JP2019189334A - Polyethylene laminate for packaging material and packaging material including the laminate - Google Patents

Abstract

To provide a polyethylene laminate for a packaging material that can remarkably reduce load on an environment and has high-printability and strength.SOLUTION: A polyethylene laminate for a packaging material includes at least a stretched polyethylene film, an adhesion layer and a heat-sealing polyethylene layer. An image is formed on at least one surface of the stretched polyethylene film by a flexographic printing method. The adhesion layer includes solventless type adhesive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polyethylene laminate for packaging material and a packaging material comprising the laminate.

  Polyethylene films have moderate flexibility, are excellent in transparency, moisture resistance, chemical resistance, and the like, and are inexpensive, and thus are used in various packaging materials. Although the melting point of polyethylene is somewhat different depending on the type, it is generally about 100 to 140 ° C., and therefore it is generally used as a heat-sealable film in the packaging material field.

On the other hand, since the polyethylene film is inferior in rigidity as compared with other thermoplastic resin films, the printability is low, and it is difficult to form a clear image on the surface. Moreover, the polyethylene film did not have a strength that can satisfy the durability required as an outer packaging material.
Therefore, a laminate is made by laminating a resin film with excellent rigidity and strength, such as a polyester film or nylon film, and a polyethylene film, and the end of the laminate is heat sealed so that the polyethylene film side of this laminate is inside. Thus, a packaging material is produced (for example, JP-A-2005-104525).

  By the way, in recent years, with the increasing demand for the construction of a recycling society, attempts have been made to recycle and use packaging materials. However, when different types of resin films as described above are bonded together, it is difficult to separate the resin films from each other, which is not suitable for recycling, and there is a demand for using a packaging material with less environmental load.

JP 2005-104525 A

  The present invention has been made to solve the above-mentioned problems, and provides a polyethylene laminate for packaging materials that can significantly reduce the environmental burden and has high printability and strength. This is a problem to be solved.

  The polyethylene laminate for packaging materials of the present invention comprises at least a stretched polyethylene film, an adhesive layer, and a heat-sealable polyethylene layer, and an image is formed on at least one surface of the stretched polyethylene film by a flexographic printing method. The adhesive layer contains a solventless adhesive.

  In one embodiment, the stretched polyethylene film comprises at least one of high density polyethylene (HDPE) and medium density polyethylene (MDPE).

  In one embodiment, the stretch ratio in the longitudinal direction (MD) of the stretched polyethylene film is 2 times or more and 10 times or less.

  In one embodiment, the stretched polyethylene film is a biaxially stretched film.

  In one embodiment, the stretched polyethylene film has a thickness of 9 μm or more and 50 μm or less.

  In one embodiment, the stretched polyethylene film has a configuration of high density polyethylene layer / medium density polyethylene layer / high density polyethylene layer.

  In one embodiment, the thickness ratio between the high density polyethylene layer and the medium density polyethylene layer is 1/10 or more and 1/1 or less.

  In one embodiment, the stretched polyethylene film is produced by an inflation molding method.

  In one embodiment, the heat sealable polyethylene layer comprises at least one of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE).

  The packaging material of the present invention is composed of the above laminate.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to reduce a load to an environment remarkably, the polyethylene laminated body for packaging materials which has high printability and intensity | strength can be provided.

It is a section schematic diagram showing one embodiment of the polyethylene layered product for packing materials by the present invention. It is a section schematic diagram showing one embodiment of the polyethylene layered product for packing materials by the present invention.

<Polyethylene laminate for packaging materials>
A polyethylene laminate for packaging material according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the polyethylene laminate 10 for packaging material includes at least a stretched polyethylene film 20, an adhesive layer 30, and a heat-sealable polyethylene layer 40.
Moreover, in one Embodiment, the polyethylene layer 50 provided with a vapor deposition film is provided between the stretched polyethylene film 20 and the heat-sealable polyethylene layer 40.
Hereinafter, each layer with which the polyethylene laminated body for packaging materials is provided is demonstrated.

<Stretched polyethylene film>
The stretched polyethylene film may be uniaxially stretched or biaxially stretched, but from the viewpoint of strength, a biaxially stretched film is preferred.

The stretching ratio in the longitudinal direction of the stretched polyethylene film (MD) is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less. Thereby, the printability and strength of the polyethylene laminate can be further improved. Thereby, the transparency of the stretched polyethylene film can be improved.
The stretching ratio in the transverse direction (TD) is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less. Thereby, the printability and strength of the polyethylene laminate can be further improved. Thereby, the transparency of the stretched polyethylene film can be improved.

