WO2022092296A1

WO2022092296A1 - Polyethylene multillayer base material, printing base material, multilayer body and packaging material

Info

Publication number: WO2022092296A1
Application number: PCT/JP2021/040142
Authority: WO
Inventors: 憲一山田; 有貴添田; 真代今泉; 圭介遠藤
Original assignee: 大日本印刷株式会社
Priority date: 2020-10-30
Filing date: 2021-10-29
Publication date: 2022-05-05

Abstract

A polyethylene multilayer base material which is sequentially provided with a first polyethylene layer, a second polyethylene layer and a third polyethylene layer in this order in the thickness direction, and which is obtained by drawing, while satisfying the requirement (A) and/or the requirement (B).　Requirement (A): The indentation elastic modulus of the first polyethylene layer is not less than 3.0 times the indentation elastic modulus of the second polyethylene layer; and the indentation elastic modulus of the third polyethylene layer is not less than 3.0 times the indentation elastic modulus of the second polyethylene layer. Requirement (B): The indentation hardness of the first polyethylene layer is not less than 2.0 times the indentation hardness of the second polyethylene layer; and the indentation hardness of the third polyethylene layer is not less than 2.0 times the indentation hardness of the second polyethylene layer.

Description

Polyethylene multilayer base material, printing base material, laminate and packaging material

Cross-reference of related applications

This application is filed in Japanese Patent Application No. 2020-182776 filed on October 30, 2020, Japanese Patent Application No. 2020-182808 filed on October 30, 2020, and filed on April 19, 2021. Japanese Patent Application No. 2021-070459, Japanese Patent Application No. 2021-070440 filed on April 19, 2021, Japanese Patent Application No. 2021-130255 filed on August 6, 2021 It claims priority based on Japanese Patent Application No. 2021-166442 filed on October 8, and Japanese Patent Application No. 2021-166438 filed on October 8, 2021, and disclosure of these in its entirety. The contents are by reference as part of the disclosure herein.

The present disclosure relates to polyethylene multilayer base materials, printing base materials, laminates and packaging materials.

Conventionally, packaging materials and the like are manufactured using a resin film composed of a resin material. The packaging material includes, for example, a base material and a heat seal layer. For example, a resin film made of a polyolefin such as polyethylene has flexibility and transparency, and is excellent in heat-sealing property, so that it is widely used as a heat-sealing layer in a packaging material (see, for example, Patent Document 1). ).

On the other hand, polyethylene is a resin that softens at a relatively low temperature compared to other thermoplastic resins, so when used as a base material for packaging materials, it may be deformed or melted during heat sheet processing. Sometimes. In addition, the polyethylene film may have insufficient strength as compared with other thermoplastic resin films. Therefore, as the base material of the packaging material, it is common to use a resin film having excellent strength and heat resistance such as a polyester film and a nylon film. For example, a base material such as a polyester film or a nylon film and a polyethylene film are laminated and heat-sealed so that the polyethylene film side is inside the packaging bag to make a bag (for example, Patent Document). See background technology in 2).

By the way, in recent years, with the growing demand for the construction of a sound material-cycle society, attempts have been made to recycle and use packaging materials. However, the laminate obtained by laminating different types of resin films as described above is difficult to separate for each type of resin material and is not suitable for recycling.

Japanese Unexamined Patent Publication No. 2009-20251 Japanese Unexamined Patent Publication No. 2017-031233

Therefore, the present disclosures have found that the strength and heat resistance of a resin film made of polyethylene can be improved by a stretching treatment, and a polyethylene multilayer base material having a plurality of polyethylene-containing layers as a base material and being stretched is provided. Was considered to be used.

Heat is applied to the base material used for packaging materials, for example, when the packaging material is heat-sealed. However, the present disclosures have found that the laminate provided with the polyethylene multilayer base material may have large heat shrinkage due to heat addition and may not have sufficient heat resistance.

In addition, images such as characters and figures are usually printed using ink on the base material used for packaging materials and the like. However, according to further studies by the present disclosers, it has been found that the polyethylene multilayer base material may not have sufficient ink adhesion or may not have sufficient interlayer strength. Further, the polyethylene multilayer base material is preferably excellent in heat resistance because heat may be applied at the time of printing or the like.

