be an aliphatic polyisocyanate, an aromatic polyisocyanate, or a mixture thereof. The aliphatic polyisocyanate may be, for example, a polyisocyanate monomer, a polyisocyanate derivative, or a polyisocyanate-terminated prepolymer.Examples of the polyisocyanate monomer include tetramethylene diisocyanate, isopropylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Examples of the polyisocyanate derivative include 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, lysine diisocyanate, and isophorone diisocyanate. Examples of the aromatic polyisocyanate include polyisocyanate monomers, polyisocyanate derivatives, and polyisocyanate-terminated prepolymers. Examples of the polyisocyanate monomer include tolylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. The polyisocyanate derivative may be, for example, an isocyanurate derived from a polyisocyanate monomer. The polyisocyanate-terminated prepolymer may be a bifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a bifunctional polyol compound such as polypropylene glycol. Alternatively, the polyisocyanate-terminated prepolymer may be a multifunctional polyisocyanate containing terminal isocyanate groups obtained by reacting a polyisocyanate monomer with a trifunctional or higher polyol compound such as trimethylolpropane.

[0197] Examples of solvent-based adhesives include urethane-based adhesives, epoxy-based adhesives, and silicone-based adhesives, but from the viewpoint of impact resistance, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are particularly preferred. The solvent used in the solvent-based adhesive is not particularly limited, but examples thereof include ethyl acetate, methanol, isopropyl alcohol, methyl ethyl ketone, and ethanol.

[0198] The coating weight (weight per unit area) of each adhesive layer after drying was 0.5 g / m ２ 3.0g / m or more ２ Preferably, 1.0 g / m or less ２ 2.0g / m or more ２The coating weight of the adhesive layer is more preferably 0.5 g / m or less. ２ If the coating weight of the adhesive layer is 3.0 g / m or more, the effect of suppressing delamination between layers can be improved. ２ If the thickness is below this range, it is possible to prevent the occurrence of winding slippage during processing of the laminate, to improve the appearance quality of the laminate, and in addition, to obtain appropriate lamination strength. As the coating method, various known methods can be selected and used, such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine method, and transfer roll coating.

[0199] The adhesive may be an adhesive (gas barrier adhesive) that exhibits gas barrier properties after curing. In other words, the adhesive layer may contain a gas barrier adhesive and may be said to be a cured product of the gas barrier adhesive. In particular, forming an adhesive layer that contacts the vapor deposition layer using an adhesive that exhibits gas barrier properties can further suppress deterioration of the gas barrier properties due to cracking of the vapor deposition layer. This further improves the gas barrier performance of the laminate 1. Examples of gas barrier adhesives include epoxy-based adhesives, polyester / polyurethane-based adhesives, and polyamine-based adhesives. Specific examples include "Maxieve" manufactured by Mitsubishi Gas Chemical Company, Inc. and "Paslim" manufactured by DIC Corporation. The adhesive layers 2 and 3 may have the same composition or different compositions. Furthermore, their thicknesses may be the same or different. The thickness can be, for example, 0.5 μm to 6 μm, preferably 0.8 μm to 5 μm, and more preferably 1.0 μm to 4.5 μm. The adhesive layers 2 and 3 can be formed by various known methods, such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine coating, and transfer roll coating. The adhesive layers 2 and 3 may be extruded resin layers. The extruded resin layer may be made of a polyethylene resin, a polypropylene resin, a cyclic polyolefin resin, or a copolymer resin, modified resin, or mixture (including alloy) containing these resins as the main component.Examples of polyolefin resins include the above-mentioned polyethylene, polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. To improve interlayer adhesion, acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. Furthermore, resins obtained by graft polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers with polyolefin resins can also be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination. The thickness of the extruded resin layer can be 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

[0200] The inventors conducted various studies to improve the durability of a light-shielding mono-material laminate for a tube against repeated squeezing. During this study, they discovered that by covering the barrier layer 12 made of aluminum, which is relatively hard and easily cracked compared to the resin material in the laminate, with a flexible barrier coat layer 15, the durability of the barrier layer 12 against repeated squeezing can be improved. This is presumably because deformation during bending is absorbed to some extent by the barrier coat layer 15 before it reaches the barrier layer 12. Furthermore, when the contents filled in the laminate tube are acidic or alkaline, the barrier coat layer 15 suppresses attack of the contents on the barrier layer 12, thereby effectively suppressing corrosion of the aluminum barrier layer 12, deterioration of the light-shielding properties, and deterioration of interlayer adhesion. Here, when the base layer 13 is primarily composed of EVOH, the base layer 13 itself also exhibits a certain level of barrier properties. As a result, even if fine cracks occur in the barrier layer 12, the barrier properties can be supplemented to prevent a rapid deterioration of barrier performance.

[0201] As will be shown in the examples in more detail, the inventors' investigations have revealed that a sufficient barrier layer protection effect can be obtained when the indentation hardness of the barrier coat layer 15 is 0.75 gigapascals (GPa) or less. These layers are located in the middle of the laminate 1F for a tube in the thickness direction, and the indentation hardness can be measured by measuring the exposed portion in the cross section with a nanoindenter. The indentation hardness of the barrier coat layer 15 can be controlled, for example, by the compounding ratio of the polyvinyl alcohol resin and the metal alkoxide. Increasing the amount of polyvinyl alcohol resin makes the barrier coat layer 15 softer, while increasing the amount of metal alkoxide makes the barrier coat layer 15 harder.

[0202] As described above, in the laminate for a tube 1F according to this embodiment, the barrier layer 12 made of metallic aluminum is covered with the flexible barrier coat layer 15. Therefore, even in the case of a mono-material configuration, the barrier layer is less susceptible to damage even when the laminate tube is repeatedly squeezed. As a result, it is possible to achieve both high recyclability and resistance to deterioration of barrier properties.

[0203] An example of a procedure for producing a laminated tube using the tube laminate 1F will be described. The tube laminate 1F is rolled so that the TD direction, which is perpendicular to the MD direction, is the circumferential direction, and the opposing portions of the first sealant layer 20 and the second sealant layer 30 are joined by heat fusion, resulting in a tubular member. One end of this tubular member is closed by heat fusion to form a body portion 110 that can be filled with contents. A shoulder portion 121, fabricated by resin molding, is attached to the open end of the body portion 110 by heat fusion to complete the laminated tube 100. The body portion 110 may be filled with contents either before or after the shoulder portion 121 is attached. When fabricating the body portion 110, either the first sealant layer 20 or the second sealant layer 30 may be on the outside. This changes the position of the barrier coat layer 15 in the completed laminated tube. When the barrier coat layer 15 is closer to the outer surface of the laminate tube, the laminate tube has an excellent barrier effect against oxygen and water vapor from the external environment. When the barrier coat layer 15 is closer to the inner surface of the laminate tube, the laminate tube has an excellent barrier effect against permeable components contained in the contents. In the example shown in Figure 3, the spout 122 of the spout 120 is sealed with a screw cap 130, so the spout 122 is provided with a thread, but instead of the screw cap 130, a fitting cap or the like may be used for sealing, in which case, of course, a thread is not required.

[0204] The second embodiment will be described with reference to Fig. 10. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted. Fig. 10 is a schematic cross-sectional view showing the layer structure of a tube laminate 1G according to this embodiment. The substrate portion 10D of the tube laminate 1G further includes a second substrate layer 16.