Examples of the polyethylene contained in the stretched polyethylene film include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Moreover, the stretched polyethylene film can contain 2 or more types of these.
Among these, high-density polyethylene (HDPE) and medium-density polyethylene (MDPE) are preferable from the viewpoint of printability, strength, heat resistance, and appropriate stretching of the polyethylene laminate, and medium-density polyethylene is more preferable from the viewpoint of appropriate stretching. .
In the present invention, high density polyethylene has a density of 0.945 g / cm ³ or more, medium density polyethylene has a density of 0.925 to 0.944 g / cm ³ , and low density polyethylene has a density of 0. .Less than 925 g / cm ³

  The above-described polyethylene having different density and branching can be obtained by appropriately selecting the polymerization method. For example, as a polymerization catalyst, using a multi-site catalyst such as a Ziegler-Natta catalyst or a single site catalyst such as a metallocene catalyst, any one of gas phase polymerization, slurry polymerization, solution polymerization, and high-pressure ion polymerization may be used. It is preferable to carry out in one stage or two or more stages.

  The above single-site catalyst is a catalyst that can form a uniform active species, and is usually adjusted by bringing a metallocene transition metal compound or a nonmetallocene transition metal compound into contact with an activation cocatalyst. . The single site catalyst is preferable because the active site structure is uniform as compared with the multisite catalyst, and a polymer having a high molecular weight and a high degree of uniformity can be polymerized. As the single site catalyst, it is particularly preferable to use a metallocene catalyst. The metallocene-based catalyst is a catalyst containing a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, and if necessary, an organometallic compound, and each catalyst component of the support. is there.

  In the group IV transition metal compound containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, or the like. . Examples of substituted cyclopentadienyl groups include hydrocarbon groups having 1 to 30 carbon atoms, silyl groups, silyl substituted alkyl groups, silyl substituted aryl groups, cyano groups, cyanoalkyl groups, cyanoaryl groups, halogen groups, haloalkyl groups, halosilyl groups. It has at least one kind of substituent selected from a group and the like. The substituted cyclopentadienyl group may have two or more substituents, and the substituents are bonded to each other to form a ring, and an indenyl ring, a fluorenyl ring, an azulenyl ring, a hydrogenated product thereof, etc. It may be formed. Rings formed by bonding substituents to each other may further have substituents.

  In the group IV transition metal compound containing a ligand having a cyclopentadienyl skeleton, examples of the transition metal include zirconium, titanium, hafnium, and zirconium and hafnium are particularly preferable. The transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and each ligand having a cyclopentadienyl skeleton is preferably bonded to each other via a bridging group. Examples of the crosslinking group include C1-C4 alkylene groups, silylene groups, dialkylsilylene groups, substituted arylene groups such as diarylsilylene groups, and substituted germylene groups such as dialkylgermylene groups and diarylgermylene groups. Preferably, it is a substituted silylene group. The transition metal compound of Group IV of the Periodic Table containing a ligand having the above cyclopentadienyl skeleton can use one or a mixture of two or more as a catalyst component.

  The co-catalyst refers to a catalyst that can effectively make the transition metal compound of Group IV of the periodic table as a polymerization catalyst, or can neutralize ionic charges in a catalytically activated state. Co-catalysts include benzene-soluble aluminoxanes of organoaluminum oxy compounds, benzene-insoluble organoaluminum oxy compounds, ion-exchange layered silicates, boron compounds, active hydrogen group-containing or non-containing cations and non-coordinating anions. Ionic compounds, lanthanoid salts such as lanthanum oxide, tin oxide, phenoxy compounds containing a fluoro group, and the like.

The group IV transition metal compound containing a ligand having a cyclopentadienyl skeleton may be used by being supported on an inorganic or organic compound carrier. The support is preferably a porous oxide of an inorganic or organic compound. Specifically, an ion-exchange layered silicate such as montmorillonite, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO ₂ or the like, or a mixture thereof. Furthermore, examples of the organometallic compound used as necessary include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organic aluminum is preferably used.

  In addition, a copolymer of ethylene and another monomer can be used as long as the characteristics of the present invention are not impaired. Examples of the ethylene copolymer include a copolymer composed of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, 3-methyl-1-butene, 4-methyl-1-pentene, 6-methyl- Examples include 1-heptene. Moreover, as long as the objective of this invention is not impaired, a copolymer with vinyl acetate, an acrylic ester, etc. may be sufficient.