One object of the present disclosure is to provide a polyethylene multilayer base material having excellent heat resistance.
One object of the present disclosure is to provide a polyethylene multilayer base material having excellent ink adhesion and interlayer strength.
One object of the present disclosure is to provide a polyethylene multilayer base material having excellent ink adhesion and heat resistance.
One object of the present disclosure is to provide a laminate having a polyethylene multilayer base material and a heat seal layer containing polyethylene as a main component and having excellent heat resistance.
One object of the present disclosure is to provide a laminate which has strength, heat sealability and recyclability and can be suitably used as a packaging material.

The polyethylene multilayer base material of the first aspect and the second aspect of the present disclosure is provided with a first polyethylene layer, a second polyethylene layer, and a third polyethylene layer in this order in the order of thickness, and is subjected to stretching treatment. Then, the requirement (A) and / or the requirement (B) described later is satisfied.

The polyethylene multilayer base material of the third aspect of the present disclosure contains a layer (A) containing medium-density polyethylene, two or more layers of multi-layer intermediate layers (B) containing polyethylene, respectively, and medium-density polyethylene. The layer (C) is provided in this order in the thickness direction and is stretched, and any polyethylene-containing layers adjacent to each other in the thickness direction in the multilayer substrate are described as the layer (1) and the layer (2). In this case, the absolute value of the difference between the density of the polyethylene constituting the layer (1) and the density of the polyethylene constituting the layer (2) is 0.030 g / cm ³ or less.

The polyethylene multilayer substrate of the fourth aspect of the present disclosure is directly composed of a first layer containing medium density polyethylene and high density polyethylene, and a second layer containing medium density polyethylene and linear low density polyethylene. A third layer containing chain low density polyethylene, a fourth layer containing medium density polyethylene and linear low density polyethylene, and a fifth layer containing medium density polyethylene and high density polyethylene. It is prepared in this order in the thickness direction and is stretched.

The polyethylene multilayer substrate of the fifth aspect of the present disclosure contains a first layer containing medium density polyethylene and high density polyethylene, a second layer containing high density polyethylene, and linear low density polyethylene. A third layer to be used, a fourth layer containing high-density polyethylene, and a fifth layer containing medium-density polyethylene and high-density polyethylene are provided in this order in the thickness direction and are stretched.

The laminate of the first aspect and the second aspect of the present disclosure includes a polyethylene multilayer base material and a heat-sealed layer containing polyethylene as a main component, and the polyethylene multilayer base material includes a first polyethylene layer and a polyethylene layer. The second polyethylene layer and the third polyethylene layer are provided in this order in the thickness direction and are stretched, and the laminate satisfies the requirements (C) and / or the requirements (D) described later.

The laminate of the third aspect and the fourth aspect of the present disclosure includes a polyethylene multilayer base material and a heat seal layer containing polyethylene as a main component, and the polyethylene multilayer base material includes a first polyethylene layer and a polyethylene layer. The second polyethylene layer and the third polyethylene layer are provided in this order in the thickness direction and are stretched, and the laminate satisfies the requirements (E) and / or the requirements (F) described later.

The laminate of the fifth aspect of the present disclosure includes a base material and a heat seal layer, the base material and the heat seal layer are made of the same type of resin material, and the base material has a multilayer structure. The base material is the base material that has been stretched, and the heat seal layer is the layer that has not been stretched.

According to the present disclosure, it is possible to provide the polyethylene multilayer base material of the first aspect and the second aspect, which are excellent in heat resistance. According to the present disclosure, it is possible to provide a polyethylene multilayer base material according to a third aspect, which is excellent in ink adhesion and interlayer strength. According to the present disclosure, it is possible to provide the polyethylene multilayer base material of the fourth aspect and the fifth aspect, which are excellent in ink adhesion and heat resistance. According to the present disclosure, it is possible to provide a laminate of the first to fourth aspects, which comprises a polyethylene multilayer base material and a heat seal layer containing polyethylene as a main component, and has excellent heat resistance. According to the present disclosure, it is possible to provide a laminate of a fifth aspect, which has strength, heat sealability and recyclability and can be suitably used as a packaging material.