[0205] Because the second substrate layer 16 is a polyethylene film, the tube laminate 1G maintains a mono-material structure. The second substrate layer 16 may have the same composition as the substrate layer 11, or may be a polyethylene film with a different composition. As with the substrate layer 11, if the main component is polyethylene, it may contain a non-polyethylene resin component, such as a polyolefin resin other than polyethylene. There is no particular restriction on whether the second substrate layer 16 is stretched or not, and it may be uniaxially stretched, biaxially stretched, or unstretched. There is also no particular restriction on the stretching method. An unstretched substrate is likely to achieve higher adhesion strength with the printed layer 17. It also has the advantages of achieving both rigidity and flexibility, reducing stress concentration and reducing cracking of the vapor-deposited film due to repeated squeezing of the laminate tube. Stretched substrates have the advantages of excellent impact resistance, heat resistance, water resistance, dimensional stability, etc. The thickness of the second substrate layer 16 can be set as appropriate. From the viewpoint of imparting excellent impact resistance and excellent gas barrier properties to the resulting laminated tube, a thickness of 3 to 250 μm is preferred. Furthermore, from the viewpoint of improving processability, rigidity, and flexibility, a thickness of 40 to 150 μm is preferred. To impart light-blocking or opaque properties to the resulting laminated tube, the second substrate layer 16 may be, for example, a colored, opaque polyethylene film using a white pigment or extender pigment such as titanium oxide, zinc oxide, calcium carbonate, or barium sulfate. The second substrate layer 16 has a printed layer 17 on one side, positioned between the substrate layer 11 and the first sealant layer 20. The printed layer 17 can be formed by known methods such as gravure printing or flexographic printing. Depending on the method used, solvent-based inks or water-based inks can be selected, but water-based inks are preferred from an environmental perspective. Furthermore, the surface of the second substrate layer 16 on which the print is to be formed may be subjected to a surface treatment such as a corona treatment or a plasma treatment to improve the adhesion of the printed layer 17. The printed layer 17 may be located on either the substrate layer 11 side or the first sealant layer 20 side, but when the second substrate layer 16 is colored and opaque, it is formed on the first sealant layer 20 side.

[0206] The second substrate layer 16 and the substrate layer 11 are bonded by an adhesive layer 4. The adhesive layer 4 can be the same as the adhesive layers 2 and 3. Of the adhesive layers 2 and 4, the one in contact with the printed layer 17 is preferably a solvent-free adhesive from the viewpoint of suppressing dimensional changes in the printed image during lamination. Examples of solvent-free adhesives include urethane-based adhesives, epoxy-based adhesives, and silicone-based adhesives. However, from the viewpoint of impact resistance, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are particularly preferred. The adhesive layer 4, like the adhesive layers 2 and 3, may be formed from an adhesive that exhibits gas barrier properties after curing.

[0207] The printed layer 17 may be provided at any position as long as it is visible from the outside of the laminate for a tube. Although Fig. 10 illustrates a layer configuration in which the printed layer 17 and the adhesive layer 2 are in contact with each other and the second base material layer 16 and the adhesive layer 4 are in contact with each other, the printed layer 17 and the second base material layer 16 may also be arranged so that the second base material layer 16 and the adhesive layer 2 are in contact with each other and the printed layer 17 and the adhesive layer 4 are in contact with each other.

[0208] A printed layer may be formed on the outside of the first sealant layer 20. In this case, a transparent protective layer may be provided on the printed layer to prevent the printed layer from being rubbed by external contact. Alternatively, a printed layer may be formed on the outside of the second sealant layer 30. In this case, the printed layer is formed between the second sealant layer 30 and the adhesive layer 3. In these cases, it is sufficient to form a printed layer on the surface of the first sealant layer 20 or the second sealant layer 30 by the above-mentioned printing method, and the second base material layer 16 does not need to be used.

[0209] A printed layer may be formed by offset printing using an active energy ray-curable ink. Active energy rays are energy rays that can generate radically active species, and examples of such rays include electromagnetic waves such as X-rays and gamma rays, particle rays such as electron beams (EB), proton beams and alpha rays, and non-ionizing radiation such as microwaves and ultraviolet rays. The active energy ray-curable ink contains an active energy ray-curable resin. After offset printing is performed on a printing surface using such ink, the ink is irradiated with active energy rays, thereby curing the ink and forming a printed layer.

[0210] The laminated body for a tube 1G having the above configuration has the same effects as those of the first embodiment. Furthermore, since the substrate portion 10D has the second substrate layer 16, there is also an advantage that the puncture resistance after repeated squeezing operations is improved.

[0211] The adhesive layer 4 according to this embodiment may be an extruded resin layer. Examples of materials for the extruded resin layer include polyethylene resins, polypropylene resins, and cyclic polyolefin resins, as well as copolymer resins, modified resins, and mixtures (including alloys) containing these resins as their main components. Examples of polyolefin resins include the above-mentioned polyethylene, polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene and polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, and ionomer resins. Furthermore, to improve interlayer adhesion, acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used. In addition, resins obtained by graft polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, or ester monomers with polyolefin resins can be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more. The thickness of the extruded resin layer can be 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

[0212] The present disclosure is outlined below. [1] A tube laminate comprising, in this order, a first sealant layer, a substrate layer, a barrier layer, an adhesive layer, and a second sealant layer, wherein the barrier layer comprises an inorganic oxide vapor-deposited layer, the substrate layer, the first sealant layer, and the second sealant layer each comprise polyethylene, and the substrate layer has a tensile modulus in the machine direction (MD) of 500 to 2000 MPa at 23°C, and the adhesive layer has a tensile modulus of 500 MPa or more at 23°C. [2] The tube laminate according to [1], wherein the adhesive layer is formed from an epoxy-based adhesive. [3] The tube laminate according to [1] or [2], wherein the adhesive layer has a thickness of 0.1 to 20 μm. [4] The tube laminate according to any one of [1] to [3], wherein the first sealant layer and the second sealant layer comprise linear low-density polyethylene. [5] The laminate for a tube according to any one of [1] to [4], wherein the first sealant layer and the second sealant layer have thicknesses of 20 to 200 μm. [6] The laminate for a tube according to any one of [1] to [5], further comprising an undercoat layer on the barrier layer side of the substrate layer. [7] The laminate for a tube according to any one of [1] to [6], wherein the inorganic oxide vapor-deposited layer contains silicon oxide or aluminum oxide. [8] The laminate for a tube according to any one of [1] to [7], wherein the polyethylene contains recycled polyethylene. [9] A laminate for a tube comprising: a substrate part having a substrate layer made of an unstretched polyethylene film and a barrier layer formed by vapor deposition on one surface of the substrate layer; a first sealant layer made of a polyethylene film and provided on one side of the substrate part; and a second sealant layer made of a polyethylene film and provided on the substrate part on the side opposite to the first sealant layer, wherein the MD elongation percentage of the substrate layer is 2.5% or more and 6.5% or less.

[10] The substrate layer has a density of 0.940 g / cm ３The laminate for a tube according to [9], which is mainly composed of the above-mentioned high-density polyethylene.

[11] The laminate for a tube according to [9] or

[10] , wherein the thickness of the base layer is 10 μm to 50 μm.

[12] The laminate for a tube according to any one of [9] to

[11] , wherein the barrier layer is made of any one of silicon oxide, aluminum oxide, and metallic aluminum.

