Laminate for packaging

Abstract

To provide a new laminate for packaging which can obtain a package excellent in processing suitability and impact resistance while thinning a sealant layer.SOLUTION: As shown in Fig. 1(a), a laminate 10a for packaging has a base material resin layer 12, and a sealant layer 14, wherein the base material resin layer 12 and the sealant layer 14 are bonded to each other through a polyethylene adhesive layer 16 composed of a polyethylene-based resin, and the polyethylene adhesive layer 16 has at least a first polyethylene-based resin layer 162 and a second polyethylene-based resin layer 164 in this order from the side of the base material resin layer 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laminated body for packaging.

Background Art

[0002] For packaging liquids or viscous substances, various flexible packages have been proposed. In the field of such flexible packages, suppressing pinholes has been proposed conventionally.

[0003] In Patent Document 1, there is disclosed a laminated body for packaging, which has a first film layer, a second film layer, and an adhesive layer that adheres the first film layer and the second film layer, and the adhesive layer is composed of a reaction-curing type adhesive containing a plasticizer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides a novel laminated body for packaging that can obtain a package with good processability and impact resistance while thinning the sealant layer.

Means for Solving the Problems

[0006] 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> It has a base resin layer and a sealant layer, the base resin layer and the sealant layer are adhered via a polyethylene adhesive layer composed of a polyethylene-based resin, The polyethylene adhesive layer has at least a first polyethylene-based resin layer and a second polyethylene-based resin layer in this order from the base resin layer side, The density of the first polyethylene-based resin constituting the first polyethylene-based resin layer is 0.910 g / cm 3 or more, and The density of the second polyethylene-based resin constituting the second polyethylene-based resin layer is 0.900 g / cm 3 or less, Laminated body for packaging. <Aspect 2> It has a base resin layer and a sealant layer, The base resin layer and the sealant layer are adhered via a polyethylene adhesive layer composed of a polyethylene-based resin, The polyethylene adhesive layer has at least a first polyethylene-based resin layer and a second polyethylene-based resin layer in this order from the base resin layer side, The first polyethylene-based resin constituting the first polyethylene-based resin layer is formed into a film with a thickness of 200 μm, punched into a dumbbell shape No. 3 conforming to JIS K 6251, and using this, when a tensile test is conducted under the condition of a fulcrum distance of 20 mm, the elastic modulus of the first polyethylene-based resin is 100 MPa or more, and The second polyethylene-based resin constituting the second polyethylene-based resin layer is punched into the dumbbell shape No. 3, and when the tensile test is conducted, the elastic modulus of the second polyethylene-based resin is 50 MPa or less, Laminated body for packaging. <Aspect 3> The ratio of the thickness of the second polyethylene-based resin layer to the thickness of the first polyethylene-based resin layer is 0.2 or more and 2.5 or less, and the laminated body for packaging according to Aspect 1 or 2. <Aspect 4> The laminated body for packaging according to any one of Aspects 1 to 3, wherein the sealant layer is composed of a polyethylene-based resin. <Aspect 5> The laminated body for packaging according to any one of Aspects 1 to 4, wherein the total thickness of the polyethylene adhesive layer and the sealant layer is 55 μm or less. <Aspect 6> The packaging laminate according to any one of Aspects 1 to 5, wherein the base resin layer has an anchor coat layer on the surface on the side of the first polyethylene-based resin layer. <Aspect 7> The packaging laminate according to any one of Aspects 1 to 6, further having a reinforcing layer on the side of the base resin layer opposite to the sealant layer. <Aspect 8> The packaging laminate according to any one of Aspects 1 to 7, which is for packaging a heavy object weighing 1 kg or more. <Aspect 9> A packaging bag having the packaging laminate according to any one of Aspects 1 to 8. <Aspect 10> A packaging bag containing the content, having the packaging bag according to Aspect 9 and the content stored in the packaging bag. <Aspect 11> The first polyethylene-based resin and the second polyethylene-based resin are co-extruded between the base resin layer and the sealant layer such that the base resin layer, the first polyethylene-based resin layer, the second polyethylene-based resin layer, and the sealant layer are laminated in this order, and the base resin layer and the sealant layer are adhered by a sand lamination method through a polyethylene adhesive layer composed of the first polyethylene-based resin layer and the second polyethylene-based resin layer. A method for manufacturing the packaging laminate according to any one of Aspects 1 to 8, including the above.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a novel packaging laminate capable of obtaining a packaging with good processing suitability and impact resistance while making the sealant layer thin.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] "Laminate for Packaging" As shown in Fig. 1(a), the packaging laminate 10a of the present invention has a base resin layer 12 and a sealant layer 14, and the base resin layer 12 and the sealant layer 14 are adhered via a polyethylene adhesive layer 16 composed of a polyethylene-based resin, and the polyethylene adhesive layer 16 has at least a first polyethylene-based resin layer 162 and a second polyethylene-based resin layer 164 in this order from the side of the base resin layer 12.

