Multilayer sealant film

Abstract

As shown in fig. 1, a multilayer sealant film 10 according to 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 that are dispersed in the thermoplastic resin, the inorganic particles are an iron-based oxygen absorbent, the sealant layer 14 is formed from a polyethylene-based resin with a melting point of 120°C or less, and the TD-direction surface roughness Ra of a surface 14a on the sealant layer 14 side is 0.2 or greater.

Description

Multi-layer sealant film

[0001] The present invention relates to a multi-layer sealant film, and more particularly to a multi-layer sealant film for laminated tube containers.

[0002] Conventionally, laminated tube containers have been manufactured by various methods. For example, a laminated sheet is manufactured, and the outermost and innermost layers at both ends are heat-sealed to form a cylindrical body. A head portion consisting of a mouth, a shoulder, and the like is then formed at one opening of the cylindrical body, and a cap is screwed onto the mouth to produce a laminated tube container. The laminated tube container manufactured in this manner can be filled with a semi-fluid content, such as toothpaste, through the open end of the cylindrical body, and the open end is hermetically sealed to form a bottom seal, thereby forming a tubular packaged product. Various embodiments of such laminated tube containers and laminates used therein have been proposed.

[0003] Patent Document 1 discloses a tubular container having an oxygen-absorbing multilayer body consisting of at least three layers, in which an inner layer containing a thermoplastic resin, an oxygen-absorbing layer made 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 material are laminated in this order, wherein 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 laminated tube containers, which includes a layer structure in which at least a sealant layer A, a substrate layer, an oxygen barrier layer, an oxygen-absorbing adhesive layer, and a sealant layer B are laminated in this order. The 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.

[0005] JP 2014-144583 A JP 2022-014238 A

[0006] The present invention provides a novel multilayer sealant film that can provide good low-temperature sealing properties and improved processability during tube formation.

[0007] After extensive investigation, the present inventors found that the above-mentioned problems could be solved by the following means, and thus completed the present invention. That is, the present invention is as follows: <Aspect 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 sealant layer is made of a polyethylene-based resin having a melting point of 120°C or less, and the surface on the sealant layer side has a surface roughness Ra in the TD direction of 0.2 or more. <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 laser diffraction to the thickness of the multilayer sealant film is 0.3 or more and 0.5 or less. <Aspect 4> A laminate for a laminated tube container, comprising the multilayer sealant film according to any one of Aspects 1 to 3, and a base layer laminated on the inorganic particle-containing layer side of the multilayer sealant film. <Aspect 5> The laminate for a laminated tube container according to Aspect 4, wherein the base layer has an inner base sealant layer located on the outermost surface on the inorganic particle-containing layer side, and the inner base sealant layer has a thickness greater than the thickness of the sealant layer of the multilayer sealant film. <Aspect 6> A laminated tube container, comprising the laminate for a laminated tube container according to Aspect 4, wherein a portion of the base layer and a portion of the sealant layer are overlapped and heat-sealed to form a side seam, thereby forming a cylindrical laminate for a laminated tube container.

[0008] According to the present invention, it is possible to provide a novel multilayer sealant film that can bring about good low-temperature sealing properties and improved processability during tube formation.

[0009] Fig. 1 is a side cross-sectional view of a multilayer sealant film of the present invention. Fig. 2 is a side cross-sectional view of a laminate for a laminated tube container of the present invention. Fig. 3(a) is a schematic side view of one embodiment of a laminated tube container of the present invention. Fig. 3(b) is a schematic cross-sectional view of one embodiment of a laminated tube container of the present invention taken along line IIIb-IIIb in Fig. 3(a). Fig. 3(c) is an enlarged view of the portion surrounded by line IIIc in Fig. 3(b).

[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, the inorganic particle-containing layer 12 contains a thermoplastic resin and inorganic particles dispersed in the thermoplastic resin, the sealant layer 14 is made of a polyethylene-based resin having a melting point of 120°C or less, and the surface roughness Ra in the TD direction of the surface 14 a 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 provide good low-temperature sealing properties and improved processability during tube formation. In particular, when the surface roughness of the sealant layer side is within the above range, laminating a substrate layer on this multilayer sealant film to form a sheet-like laminate reduces the resistance of the innermost layer of this laminate when formed into a tube, resulting in smooth film delivery during processing.

[0012] In particular, the above properties are useful when the multilayer sealant film of the present invention is used in a laminate for a laminate tube container. That is, the multilayer sealant film of the present invention may be used for a laminate 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 be 1.0 or less, 0.8 or less, 0.7 or less, or 0.6 or less.