  In the present invention, biomass-derived ethylene may be used in place of ethylene obtained from fossil fuel as a raw material for obtaining the high-density polyethylene and the like. Since such biomass-derived polyethylene is a carbon-neutral material, it can be made into a packaging material with even less environmental impact. Such polyethylene derived from biomass can be produced, for example, by a method described in JP2013-177531A. Moreover, you may use the biomass-derived polyethylene (For example, green PE etc. which are marketed from a Braschem company) marketed.

  The polyethylene content in the stretched polyethylene film is preferably 50% by mass or more, and more preferably 70% by mass or more.

  The stretched polyethylene film can contain additives as long as the properties of the present invention are not impaired. For example, a cross-linking agent, an antioxidant, an antiblocking agent, a slipping agent, an ultraviolet absorber, a light stabilizer, Examples thereof include fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

In one embodiment, the stretched polyethylene film has a multilayer structure. Preferably, it comprises a layer comprising high density polyethylene (HDPE) and a layer comprising medium density polyethylene (MDPE).
For example, it has a configuration consisting of a high density polyethylene layer / medium density polyethylene layer / high density polyethylene layer. By setting it as such a structure, the printability and intensity | strength of a polyethylene laminated body can be improved more. At this time, the thickness ratio between the high-density polyethylene layer and the medium-density polyethylene layer is preferably 1/10 or more and 1/1 or less, more preferably 1/5 or more and 1/2 or less. preferable.

  The thickness of the stretched polyethylene film is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 30 μm or less. By setting the thickness of the stretched polyethylene film within the above numerical range, the printability, strength, and heat resistance of the polyethylene laminate can be further improved.

In one embodiment, the stretched polyethylene film has an inorganic oxide such as a metal such as aluminum, aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide on one surface. A vapor deposition film containing an object is provided. Thereby, the gas barrier property of the polyethylene laminated body by this invention can be improved.
As a vapor deposition method, a conventionally known method can be adopted. For example, a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum vapor deposition method, a sputtering method, an ion plating method, or a plasma chemical vapor deposition method. And chemical vapor deposition (chemical vapor deposition, CVD) such as thermal chemical vapor deposition and photochemical vapor deposition.

  Further, the thickness of the deposited film is preferably 0.002 μm or more and 0.4 μm or less, and more preferably 0.005 μm or more and 0.1 μm or less. By setting the thickness of the vapor deposition film within the above numerical range, it is possible to prevent the occurrence of cracks and the like in the vapor deposition film while maintaining gas barrier properties.

  In addition, for example, a composite film composed of two or more vapor-deposited films of different kinds of inorganic oxides can be formed by using both physical vapor deposition and chemical vapor deposition. The degree of vacuum in the vapor deposition chamber is preferably about 10-2 to 10-8 mbar, particularly about 10-3 to 10-7 mbar before introducing oxygen, and about 10-1 to 10-6 mbar after introducing oxygen. In particular, about 10-2 to 10-5 mbar is preferable. The amount of oxygen introduced varies depending on the size of the vapor deposition machine. For the oxygen to be introduced, an inert gas such as argon gas, helium gas, nitrogen gas or the like may be used as a carrier gas within a range where there is no problem. As a conveyance speed of a film, about 10-800 m / min, especially about 50-600 m / min are preferable.

The stretched polyethylene film is characterized in that an image is formed on at least one surface by a flexographic printing method. By performing image formation by the flexographic printing method, the burden on the environment can be reduced.
The formed image is not particularly limited, and characters, patterns, symbols, and the like may be formed.
In addition, since it is possible to prevent deterioration of the image over time, it is preferable to form an image on the side of the stretched polyethylene film on which the heat-sealable polyethylene layer is laminated.

  The stretched polyethylene film can be obtained by melting a resin material containing polyethylene, forming the film by a melt extrusion molding method such as an inflation molding method or a T-die molding method, and then stretching. Since the stretching process can be performed more easily, it is preferable to produce the film by an inflation molding method. A stretched polyethylene film having a multilayer structure can be produced by melt coextrusion of a plurality of resin materials.

  The melt flow rate (MFR) of the resin material is preferably 0.5 g / 10 min or more and 20 g / 10 min or less, and more preferably 0.8 g / 10 min or more and 5 g / 10 min or less. By setting the MFR of the resin material within the above numerical range, the stretching process can be performed more easily.