[13] The laminate for a tube according to any one of [9] to

[12] , further comprising a barrier coat layer formed on the barrier layer, the barrier coat layer containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide, and a water-soluble polymer.

[14] The laminate for a tube according to

[13] , wherein the barrier coat layer further contains at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent.

[15] The laminate for a tube according to any one of [9] to

[14] , further comprising a second base material layer made of an unstretched polyethylene film having a printed layer on one surface thereof and bonded to one surface of the base material, wherein the second base material layer and the first sealant layer are bonded together.

[16] The laminate for a tube according to any one of [9] to

[15] , wherein the base material and the second sealant layer are bonded together with a barrier adhesive.

[17] A laminate for a tube, comprising: a substrate portion having a base layer made of a polyethylene film, a primer layer containing ethylene vinyl alcohol as a main component and formed on a first surface of the base layer, and a barrier layer formed on the primer layer; a barrier coat layer arranged so as to sandwich the barrier layer between the primer layer and the barrier coat layer; a first sealant layer made of a polyethylene film and provided on a second surface of the base layer opposite to the first surface; and a second sealant layer made of a polyethylene film and provided on the barrier coat layer; wherein the primer layer has a cross-sectional indentation hardness of 0.05 to 0.1 gigapascals, and the barrier coat layer contains a polyvinyl alcohol-based resin and has a cross-sectional indentation hardness of 0.5 gigapascals or less.

[18] The laminate for a tube according to

[17] , wherein the ratio S2 / S1 of the cross-sectional indentation hardness S1 of the underlayer to the cross-sectional indentation hardness S2 of the barrier coat layer is 3.0 or more and 5.0 or less.

[19] The laminate for a tube according to

[17] or

[18] , wherein the base layer and the base layer are formed by co-extrusion.

[20] A laminate for a tube comprising: a base portion having a base layer made of a polyethylene film and a barrier layer made of a vapor-deposited film of metal aluminum formed on a first surface side of the base layer; a barrier coat layer arranged to cover the barrier layer; a first sealant layer made of a polyethylene film and provided on a second surface side of the base layer opposite the first surface; and a second sealant layer made of a polyethylene film and provided on the barrier coat layer, wherein the cross-sectional indentation hardness of the barrier coat layer is 0.75 gigapascals or less.

[21] The laminate for a tube according to

[20] , wherein the cross-sectional indentation hardness of the barrier coat layer is 0.03 gigapascals or more.

[22] The laminate for a tube according to

[20] or

[21] , wherein the barrier coat layer contains an acid-modified polyolefin resin.

[23] The laminate for a tube according to any one of [1] to [8] and

[17] to

[22] , wherein the base layer is an unstretched film.

[24] The laminate for a tube according to any one of

[17] to

[23] , wherein the barrier coat layer contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolysate of a metal alkoxide.

[25] The laminate for a tube according to any one of

[20] to

[24] , wherein the barrier coat layer further contains at least one of a polyvinyl alcohol resin, a silane coupling agent, a hydrolysate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolysate of a silane coupling agent.

[26] The laminate for a tube according to

[24] , wherein the barrier coat layer further contains at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent.

[27] The laminate for a tube according to any one of

[17] to

[26] , wherein the base material layer contains high-density polyethylene.

[28] The laminate for a tube according to any one of [9] to

[27] , wherein at least one of the base material layer, the first sealant layer, and the second sealant layer contains recycled polyethylene.

[29] A laminate tube formed into a tubular shape using the laminate for a tube according to any one of [1] to

[28] , comprising: a body portion having one end sealed; and a shoulder portion attached to the other end of the body portion.

[0213] [First Aspect] The first aspect of the present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples.

[0214] <Preparation of Laminated Body for Tube Containers> Laminated bodies for tube containers having the layer structures shown in Tables 1 and 2 were prepared.

[0215] (Preparation of anchor coating agent) Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate so that the total solids content (total amount of acrylic polyol and tolylene diisocyanate) was 5 mass%. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and mixed to prepare an acrylic polyol-based anchor coating agent.

[0216] (Preparation of Overcoat Agent) The following (a) to (c) were prepared. In Example 5a, (a):(b) were mixed in a mass ratio of 60:40, and in Example 7a, (a):(b):(c) were mixed in a mass ratio of 70:20:10 to prepare the respective overcoat agents. (a) Tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of TEOS (hereinafter abbreviated as TEOS) and 10 g of methanol, and the mixture was stirred for 30 minutes to hydrolyze the solid content of 5 mass % (weight ratio of SiO ２(b) A 5% by mass solution of polyvinyl alcohol (PVA) in water / methanol (water:methanol mass ratio 95:5). (c) A hydrolysis solution obtained by diluting 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate (hereinafter abbreviated as SC agent) with a water / isopropyl alcohol mixture (water:isopropyl alcohol mass ratio 1:1) to a solids content of 5% by mass.

[0217] (Examples 1a and 2a) Step 1: An anchor coating agent was applied to one side of an unstretched HDPE film by gravure coating to form an anchor coating layer. Step 2: A silicon oxide layer was formed on the anchor coating layer formed in Step 1 by vacuum deposition using electron beam heating. Step 3: An unstretched LLDPE film was laminated on the silicon oxide layer formed in Step 2 via an epoxy-based adhesive using a dry lamination method. Step 4: A urethane-based adhesive was applied to the unstretched HDPE side of the laminate formed in Step 3. Next, an unstretched LLDPE film was bonded via LDPE resin using extruder lamination to obtain a laminate consisting of a layer structure of unstretched LLDPE / Ext. LDPE / urethane-based adhesive / unstretched HDPE / anchor coating layer / silicon oxide vapor deposition layer / epoxy-based adhesive / unstretched LLDPE.

[0218] Examples 3a and 4a Laminates having a layer structure of unstretched LLDPE / Ext. LDPE / urethane-based adhesive / biaxially oriented HDPE / anchor coat layer / silicon oxide vapor-deposited layer / epoxy-based adhesive / unstretched LLDPE were obtained in the same manner as in Examples 1a and 2a, except that the unstretched HDPE film in step 1 was changed to a biaxially oriented HDPE film.

[0219] Example 5a A laminate having a layer structure of unstretched LLDPE / Ext. LDPE / urethane-based adhesive / coextruded unstretched HDPE / EVOH / silicon oxide vapor-deposited layer / overcoat layer / epoxy-based adhesive / unstretched LLDPE was obtained in the same manner as in Examples 1a and 2a, except that the unstretched HDPE film in step 1 was replaced with an unstretched co-extruded film of HDPE and EVOH, and an overcoat layer was formed by applying an overcoat agent onto the silicon oxide vapor-deposited layer in step 3.

[0220] Example 6a A laminate having a layer structure of unstretched milky-white LDPE / ext. LDPE / urethane-based adhesive / unstretched HDPE / anchor coat layer / silicon oxide vapor-deposited layer / epoxy-based adhesive / unstretched LLDPE was obtained in the same manner as in Examples 1a and 2a, except that an unstretched milky-white LDPE (containing titanium oxide) film was laminated instead of the unstretched LLDPE film in step 4. In an additional step, a urethane-based adhesive was applied to the unstretched milky-white LDPE of the laminate, and then an unstretched LLDPE film was laminated via the LDPE resin by extruder lamination to obtain a laminate having a layer structure of unstretched LLDPE / ext. LDPE / urethane-based adhesive / unstretched milky-white LDPE / ext. LDPE / urethane-based adhesive / unstretched HDPE / anchor coat layer / silicon oxide vapor-deposited layer / epoxy-based adhesive / unstretched LLDPE.

