Multilayer sealant film

Abstract

To provide a new multilayer sealant film which can attain good low temperature sealability and improvement of workability during tube molding.SOLUTION: As shown in Figure 1, a multilayer sealant film 10 has an inorganic particle-containing layer 12, and a sealant layer 14. The inorganic particle-containing layer 12 contains a thermoplastic resin, and inorganic particles dispersed in the thermoplastic resin. The inorganic particles are ferrous oxygen absorbers. The sealant layer 14 is composed of a polyethylene-based resin having a melting point of 120°C or lower. Surface roughness Ra in a TD direction of a surface 14a on the side of the sealant layer 14 is 0.2 or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a multilayer sealant film, particularly a multilayer sealant film for a laminated tube container.

Background Art

[0002] Conventionally, laminated tube containers have been manufactured in various ways. For example, a laminated sheet is produced, the outermost layer and the innermost layer at both ends thereof are heat-sealed to produce a cylindrical body portion, and then, a head portion including a mouth portion, a shoulder portion, etc. is formed at one opening of the cylindrical body portion, and a laminated tube container is produced by screwing a cap onto the mouth portion. The laminated tube container thus produced can be filled with a semi-fluid content such as toothpaste from the open end of the cylindrical body portion, and the open end is hermetically sealed to form a bottom seal portion to obtain a tube-shaped packaged product. Various forms of such laminated tube containers and laminates used therefor have been proposed.

[0003] Patent Document 1 discloses a tubular container including an oxygen-absorbing multilayer body composed of at least three layers, in which an inner layer containing a thermoplastic resin, an oxygen-absorbing layer composed of an oxygen-absorbing resin composition containing a copolymerized polyolefin compound and a transition metal catalyst, and a gas barrier layer containing a gas barrier substance are laminated in this order, and the copolymerized polyolefin compound is a copolymerized polyolefin compound containing a structural unit represented by a given general formula.

[0004] Patent Document 2 discloses an oxygen-absorbing laminate for a laminated tube container including at least a layer structure in which a sealant layer A, a base material layer, an oxygen barrier layer, an oxygen-absorbing adhesive layer, and a sealant layer B are laminated in this order. This oxygen-absorbing adhesive layer is a layer formed from an oxygen-absorbing adhesive composition, and the oxygen-absorbing adhesive composition contains at least a specific oxygen-absorbing compound and an oxidation-promoting catalyst.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a novel multilayer sealant film capable of providing good low-temperature sealability and improved processability during tube forming.

Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows: <Aspect 1> having an inorganic particle-containing layer and a sealant layer, wherein the inorganic particle-containing layer contains a thermoplastic resin and inorganic particles dispersed in the thermoplastic resin, the sealant layer is composed of a polyethylene-based resin having a melting point of 120°C or lower, and the surface roughness Ra in the TD direction of the surface on the sealant layer side is 0.2 or more, a multilayer sealant film. <Aspect 2> The multilayer sealant film according to Aspect 1, wherein the inorganic particles are an iron-based oxygen absorber. <Aspect 3> The multilayer sealant film according to Aspect 1 or 2, wherein the ratio of D50 of the inorganic particles measured by the laser diffraction method to the thickness of the multilayer sealant film is 0.3 or more and 0.5 or less. <Aspect 4> A laminate tube container laminate having the multilayer sealant film according to any one of Aspects 1 to 3 and a base material layer laminated on the inorganic particle-containing layer side of the multilayer sealant film. <Aspect 5> The base material layer has an inner base material sealant layer located on the outermost surface on the inorganic particle-containing layer side. The laminate for a laminate tube container according to Aspect 4, wherein the thickness of the inner base material sealant layer is thicker than the thickness of the sealant layer of the multilayer sealant film. <Aspect 6> Having the laminate for a laminate tube container according to Aspect 4, A part of the base material layer and a part of the sealant layer are overlapped and heat-sealed to form a side seam portion, and the laminate for a laminate tube container is formed into a tubular shape. Laminate tube container.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a novel multilayer sealant film that can bring about good low-temperature sealability and improvement in processability during tube forming.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0010] 《Multilayer Sealant Film》 As shown in FIG. 1, the multilayer sealant film 10 of the present invention has an inorganic particle-containing layer 12 and a sealant layer 14, wherein the inorganic particle-containing layer 12 contains a thermoplastic resin and inorganic particles dispersed in the thermoplastic resin, the sealant layer 14 is composed of a polyethylene-based resin having a melting point of 120° C. or lower, and the surface roughness Ra in the TD direction of the surface 14a on the sealant layer 14 side is 0.2 or more.