It is sectional drawing which shows one Embodiment of the polyethylene multilayer base material of this disclosure. It is sectional drawing which shows one Embodiment of the polyethylene multilayer base material of this disclosure. It is sectional drawing which shows one Embodiment of the laminated body of this disclosure. It is sectional drawing which shows one Embodiment of the laminated body of this disclosure. It is sectional drawing which shows one Embodiment of the laminated body of this disclosure. It is sectional drawing which shows one Embodiment of the laminated body of this disclosure. It is a schematic diagram explaining the method of measuring the heat shrinkage rate of a laminated body. It is sectional drawing which shows one Embodiment of the laminated body of this disclosure. It is sectional drawing which shows one Embodiment of the laminated body of this disclosure.

[the term]
The terms used in the present disclosure will be described below.
"Polyethylene" refers to a polymer in which the content ratio of ethylene-derived constituent units is 50 mol% or more in all the repeating constituent units. In the polymer, the content ratio of the structural unit derived from ethylene is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The above content ratio is measured by a nuclear magnetic resonance method (NMR method).

The "polyethylene layer" is a layer containing polyethylene as a main component, that is, a layer containing polyethylene in a range of more than 50% by mass. The content ratio of polyethylene in the polyethylene layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more.

In the present disclosure, the density of each polyethylene is preferably as follows. The density of high density polyethylene preferably exceeds 0.945 g / cm ³ . The upper limit of the density of high-density polyethylene is, for example, 0.965 g / cm ³ . The density of the medium density polyethylene is preferably more than 0.925 g / cm ³ and 0.945 g / cm ³ or less. The density of the low density polyethylene is preferably more than 0.900 g / cm ³ and 0.925 g / cm ³ or less. The density of the linear low density polyethylene is preferably more than 0.900 g / cm ³ and 0.925 g / cm ³ or less. The density of the ultra-low density polyethylene is preferably 0.900 g / cm ³ or less. The lower limit of the density of ultra-low density polyethylene is, for example, 0.860 g / cm ³ . The density of polyethylene is measured according to JIS K7112 (1999), particularly the D method (density gradient tube method, 23 ° C.).

In the present disclosure, examples of polyethylene include homopolymers of ethylene and copolymers of ethylene and other monomers. Examples of other monomers include α-olefins having 3 or more carbon atoms and 20 or less carbon atoms, vinyl acetate, and (meth) acrylic acid esters. Examples of the α-olefin having 3 or more carbon atoms and 20 or less carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1 -Octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene and 6-methyl-1-heptene can be mentioned. Examples of the (meth) acrylic acid ester include alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate.

Examples of the copolymer include a copolymer of ethylene and an α-olefin having 3 or more and 20 or less carbon atoms, ethylene, and at least one selected from vinyl acetate and (meth) acrylic acid ester. Examples thereof include polymers and copolymers of ethylene, α-olefins having 3 or more and 20 or less carbon atoms, and at least one selected from vinyl acetate and (meth) acrylic acid esters.

Polyethylenes with different densities or branches can be obtained by appropriately selecting the polymerization method. For example, using a multisite catalyst such as a Cheegler-Natta catalyst or a single site catalyst such as a metallocene catalyst as the polymerization catalyst, one step is carried out by any of gas phase polymerization, slurry polymerization, solution polymerization and high pressure ion polymerization. Alternatively, it is preferable to carry out the polymerization in multiple stages of two or more stages.

The single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene-based transition metal compound or a non-metallocene-based transition metal compound with an activation co-catalyst. The single-site catalyst is preferable because the structure of the active site is uniform as compared with the multi-site catalyst, so that a polymer having a high molecular weight and a high uniformity structure can be obtained.

As the single-site catalyst, a metallocene catalyst is preferable. The metallocene 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, an organometallic compound if necessary, and a carrier if necessary.

Examples of the transition metal in the transition metal compound include zirconium, titanium and hafnium, and zirconium and hafnium are preferable.

The cyclopentadienyl skeleton in the transition metal compound is a cyclopentadienyl group or a substituted cyclopentadienyl group. The substituted cyclopentadienyl group is, for example, a hydrocarbon group having 1 or more and 30 or less carbon atoms, a silyl group, a silyl substituted alkyl group, a silyl substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group and a haloalkyl group. , And at least one substituent selected from the halosilyl group. The substituted cyclopentadienyl group has one or more substituents, and the substituents are bonded to each other to form a ring, and an indenyl ring, a fluorenyl ring, an azurenyl ring, or a hydrogenated product thereof can be used. It may be formed. A ring formed by bonding substituents to each other may further have a substituent.