[0221] Example 7a A laminate having a layer structure of unstretched LDPE / Ext. LDPE / urethane-based adhesive / coextruded unstretched HDPE / EVOH / silicon oxide vapor-deposited layer / overcoat layer / epoxy-based adhesive / unstretched LLDPE was obtained in the same manner as in Examples 1a and 2a, except that the unstretched HDPE film in step 1 was replaced with an unstretched coextruded film of HDPE and EVOH, an overcoat layer was formed by applying an overcoat agent onto the silicon oxide vapor-deposited layer in step 3, and an unstretched LDPE film was laminated instead of the unstretched LLDPE film in step 4. In an additional step, a urethane-based adhesive was applied to the unstretched LDPE of the above laminate, and then an unstretched LLDPE film was laminated via the LDPE resin by extruder lamination to obtain a laminate of unstretched LLDPE / Ext. LDPE / urethane-based adhesive / unstretched LDPE / Ext. A laminate having a layer structure of LDPE / urethane adhesive / coextruded unstretched HDPE / EVOH / vapor-deposited silicon oxide layer / overcoat layer / epoxy adhesive / unstretched LLDPE was obtained.

[0222] Comparative Examples 1a to 5a Laminates were produced in accordance with Example 1a except that the materials used were changed as shown in Table 2.

[0223] <Materials used> First sealant layer: Unstretched LLDPE Second sealant layer: Unstretched LLDPE First extruded polyethylene layer: Ext. LDPE Second extruded polyethylene layer: Ext. LDPE Adhesive for extruded polyethylene layer: Urethane-based adhesive (thickness 0.3 μm) Printing base layer: Unstretched milky white LDPE or unstretched LDPE Base layer: Unstretched HDPE, unstretched LLDPE, uniaxially oriented HDPE, or biaxially oriented HDPE Anchor coat layer (primer layer): Acrylic polyol-based anchor coat agent Barrier layer: Silicon oxide vapor deposition layer Overcoat layer: TEOS + PVA or TEOS + PVA + SC agent Adhesive layer: Epoxy-based dry laminate (DL) adhesive or urethane-based dry laminate (DL) adhesive

[0224] <Measurement of Tensile Modulus> The tensile modulus of the substrate layer and the adhesive layer was measured at 23° C. The results are shown in Tables 1 and 2.

[0225] (Measurement of tensile modulus of base layer) Sample: The base layer was cut into a size of 15 mm width x 5 cm length (width in TD, length in MD, conforming to JIS K-7161). Measuring device: Tensilon universal testing machine RTC-1250 (manufactured by Orientec Co., Ltd.). Measurement method: Strain from tensile elongation of 0.05% to 0.25% when tensile test was performed at 23°C with a chuck distance of 5 cm and a tensile speed of 200 mm / min. The slope of the stress / strain curve corresponding to the two points was taken as the tensile modulus of the film.

[0226] (Measurement of tensile modulus of elasticity of adhesive layer) Sample: An adhesive layer having a thickness of 30 to 40 μm cut into a size of 15 mm width x 5 cm length. Measuring device: Same as for measuring the tensile modulus of elasticity of the base material layer. Measuring method: Same as for measuring the tensile modulus of elasticity of the base material layer.

[0227] <Evaluation> The laminates of each example were evaluated as follows. The results are shown in Tables 1 and 2. Note that the polyethylene content of all the laminates of the examples was 80% by mass or more.

[0228] (Squeeze resistance: oxygen permeability) Sample: Laminate of each example. Measuring device: Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.). Measuring method: The sample was set in the Gelbo Flex Tester and bent 100 times at room temperature (23°C). The oxygen permeability of the bent sample was measured (in accordance with JIS K-7126, method B) under conditions of 30°C and a relative humidity of 70%. The oxygen permeability of the unbent sample was also measured in the same manner, and this was used as a reference value. The ratio of the oxygen permeability of the bent sample to this reference value was calculated. Evaluation criteria: Evaluation was made according to the following criteria. A: Less than 150%. B: 150% or more and less than 200%. C: 200% or more and less than 300%. D: 300% or more.

[0229] (Squeeze resistance: pinholes) Sample: Laminate of each example. Measuring device: Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.). Measuring method: The sample was set in the Gelbo Flex Tester and bent 300 times at room temperature (23°C). The bent sample was then attached to a mount, a liquid pinhole checker was applied, and the number of pinholes that had seeped into the mount was counted. Evaluation criteria: Evaluation was made according to the following criteria. A: There were 10 or fewer pinholes. B: There were 11 or more but less than 30 pinholes. C: There were 30 or more pinholes.

[0230] (Puncture Strength) Sample: Laminate of each example. Measuring device: Tensilon universal testing machine RTC-1250 (manufactured by Orientec Co., Ltd.). Measuring method: The puncture strength of the sample was measured (in accordance with JIS Z1707). Evaluation criteria: Evaluation was made according to the following criteria. A: 15 N or more. B: 10 N or more but less than 15 N. C: Less than 10 N.

[0231]

[0232]

[0233] [Second Aspect] The second aspect of the present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples.

[0234] (Preparation of Primer) Acrylic polyol and tolylene diisocyanate were mixed so that the number of OH groups in the acrylic polyol was equal to the number of NCO groups in the tolylene diisocyanate, and the mixture was diluted with ethyl acetate to a total solids content (total amount of acrylic polyol and tolylene diisocyanate) of 5% by mass. An acrylic polyol-based primer was prepared by adding β-(3,4-epoxycyclohexyl)trimethoxysilane to the diluted mixture in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate and mixing. (Preparation of Gas Barrier Coating Agent) The following (a) to (c) were prepared. In Example 3b, (a):(b) was mixed at a mass ratio of 60:40, and in Examples 1b, 2b, 6b, Comparative Example 1b, 2b, and 3b, (a):(b):(c) was mixed at a mass ratio of 70:20:10 to prepare the respective overcoat agents. (a) A hydrolysis solution with a solid content of 5% by mass (weight ratio calculated as SiO2) obtained by adding 72.1 g of 0.1 N hydrochloric acid to 17.9 g of tetraethoxysilane (Si(OC2H5)4; hereinafter abbreviated as TEOS) and 10 g of methanol and stirring for 30 minutes. (b) A 5% by mass water / methanol solution of polyvinyl alcohol (PVA) (water:methanol mass ratio 95:5). (c) A hydrolysis solution obtained by diluting 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate (hereinafter abbreviated as SC agent) with a water / isopropyl alcohol mixture (water:isopropyl alcohol mass ratio 1:1) to a solid content of 5% by mass.

[0235] (Example 1b) This example was produced using the following procedure. Step 1: A primer was applied to one side of an unstretched HDPE film (MD elongation rate: 3.0%) by gravure coating to form a primer layer. Step 2: A barrier layer made of silicon oxide was formed on the primer layer formed in Step 1 by vacuum deposition using electron beam heating. Step 3: A gas barrier coating agent was applied to the barrier layer formed in Step 2 to form a barrier coat layer. Step 4: A urethane adhesive was applied to the barrier coat layer formed in Step 3 by dry lamination to bond a second sealant layer. Step 5: A urethane anchor coating agent was applied to the side of the laminate bonded in Step 4 opposite the second sealant layer to form an anchor coat layer. Next, an extruded resin layer was formed via LDPE resin by extruder lamination, and a first sealant layer was bonded to it.