[0011] The inventors have found that the above melting point and surface roughness can bring about good low-temperature sealability and improvement in processability during tube forming. In particular, when the surface roughness on the sealant layer side is within the above range, by laminating a base material layer on this multilayer sealant film to form a sheet-like laminate, when forming into a tube shape, the resistance of the innermost layer of this laminate becomes small, and as a result, the feeding of the film during processing can be made smooth.

[0012] In particular, the above properties are useful when the multilayer sealant film of the present invention is used in a laminate for a laminated tube container. That is, the multilayer sealant film of the present invention may be for a laminated tube container.

[0013] The surface roughness Ra in the TD direction on the sealant layer side of the multilayer sealant film of the present invention may be 0.2 or more and 1.0 or less, for example, 0.2 or more, 0.3 or more, or 0.4 or more, and may also be 1.0 or less, 0.8 or less, 0.7 or less, or 0.6 or less.

[0014] By controlling the surface roughness Ra in the TD direction on the sealant layer side, the feeding of the film during tube forming can be made smooth. Here, the surface roughness is the arithmetic mean roughness Ra measured in accordance with JIS B0601-2013. Specifically, the surface roughness is obtained by extracting only the reference length l in the direction of the mean line from the roughness curve, taking the x-axis in the direction of the mean line of this extracted portion and the y-axis in the direction of the longitudinal magnification, and when the roughness curve is represented by y = f(x), it refers to the value obtained by the following formula and expressed in micrometers (μm).

[0015] [Number]

[0016] This surface roughness can be measured using a contact-type roughness meter (ET4000AK, Kosaka Laboratory Ltd.) under the following conditions. Cutoff 0.8mm Filter Gaussian E.length 4.000mm S.length 0.800mm Levelling Straight line (entire area) Polarity normal Start-up Cutoff × 1 Data 8000points

[0017] Also, in the present invention, the "TD direction" (Transverse Direction) means the direction perpendicular to the "MD direction" (Machine Direction) when the flow direction of the machine is defined as the "MD direction".

[0018] Hereinafter, each component of the present invention will be described.

[0019] 〈Inorganic particle-containing layer〉 The inorganic particle-containing layer contains a thermoplastic resin and inorganic particles dispersed in the thermoplastic resin.

[0020] The thickness of the inorganic particle-containing layer may be, for example, 15 μm or more and 50 μm or less. This thickness may be 15 μm or more, 18 μm or more, 20 μm or more, 25 μm or more, or 28 μm or more, and may also be 50 μm or less, 48 μm or less, 45 μm or less, 42 μm or less, 40 μm or less, 38 μm or less, 35 μm or less, or 32 μm or less.

[0021] The inorganic particle-containing layer can be obtained, for example, by extruding a composition obtained by melt-mixing the components constituting this layer onto a film of a polyethylene-based resin constituting the sealant layer. It may be directly laminated. That is, the inorganic particle-containing layer may be directly laminated on the sealant layer, and particularly may be fused.

[0022] (Thermoplastic resin) As the thermoplastic resin, for example, a polyolefin-based resin can be used.

[0023] As the polyolefin-based resin, for example, a polyethylene-based resin or a polypropylene-based resin can be used.

[0024] In this specification, the polyethylene-based resin is a resin containing, in the main chain of the polymer, a repeating unit of an ethylene group in an amount exceeding 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more. For example, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and derivatives thereof, and mixtures thereof are selected from the group consisting of.

[0025] In this specification, the polypropylene-based resin is a resin containing, in the main chain of the polymer, repeating units of propylene groups in an amount exceeding 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more. Examples thereof include polypropylene (PP) homopolymer, random polypropylene (random PP), block polypropylene (block PP), chlorinated polypropylene, acid-modified polypropylene, and derivatives thereof, as well as mixtures thereof.

[0026] As the thermoplastic resin, among others, it is preferable to use a polyethylene-based resin, particularly low-density polyethylene or linear low-density polyethylene, from the viewpoint of improving the adhesive strength between layers with the sealant layer.

[0027] (Inorganic particles) The inorganic particles are inorganic particles dispersed in the thermoplastic resin.

[0028] As the inorganic particles, for example, a gas absorbent, an inorganic pigment, etc. can be used.