The transition metal compound usually has two ligands having a cyclopentadienyl skeleton. The ligands having each cyclopentadienyl skeleton are preferably bonded to each other by a cross-linking group. Examples of the cross-linking group include a substituted silylene group such as an alkylene group having 1 or more carbon atoms and 4 or less carbon atoms, a silylene group, a dialkylcyrylene group and a diallylsilylene group, and a substituted gelmilene group such as a dialkylgelmylene group and a diarylgermylene group. .. Among these, a substituted silylene group is preferable.

The co-catalyst is a component capable of effectively functioning as a polymerization catalyst of a transition metal compound of Group IV of the periodic table, or a component capable of balancing ionic charges in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxane or benzene-insoluble organic aluminum oxy compound, ion-exchangeable layered silicate, boron compound, active hydrogen group-containing or non-containing cation, and non-coordinating anion. Examples thereof include sex compounds, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.

Examples of the organometallic compound used as necessary include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Among these, organoaluminum compounds are preferable.

The transition metal compound may be used by being carried on a carrier of an inorganic or organic compound. As the carrier, a porous oxide of an inorganic or organic compound is preferable, and specifically, an ion-exchangeable 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 a mixture thereof can be mentioned.

As a raw material for obtaining polyethylene, ethylene derived from biomass may be used instead of ethylene obtained from fossil fuel. Since polyethylene derived from biomass is a carbon-neutral material, it is possible to reduce the environmental load of packaging materials manufactured using a polyethylene multilayer base material. Biomass-derived polyethylene can be produced, for example, by the method described in JP2013-177531A. Commercially available biomass-derived polyethylene (eg, green PE commercially available from Braskem) may be used.

Polyethylene recycled by mechanical recycling may be used. Mechanical recycling generally means that the recovered polyethylene film or the like is crushed and alkaline-cleaned to remove stains and foreign substances on the film surface, and then dried under high temperature and reduced pressure for a certain period of time to stay inside the film. This is a method in which contaminants are diffused and decontaminated to remove stains on a film made of polyethylene, and then returned to polyethylene.

In the following description, each component (for example, polyethylene such as high density polyethylene, medium density polyethylene, low density polyethylene and linear low density polyethylene, additives, colorants, resin materials, adhesives) is 1 each. Seeds may be used, or two or more kinds may be used.

Hereinafter, the polyethylene multilayer base material is also simply referred to as a “multilayer base material”.
The multilayer base material has a multilayer structure of two or more layers. In one embodiment, the number of layers of the multilayer base material is preferably 2 layers or more and 7 layers or less, and more preferably 3 layers or more and 5 layers or less. When the base material has a multilayer structure, for example, the balance between rigidity, strength, heat resistance, printability and stretchability of the base material can be improved.

Examples of the polyethylene contained in the multilayer base material of the present disclosure include high-density polyethylene, medium-density polyethylene, low-density polyethylene (high-pressure method low-density polyethylene), linear low-density polyethylene, and ultra-low-density polyethylene.

The melt flow rate (MFR) of polyethylene contained in the multilayer substrate of the present disclosure is preferably 0.1 g / 10 minutes or more and 50 g / 10 minutes or less from the viewpoint of film forming property and processing suitability of the multilayer substrate. It is preferably 0.2 g / 10 minutes or more and 30 g / 10 minutes or less, more preferably 0.2 g / 10 minutes or more and 15 g / 10 minutes or less, still more preferably 0.2 g / 10 minutes or more and 10 g / 10 minutes or less, and particularly preferably. Is 0.2 g / 10 minutes or more and 5 g / 10 minutes or less. In the present disclosure, the MFR is measured in accordance with ASTM D1238 under the conditions of a temperature of 190 ° C. and a load of 2.16 kg.

Hereinafter, the polyethylene multilayer base material of the first to fifth aspects will be described, but when referring to the multilayer base material in common with the polyethylene multilayer base materials of these embodiments, "the polyethylene multilayer base material of the present disclosure" is used. Or "multilayer substrate of the present disclosure".

[Polyethylene multilayer base material of the first aspect and the second aspect]
The polyethylene multilayer substrate of the first aspect and the second aspect of the present disclosure is
With the first polyethylene layer,
With the second polyethylene layer,
A third polyethylene layer is provided in this order in the thickness direction, and is stretched.