<Adhesive layer>
The polyethylene laminated body for packaging materials of this invention is equipped with the contact bonding layer containing a solventless type adhesive agent between a stretched polyethylene film and a heat-sealable polyethylene layer.
Moreover, when the polyethylene laminated body for packaging materials of this invention is equipped with the polyethylene layer provided with a vapor deposition film, between the stretched polyethylene film and the polyethylene layer provided with a vapor deposition film, the polyethylene layer provided with a vapor deposition film, and heat-sealability The adhesive layer is provided between the polyethylene layer.
The adhesive layer with which the polyethylene laminated body for packaging materials of this invention is equipped contains a solvent-free-type adhesive agent, and can reduce the load to an environment.

  Examples of the adhesive include a polyvinyl acetate adhesive, a polyacrylate adhesive, a cyanoacrylate adhesive, an ethylene copolymer adhesive, a cellulose adhesive, a polyester adhesive, and a polyether adhesive. , Polyamide adhesives, polyimide adhesives, amino resin adhesives, phenol resin adhesives, epoxy adhesives, urethane adhesives, rubber adhesives, and silicone adhesives.

  The thickness of the adhesive layer is not particularly limited, but can be 0.5 μm or more and 5 μm or less.

<Heat-sealable polyethylene layer>
The heat-sealable polyethylene layer is composed of at least one of high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), a copolymer of ethylene and other monomers. Contains one. Among these, from the viewpoint of heat sealability, low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) are preferable. From the viewpoint of environmental load, these polyethylenes are preferably derived from biomass.

  The polyethylene content in the heat-sealable polyethylene layer is preferably 50% by mass or more, and more preferably 70% by mass or more.

  The heat-sealable polyethylene layer can contain additives as long as the properties of the present invention are not impaired, for example, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, and an antistatic agent. Agents, pigments, modifying resins and the like.

  The thickness of the heat-sealable polyethylene layer is preferably 20 μm or more and 200 μm or less, and more preferably 30 μm or more and 150 μm or less. By setting the thickness of the heat-sealable polyethylene layer within the above numerical range, the heat-sealability can be improved.

  The heat-sealable polyethylene layer is produced by forming a polyethylene film by forming a resin material containing polyethylene by a melt extrusion molding method such as inflation molding or T-die molding, and this is stretched polyethylene film through an adhesive layer. Or it can form by laminating | stacking on a polyethylene layer provided with a vapor deposition film.

<Polyethylene layer with a deposited film>
In one embodiment, the polyethylene laminate according to the present invention includes a polyethylene layer including a deposited film between a stretched polyethylene film and a heat-sealable polyethylene layer. Thereby, the gas barrier property of the polyethylene laminated body by this invention can be improved.

  The polyethylene layer provided with the vapor deposition film may be composed of a stretched film or an unstretched film, but from the viewpoint of printability, strength and heat resistance of the polyethylene laminate. It is preferable that it has been stretched. Further, it may be uniaxially stretched or biaxially stretched, but from the viewpoint of strength, it is preferably biaxially stretched.

  The polyethylene layer with the deposited film is made of high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), a copolymer of ethylene and other monomers. Including at least one. Among these, high-density polyethylene (HDPE) and medium-density polyethylene (MDPE) are preferable, and high-density polyethylene (HDPE) is more preferable from the viewpoints of printability, strength, and heat resistance. From the viewpoint of environmental load, these polyethylenes are preferably derived from biomass.

  The polyethylene content in the polyethylene layer provided with the vapor deposition film is preferably 50% by mass or more, and more preferably 70% by mass or more.

  The polyethylene layer provided with the vapor deposition film can contain an additive as long as the properties of the present invention are not impaired, for example, a crosslinking agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, a charging agent. Examples thereof include an inhibitor, a pigment, and a modifying resin.

The thickness of the polyethylene layer provided with the deposited film is preferably 9 μm or more and 50 μm or less, and more preferably 12 μm or more and 30 μm or less from the viewpoint of productivity and economy.
The thickness of the deposited film is preferably 0.002 μm or more and 0.4 μm or less, and more preferably 0.005 μm or more and 0.1 μm or less. By setting the thickness of the vapor deposition film within the above numerical range, it is possible to prevent the occurrence of cracks and the like in the vapor deposition film while maintaining gas barrier properties.

  As for the polyethylene layer provided with a vapor deposition film, the image may be formed in the surface. The image forming method is as described above.