[0029] As the gas absorbent, an oxygen absorbent such as an iron powder-based oxygen absorbent, an organic gas absorbent such as a hydrophobic zeolite, etc. can be used. In particular, when the multi-layer sealant film of the present invention is used for a laminated tube container, by using an iron powder-based oxygen absorbent as the inorganic particles, the oxygen remaining in the headspace of the laminated tube container, particularly in the vicinity of the bottom seal portion described later, can be absorbed, thereby suppressing the deterioration of the contents.

[0030] As the inorganic pigment, for example, a known inorganic coloring pigment, a flaky metal pigment such as aluminum powder, a lustrous pigment such as a pearl pigment, etc. can be used.

[0031] The D50 of the inorganic particles measured by the laser diffraction method can be from 15 μm to 50 μm, and can be, for example, 15 μm or more, 18 μm or more, 20 μm or more, 22 μm or more, 25 μm or more, or 28 μm or more, and can also be 50 μm or less, 45 μm or less, 42 μm or less, 40 μm or less, 38 μm or less, 35 μm or less, or 32 μm or less.

[0032] From the viewpoint of obtaining the above surface roughness, the ratio of the D50 of the inorganic particles measured by the laser diffraction method to the thickness of the multilayer sealant film is preferably from 0.30 to 0.50. This ratio can be 0.30 or more, 0.33 or more, 0.35 or more, or 0.37 or more, and can also be 0.50 or less, 0.45 or less, 0.42 or less, or 0.40 or less.

[0033] The content of the inorganic particles is not particularly limited, but from the viewpoint of achieving both the above surface roughness and moldability, it is preferably from 15% by mass to 50% by mass based on the mass of the inorganic particle-containing layer. This content can be 15% by mass or more, 18% by mass or more, 20% by mass or more, 22% by mass or more, 25% by mass or more, or 28% by mass or more based on the mass of the inorganic particle-containing layer, and can also be 50% by mass or less, 45% by mass or less, 42% by mass or less, 40% by mass or less, 38% by mass or less, 35% by mass or less, or 32% by mass or less.

[0034] 〈Sealant layer〉 The sealant layer is composed of a polyethylene-based resin.

[0035] The melting point of the polyethylene-based resin constituting the sealant layer is 120°C or lower, particularly 110°C or higher and 120°C or lower. Here, the melting point means the melting point measured by a differential scanning calorimeter (DSC) in accordance with JIS K7121:1987.

[0036] As the polyethylene-based resin, among those listed for the inorganic particle-containing layer, a polyethylene-based resin satisfying the above melting point can be used. Among them, it is preferable to use linear low-density polyethylene from the viewpoint of heat sealability.

[0037] The density of the polyethylene-based resin is 0.900 g / cm 3 or more, 0.905 g / cm 3 or more, 0.910 g / cm 3 or more, 0.915 g / cm 3 or more, or 0.918 g / cm 3 or more, and may be 0.950 g / cm 3 or less, 0.945 g / cm 3 or less, 0.940 g / cm 3 or less, 0.935 g / cm 3 or less, or 0.930 g / cm 3 or less. In particular, it is preferable that the density is 0.930 g / cm 3 or less from the viewpoint of heat seal strength.

[0038] The thickness of the sealant layer is not particularly limited, but it is preferable from the viewpoint of obtaining the above surface roughness that the thickness satisfies the ratio of the D50 of the above inorganic particles to the thickness of the multilayer sealant film. This thickness may be 40 μm or more and 60 μm or less, for example, 40 μm or more, 42 μm or more, 45 μm or more, or 47 μm or more, and may also be 60 μm or less, 58 μm or less, 55 μm or less, or 53 μm or less.

[0039] 《Laminate for laminated tube container》 As shown in FIG. 2, the laminate 20 for a laminated tube of the present invention has the above multilayer sealant film 10 and a base material layer 20 laminated on the inorganic particle-containing layer 12 side of the multilayer sealant film 10.

[0040] The inorganic particle-containing layer of the multilayer sealant film and the base material layer may be adhered via an adhesive layer.

[0041] 〈Base material layer〉 The base material layer is generally an impermeable base material. In particular, the base material layer of the laminate tube container laminate of the present invention has a base material sealant layer on the surface. The base material layer may be a single layer or a laminate in which a plurality of layers are laminated, and may include a plurality of layers of the same type.