[0014] Controlling the surface roughness Ra in the TD direction on the sealant layer side can ensure smooth film delivery during tube formation. Here, the surface roughness refers to the arithmetic mean roughness Ra measured in accordance with JIS B0601-2013. Specifically, the surface roughness refers to the value, expressed in micrometers (μm), calculated by the following formula when a reference length l is extracted from a roughness curve in the direction of the mean line, the x-axis is taken in the direction of the mean line of this extracted portion, and the y-axis is taken in the direction of the longitudinal magnification, and the roughness curve is expressed as y = f(x):

[0015]

[0016] This surface roughness can be measured using a contact type roughness meter (ET4000AK, Kosaka Laboratory Co., Ltd.) under the following conditions: Cutoff 0.8 mm Filter Gauss E. length 4.000 mm S. length 0.800 mm Leveling Linear (full area) Polarity Normal Start-up Cutoff × 1 Data 8000 points

[0017] In the present invention, the "TD direction" (Transverse Direction) means a direction perpendicular to the "MD direction" (Machine Direction), where the machine flow direction is the "MD direction."

[0018] Each component of the present invention will be described below.

[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 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 melt-mixing the components constituting this layer to obtain a composition, and extruding the composition onto a polyethylene resin film constituting the sealant layer. The inorganic particle-containing layer may be directly laminated. That is, the inorganic particle-containing layer may be directly laminated to the sealant layer, and in particular, may be fused thereto.

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

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

[0024] In this specification, a polyethylene-based resin is a resin that contains more than 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more of repeating units of ethylene groups in the main chain of the polymer, and is, for example, selected from the group consisting of 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), derivatives thereof, and mixtures thereof.

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

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

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

[0028] As the inorganic particles, for example, gas absorbents, inorganic pigments, etc. can be used.

[0029] Examples of gas absorbents that can be used include oxygen absorbers such as iron powder-based oxygen absorbers and organic gas absorbers such as hydrophobic zeolites. In particular, when the multilayer sealant film of the present invention is used in a laminated tube container, the use of iron powder-based oxygen absorbers as inorganic particles can absorb oxygen remaining in the head space of the laminated tube container, particularly in the vicinity of the end seal portion described below, thereby suppressing deterioration of the contents.

[0030] Examples of inorganic pigments that can be used include known inorganic color pigments, flaky metal pigments such as aluminum powder, and luster pigments such as pearl pigments.

[0031] The D50 of the inorganic particles measured by a laser diffraction method can be 15 μm to 50 μm, and may 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 may 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-mentioned surface roughness, it is preferable that the ratio of D50 of the inorganic particles measured by a laser diffraction method to the thickness of the multilayer sealant film is 0.30 or more and 0.50 or less. This ratio may be 0.30 or more, 0.33 or more, 0.35 or more, or 0.37 or more, and may be 0.50 or less, 0.45 or less, 0.42 or less, or 0.40 or less.

[0033] The content of inorganic particles is not particularly limited, but is preferably 15% by mass or more and 50% by mass or less, relative to the mass of the inorganic particle-containing layer, from the viewpoint of achieving both the surface roughness and moldability. This content may 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, relative to the mass of the inorganic particle-containing layer, or may 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 made of a polyethylene resin.

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

[0036] As the polyethylene-based resin, any polyethylene-based resin satisfying the melting point described above can be used among those listed for the inorganic particle-containing layer, and among them, linear low-density polyethylene is preferably used from the viewpoint of heat sealability.

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

[0038] The thickness of the sealant layer is not particularly limited, but is preferably a thickness that satisfies the ratio of the D50 of the inorganic particles to the thickness of the multilayer sealant film from the viewpoint of obtaining the above-mentioned surface roughness. 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, or may be 60 μm or less, 58 μm or less, 55 μm or less, or 53 μm or less.

[0039] <<Laminate for Laminated Tube Containers>> As shown in FIG. 2 , the laminate for laminated tubes 20 of the present invention has the above-mentioned 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 and the substrate layer of the multilayer sealant film may be bonded via an adhesive layer.

[0041] <Substrate layer> The substrate layer is generally an impermeable substrate. In particular, the substrate layer of the laminate for a laminated tube container of the present invention has a substrate sealant layer on its surface. The substrate layer may be a single layer, or may be a laminate in which multiple layers are laminated, and may include multiple layers of the same type.