The polyethylene multilayer base material of the first aspect of the present disclosure satisfies the following requirement (A). The polyethylene multilayer substrate of the second aspect of the present disclosure satisfies the following requirement (B). The polyethylene multilayer base material of the first aspect may further satisfy the following requirement (B).
Requirement (A): The indentation elastic modulus of the first polyethylene layer is 3.0 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the third polyethylene layer is the second polyethylene layer. It is 3.0 times or more of the indentation elastic modulus of.
Requirement (B): The indentation hardness of the first polyethylene layer is 2.0 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the third polyethylene layer is the indentation hardness of the second polyethylene layer. It is more than 2.0 times.

The multilayer substrate of the first aspect and the second aspect of the present disclosure includes a second polyethylene layer, a second polyethylene layer and a third polyethylene layer between the first polyethylene layer and the second polyethylene layer. A second b polyethylene layer may be further provided between the two. In this case, the multilayer base material has a first polyethylene layer, a second polyethylene layer, a second polyethylene layer, a second polyethylene layer, and a third polyethylene layer in this order in the thickness direction. Be prepared. The second polyethylene layer, the second polyethylene layer, and the second polyethylene layer form an intermediate layer (multilayer intermediate layer) in the multilayer base material.

In one embodiment, the surface layer on one side of the multilayer substrate of the first aspect and the second embodiment is the first polyethylene layer, and the surface layer on the other side of the multilayer substrate is the third polyethylene layer. .. The multilayer substrate of the first aspect and the second aspect is formed between at least one layer in the first polyethylene layer, the second polyethylene layer, the second polyethylene layer, the second polyethylene layer and the third polyethylene layer. Other layers may be provided.

In one embodiment, the multilayer substrate of the first aspect and the second aspect is only the first polyethylene layer, the second polyethylene layer, the second polyethylene layer, the second polyethylene layer and the third polyethylene layer. Consists of.

Hereinafter, the polyethylene layer is also referred to as a "PE layer".

In the present disclosure, the indentation modulus of the first PE layer, the second PE layer, the second PE layer, the second PE layer, and the third PE layer in the polyethylene multilayer base material or the laminate described later is determined. The indentation elastic modulus 1, the indentation elastic modulus 2a, the indentation elastic modulus 2, the indentation elastic modulus 2b, and the indentation elastic modulus 3 are also described, respectively. The ratio of the indentation elastic modulus of the first PE layer to the indentation elastic modulus of the second PE layer is also described as a ratio (elastic modulus 1 / elastic modulus 2). The same applies to other cases.

In the present disclosure, the indentation hardness of the first PE layer, the second PE layer, the second PE layer, the second PE layer, and the third PE layer in the polyethylene multilayer base material or the laminate described later is determined, respectively. , Push-in hardness 1, push-in hardness 2a, push-in hardness 2, push-in hardness 2b, and push-in hardness 3 are also described. The ratio of the indentation hardness of the first PE layer to the indentation hardness of the second PE layer is also described as a ratio (hardness 1 / hardness 2). The same applies to other cases.

In the multilayer substrate of the first aspect of the present disclosure, the indentation elastic modulus of the first PE layer is 3.0 times or more the indentation elastic modulus of the second PE layer, and the indentation elasticity of the third PE layer. The ratio is 3.0 times or more the indentation elastic modulus of the second PE layer. As a result, the heat resistance of the multilayer base material can be improved, and for example, heat shrinkage of the multilayer base material during heat application such as heat sealing can be suppressed.

The ratio (elastic modulus 1 / elastic modulus 2) and the ratio (elastic modulus 3 / elastic modulus 2) in the multilayer substrate of the first aspect are independently 3.0 or more, preferably 4.0 or more. More preferably 5.0 or more, still more preferably 6.0 or more, even more preferably 7.0 or more; preferably 22.0 or less, more preferably 20.0 or less, still more preferably 18.0 or less, Even more preferably 16.0 or less, particularly preferably 14.0 or less, 13.0 or less or 12.0 or less. The range of the ratio (modulus of elasticity 1 / elastic modulus 2) and the range of the ratio (modulus of elasticity 3 / elastic modulus 2) may be any combination of the above lower limit value and upper limit value, for example, 3.0. It may be 22.0 or less.

In the multilayer substrate of the first aspect of the present disclosure, the indentation elastic modulus of the second PE layer is preferably 2.0 times or more the indentation elastic modulus of the second PE layer, and the indentation elastic modulus of the second PE layer is preferably 2.0 times or more. The indentation elastic modulus of the second PE layer is preferably 2.0 times or more the indentation elastic modulus of the second PE layer. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed.