[0010] In the first aspect of the packaging laminate of the present invention, the density of the first polyethylene-based resin constituting the first polyethylene-based resin layer is 0.910 g / cm 3 or more, and the density of the second polyethylene-based resin constituting the second polyethylene-based resin layer is 0.900 g / cm 3 or less.

[0011] In the second aspect of the packaging laminate of the present invention, the first polyethylene-based resin constituting the first polyethylene-based resin layer is formed into a film with a thickness of 200 μm, punched into a dumbbell-shaped No. 3 shape conforming to JIS K 6251, and using this, when a tensile test is performed under the condition of a fulcrum distance of 20 mm, the elastic modulus of the first polyethylene-based resin is 100 MPa or more, and the second polyethylene-based resin constituting the second polyethylene-based resin layer is punched into the dumbbell-shaped No. 3 shape, and when the tensile test is performed, the elastic modulus of the second polyethylene-based resin is 50 MPa or less.

[0012] In recent years, due to concerns about environmental problems, attention has been paid to reducing the use of plastics. In fact, in rigid packaging such as plastic bottles, the material has been made thinner.

[0013] On the other hand, when such thinning is simply applied to conventional flexible packaging, such as the flexible packaging described in Patent Document 1, when the package containing the contents is dropped or during transportation, tiny holes (pinholes), cracks, etc. are formed in the packaging laminate, which can cause the bag to break. This breakage is particularly noticeable when the contents are heavy, for example, weighing 1 kg or more.

[0014] In addition, depending on the configuration of the packaging laminate, a manufacturing process at a high temperature significantly higher than the melting point of the polyethylene resin, particularly lamination at 300° C. or higher, may be required. When a manufacturing process is carried out at such a high temperature, depending on the type of resin, processing defects may occur.

[0015] In response to this, the inventors have discovered that these problems can be solved by configuring the polyethylene adhesive layer to have, from the substrate resin layer side, the above-mentioned first polyethylene-based resin layer and the above-mentioned second polyethylene-based resin layer.

[0016] Without being limited by theory, it is believed that this is because the first polyethylene-based resin is relatively robust and has high resistance to high temperatures, while the second polyethylene-based resin is relatively flexible and can provide good moldability.

[0017] In the present invention, "bonded via a polyethylene adhesive layer" includes not only the case where the substrate resin layer 12 and the sealant layer 14 are both in direct contact with the polyethylene adhesive layer 16 as shown in FIG. 1(a), but also the case where an anchor coat layer 15 is present between the polyethylene adhesive layer 16 and at least one of these layers, for example the substrate resin layer 12, as shown in FIG. 1(b).

[0018] According to the present invention, the combined thickness of the polyethylene adhesive layer and the sealant layer can be 57 μm or less, 55 μm or less, or 53 μm or less.

[0019] When the laminated body for packaging of the present invention does not have a reinforcing layer, the thickness may be 20 μm or more, 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, 55 μm or more, or 60 μm or more, and may also be 125 μm or less, 120 μm or less, 110 μm or less, 100 μm or less, 90 μm or less, 80 μm or less, 75 μm or less, or 70 μm or less.

[0020] As shown in FIG. 1(c), the laminated body 10c for packaging of the present invention may have an optional reinforcing layer 18 on the side of the base resin layer 12 opposite to the sealant layer 14. The reinforcing layer may be adhered via an adhesive layer 17 separate from the polyethylene adhesive layer 16.

[0021] When the laminated body for packaging of the present invention has a reinforcing layer, the thickness may be 25 μm or more, 30 μm or more, 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, 55 μm or more, 60 μm or more, 65 μm or more, 70 μm or more, or 80 μm or more, and may also be 175 μm or less, 170 μm or less, 160 μm or less, 150 μm or less, 140 μm or less, 130 μm or less, 120 μm or less, 110 μm or less, 100 μm or less, or 90 μm or less.