[0042] The substrate layer may have, for example, an outer substrate sealant layer, a printable layer, a barrier layer, a reinforcing layer, and an inner substrate sealant layer. These layers may be laminated by any lamination means, for example, via an adhesive layer. An optional printing layer may be laminated on the printable layer. In particular, when the inorganic particles are iron powder-based oxygen absorbers, the oxygen permeability of the substrate layer may be lower 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 substrate layer, for example, a substrate having the following layer structure can be used: LDPE (75 μm) / milky white LDPE (160 μm) / LDPE (50 μm) / PET (12 μm) / LLDPE (100 μm) LLDPE (55 μm) / transparent LDPE (80 μm) / EAA (20 μm) / AL (12 μm) / EMAA (25 μm) / PET (12 μm) / LLDPE (100 μm)

[0044] (Outer substrate sealant layer) The outer substrate sealant layer is a sealant layer located on the outermost surface of the substrate layer opposite the inorganic particle-containing layer. When a laminated tubular container is obtained using the laminate for laminated tubular containers of the present invention, the outer substrate sealant layer can be a layer that is heat-sealed to the sealant layer of the multilayer sealant film.

[0045] The outer substrate sealant layer may be made of the polyethylene resins listed as examples of the sealant layer of the multilayer sealant film.

[0046] (Printable Layer) The printable layer is not particularly limited as long as it is a layer that is impermeable to such an extent that the printing layer can be printed thereon, and may be, for example, a resin layer.

[0047] The printable layer may be made of a thermoplastic resin, such as a polyolefin resin, a vinyl polymer, a polyester resin, or a polyamide resin, either singly or in combination. Such a thermoplastic resin may be used in the form of a film or an extruded resin. The film may be either a stretched film or a non-stretched film.

[0048] As the polyolefin resin, for example, a polyethylene resin or a polypropylene resin can be used. For specific details, the description of the inorganic particle-containing layer can be referred to.

[0049] An example of the vinyl polymer is polyvinyl chloride (PVC).

[0050] Examples of polyester resins include polyethylene terephthalate (PET) and polybutylene terephthalate.

[0051] Examples of polyamide resins include nylons 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, or the like can be used.

[0053] Examples of inorganic vapor-deposited layers that can be used include silica vapor-deposited films, aluminum vapor-deposited films, alumina vapor-deposited films, and silica-alumina vapor-deposited films.

[0054] As the metal foil layer, for example, a single metal foil such as aluminum foil, copper foil, or titanium foil, or an alloy foil such as aluminum alloy foil or 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, 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 from the viewpoint of ensuring strength and barrier properties, and is preferably 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less from the viewpoint of improving handleability as a laminate for a tube.

[0057] When a metal foil layer is used as the barrier layer, 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 from the viewpoint of ensuring strength and barrier properties, and 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 from the viewpoint of improving handleability as a laminate for a tube.

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

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

[0060] When the reinforcing layer is composed of a stretched film, the stretched film constituting the reinforcing layer may be a stretched film obtained by, for example, 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 simultaneous biaxially stretched film, or may be a stretched film obtained by performing these stretching operations multiple 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 restorability over time to the laminated tube container, whereas 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 short-term shape retention and not excessively increasing the total thickness of the laminate for a laminated tube container.

[0062] (Inner substrate sealant layer) The inner substrate sealant layer is a layer located on the inorganic particle-containing layer side of the multilayer sealant film, i.e., on the outermost surface of the substrate layer opposite the substrate sealant layer. The resin constituting the inner substrate sealant layer can be the polyethylene-based resin listed for the outer substrate sealant layer.

[0063] The thickness of the inner substrate 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 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 iron powder-based oxygen absorbers, it is preferable that the thickness of the inner substrate sealant layer be 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 substrate layer and the inorganic particle-containing layer of the multilayer sealant film, and optionally between each layer that constitutes the substrate layer, thereby bonding them to each other.

[0066] The adhesive layer may be made of, for example, a dry laminating adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent laminating adhesive, or a thermoplastic resin for extrusion laminating. Among these, it is preferable to use a dry laminating adhesive, particularly a two-component curing dry laminating adhesive.

[0067] 2, a laminated tube container 200 of the present invention has the laminated tube container laminate 100. A portion of the sealant layer 14 of the multilayer sealant film and a portion of the base sealant layer (not shown) of the base layer 20 are overlapped and heat-sealed to form a side seam portion 210, thereby forming the laminated tube laminate 100 into a cylindrical shape.

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

[0069] Laminated tube containers can be filled with contents such as medicines, cosmetics, and food, including toothpaste, moisturizing cream, and sunscreen.

[0070] A laminated tube container can be produced, for example, by a method including the following steps: a step of rolling up a laminated tube laminate so that the base material, particularly the sealant layer of the base material, is on the inside, and overlapping and heat-sealing the ends of the laminate to form a side seam portion to obtain a body portion; and a step of joining a head portion having a shoulder portion and a cap portion to the periphery of the opening of the body portion to obtain a laminated tube container.

[0071] The present invention will be specifically explained with reference to examples and comparative examples, but the present invention is not limited to these.