[0042] The base material layer may have, for example, an outer base material sealant layer, a printed layer, a barrier layer, a reinforcing layer, and an inner base material sealant layer. These layers may be laminated by any lamination means, for example, they may be laminated via an adhesive layer. Further, an arbitrary printed layer may be laminated on the printed layer. In particular, when the inorganic particles are an iron powder-based oxygen absorber, the oxygen permeability of the base material layer may be less than that of the sealant layer. Here, this oxygen permeability may be measured in accordance with JIS K7126-1 at a temperature of 25°C and a relative humidity of 0%.

[0043] As such a base material layer, for example, a base material having the following layer structure can be used: · LDPE (75μm) / milky white LDPE (160μm) / LDPE (50μm) / PET (12μm) / LLDPE (100μm) · LLDPE (55μm) / transparent LDPE (80μm) / EAA (20μm) / AL (12μm) / EMAA (25μm) / PET (12μm) / LLDPE (100μm)

[0044] (Outer base material sealant layer) The outer base material sealant layer is a sealant layer located on the outermost surface of the base material layer on the side opposite to the inorganic particle-containing layer. When obtaining a laminate tube container using the laminate of the laminate tube container of the present invention, it can be a layer to be heat-sealed with the sealant layer of the multilayer sealant film.

[0045] As the outer base material sealant layer, the polyethylene-based resin mentioned as the sealant layer of the multilayer sealant film can be used.

[0046] (Printed layer) The printed layer is not particularly limited as long as it has a non-permeability to the extent that the printing layer can be printed, and may be, for example, a resin layer.

[0047] As the printed layer, for example, thermoplastic resins such as polyolefin resins, vinyl polymers, polyester resins, and polyamide resins can be used alone or in combination of two or more kinds in a multilayer. Such thermoplastic resins can be used in the form of a film or an extruded resin. The film may be a stretched film or an unstretched film.

[0048] As the polyolefin resin, for example, polyethylene resin and polypropylene resin can be used. Specifically, reference can be made to the description regarding the inorganic particle-containing layer.

[0049] Examples of the vinyl polymer include polyvinyl chloride (PVC).

[0050] Examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, etc.

[0051] Examples of the polyamide resin include nylon such as nylon (registered trademark) 6 and nylon MXD6.

[0052] (Barrier layer) As the barrier layer, for example, an inorganic vapor deposition layer, a metal foil layer, an organic coating layer, etc. can be used.

[0053] As the inorganic vapor deposition layer, for example, a silica vapor deposition film, an aluminum vapor deposition film, an alumina vapor deposition film, and a silica-alumina vapor deposition film can be used.

[0054] As the metal foil layer, for example, single metal foils such as aluminum foil, copper foil, and titanium foil, and alloy foils such as aluminum alloy foil and stainless steel foil can be used.

[0055] As the organic coating layer, for example, a vinylidene chloride coating layer or a polyvinylidene fluoride coating layer can be used.

[0056] When an inorganic vapor deposition film or an organic coating layer is used as the barrier layer, from the viewpoint of ensuring strength and barrier properties, the thickness of the barrier layer is preferably 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, or 1 μm or more. Also, from the viewpoint of improving the handleability of the laminate for tubes, it is preferably 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less.

[0057] When a metal foil layer is used as the barrier layer, from the viewpoint of ensuring strength and barrier properties, the thickness of the barrier layer is preferably 3 μm or more, 5 μm or more, 7 μm or more, 10 μm or more, or 15 μm or more. Also, from the viewpoint of improving the handleability of the laminate for tubes, it is preferably 100 μm or less, 80 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less.

[0058] (Reinforcing layer) The reinforcing layer may be a layer composed of a stretched film.

[0059] The reinforcing layer may be, for example, a stretched film composed of a polyester resin, a polyamide resin, a polypropylene resin, etc. For these resins, reference can be made to the description regarding the layer to be printed.

[0060] When the reinforcing layer is composed of a stretched film, the stretched film constituting the reinforcing layer may be, for example, a stretched film obtained by flat stretching, and may be a uniaxially stretched film or a biaxially stretched film. The biaxially stretched film may be a sequentially biaxially stretched film or a simultaneously biaxially stretched film, or a stretched film obtained by performing these stretching operations a plurality of times.