[0022] Hereinafter, each component of the present invention will be described.

[0023] 〈Base resin layer〉 The base resin layer is a layer adhered to the sealant layer via an adhesive layer.

[0024] From the viewpoint of suppressing bag breakage, it is preferable that the tensile strength of the base resin layer is 150 MPa or more, 180 MPa or more, 200 MPa or more, or 230 MPa or more.

[0025] In the case of an injection molded product, for this tensile strength, the higher tensile strength among the tensile strengths in the molding direction (MD direction) and the transverse direction (TD direction) can be adopted.

[0026] As the resin having the above-mentioned tensile strength, for example, polyamide-based resins, polyester-based resins, and polypropylene-based resins can be used.

[0027] As the polyamide-based resin, for example, nylon such as Nylon (registered trademark) 6, Nylon MXD6, etc. can be used.

[0028] As the polyester-based resin, for example, polyethylene terephthalate, polybutylene terephthalate, etc. can be used.

[0029] The polypropylene-based resin is a resin containing repeating units of propylene groups in the main chain of the polymer in an amount exceeding 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more. As the polypropylene-based resin, for example, polypropylene (PP) homopolymer, random polypropylene (random PP), block polypropylene (block PP), chlorinated polypropylene, acid-modified polypropylene, and derivatives thereof, and mixtures thereof can be used.

[0030] The thickness of the base resin layer may be 5 μm or more, 10 μm or more, or 12 μm or more, and may also be 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, or 18 μm or less.

[0031] 〈Polyethylene adhesive layer〉 The polyethylene adhesive layer is an adhesive layer composed of a polyethylene-based resin, and at least contains a first polyethylene-based resin layer and a second polyethylene-based resin layer in this order from the side of the base resin layer.

[0032] The polyethylene-based resin is a resin containing, in the main chain of the polymer, repeating units of ethylene groups in an amount exceeding 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more. Examples thereof include 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, and are selected from the group consisting of these.

[0033] The thickness of the polyethylene adhesive layer, that is, the total thickness of the first polyethylene-based resin layer and the second polyethylene-based resin layer, may be 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, or 28 μm or less, and may also be 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, or 23 μm or more.

[0034] The ratio of the thickness of the second polyethylene-based resin layer to the thickness of the first polyethylene-based resin layer may be 0.2 or more and 2.5 or less. For example, it may be 0.2 or more, 0.4 or more, 0.6 or more, 0.8 or more, or 0.9 or more, and may also be 2.5 or less, 2.3 or less, 2.1 or less, 2.0 or less, 1.7 or less, 1.5 or less, 1.3 or less, or 1.1 or less.

[0035] (First polyethylene-based resin layer) The first polyethylene-based resin layer is a layer composed of the first polyethylene-based resin.

[0036] In the first aspect, the first polyethylene-based resin is a polyethylene-based resin having a density of 0.910 g / cm 3 or more. This density may be 0.913 g / cm 3 or more, 0.915 g / cm 3 or more, or 0.917 g / cm 3 or more, and may also be 0.925 g / cm 3 or less, 0.923 g / cm 3or 0.920 g / cm 3 or less.

[0037] In the second aspect, the first polyethylene-based resin is a polyethylene-based resin having an elastic modulus of 80 MPa or more when the above tensile test is performed. This elastic modulus may be 85 MPa or more, 90 MPa or more, 95 MPa or more, or 100 MPa or more, and may also be 170 MPa or less, 160 MPa or less, 150 MPa or less, 145 MPa or less, 140 MPa or less, or 135 MPa or less.

[0038] By including the polyethylene-based resin having the above physical properties in the polyethylene adhesive layer, the processability at high temperatures, particularly at temperatures of 300 °C or higher, can be improved. The processability at this temperature promotes the oxidation of the resin, thereby improving the adhesiveness when an anchor coat layer is used.

[0039] The breaking strength of the first polyethylene-based resin when the above tensile test is performed is 8 N / mm 2 or more, 10 N / mm 2 or more, 12 N / mm 2 or more, 15 N / mm 2 or more, or 18 N / mm 2 or more, and may also be 50 N / mm 2 or less, 45 N / mm 2 or less, 40 N / mm 2 or less, 38 N / mm 2 or less, 35 N / mm 2 or less, 33 N / mm 2 or less, or 30 N / mm 2 or less.