[0236] (Example 2b) This was produced in the same manner as Example 1b, except that the unstretched HDPE film in step 1 was replaced with an unstretched HDPE film (MD elongation: 3.3%). (Example 3b) This was produced in the same manner as Example 1b, except that the barrier layer in step 3 was an aluminum vapor-deposited film. (Example 4b) This was produced in the same manner as Example 1b, except that in step 1, instead of a primer, a base layer and an underlayer were formed by co-extrusion using polyethylene and EVOH, and no barrier coat layer was formed in step 3, and step 4 was performed using an epoxy-based adhesive. (Example 5b) This was produced in the same manner as Example 4b, except that in step 5, an unstretched LLDPE film (MD elongation: 3.5%) was used instead of the unstretched HDPE film. (Example 6b) This example was produced in the same manner as in Example 1b, except that an unstretched milky-white LLDPE (containing titanium oxide) film with a flexographically printed pattern was placed between the unstretched HDPE film and the first sealant layer.

[0237] (Comparative Example 1b) A film was produced in the same manner as in Example 1b, except that the unstretched HDPE film in step 1 was a uniaxially stretched HDPE film (MD elongation: 0.4%). (Comparative Example 2b) A film was produced in the same manner as in Example 1b, except that the unstretched HDPE film in step 1 was a biaxially stretched HDPE film (MD elongation: 2.2%). (Comparative Example 3b) A film was produced in the same manner as in Example 1b, except that the unstretched HDPE film in step 1 was an unstretched LLDPE film (MD elongation: 7.1%).

[0238] The detailed configurations of Examples 1b to 5b and Comparative Examples 1b to 3b are shown in Table 3. The layers in the layer configuration are denoted by the reference numerals shown in Figures 4, 5, and 6 to make the corresponding relationships easier to understand.

[0239]

[0240] The configuration of Example 6b is shown in Table 4. Example 6b has the same configuration as the third embodiment, including the second base material layer, and is therefore listed in a separate table.

[0241]

[0242] The laminate for tube of each example was evaluated as follows. (Barrier property after repeated bending) A test piece of the laminate according to each example was set in a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) and bent 100 times at room temperature (23°C). Using the bent test piece, the oxygen transmission rate was measured in accordance with JIS K-7126, Method B under conditions of 30°C and 70% relative humidity. The oxygen transmission rate measured before bending was used as a reference value, and the increase in the oxygen transmission rate after repeated bending relative to this reference value was calculated. The evaluation was based on the following three levels, with A and B being considered acceptable. A: less than 150% B: 150% or more but less than 200% C: 200% or more (Pinholes after repeated bending) A test piece of the laminate according to each example (290 mm in the MD direction, 200 mm in the TD direction) was set in a Gelbo Flex Tester and bent 300 times at room temperature (23°C). Thereafter, the test piece was attached to a mount and a liquid pinhole checker was applied, and the number of pinholes that had seeped through to the mount was counted. Evaluation was based on the following three levels, with A and B being considered acceptable. A: 10 or fewer pinholes B: 11 to less than 30 pinholes C: 30 or more pinholes (Puncture Strength) Measurement was performed in accordance with JIS Z1707 using a Tensilon universal testing machine RTC-1250 (manufactured by Orientec Co., Ltd.). Evaluation was based on the following three levels, with A and B being considered acceptable. A: 15 N or more B: 10 N or more but less than 15 N C: Less than 10 N The results are shown in Table 5.

[0243]

[0244] In all of the Examples, unstretched polyethylene film was used for the substrate, so barrier properties were well maintained and pinhole formation was suppressed during repeated bending. Example 5b also demonstrated that the material of the substrate layer is not limited to HDPE. On the other hand, in Comparative Examples 1b and 2b, which used stretched polyethylene film for the substrate, numerous pinholes occurred after repeated bending, and barrier properties were significantly reduced. Comparative Example 3b used the same unstretched polyethylene film as Example 5b for the substrate, but because it was thinner than Example 5b, its MD elongation exceeded 5%, resulting in insufficient barrier properties after repeated bending. This demonstrated that the MD elongation value of the unstretched polyethylene film in the substrate is important for achieving the desired effect. In addition to changing the thickness as described above, methods for adjusting the MD elongation of the unstretched polyethylene film used in the substrate include changing the film-forming method, changing the type of polyethylene (molecular weight or density) or mixing ratio, and using a multilayer structure, but are not limited to these and may also be adjusted by other methods.

[0245] The second aspect of the present disclosure has been described above in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and configuration changes and combinations within the scope that do not deviate from the gist of the present invention are also included.

[0246] In the second aspect of the present disclosure, the haze of the substrate layer can be appropriately set, but since it is somewhat linked to the MD elongation rate, it is preferably 3% or more, more preferably 5% or more. From the viewpoint of ensuring visibility, it is preferably 30% or less, more preferably 20% or less. The haze is measured using a haze meter NDH700 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7136.

[0247] The substrate layer, second substrate layer, and sealant layer (first sealant layer, second sealant layer) constituting the tube laminate according to the second aspect of the present disclosure may be made of a film containing recycled polyethylene. Because recycled polyethylene film contains fine particles of substances other than polyethylene, stretched films may be prone to tearing in the stretching direction. However, unstretched films do not exhibit this tendency to be easily cut, which has the advantage of allowing them to be used for a long period of time when applied to laminated tubes.

[0248] [Third Aspect] The third aspect of the present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples.

[0249] (Preparation of Gas Barrier Coating Agents) The following (a) to (c) were prepared. For Examples 1c, 2c, 3c, 5c, and 6c, and Comparative Examples 1c, 2c, and 5c, (a):(b):(c) were mixed at a mass ratio of 45:45:10, for Example 4c, at a mass ratio of 30:60:10, and for Comparative Examples 3c and 4c, at a mass ratio of 20:70:10, to prepare the respective gas barrier coating agents. (a) 5 mass% polyvinyl alcohol (PVA) water / methanol solution (mass ratio of water:methanol: 95:5). (b) tetraethoxysilane (Si(OC ２ H ５ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of TEOS (hereinafter abbreviated as TEOS) and 10 g of methanol, and the mixture was stirred for 30 minutes to hydrolyze the solid content of 5 mass % (weight ratio of SiO ２ (c) A hydrolysis solution obtained by diluting 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate (hereinafter abbreviated as SC agent) with a mixed solution of water / isopropyl alcohol (water:isopropyl alcohol mass ratio 1:1) to a solid content of 5 mass %.

[0250] (Examples 1c to 3c, Comparative Examples 1c and 2c) The following procedures were used to prepare the laminates. Examples 1c to 3c and Comparative Examples 1c and 2c differ only in the EVOH used for the underlayer 13. Step 1: The substrate layer 11 and the underlayer 13 were formed by co-extrusion of HDPE and EVOH. The substrate layer 11 had a thickness of 32 μm, and the underlayer 13 had a thickness of 1 μm. Step 2: A 30-nm-thick barrier layer made of silicon oxide was formed on the underlayer formed in Step 1 by vacuum deposition using an electron beam heating method. Step 3: A gas barrier coating agent was applied to the barrier layer formed in Step 2 to form a barrier coating layer. Step 4: A urethane adhesive was applied to the barrier coating layer formed in Step 3 using a dry lamination method to bond a second sealant layer. Step 5: A urethane-based anchor coating agent was applied to the side of the laminate formed in Step 4 opposite the second sealant layer to form an anchor coating layer. Next, an adhesive layer made of an extruded resin was formed via an LDPE resin by extruder lamination, and the first sealant layer was attached.