[0061] The thickness of the reinforcing layer is preferably 5 μm or more, 7 μm or more, 10 μm or more, 12 μm or more, or 25 μm or more from the viewpoint of imparting practical restoration over time to the laminated tube container. On the other hand, the thickness of the reinforcing layer is preferably 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, 15 μm or less, or 12 μm or less from the viewpoint of not impairing the short-term shape retention and not excessively increasing the total thickness of the laminate for the laminated tube container.

[0062] (Inner base material sealant layer) The inner base material sealant layer is a layer located on the outermost surface of the base material layer on the side of the inorganic particle-containing layer of the multilayer sealant film, that is, on the side opposite to the base material sealant layer. As the resin constituting the inner base material sealant layer, the polyethylene-based resin mentioned for the outer base material sealant layer can be used.

[0063] The thickness of the inner base material sealant layer may be 50 μm or more, 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, or 95 μm or more, and may also be 150 μm or less, 140 μm or less, 130 μm or less, 120 μm or less, 110 μm or less, or 105 μm or less.

[0064] In particular, when the inorganic particles are an iron powder-based oxygen absorber, it is preferable that the thickness of the inner base material sealant layer is thicker than the thickness of the sealant layer of the multilayer sealant film from the viewpoint of facilitating oxygen absorption.

[0065] 〈Adhesive layer〉 The adhesive layer is a layer that exists between the base material layer and the inorganic particle-containing layer of the multilayer sealant film and, optionally, between each layer constituting the base material layer, thereby adhering these to each other.

[0066] As the adhesive layer, for example, a dry laminate adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent laminate adhesive, and a thermoplastic resin for extrusion lamination can be used. Among them, it is preferable to use a dry laminate adhesive, particularly a two-component curable dry laminate adhesive.

[0067] <Laminated Tube Container> As shown in FIG. 2, the laminated tube container 200 of the present invention has the above-described laminate 100 for a laminated tube container. A part of the sealant layer 14 of the multi-layer sealant film and a part of the base material sealant layer (not shown) of the base material layer 20 are overlapped and heat-sealed to form the side seam portion 210, so that the laminate 100 for a laminated tube is formed into a cylindrical shape.

[0068] Although not shown, the laminated tube container of the present invention may have a head having a shoulder and a cap portion, and a bottom seal portion existing on the side opposite to the head.

[0069] The laminated tube container can be filled with contents such as drugs, cosmetics, and foods. Examples of the contents include toothpaste, moisturizing cream, sunscreen, etc.

[0070] The laminated tube container can be manufactured, for example, by a method including the following steps: A step of forming a side seam portion by heat-sealing the ends of the laminate while rolling the laminate for a laminated tube so that the base material, particularly the sealant layer of the base material, faces inward to obtain a body portion; and A step of obtaining a laminated tube container by joining a head having a shoulder and a cap portion to the periphery of the opening of the body portion.

Example

[0071] The present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited thereto.

[0072] <Production of Multi-Layer Sealant Film> 〈Example 1〉 A linear low-density polyethylene (LLDPE) film (density 0.920 g / cm as a sealant layer 3, a resin composition for an oxygen absorption layer as an inorganic particle-containing layer (thickness: 30 μm) was extrusion laminated onto LLDPE1) having a melting point of 113°C and a thickness of 50 μm to produce the multilayer sealant film of Example 1.

[0073] As the resin composition for the oxygen absorption layer, a resin composition obtained by dispersing an iron-based oxygen absorber (D50: 30 μm) in a polyethylene-based resin at a content rate of 25 to 30% by mass based on the mass of the oxygen absorption layer was used.

[0074] 〈Example 2 and Comparative Example 1〉 Multilayer sealant films of Example 2 and Comparative Example 1 were produced in the same manner as in Example 1, except that those shown in Table 1 were used as the sealant layer. The details of the materials shown in Table 1 are as follows. LLDPE2: Linear low-density polyethylene film (melting point 116°C) LLDPE3: Linear low-density polyethylene film (melting point 122°C)

[0075] 《Measurement of surface roughness》 The surface roughness of the produced multilayer sealant film was measured using a contact-type roughness meter (ET4000AK, Kosaka Laboratory Ltd.) under the following conditions. Cutoff 0.8 mm Filter Gaussian E.length 4.000 mm S.length 0.800 mm Levelling straight line (entire area) Polarity normal Start-up Cutoff × 1 Data 8000 points

[0076] The measurement was performed in both the MD direction and the TD direction, respectively, from the side of the inorganic particle-containing layer and the side of the sealant layer. The same measurement was performed 6 times to calculate the average value, which was used as the surface roughness in the MD direction and the TD direction, respectively.