[0040] The tensile elongation of the first polyethylene-based resin when the above tensile test is performed may be 600% or more, 700% or more, 800% or more, 900% or more, 1000% or more, or 1100% or more, and may also be 2000% or less, 1900% or less, 1800% or less, 1700% or less, 1600% or less, 1500% or less, or 1400% or less.

[0041] The melt mass flow rate (MFR) of the first polyethylene resin is 3.0 g / 10 min or more, 4.0 g / 10 min or more, 5.0 g / 10 min or more, 5.5 g / 10 min or more, or 6.0 g / 10 min or more, and may be 10.0 g / 10 min or less, 9.0 g / 10 min or less, 8.0 g / 10 min or less, or 7.0 g / 10 min or less when measured in accordance with JIS K6922-1 and -2 and JIS K7210-1 under the conditions of a temperature of 190 °C and a load of 21.18 N.

[0042] The thickness of the first polyethylene resin layer may be 1 μm or more and 30 μm or less, for example, 1 μm or more, 3 μm or more, 5 μm or more, 6 μm or more, 7 μm or more, 8 μm or more, or 9 μm or more, and may be 30 μm or less, 25 μm or less, 20 μm or less, 17 μm or less, 15 μm or less, 14 μm or less, 13 μm or less, 12 μm or less, or 11 μm or less.

[0043] (Second polyethylene resin layer) The second polyethylene resin layer is a layer composed of the second polyethylene resin.

[0044] In the first aspect, the second polyethylene resin is a polyethylene resin having a density of 0.900 g / cm 3 or less. This density may be 0.895 g / cm 3 or less, or 0.890 g / cm 3 or less, and may be 0.860 g / cm 3 or more, or 0.865 g / cm 3 or more.

[0045] In the second aspect, the second polyethylene resin is a polyethylene resin having an elastic modulus of 50 MPa or less when the above tensile test is performed. This elastic modulus may be 45 MPa or less, 40 MPa or less, or 35 MPa or less, and may be 5 MPa or more, 7 MPa or more, 10 MPa or more, 15 MPa or more, or 20 MPa or more.

[0046] By incorporating the polyethylene resin having the above physical properties into the polyethylene adhesive layer, the physical strength as a sealant layer, particularly the impact resistance, can be improved.

[0047] Due to this physical strength, when packaging heavy objects, for example, heavy objects weighing 1 kg or more, it is possible to suppress bag breakage that occurs during dropping. Although not wishing to be bound by theory, this is thought to be because the above elastic modulus of the second polyethylene resin enables it to withstand the impact when dropped with the contents packaged.

[0048] The breaking strength of the second polyethylene resin when the above tensile test is performed is 8 N / mm 2 or more, 10 N / mm 2 or more, 12 N / mm 2 or more, 15 N / mm 2 or more, or 18 N / mm 2 or more, and may be 50 N / mm 2 or less, 45 N / mm 2 or less, 40 N / mm 2 or less, 38 N / mm 2 or less, 35 N / mm 2 or less, 33 N / mm 2 or less, or 30 N / mm 2 or less.

[0049] The tensile elongation of the second polyethylene resin when the above tensile test is performed may be 900% or more, 1000% or more, 1100% or more, or 1200% or more, and may also be 2000% or less, 1900% or less, 1800% or less, 1700% or less, 1600% or less, 1500% or less, or 1400% or less.

[0050] The melt mass flow rate (MFR) of the second polyethylene-based resin is 2.0 g / 10 min or more, 3.0 g / 10 min or more, 4.0 g / 10 min or more, 5.0 g / 10 min or more, 5.5 g / 10 min or more, or 6.0 g / 10 min or more, and may be 25.0 g / 10 min or less, 22.0 g / 10 min or less, 20.0 g / 10 min or less, 18.0 g / 10 min or less, 15.0 g / 10 min or less, 12.0 g / 10 min or less, 10.0 g / 10 min or less, 9.0 g / 10 min or less, 8.0 g / 10 min or less, or 7.0 g / 10 min or less when measured in accordance with JIS K6922-1 and -2 and JIS K7210-1 under the conditions of a temperature of 190 °C and a load of 21.18 N.