[0251] (Example 4c) This was produced in the same manner as in Example 1c, except that the gas barrier coating agent had the above composition. (Example 5c) This was produced in the same manner as in Example 1c, except that a biaxially oriented HDPE film was used as the substrate layer. (Example 6c) This was produced in the same manner as in Example 1c, except that an unstretched milky-white LLDPE (containing titanium oxide) film was placed as the second substrate layer between the substrate layer and the first sealant layer. The first substrate layer, second substrate layer, etc. were bonded in the same manner as in step 5 above.

[0252] (Comparative Examples 3c and 4c) These were produced in the same manner as in Example 1c, except that the gas barrier coating agent had the above composition and a different EVOH was used for the underlayer 13. (Comparative Example 5c) This was produced in the same manner as in Example 1c, except that no underlayer was provided and only the surface of the base layer was subjected to corona treatment. (Comparative Example 6c) This was produced in the same manner as in Example 1c, except that no barrier coating layer was provided.

[0253] The detailed configurations of Examples 1c to 5c and Comparative Examples 1c to 6c are shown in Table 6. The layers in the layer configuration are denoted by the reference numerals shown in FIG. 7 to make the corresponding relationships easier to understand.

[0254]

[0255] The configuration of Example 6c is shown in Table 7. Since Example 6c is the only one that includes a second base material layer, it is listed in a separate table.

[0256]

[0257] The laminate for a tube of each example was evaluated as follows. (Measurement of indentation hardness of base layer and barrier coat layer) The indentation hardness of the base layer and barrier coat layer was measured by nanoindentation. Nanoindentation is a measurement method in which a quasi-static indentation test is performed on a target object to obtain the mechanical properties of the sample.

[0258] Measurement samples (cross-sectional samples) were prepared as follows. That is, after corona treatment was performed on both sides of the laminate according to each example, it was embedded in visible light curable resin D-800. Then, using an ultramicrotome Leica EM UC7 with a diamond knife Microstar LH, the gas barrier laminate was cut perpendicular to the lamination direction. The resulting cross section was subjected to a finishing process under conditions of a cutting thickness feed of 100 nm and a cutting speed of 1 mm / s to prepare a measurement sample.

[0259] The measurement device used was a Hysitron TI-Premier (trade name) manufactured by Bruker Japan Co., Ltd., and the indenter used was a Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. The measurement conditions were as follows: Temperature: Room temperature (25°C); Mode: Load-controlled mode; Indentation and unloading: Indentation was performed at a rate of 1.5 μN / sec up to a load of 15 μN, followed by holding at the maximum load for 5 seconds and then unloading at a rate of 1.5 μN / sec. Measurement location: Using the shape measurement function of the measurement device, which scans the sample surface with an indenter, a cross-sectional shape image of the barrier coat layer was obtained, and 20 points were designated on the cross-section of the barrier coat layer at intervals of 1 μm or more from the shape image. When calculating the indentation hardness, fused quartz was used as a standard sample to calibrate the relationship between the contact depth and contact projected area between the indenter and the sample. The unloading curve for the region from 60 to 95% of the maximum load at the time of unloading was then analyzed using the Oliver-Pharr method, and the indentation hardness was calculated.

[0260] (Barrier properties after repeated bending) A test piece of the laminate according to each example was set in a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) and bent 100 times at room temperature (23°C). After bending, the test piece was used to measure oxygen transmission rate (OTR) in accordance with JIS K-7126, Method B under conditions of 30°C and a relative humidity of 70%. The OTR after bending was 1.5 cc / m ２ It can be said that a sufficient effect of suppressing the deterioration of the barrier layer is achieved if the OTR is equal to or less than 1 / 4 day / atm. Table 1 also shows the OTR before bending, which was measured in advance, for reference.

[0261] In all examples where the indentation hardness of the underlayer 13 was within the range of 0.05 to 0.1 gigapascals (GPa) and the indentation hardness of the barrier coat layer 15 was 0.5 GPa or less, the barrier properties were well maintained against repeated bending. Examples 5c and 6c also demonstrated that the effect was exhibited regardless of the configuration of the base layer or the presence or absence of a second base layer. Examples where the S2 / S1 value was 3 or greater and 5 or less tended to exhibit better barrier properties after bending. Comparative Examples 6c and 7c, which lacked either the underlayer 13 or the barrier coat layer 15, showed a significant decrease in barrier properties after repeated bending. Other comparative examples that included both had values ​​for at least one of S1 and S2 outside the preferred range, resulting in insufficient barrier properties after repeated bending. In Comparative Examples 3c and 4c, one possible cause was an insufficient amount of polyvinyl alcohol-based resin due to the composition of the gas barrier coating agent, resulting in the barrier coat layer becoming too hard.

[0262] The third aspect of the present disclosure has been described above in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and configuration changes and combinations within the scope that do not deviate from the gist of the present invention are also included.

[0263] In the third aspect of the present disclosure, the haze of the substrate layer can be appropriately set, but since it is somewhat linked to the MD elongation rate, it is preferably 3% or more, more preferably 5% or more. From the viewpoint of ensuring visibility, it is preferably 30% or less, more preferably 20% or less. The haze is measured using a haze meter NDH700 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7136.

[0264] The substrate layer, second substrate layer, and sealant layer (first sealant layer, second sealant layer) constituting the laminate for a tube according to the third aspect of the present disclosure may be made of a film containing biomass polyethylene or recycled polyethylene. The recycled polyethylene may be mechanically recycled polyethylene or chemically recycled polyethylene.

[0265] [Fourth Aspect] The fourth aspect of the present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to these examples.

[0266] (Preparation of Gas Barrier Coating Agents) The following (a) to (c) were prepared. In Example 1d, (a):(b):(c) were mixed at a mass ratio of 45:45:10, in Examples 2d, 4d, and 5d, they were mixed at a mass ratio of 30:60:10, and in Comparative Example 1d, they were mixed at a mass ratio of 20:70:10 to prepare the respective gas barrier coating agents. (a) 5 mass% polyvinyl alcohol (PVA) water / methanol solution (mass ratio of water:methanol was 95:5). (b) Tetraethoxysilane (Si(OC ２ H ５ ) ４ 72.1 g of 0.1N hydrochloric acid was added to 17.9 g of TEOS (hereinafter abbreviated as TEOS) and 10 g of methanol, and the mixture was stirred for 30 minutes to hydrolyze the solid content of 5 mass % (weight ratio of SiO ２ (c) A hydrolysis solution obtained by diluting 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate (hereinafter abbreviated as SC agent) with a mixed solution of water / isopropyl alcohol (water:isopropyl alcohol mass ratio 1:1) to a solid content of 5 mass %.

[0267] (Preparation of Undercoat Layer-Forming Composition) Acrylic polyol and tolylene diisocyanate were mixed such that the number of NCO groups in tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate to a total solids content (total amount of acrylic polyol and tolylene diisocyanate) of 5 mass %. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare a undercoat layer-forming composition (anchor coating agent).