  The polyethylene layer having a deposited film is a polyethylene film formed by forming a resin material containing polyethylene by a melt extrusion molding method such as inflation molding or T-die molding, and the above-mentioned film is formed on at least one surface of the polyethylene film. After forming the vapor deposition film by the above method, it can be formed by laminating on the stretched polyethylene film via the adhesive layer. In this case, the polyethylene film may be stretched before vapor deposition and before lamination.

<Packaging materials>
In one embodiment, the packaging material according to the present invention can be manufactured by folding in two so that the heat-sealable polyethylene layer of the polyethylene laminate is on the inside, and heat-sealing the ends thereof. it can.
Moreover, two polyethylene laminated bodies can be manufactured by superimposing the heat-sealable polyethylene layers so as to face each other and heat-sealing the end portions.
Depending on the sealing method, for example, side seal type, two-side seal type, three-side seal type, four-side seal type, envelope-attached seal type, palm-attached seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal Various forms of packaging materials can be manufactured by heat sealing using a heat sealing form such as a mold, a gusset mold, and the like.
In addition, for example, a self-supporting packaging bag (standing pouch) is also possible. As a heat sealing method, for example, a known method such as a bar seal, a rotary roll seal, a belt seal, an impulse seal, a high frequency seal, or an ultrasonic seal can be used.

  Even if the polyethylene laminate according to the present invention is a laminate comprising only one kind of resin (ie, polyethylene), the stretched polyethylene film satisfies the strength and printability required as the outer film of the packaging material, and the heat-sealable polyethylene layer Enables packaging. Therefore, it is extremely suitable as a material constituting a packaging material requiring recyclability.

  Examples The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<Example 1>
Medium density polyethylene (density: 0.941 g / cm ³ , melting point 129 ° C., MFR: 1.3 g / 10 min, manufactured by Dowchemical, trade name: Elite 5538G) is formed by an inflation molding method, and a polyethylene film having a thickness of 100 μm Got.
This polyethylene film was stretched in the longitudinal direction (MD) at a stretch ratio of 5 times to obtain a stretched polyethylene film having a thickness of 20 μm.

  Two-component curing solvent-free polyester adhesive (Lock It laminated | stacked through the paint Co., Ltd. make, brand name RN-920 / HN: 920), and the polyethylene laminated body was obtained.

<Example 2>
High density polyethylene (density: 0.961 g / cm ³ , melting point 135 ° C., MFR: 0.7 g / 10 min, manufactured by ExxonMobil, trade name: HTA108) and medium density polyethylene (density: 0.941 g / cm ³ , melting point) 129 ° C., MFR: 1.3 g / 10 min, manufactured by Dowchemical, trade name: Elite 5538G) by an inflation molding method to form a polyethylene film comprising a high density polyethylene layer / medium density polyethylene layer / high density polyethylene layer Produced. The thickness of the high density polyethylene layer was 20 μm, and the thickness of the medium density polyethylene layer was 60 μm.
This polyethylene film was stretched in the longitudinal direction (MD) at a stretch ratio of 5 times to obtain a stretched polyethylene film having a thickness of 20 μm.

  Two-component curing solvent-free polyester adhesive (Lock It laminated | stacked through the paint Co., Ltd. make, brand name RN-920 / HN: 920), and the polyethylene laminated body was obtained.

<Example 3>
Medium density polyethylene (density: 0.941 g / cm ³ , melting point 129 ° C., MFR: 1.3 g / 10 min, manufactured by Dowchemical, trade name: Elite 5538G) is formed by an inflation molding method, and a polyethylene film having a thickness of 100 μm Got.
This polyethylene film was stretched in the longitudinal direction (MD) and the width direction (TD) at a stretching ratio of 2.24 times to obtain a stretched polyethylene film having a thickness of 20 μm.
A two-component curable solventless polyester adhesive (locked) comprising the stretched polyethylene film and an unstretched linear low-density polyethylene (LLDPE) film (product name: L6100, manufactured by Toyobo Co., Ltd.) having a thickness of 40 μm. It laminated | stacked through the paint Co., Ltd. make, brand name RN-920 / HN: 920), and the polyethylene laminated body was obtained.

<Comparative Example 1>
Medium density polyethylene (density: 0.941 g / cm ³ , melting point 129 ° C., MFR: 1.3 g / 10 min, manufactured by Dowchemical, trade name: Elite 5538G) is formed by an inflation molding method, and a polyethylene film having a thickness of 20 μm Got.