[0051] The thickness of the second polyethylene-based resin layer may be 1 μm or more and 30 μm or less, for example, 1 μm or more, 3 μm or more, 5 μm or more, 6 μm or more, 7 μm or more, 8 μm or more, or 9 μm or more, and may also be 30 μm or less, 25 μm or less, 20 μm or less, 17 μm or less, 15 μm or less, 14 μm or less, 13 μm or less, 12 μm or less, or 11 μm or less.

[0052] 〈Sealing layer〉 The sealing layer is a layer for heat-sealing to the opposing resin layer, for example, a layer for heat-sealing with the layers facing each other, or a layer for heat-sealing the packaging laminate to another film. This layer can be located on the content side when a packaging bag is obtained using the packaging laminate.

[0053] The resin constituting the sealing layer may be a polyethylene-based resin. As the polyethylene-based resin, those mentioned for the polyethylene adhesive layer can be used. The sealing layer may be a single-layer polyethylene film, or a polyethylene laminated film composed of multiple layers of polyethylene-based resins.

[0054] The thickness of the sealant layer may be 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 33 μm or less, 30 μm or less, or 28 μm or less, and may also be 10 μm or more, 15 μm or more, 20 μm or more, or 22 μm or more.

[0055] 〈Reinforcing layer〉 The reinforcing layer is an optional layer existing on the side of the base resin layer opposite to the sealant layer.

[0056] As the resin constituting the reinforcing layer, the resins listed for the base resin layer can be used.

[0057] The thickness of the reinforcing layer may be 5 μm or more, 10 μm or more, 12 μm or more, or 15 μm or more, and may also be 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 22 μm or less, or 20 μm or less.

[0058] 〈Other layers〉 The laminated body for packaging of the present invention may have an optional other layer. As the other layer, for example, an adhesive layer between the reinforcing layer and the base resin layer, an anchor coat layer, a barrier layer, etc. can be used.

[0059] As the above adhesive layer, for example, a dry laminate adhesive, a hot laminate adhesive, etc. can be used.

[0060] The anchor coat layer is generally a layer provided on the surface of the object to be adhered to modify this surface, thereby promoting adhesion. In particular, when laminating an anchor coat layer having a polar group on a resin layer, this anchor coat layer generally promotes the oxidation of the surface of the resin layer, thereby promoting the polar adhesion between this surface and the anchor coat layer. Therefore, it is subjected to a treatment at a high temperature, for example, a treatment at a temperature of 300 °C or more, 310 °C or more, 320 °C or more, or 330 °C or more.

[0061] In particular, in the present invention, the anchor coat layer may be present between the base resin layer and the first polyethylene-based resin layer. In particular, at the manufacturing stage, it may be laminated on the side where the first polyethylene-based resin layer of the base resin layer is provided in advance before sand lamination. In this case, the sand lamination may be performed in the above-described high-temperature environment.

[0062] As the anchor coat layer, for example, an anchor coating agent such as an aliphatic ester-based, urethane-based, polyethyleneimine-based, titanate-based, butadiene-based one can be used.

[0063] As the barrier layer, a material that can suppress the permeation of moisture, organic gas, and inorganic gas from the outside to the gas absorption layer can be used. As such a barrier layer, for example, a single metal foil layer such as a copper foil or an aluminum foil, an alloy foil layer such as a stainless steel foil, an inorganic vapor deposition film such as a silica vapor deposition film, an alumina vapor deposition film, or a silica-alumina binary vapor deposition film, or an organic coating film such as a polyvinylidene chloride coating film, a polychlorotrifluoroethylene coating film, or a polyvinylidene fluoride coating film can be used.

[0064] When an inorganic vapor deposition film or an organic coating film 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 reducing the thickness of the entire packaging laminate.

[0065] When a metal foil layer or a barrier resin layer is used as the barrier layer, the thickness of the barrier layer is preferably 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 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less from the viewpoint of reducing the thickness of the entire packaging laminate.

[0066] 《Packaging Bag》 The packaging bag of the present invention is a packaging bag having the above-described packaging laminate.

[0067] In particular, the packaging bag of the present invention includes one or more of the above-described packaging laminates, and a part of one or more packaging laminates is heat-sealed to another part of this packaging laminate or another film to form a bag shape. Here, the other film may be another packaging laminate or another film other than the packaging laminate.

[0068] The packaging bag of the present invention can be a packaging bag containing contents, having the above-described packaging bag and the contents stored in this packaging bag.