The ratio (elastic modulus 2a / elastic modulus 2) and the ratio (elastic modulus 2b / elastic modulus 2) in the multilayer substrate of the first aspect are independently, preferably 2.0 or more, more preferably 2.5 or more, respectively. It is more preferably 3.0 or more; preferably 18.0 or less, more preferably 16.0 or less, still more preferably 14.0 or less, still more preferably 13.0 or less, and particularly preferably 12.0 or less. It is 11.0 or less or 10.0 or less. The range of the ratio (elastic modulus 2a / elastic modulus 2) and the range of the ratio (elastic modulus 2b / elastic modulus 2) may be independently any combination of the above lower limit value and upper limit value, for example, 2.0. It may be 18.0 or less.

The indentation elastic modulus 1 and the indentation elastic modulus 3 in the multilayer substrate of the first aspect are independently, preferably 1.1 GPa or more, more preferably 1.15 GPa or more, still more preferably 1.2 GPa or more, still more preferable. Is 1.4 GPa or more; preferably 6.0 GPa or less, more preferably 5.5 GPa or less, still more preferably 5.0 GPa or less, still more preferably 4.5 GPa or less, particularly preferably 4.0 GPa or less, 3. It is 5 GPa or less or 3.0 GPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed. The ranges of the indentation elastic modulus 1 and the indentation elastic modulus 3 may be independently arbitrary combinations of the above lower limit value and upper limit value, and may be, for example, 1.1 GPa or more and 6.0 GPa or less.

The indentation elastic modulus 2 in the multilayer substrate of the first aspect is preferably 0.03 GPa or more, more preferably 0.05 GPa or more, still more preferably 0.1 GPa or more, still more preferably 0.13 GPa or more, and particularly preferably 0.13 GPa or more. It is 0.15 GPa or more; preferably 0.7 GPa or less, more preferably 0.6 GPa or less, still more preferably 0.5 GPa or less, still more preferably 0.4 GPa or less, and particularly preferably 0.3 GPa or less. With such a design, for example, the stretchability of the pre-stretched laminate tends to be more excellent. The range of the indentation elastic modulus 2 may be any combination of the above lower limit value and upper limit value, and may be, for example, 0.03 GPa or more and 0.7 GPa or less.

The indentation elastic modulus 2a and the indentation elastic modulus 2b in the multilayer substrate of the first aspect are independently, preferably 0.3 GPa or more, more preferably 0.4 GPa or more, still more preferably 0.5 GPa or more, still more preferable. Is 0.6 GPa or more; preferably 4.0 GPa or less, more preferably 3.5 GPa or less, still more preferably 3.0 GPa or less, still more preferably 2.5 GPa or less, and particularly preferably 2.0 GPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed. The ranges of the indentation elastic modulus 2a and the indentation elastic modulus 2b may be independently arbitrary combinations of the above lower limit value and upper limit value, and may be, for example, 0.3 GPa or more and 4.0 GPa or less.

In the multilayer substrate of the first aspect, the magnitude of the indentation elastic modulus of each PE layer preferably satisfies the relationship of indentation elastic modulus 1> indentation elastic modulus 2a> indentation elastic modulus 2, and indentation elastic modulus 3> indentation. It is preferable to satisfy the relationship of elastic modulus 2b> indentation elastic modulus 2. This tends to further improve the balance between the heat resistance of the multilayer base material and the stretchability (processability, productivity), for example.

In the multilayer substrate of the first aspect, the ratio (elastic modulus 1 / elastic modulus 3) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0. It is 8 or more and 1.2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the multilayer substrate of the first aspect, the ratio (elastic modulus 2a / elastic modulus 2b) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0. It is 8 or more and 1.2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the multilayer substrate of the second aspect of the present disclosure, the indentation hardness of the first PE layer is 2.0 times or more the indentation hardness of the second PE layer, and the indentation hardness of the third PE layer is It is characterized in that it is 2.0 times or more the indentation hardness of the second PE layer. As a result, the heat resistance of the multilayer base material can be improved, and for example, heat shrinkage of the multilayer base material during heat application such as heat sealing can be suppressed.