  The above-mentioned polyethylene film and an unstretched linear low-density polyethylene (LLDPE) film (product name: L6100, manufactured by Toyobo Co., Ltd.) having a thickness of 40 μm are two-component curing solventless polyester adhesive (lock paint) It laminated | stacked through Co., Ltd. make, brand name RN-920 / HN: 920, and the polyethylene laminated body was obtained.

<Comparative example 2>
High density polyethylene (density: 0.961 g / cm ³ , melting point 135 ° C., MFR: 0.7 g / 10 min, manufactured by ExxonMobil, trade name: HTA108) and medium density polyethylene (density: 0.941 g / cm ³ , melting point) 129 ° C., MFR: 1.3 g / 10 min, manufactured by Dowchemical, trade name: Elite 5538G) by an inflation molding method to form a polyethylene film comprising a high density polyethylene layer / medium density polyethylene layer / high density polyethylene layer Produced. The thickness of the high density polyethylene layer was 4 μm, and the thickness of the medium density polyethylene layer was 12 μm.

  The above-mentioned polyethylene film and an unstretched linear low-density polyethylene (LLDPE) film (product name: L6100, manufactured by Toyobo Co., Ltd.) having a thickness of 40 μm are two-component curing solventless polyester adhesive (lock paint) It laminated | stacked through Co., Ltd. product, brand name RN-920 / HN: 920), and the polyethylene laminated body was obtained.

<Printability evaluation>
An image was formed on one surface of the stretched polyethylene film and the polyethylene film prepared in the above Examples and Comparative Examples by using a flexographic printing method using a water-based flexographic ink (manufactured by Toyo Ink Co., Ltd., trade name: Aquariona). . The formed image was observed visually, and the printability of the stretched polyethylene film and the polyethylene film was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: The dimensional stability at the time of printing was good, and a good image free from rubbing and bleeding could be formed.
X: Stretching / shrinkage of the film occurred during printing, and the formed image was rubbed or smeared.

<Rigidity evaluation>
The stretched polyethylene film and the polyethylene film prepared in the above Examples and Comparative Examples were used as test pieces having a width of 15 mm, and the rigidity was measured with a loop stiffness measurement tester (trade name: Loop Stiffness Tester, manufactured by Toyo Seiki Seisakusho). The loop length was 60 mm. The measurement results are summarized in Table 1.

<Strength evaluation>
The stretched polyethylene film and the polyethylene film prepared in the above examples and comparative examples were used as 10 mm wide dumbbell-type test pieces. The tensile strength in the MD direction of this test piece was measured with a tensile tester (Orientec Co., Ltd., RTC-1310A). The distance between chucks was 10 mm, and the pulling speed was 300 mm / min. The measurement results are summarized in Table 1.

10: polyethylene laminate for packaging material, 20: stretched polyethylene film, 30: adhesive layer,
40: heat-sealable polyethylene layer, 50: polyethylene layer provided with a deposited film

Claims (10)

It comprises at least a stretched polyethylene film, an adhesive layer, and a heat-sealable polyethylene layer,
An image is formed by flexographic printing on at least one surface of the stretched polyethylene film,
The polyethylene laminate for packaging materials, wherein the adhesive layer contains a solventless adhesive.   The polyethylene laminate for packaging materials according to claim 1, wherein the stretched polyethylene film contains at least one of high density polyethylene (HDPE) and medium density polyethylene (MDPE).   The polyethylene laminated body for packaging materials of Claim 1 or 2 whose draw ratio of the longitudinal direction (MD) of the said stretched polyethylene film is 2 times or more and 10 times or less.   The polyethylene laminate for packaging materials according to any one of claims 1 to 3, wherein the stretched polyethylene film is a biaxially stretched film.   The polyethylene laminated body for packaging materials as described in any one of Claims 1-4 whose thickness of the said extending | stretching polyethylene film is 9 micrometers or more and 50 micrometers or less.   The polyethylene laminate for packaging materials according to any one of claims 1 to 5, wherein the stretched polyethylene film has a configuration of a high density polyethylene layer / a medium density polyethylene layer / a high density polyethylene layer.   The polyethylene laminate for a packaging material according to claim 6, wherein a ratio of thickness between the high-density polyethylene layer and the medium-density polyethylene layer is 1/10 or more and 1/1 or less.   The polyethylene laminate for packaging materials according to any one of claims 1 to 7, wherein the stretched polyethylene film is produced by an inflation molding method.   The polyethylene laminate for packaging materials according to any one of claims 1 to 8, wherein the heat-sealable polyethylene layer includes at least one of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). body.   The packaging material comprised from the laminated body as described in any one of Claims 1-9.