[0077] 《Production of laminate for laminated tube container》 As the base material layer, a laminate having the following layer structure was prepared: LLDPE (55 μm) / transparent LDPE (80 μm) / EAA (20 μm) / AL (12 μm) / EMAA (25 μm) / PET (12 μm) / LLDPE4 (100 μm)

[0078] The surface on the "LLDPE4 (100 μm)" side of the above base material layer and the inorganic particle-containing layer of the multilayer sealant film of Example 1 were laminated with a dry laminating adhesive to produce a laminate for a laminated tube container.

[0079] For the laminate for a laminated tube container using the multilayer sealant films of Example 2 and Comparative Example 1 instead of the multilayer sealant film of Example 1, it was produced in the same manner. Also, the laminate using the above base material layer alone is referred to as the laminated tube laminate of Comparative Example 2. In Comparative Example 2, "LLDPE4" of the base material layer was used as the sealant layer on the multilayer sealant film side.

[0080] The surface roughness on the sealant layer side of the obtained laminate for a laminated tube container was measured under the same conditions as above.

[0081] 《Evaluation》 〈Low-temperature sealability〉 Two identical laminates for a laminated tube container produced were prepared. The innermost layer of the other laminate was overlapped on the outermost layer of one laminate, and heat-sealed under the conditions of a temperature of 160 °C, a pressure of 0.3 MPa, and a seal time of 1.0 second. It was cut out to a width of 15 mm so that the heat-sealed part and the non-heat-sealed part each existed in half in the length direction. The cut-out laminate was subjected to T-peel under the conditions of a width of 15 mm, a chuck distance of 50 mm, and a tensile speed of 300 mm / min to measure the heat-seal strength. The same measurement was performed 5 times to calculate the average value, which was taken as the heat-seal strength.

[0082] 〈Workability during tube forming〉 A laminate tube was produced using the obtained laminate for a laminated tube, and the workability during tube forming was evaluated according to the following evaluation criteria. A: Processing was possible without problems. B: Processing did not proceed smoothly, and adjustment of processing conditions was required.

[0083] The configurations and evaluation results of the examples and comparative examples are shown in Table 1.

[0084] [Table 1]

[0085] It can be understood that a laminate for a laminated tube container using a multi-layer sealant film of an example, in which the sealant layer is composed of a polyethylene-based resin having a melting point of 120°C or lower and the surface roughness Ra in the TD direction of the surface on the sealant layer side is 0.2 or more, has both good low-temperature sealability and workability during tube forming.

[0086] In addition, the laminated tube containers obtained using the laminates for laminated tube containers using the multi-layer sealant films of Examples 1 and 2 had a thickness and physical strength that were practically acceptable. [Explanation of Symbols]

[0087] 10 Multi-layer sealant film 12 Inorganic particle-containing layer 14 Sealant layer 14a Surface on the sealant layer side of the multi-layer sealant film 20 Base material layer 100 Laminate for laminated tube container 200 Laminate tube container 210 Side seam part

Claims

1. A multilayer sealant film having an inorganic particle-containing layer and a sealant layer, wherein the inorganic particle-containing layer contains a thermoplastic resin and inorganic particles dispersed in the thermoplastic resin, the inorganic particles are an iron-based oxygen absorber, the sealant layer is composed of a polyethylene-based resin having a melting point of 120°C or lower, and the surface roughness Ra in the TD direction of the surface on the sealant layer side is 0.2 or more. Multilayer sealant film.

2. The multilayer sealant film according to Claim 1, wherein the ratio of D50 of the inorganic particles measured by the laser diffraction method to the thickness of the multilayer sealant film is 0.3 or more and 0.5 or less.

3. A laminate for a laminated tube container, having the multilayer sealant film according to Claim 1 or 2 and a base material layer laminated on the inorganic particle-containing layer side of the multilayer sealant film.

4. The base material layer has an inner base material sealant layer located on the outermost surface on the inorganic particle-containing layer side, and the thickness of the inner base material sealant layer is thicker than the thickness of the sealant layer of the multilayer sealant film. The laminate for a laminated tube container according to Claim 3.

5. A laminated tube container having the laminate for a laminated tube container according to Claim 3, wherein a side seam portion is formed by overlapping and heat-sealing a part of the base material layer and a part of the sealant layer, and the laminate for a laminated tube container is formed into a cylindrical shape. Laminated tube container.

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