[0069] The packaging bag of the present invention may be in the form of, for example, a three-side seal bag, a four-side seal bag, a pillow bag, a gusset bag, a standing pouch, or the like.

[0070] 〈Contents〉 The contents are the contents stored in the packaging bag. The contents are not limited as long as they can be deteriorated by contact with the outside air, and examples include, in addition to drugs, foods, cosmetics, medical devices, medical equipment, electronic components, precision machinery, recording materials, and the like. Further, the drugs include, in addition to pharmaceutical preparations, detergents, agricultural chemicals, and the like.

[0071] Among them, when the contents are heavy objects, particularly heavy objects weighing 1 kg or more, generally, the packaging laminate of the present invention is beneficial because the packaging bag is likely to be broken during dropping.

[0072] 《Method for Manufacturing Packaging Laminate》 The method of the present invention for manufacturing a packaging laminate is such that a base resin layer, a first polyethylene-based resin layer, a second polyethylene-based resin layer, and a sealant layer are laminated in this order, and the first polyethylene-based resin and the second polyethylene-based resin are co-extruded between the base resin layer and the sealant layer, and The base resin layer and the sealant layer are adhered by the sand lamination method through a polyethylene adhesive layer composed of the first polyethylene resin layer and the second polyethylene resin layer. including.

[0073] 〈Coextrusion of the first polyethylene resin and the second polyethylene resin〉 As shown in FIG. 2, the coextrusion of the first polyethylene resin and the second polyethylene resin is performed between the base resin layer 12 and the sealant layer 14 so that the base resin layer 12, the first polyethylene resin layer 162, the second polyethylene resin layer 164, and the sealant layer 14 are laminated in this order. The coextrusion can be performed by a known coextrusion machine 30.

[0074] As the coextrusion machine 30, a coextrusion machine that can individually melt and knead the first polyethylene resin, that is, the polyethylene resin to be disposed on the base resin layer 12 side, and the second polyethylene resin, that is, the resin to be disposed on the sealant layer 14 side, and then combine these resins to form the first polyethylene resin layer 162 and the second polyethylene resin layer 164 and perform film formation can be used.

[0075] This coextrusion machine 30 may be a coextrusion machine capable of individually setting kneading conditions such as the melting temperature of the first and second polyethylene resins. In this case, the melting temperature of the first polyethylene resin and the melting temperature of the second polyethylene resin may be the same or different.

[0076] In particular, when an anchor coat layer is laminated on the base resin layer 12, the melting temperature of the first polyethylene resin is preferably 310 ° C or higher, 320 ° C or higher, or 330 ° C or higher from the viewpoint of oxidizing the first polyethylene resin and thereby promoting the adhesion between the first polyethylene resin layer 162 and the base resin layer 12. This melting temperature may be 360 ° C or lower, or 350 ° C or lower.

[0077] The melting temperature of the second polyethylene-based resin is preferably less than 310°C, or 305°C or less, from the viewpoint of suppressing processing defects in the second polyethylene-based resin layer 164. This melting temperature may be 250°C or higher, 260°C or higher, 270°C or higher, 280°C or higher, or 290°C or higher.

[0078] 〈Adhesion between the base resin layer and the sealant layer〉 The adhesion between the base resin layer 12 and the sealant layer 14 is performed by the sand laminating method through a polyethylene adhesive layer composed of the first polyethylene-based resin layer 162 and the second polyethylene-based resin layer 164. The sand laminating method may be performed by feeding out each layer constituting the packaging laminate in the direction indicated by the arrows in FIG. 2. More specifically, it may be performed by sandwiching the first polyethylene-based resin layer 162 and the second polyethylene-based resin layer 164 between the base resin layer 12 fed out from the roll 22 side and the sealant layer fed out from the roll 24 side. The obtained packaging laminate may be advanced in the rotational direction of the roll 24 indicated by the dotted arrow in FIG. 2 while being cooled by the roll 24, and subsequent processes such as a trimming process and a winding process may be performed.

[0079] Further, before the adhesion between the base resin layer 12 and the sealant layer 14, a step of laminating an anchor coat layer (not shown) on the side of the first polyethylene-based resin layer 162 of the base resin layer 12 that is adhered may be further included.

Examples

[0080] The present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited thereto.

[0081] 〈Example 1〉 An aliphatic ester-based anchor coat agent was applied at a coating amount of 0.5 g / m on one surface of a nylon film (Ny, thickness 15 μm, MD tensile strength 250 MPa, TD tensile strength 350 MPa) as the base resin layer. 2 and coated.