[0072] <<Preparation of Multilayer Sealant Film>> <Example 1> A linear low-density polyethylene (LLDPE) film (density 0.920 g / cm 3) was used as a sealant layer. ３ The resin composition for an oxygen absorbing layer (thickness: 30 μm) as an inorganic particle-containing layer was extrusion laminated onto LLDPE (1), melting point: 113° C., thickness: 50 μm, to prepare the multilayer sealant film of Example 1.

[0073] The resin composition for the oxygen absorbing layer was prepared by dispersing an iron-based oxygen absorber (D50: 30 μm) in a polyethylene resin so that the content of the iron-based oxygen absorber (D50: 30 μm) was 25 to 30% by mass relative to the mass of the oxygen absorbing layer.

[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 the sealant layers used were those shown in Table 1. 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 prepared multilayer sealant film was measured using a contact roughness meter (ET4000AK, Kosaka Laboratory Co., Ltd.) under the following conditions: Cutoff 0.8 mm Filter Gauss E. length 4.000 mm S. length 0.800 mm Leveling Linear (full area) Polarity Normal Start-up Cutoff × 1 Data 8000 points

[0076] The measurements were carried out from the inorganic particle-containing layer side and the sealant layer side in both the MD and TD directions. The same measurements were carried out six times, and the average values ​​were calculated to determine the surface roughness in the MD and TD directions, respectively.

[0077] <<Preparation of Laminated Tube Container Laminate>> A laminate having the following layer structure was prepared as a substrate layer: LLDPE (55 μm) / transparent LDPE (80 μm) / EAA (20 μm) / AL (12 μm) / EMAA (25 μm) / PET (12 μm) / LLDPE4 (100 μm)

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

[0079] Laminates for laminated tube containers were also produced in the same manner, using the multilayer sealant films of Example 2 and Comparative Example 1 instead of the multilayer sealant film of Example 1. A laminate using the above-mentioned substrate layer alone is referred to as the laminated tube laminate of Comparative Example 2. In Comparative Example 2, the substrate layer "LLDPE4" was used as the sealant layer on the multilayer sealant film side.

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

[0081] Evaluation Low-Temperature Sealability Two identical laminated tube container laminates were prepared, and the innermost layer of one laminate was placed on the outermost layer of the other laminate. These were heat-sealed at a temperature of 160°C, a pressure of 0.3 MPa, and a sealing time of 1.0 second. The laminates were then cut into 15 mm wide strips so that half of the strips were heat-sealed and half were not. The cut laminates were subjected to T-peel testing at a width of 15 mm, a chuck distance of 50 mm, and a pulling speed of 300 mm / min, to measure the heat-seal strength. The same measurement was repeated five times, and the average value was calculated to determine the heat-seal strength.

[0082] <Processability during tube molding> A tube was produced using the obtained laminate for a laminate tube, and the processability during tube molding was evaluated according to the following criteria: A: Processing was possible without any problems. B: Processing did not proceed smoothly, and adjustment of processing conditions was required.

[0083] Table 1 shows the configurations and evaluation results of the examples and comparative examples.

[0084]

[0085] It can be seen that the laminate for a laminated tube container using the multilayer sealant film of the example, in which the sealant layer is made of a polyethylene-based resin with a melting point of 120°C or less and the surface roughness in the TD direction on the surface on the sealant layer side is 0.2 or more, has both good low-temperature sealing properties and processability during tube molding.

[0086] Furthermore, the laminated tube containers obtained using the laminated bodies for laminated tube containers using the multilayer sealant films of Examples 1 and 2 had thicknesses and physical strengths that were practically acceptable.

[0087] REFERENCE SIGNS LIST 10 Multilayer sealant film 12 Inorganic particle-containing layer 14 Sealant layer 14a Surface of multilayer sealant film on sealant layer side 20 Base layer 100 Laminate for laminated tube container 200 Laminated tube container 210 Side seam portion

Claims

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

2. The multilayer sealant film according to claim 1, wherein the ratio of D50 of the inorganic particles measured by a 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 laminated tube containers, comprising the multilayer sealant film according to claim 1 or 2, and a base layer laminated on the inorganic particle-containing layer side of the multilayer sealant film.

4. A laminate for laminated tube containers as described in claim 3, wherein the base material layer has an inner base material sealant layer located on the outermost surface side of the inorganic particle-containing layer, and the thickness of the inner base material sealant layer is greater than the thickness of the sealant layer of the multilayer sealant film.

5. A laminated tube container comprising the laminate for laminated tube containers according to claim 3, wherein 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, thereby forming the laminate for laminated tube containers into a cylindrical shape.

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