The ratio (hardness 1 / hardness 2) and the ratio (hardness 3 / hardness 2) in the multilayer substrate of the second aspect are independently 2.0 or more, preferably 2.2 or more, and more preferably 2. 0.4 or more, more preferably 2.6 or more; preferably 8.5 or less, more preferably 8.0 or less, still more preferably 7.5 or less, even more preferably 7.0 or less, particularly preferably 6. It is 5.5 or less, 6.0 or less, or 5.5 or less. The range of the ratio (hardness 1 / hardness 2) and the range of the ratio (hardness 3 / hardness 2) may be independently any combination of the above lower limit value and upper limit value, for example, 2.0 or more and 8.5. It may be as follows. The multilayer substrate of the first aspect may further satisfy the above requirements relating to the ratio (hardness 1 / hardness 2) and the ratio (hardness 3 / hardness 2).

In the multilayer substrate of the second aspect of the present disclosure, the indentation hardness of the second PE layer is preferably 1.4 times or more the indentation hardness of the second PE layer, and the indentation hardness of the second PE layer is preferable. The hardness is preferably 1.4 times or more the indentation hardness of the second PE layer. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed.

The ratio (hardness 2a / hardness 2) and the ratio (hardness 2b / hardness 2) in the multilayer substrate of the second aspect are independently, preferably 1.4 or more, more preferably 1.6 or more, still more preferably. 1.7 or more; preferably 8.0 or less, more preferably 7.5 or less, still more preferably 7.0 or less, still more preferably 6.5 or less, particularly preferably 6.0 or less, 5.5 or less. Or less or 5.0 or less. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed. The range of the ratio (hardness 2a / hardness 2) and the range of the ratio (hardness 2b / hardness 2) may be independently any combination of the above lower limit value and upper limit value, for example, 1.4 or more and 8.0. It may be as follows. The multilayer substrate of the first aspect may further satisfy the above requirements relating to the ratio (hardness 2a / hardness 2) and the ratio (hardness 2b / hardness 2).

The indentation hardness 1 and the indentation hardness 3 in the multilayer substrate of the second aspect are independently, preferably 45 MPa or more, more preferably 47 MPa or more, still more preferably 49 MPa or more, still more preferably 54 MPa or more; preferably. It is 150 MPa or less, more preferably 130 MPa or less, still more preferably 110 MPa or less, still more preferably 100 MPa or less, and particularly preferably 90 MPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed. The range of the indentation hardness 1 and the indentation hardness 3 may be any combination of the above lower limit value and the upper limit value independently, and may be, for example, 45 MPa or more and 150 MPa or less. The multilayer substrate of the first aspect may further satisfy the above requirements relating to the indentation hardness 1 and the indentation hardness 3.

The indentation hardness 2 in the multilayer substrate of the second aspect is preferably 1 MPa or more, more preferably 3 MPa or more, still more preferably 7 MPa or more, still more preferably 10 MPa or more, particularly preferably 15 MPa or more; preferably 40 MPa or less. It is more preferably 35 MPa or less, further preferably 30 MPa or less, still more preferably 26 MPa or less, and particularly preferably 23 MPa or less. With such a design, for example, the stretchability of the pre-stretched laminate tends to be more excellent. The range of the indentation hardness 2 may be any combination of the above lower limit value and the upper limit value, and may be, for example, 1 MPa or more and 40 MPa or less. The multilayer substrate of the first aspect may further satisfy the above requirement relating to the indentation hardness 2.

The indentation hardness 2a and the indentation hardness 2b in the multilayer substrate of the second aspect are independently, preferably 20 MPa or more, more preferably 25 MPa or more, still more preferably 30 MPa or more, still more preferably 32 MPa or more, and particularly preferably 34 MPa or more. It is more than 140 MPa or less, more preferably 120 MPa or less, still more preferably 100 MPa or less, still more preferably 90 MPa or less, and particularly preferably 85 MPa or less or 80 MPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the multilayer base material at the time of heat sealing can be further suppressed. The range of the indentation hardness 2a and the indentation hardness 2b may be any combination of the above lower limit value and the upper limit value, and may be, for example, 20 MPa or more and 140 MPa or less. The multilayer substrate of the first aspect may further satisfy the above requirements relating to the indentation hardness 2a and the indentation hardness 2b.