[0082] Next, between the surface coated with the anchor coating agent of this nylon film and the polyethylene film (LLDPE, Unilax LS711C, Idemitsu Unitech Co., Ltd.) as the sealant layer, the total thickness of the polyethylene adhesive layer and the sealant layer was set to 50 μm, and the first polyethylene-based resin and the second polyethylene-based resin were co-extruded in this order, and sand laminated using an extrusion laminator to adhere this nylon film and this polyethylene film via the polyethylene adhesive layer, thereby producing the laminated body for packaging of Example 1. In Example 1, a 30-μm thick LLDPE film was used. Also, in the co-extrusion, the melting temperature of the first polyethylene-based resin was set to 340°C, and the melting temperature of the second polyethylene-based resin was set to 300°C.

[0083] The first and second polyethylene-based resins constituting the polyethylene adhesive layer in Example 1 were PE1 and PE3 shown in Table 1.

[0084] Using the produced laminated body for packaging cut into 430 mm × 380 mm, heat seal was performed under the conditions of a width of 10 mm for the upper and lower seal portions and a width of 15 mm for the back seal portion, and 2 kg of water as the content was filled to produce a sufficient number of pillow bags containing the content with an outer dimension of 200 mm × 380 mm for the following evaluation. A vertical pillow machine (ONPAC-2530II, Orihiro Co., Ltd.) was used for making the pillow bags.

[0085] 〈Examples 2 to 6 and Comparative Examples 1 to 4〉 Except that the types of polyethylene-based resins used and the thicknesses of each layer were changed to those shown in Tables 1 and 2, in the same manner as in Example 1, a plurality of laminated bodies for packaging of Examples 2 to 6 and Comparative Examples 1 to 4 and pillow bags containing the content using these were produced. Note that "dry lamination" in Comparative Example 1 means that a dry lamination adhesive was used instead of the polyethylene adhesive layer.

[0086] 《Physical Properties of Resins Constituting Adhesive Layer》 Each polyethylene resin was formed into a film with a thickness of 200 μm, punched into a dumbbell-shaped No. 3 according to JIS K 6251, and a tensile test was carried out under the condition of a distance between fulcrums of 20 mm using this, thereby measuring their breaking strength, tensile elongation and elastic modulus.

[0087] For each polyethylene resin, using a melt indexer (Technoseven Co., Ltd.), under the conditions of a temperature of 190 °C and a load of 21.18 N, in accordance with JIS K6922-1 and -2 and JIS K7210-1, the melt mass flow rate (MFR) was measured.

[0088] The details of the polyethylene resins used in the examples and comparative examples are shown in Table 1.

[0089]

Table 1

[0090] What is referred to as "dry lamination" in Table 2 means that instead of sand laminating with a polyethylene adhesive layer, a two-component dry lamination adhesive (Dick Dry LX500 / KR90S, DIC Graphics Co., Ltd.) was used at a coating amount of 3.5 g / m 2 to dry laminate the base resin layer and the sealant layer.

[0091] 《Evaluation》 〈Processability〉 The appearance of the packaging laminate constituting the obtained packaging bag was visually confirmed. The evaluation criteria are as follows. A: A smooth packaging laminate was obtained. B: Ear folding of the packaging laminate and unevenness of the film were visible.

[0092] 〈Drop Test〉 Two pillow bags containing the contents obtained using the packaging laminate of Example 1 were stacked and packed in a cardboard box with inner dimensions of 293 mm × 176 mm × 118 mm, and stored for 24 hours in an environment at a temperature of 5°C. After storage, a drop test was conducted using this cardboard box containing the pillow bags. The drop test was performed 10 times (1 time at a corner, 3 times at an edge, and 6 times on a face) with different drop positions as one set, and the number of sets until the bag was torn was recorded. The same test was conducted 3 times, and the average value was calculated. The same evaluation was also performed for Examples 2 to 6 and Comparative Examples 1 to 4.

[0093] The configurations and evaluation results of the examples and comparative examples are shown in Table 2. Note that the "※" for thickness A in Table 2 means that it is equivalent in thickness. 2 It means that it is a corresponding thickness.