[0268] (Examples 1d, 2d, and Comparative Example 1d) The following procedures were used for preparation. Step 1: A base layer 11 and a base layer 13 were formed by applying and drying a base layer-forming composition onto an HDPE film. The base layer 11 had a thickness of 32 μm, and the base layer 13 had a thickness of 0.1 μm. Step 2: A 50-nm-thick barrier layer made of an aluminum vapor-deposited film was formed on the base layer formed in Step 1 by vacuum deposition using an electron beam heating method. Step 3: A gas barrier coating agent was applied to the barrier layer formed in Step 2 to form a barrier coating layer. Step 4: A urethane adhesive was applied to the barrier coating layer formed in Step 3 by dry lamination, and a second sealant layer was bonded to it. Step 5: A urethane-based anchor coating agent was applied to the side of the laminate bonded in Step 4 opposite the second sealant layer to form an anchor coating layer. Next, an adhesive layer made of extruded resin was formed via LDPE resin by extruder lamination, and a first sealant layer was bonded to it.

[0269] (Example 3d) This was produced in the same manner as in Example 1d, except that a barrier coat layer was formed by coating and drying an emulsion of polyethylene copolymer resin. (Example 4d) This was produced in the same manner as in Example 2d, except that the underlayer was formed of EVOH by co-extrusion of HDPE and EVOH. The thickness of the base layer was 32 μm, and the thickness of the underlayer was 1.0 μm. (Example 5d) This was produced in the same manner as in Example 4d, except that a biaxially oriented HDPE film (thickness: 25 μm) was used as the base layer. (Example 6d) This was produced in the same manner as in Example 2d, except that an unstretched milky-white LLDPE (containing titanium oxide) film was placed as the second base layer between the base layer and the first sealant layer. The first base layer, second base layer, etc. were bonded in the same manner as in Step 5 above. The second base layer had a printed layer formed by flexographic printing.

[0270] Comparative Example 2d: This was produced in the same manner as in Example 1d, except that no barrier coating layer was provided. Comparative Example 3d: This was produced in the same manner as in Example 1d, except that a urethane-based one-component adhesive was used to form the barrier coating layer.

[0271] Details of Examples 1d to 5d and Comparative Examples 1d to 3d are shown in Tables 8 and 9. The layers in the layer structure are denoted by the reference numerals shown in FIG. 9 to make the corresponding relationships easier to understand.

[0272]

[0273]

[0274] Details of Example 6d are shown in Table 10. Since Example 6d was the only example that had a second base material layer, it is listed in a separate table.

[0275]

[0276] The laminate for a tube of each example was evaluated as follows. (Measurement of indentation hardness of barrier coat layer) The indentation hardness of the barrier coat layer was measured by nanoindentation. Nanoindentation is a measurement method in which a quasi-static indentation test is performed on a target object to obtain the mechanical properties of the sample.

[0277] Measurement samples (cross-sectional samples) were prepared as follows. That is, after corona treatment was performed on both sides of the laminate according to each example, it was embedded in visible light curable resin D-800. Then, using an ultramicrotome Leica EM UC7 with a diamond knife Microstar LH, the gas barrier laminate was cut perpendicular to the lamination direction. The resulting cross section was subjected to a finishing process under conditions of a cutting thickness feed of 100 nm and a cutting speed of 1 mm / s to prepare a measurement sample.

[0278] The measurement device used was a Hysitron TI-Premier (trade name) manufactured by Bruker Japan Co., Ltd., and the indenter used was a Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. The measurement conditions were as follows: Temperature: Room temperature (25°C); Mode: Load-controlled mode; Indentation and unloading: Indentation was performed at a rate of 1.5 μN / sec up to a load of 15 μN, followed by holding at the maximum load for 5 seconds and then unloading at a rate of 1.5 μN / sec. Measurement location: Using the shape measurement function of the measurement device, which scans the sample surface with an indenter, a cross-sectional shape image of the barrier coat layer was obtained, and 20 points were designated on the cross-section of the barrier coat layer at intervals of 1 μm or more from the shape image. When calculating the indentation hardness, fused quartz was used as a standard sample to calibrate the relationship between the contact depth and contact projected area between the indenter and the sample. The unloading curve for the region from 60 to 95% of the maximum load at the time of unloading was then analyzed using the Oliver-Pharr method, and the indentation hardness was calculated.

[0279] (Barrier properties after repeated bending) A test piece (A4 size) of the laminate according to each example was set in a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) and bent 100 times at room temperature (23°C). Sample pieces (10 x 10 mm) cut out from the bent test pieces were used to measure the oxygen transmission rate (OTR) at 30°C and a relative humidity of 70% in accordance with JIS K7126-2, and the water vapor transmission rate (WVTR) at 40°C and a relative humidity of 90% in accordance with JIS K7129B. The OTR after bending was 1.5 cc / m ２ · day · atm or less, and WVTR after bending is 2.0 g / m ２ It can be said that a sufficient effect of suppressing the deterioration of the barrier layer is achieved if the bending pressure is equal to or less than 1 / 4 day / atm. Table 9 also shows the OTR and WVTR measured before bending for reference.

[0280] (Evaluation of Resistance to Contents) Using the tube laminates according to each example, laminate tubes (length 169 mm, outer diameter 38.1 mm) were prepared with the second sealant layer facing inward. A pH 5.5 paste was filled inside the tubes, and the tubes were stored for 30 days at 40°C and 90% relative humidity. After storage, the entire contents were extracted and removed, and the tubes were then subjected to a bending operation in which both ends were fixed and twisted 180 degrees left and right ten times. After the bending operation, the tubes were cut open and washed, and the following two items were evaluated: - Average light transmittance (%) in the visible light range (wavelengths 350 to 770 nm) - Lamination strength (N / 15 mm) between the base layer and the second sealant layer. The average light transmittance was evaluated as an index of the corrosion of the barrier layer due to attack by the contents and the formation of fine pores due to further bending. The laminate strength was evaluated as an index of the corrosion of the barrier layer due to attack by the contents and the deterioration of adhesion between the layers due to further bending.

[0281] (Measurement of average light transmittance) Using a UV-visible spectrophotometer (Shimadzu Corporation, UV-2450), light transmittance was measured at 1 nm intervals in the wavelength range of 350 to 770 nm, and the average light transmittance was calculated. Measurement samples were prepared by cutting out 20 x 20 mm pieces near the center of the laminate tube. (Measurement of laminate strength) Using a tensile tester (A&D Corporation, RTG-1225), T-peel was performed at 300 mm / min, and the laminate strength between the base layer 11 and the second sealant layer 30 was measured in accordance with JIS Z0238. The size of the measurement sample was 15 mm in width (TD direction).

[0282] As shown in Tables 8 and 10, in all examples where the indentation hardness of the barrier coating layer 15 measured by nanoindentation was within the range of 0.02 to 0.75 gigapascals (GPa), the barrier properties were well maintained even after repeated bending. Examples 5d and 6d also demonstrated that the effect was achieved regardless of the configuration of the substrate layer or the presence or absence of a second substrate layer. Comparative Example 2d, which did not include the barrier coating layer 15, showed a significant decrease in barrier properties after repeated bending. Other comparative examples, which included a barrier coating layer but had indentation hardness values ​​outside the above range, also showed insufficient barrier properties after repeated bending. In all comparative examples, the laminate strength in the contents resistance evaluation was below 2 N / 15 mm, suggesting that corrosion of the barrier layer due to the contents had occurred.