[0094]

Table 2

[0095] From Table 2, it can be understood that the packaging laminates of Examples 1 to 6 having a first polyethylene-based resin layer composed of a first polyethylene-based resin having a density of 0.910 g / cm 3 or more and / or an elastic modulus of 100 MPa or more, and a second polyethylene-based resin layer composed of a second polyethylene-based resin having a density of 0.900 g / cm 3 or less and / or an elastic modulus of 50 MPa or less, were good in both processing suitability and the results of the drop test.

[0096] In particular, regarding the results of the drop test, the packaging laminates of Examples 1 to 8, compared with Comparative Example 1 using a dry laminate adhesive instead of the polyethylene adhesive layer, while reducing the thickness of the sealant layer, obtained results equivalent to or better than those of Comparative Example 1.

[0097] On the other hand, the packaging laminates of Comparative Examples 2 and 3 using the above first polyethylene-based resin alone had poor results in the drop test. Also, the packaging laminate of Comparative Example 4 using the above second polyethylene-based resin alone had poor processing suitability.

Description of Symbols

[0098] 10a, 10b, 10c Laminates for Packaging 12 Base Resin Layer 14 Sealant Layer 15 Anchor Coat Layer 16 Polyethylene Adhesive Layer 162 First Polyethylene - based Resin Layer 164 Second Polyethylene - based Resin Layer 17 Adhesive Layer 18 Reinforcement Layer 22, 24 Rolls 30 Co - extruder

Claims

1. It has a base resin layer and a sealant layer, wherein the base resin layer and the sealant layer are adhered via a polyethylene adhesive layer composed of a polyethylene-based resin, the polyethylene adhesive layer has at least a first polyethylene-based resin layer and a second polyethylene-based resin layer in this order from the base resin layer side, The density of the first polyethylene-based resin constituting the first polyethylene-based resin layer is 0.910 g / cm ３ or more, and The density of the second polyethylene-based resin constituting the second polyethylene-based resin layer is 0.900 g / cm ３ or less. A laminated body for packaging.

2. It has a base resin layer and a sealant layer, wherein the base resin layer and the sealant layer are adhered via a polyethylene adhesive layer composed of a polyethylene-based resin, the polyethylene adhesive layer has at least a first polyethylene-based resin layer and a second polyethylene-based resin layer in this order from the base resin layer side, when the first polyethylene-based resin constituting the first polyethylene-based resin layer is formed into a film with a thickness of 200 μm, punched into a dumbbell shape No. 3 conforming to JIS K 6251, and a tensile test is performed under the condition of a fulcrum distance of 20 mm using this, the elastic modulus of the first polyethylene-based resin is 100 MPa or more, and when the second polyethylene-based resin constituting the second polyethylene-based resin layer is punched into the dumbbell shape No. 3 and the tensile test is performed, the elastic modulus of the second polyethylene-based resin is 50 MPa or less, A laminated body for packaging.

3. The ratio of the thickness of the second polyethylene-based resin layer to the thickness of the first polyethylene-based resin layer is 0.2 or more and 2.5 or less. The laminated body for packaging according to Claim 1 or 2.

4. The laminated body for packaging according to Claim 1 or 2, wherein the sealant layer is composed of a polyethylene-based resin.

5. The laminated body for packaging according to Claim 1 or 2, wherein the total thickness of the polyethylene adhesive layer and the sealant layer is 55 μm or less.

6. The laminated body for packaging according to Claim 1 or 2, wherein the base resin layer has an anchor coat layer on the surface on the side of the first polyethylene-based resin layer.

7. The laminated body for packaging according to Claim 1 or 2, further having a reinforcing layer on the side of the base resin layer opposite to the sealant layer.

8. It is for packaging a heavy object with a weight of 1 kg or more. The laminated body for packaging according to Claim 1 or 2.

9. A packaging bag having the laminated body for packaging according to Claim 1 or 2.

10. A packaging bag containing contents, which has the packaging bag according to claim 9 and the contents stored in the packaging bag.

11. The first polyethylene-based resin and the second polyethylene-based resin are co-extruded between the base resin layer and the sealant layer such that the base resin layer, the first polyethylene-based resin layer, the second polyethylene-based resin layer, and the sealant layer are laminated in this order, and the base resin layer and the sealant layer are adhered by a sand lamination method through a polyethylene adhesive layer composed of the first polyethylene-based resin layer and the second polyethylene-based resin layer A method for producing a packaging laminate according to claim 1 or 2, comprising the above.

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