[0283] The fourth aspect of the present disclosure has been described above in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and configuration changes and combinations within the scope that do not deviate from the gist of the present invention are also included.

[0284] For example, a film containing biomass polyethylene or recycled polyethylene may be used for the substrate layer, second substrate layer, and sealant layer (first sealant layer, second sealant layer) constituting the laminate for a tube according to the fourth aspect of the present disclosure. The recycled polyethylene may be mechanically recycled polyethylene or chemically recycled polyethylene.

[0285] 50, 60...Laminate for tube container, 51a...First sealant layer, 51b...Second sealant layer, 52...Base material layer, 53...Barrier layer, 54...Adhesive layer, 65a...First extruded polyethylene layer, 65b...Second extruded polyethylene layer, 66a...Printed layer, 66b...Printed base material layer, 67...Base layer, 68...Overcoat layer, 110...Body portion, 111...Bottom portion, 113...Seal portion, 120...Pour-out portion Mouth portion, 121...shoulder portion, 122...mouth portion, 130...cap, 100...tube container (laminated tube), 1A, 1B, 1C, 1D, 1E, 1F, 1G...laminated body for tube, 10A, 10B, 10C, 10D...substrate portion, 11...substrate layer, 12...barrier layer, 13...priming layer, 15...barrier coat layer, 16...second substrate layer, 20...first sealant layer, 30...second sealant layer.

Claims

1. A laminate for a tube comprising a first sealant layer, a substrate layer, a barrier layer, an adhesive layer, and a second sealant layer in this order, wherein the barrier layer comprises an inorganic oxide vapor-deposited layer, the substrate layer, the first sealant layer, and the second sealant layer each comprise polyethylene, and the substrate layer has a tensile modulus in the machine direction (MD) of 500 to 2000 MPa at 23°C, and the adhesive layer has a tensile modulus of 500 MPa or more at 23°C.

2. The tubing laminate according to claim 1, wherein said adhesive layer is formed from an epoxy adhesive.

3. The laminate for a tube according to claim 1, wherein the thickness of the adhesive layer is 0.1 to 20 μm.

4. The tubing laminate of claim 1, wherein said first sealant layer and said second sealant layer comprise linear low density polyethylene.

5. The laminate for a tube according to claim 1, wherein the thickness of the first sealant layer and the second sealant layer is 20 to 200 μm.

6. The laminate for a tube according to claim 1, further comprising an underlayer on the barrier layer side of the substrate layer.

7. The laminate for a tube according to claim 1, wherein the inorganic oxide vapor-deposited layer comprises silicon oxide or aluminum oxide.

8. The tubing laminate of claim 1, wherein the polyethylene comprises recycled polyethylene.

9. A laminate for a tube comprising: a substrate part having a substrate layer made of unstretched polyethylene film and a barrier layer formed by vapor deposition on one surface of the substrate layer; a first sealant layer made of polyethylene film and provided on one side of the substrate part; and a second sealant layer made of polyethylene film and provided on the side of the substrate part opposite to the first sealant layer, wherein the MD elongation rate of the substrate layer is 2.5% or more and 6.5% or less.

10. The substrate layer has a density of 0.940 g / cm ３ 10. The laminate for a tube according to claim 9, which comprises the above high-density polyethylene as a main component.

11. The laminate for a tube according to claim 9, wherein the thickness of the substrate layer is 10 μm to 50 μm.

12. The laminate for a tube according to claim 9, wherein the barrier layer is made of any one of silicon oxide, aluminum oxide, and metallic aluminum.

13. The laminate for a tube according to claim 9, further comprising a barrier coat layer formed on the barrier layer, the barrier coat layer comprising at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolysate of a metal alkoxide, and a water-soluble polymer.

14. The tubing laminate of claim 13, wherein the barrier coat layer further comprises at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent.

15. The laminate for a tube according to claim 9, further comprising a second substrate layer made of an unstretched polyethylene film having a printed layer on one surface thereof and bonded to one surface of the substrate portion, wherein the second substrate layer and the first sealant layer are bonded to each other.

16. The laminate for a tube according to claim 9, wherein the substrate portion and the second sealant layer are bonded together with a barrier adhesive.

17. A laminate for a tube comprising: a substrate portion having a base layer made of polyethylene film, a primer layer composed primarily of ethylene vinyl alcohol and formed on a first surface of the base layer, and a barrier layer formed on the primer layer; a barrier coat layer arranged so as to sandwich the barrier layer between the primer layer and the barrier coat layer; a first sealant layer made of polyethylene film and provided on a second surface of the base layer opposite the first surface; and a second sealant layer made of polyethylene film and provided on the barrier coat layer; wherein the primer layer has a cross-sectional indentation hardness of 0.05 to 0.1 gigapascals, and the barrier coat layer contains a polyvinyl alcohol-based resin and has a cross-sectional indentation hardness of 0.5 gigapascals or less.

18. A laminate for a tube according to claim 17, wherein the ratio S2 / S1 of the cross-sectional indentation hardness S1 of the underlayer to the cross-sectional indentation hardness S2 of the barrier coat layer is 3.0 or more and 5.0 or less.

19. The laminate for a tube according to claim 17, wherein the substrate layer and the undercoat layer are formed by coextrusion.

20. A laminate for a tube comprising: a substrate portion having a substrate layer made of a polyethylene film and a barrier layer made of a vapor-deposited film of metallic aluminum formed on a first surface side of the substrate layer; a barrier coat layer arranged to cover the barrier layer; a first sealant layer made of a polyethylene film and provided on a second surface side of the substrate layer opposite the first surface; and a second sealant layer made of a polyethylene film and provided on the barrier coat layer, wherein the cross-sectional indentation hardness of the barrier coat layer is 0.75 gigapascals or less.

21. The laminate for a tube according to claim 20, wherein the cross-sectional indentation hardness of the barrier coat layer is 0.03 gigapascals or more.

22. The laminate for a tube according to claim 20, wherein the barrier coat layer contains an acid-modified polyolefin resin.

23. A laminate for a tube according to any one of claims 1, 17 and 20, wherein the substrate layer is an unstretched film.

24. The laminate for a tube according to claim 17 or 20, wherein the barrier coat layer comprises at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a reaction product of a metal alkoxide, and a reaction product of a hydrolyzate of a metal alkoxide.

25. The laminate for a tube according to claim 20, wherein the barrier coat layer further comprises at least one of a polyvinyl alcohol resin, a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent.

26. The tubing laminate of claim 24, wherein the barrier coat layer further comprises at least one of a silane coupling agent, a hydrolyzate of a silane coupling agent, a reaction product of a silane coupling agent, and a reaction product of a hydrolyzate of a silane coupling agent.

27. The laminate for a tube according to claim 17 or 20, wherein the substrate layer contains high-density polyethylene.

28. The tubing laminate of any one of claims 9, 17, and 20, wherein at least one of the substrate layer, the first sealant layer, and the second sealant layer contains recycled polyethylene.

29. A laminated tube formed into a cylindrical shape using the laminate for a tube according to any one of claims 1, 9, 17 and 20, and comprising a body portion with one end sealed, and a shoulder portion attached to the other end of the body portion.