In the multilayer substrate of the second aspect, the magnitude of the indentation hardness of each PE layer preferably satisfies the relationship of indentation hardness 1> indentation hardness 2a> indentation hardness 2, indentation hardness 3> indentation hardness 2b> indentation hardness. It is preferable to satisfy the relationship of 2. This tends to further improve the balance between the heat resistance of the multilayer base material and the stretchability (processability, productivity), for example.

In the multilayer substrate of the second aspect, the ratio (hardness 1 / hardness 3) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0.8 or more. It is 1.2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the multilayer substrate of the second aspect, the ratio (hardness 2a / hardness 2b) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0.8 or more. It is 1.2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the present disclosure, the indentation elastic modulus and indentation hardness of each PE layer can be adjusted, for example, by appropriately selecting polyethylene contained in each PE layer. By increasing the content ratio of high-density polyethylene such as high-density polyethylene in the PE layer, the indentation elastic modulus and the indentation hardness tend to increase. By increasing the content ratio of low-density polyethylene such as low-density polyethylene and linear low-density polyethylene in the PE layer, the indentation elastic modulus and the indentation hardness tend to be lowered. The indentation elastic modulus and indentation hardness of each PE layer can also be adjusted by the draw ratio. For example, when the draw ratio is high, the indentation elastic modulus and the indentation hardness of each PE layer tend to be high. For example, when the draw ratio is low, the indentation elastic modulus and the indentation hardness of each PE layer tend to be low.

In the present disclosure, the indentation elastic modulus and the indentation hardness of each PE layer are measured by the nanoindentation method. Specifically, with respect to the polyethylene multilayer base material and the laminate described later, the indentation elastic modulus and the indentation elastic modulus and the indentation elastic modulus and the indentation are made by using a nanoindenter and using a cross section of each PE layer of the polyethylene multilayer base material parallel to the TD direction as a measurement surface. Measure the hardness. The measurement conditions are as follows. As the indenter of the nano indenter, a Berkovich indenter (triangular pyramid indenter) is used. The indenter was pushed into the PE layer from a cross section parallel to the TD direction of the polyethylene multilayer base material and the laminate to a pushing depth of 200 nm over 10 seconds, held in that state for 5 seconds, and then unloaded over 10 seconds. The maximum load Pmax, the contact projection area A at the maximum depth and the load-displacement curve are obtained. From the obtained load-displacement curve, the elastic modulus and hardness values are calculated. The measurement is carried out in a room temperature (25 ° C.) environment. The measurement is carried out at five points on the same cross section, and the average value of the elastic modulus is taken as the indentation elastic modulus and the average value of the hardness is taken as the indentation hardness. Details of the measurement conditions will be described in the Examples column.

For example, the first PE layer may contain medium-density polyethylene and high-density polyethylene, and the third PE layer may contain medium-density polyethylene and high-density polyethylene. By adjusting the amount ratio of the medium-density polyethylene and the high-density polyethylene, for example, the indentation elastic modulus and the indentation hardness can be adjusted. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the first PE layer and the third PE layer is independently, preferably 1.1 or more and 5 or less, more preferably. Is 1.5 or more and 3 or less. This makes it possible to further improve the balance between ink adhesion and heat resistance.

The total content of the medium-density polyethylene and the high-density polyethylene in the first PE layer and the third PE layer is independently, preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass. % Or more. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

For example, the second PE layer may contain linear low-density polyethylene. With such a configuration, for example, the indentation elastic modulus and the indentation hardness tend to be adjusted in a low range. This makes it possible to improve the stretchability of the laminate, which is a precursor of the multilayer substrate.

The content ratio of the linear low-density polyethylene in the second PE layer is preferably more than 50% by mass, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, 90. By mass or more, or 95% by mass or more. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.

The PE layer of the second a and the PE layer of the second b may each contain high-density polyethylene in one embodiment. With such a configuration, for example, the indentation elastic modulus and the indentation hardness tend to be adjusted in a high range. These layers contribute to the improvement of heat resistance of the multilayer base material. That is, by incorporating high-density polyethylene in the second PE layer and the second PE layer in addition to the first PE layer and the third PE layer, the heat resistance of the multilayer base material can be further improved.

The PE layer of the second a and the PE layer of the second b may each further contain low-density polyethylene in one embodiment. With such a configuration, for example, the indentation elastic modulus and the indentation hardness may be adjusted. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.

The mass ratio of high-density polyethylene to low-density polyethylene (high-density polyethylene / low-density polyethylene) in the second PE layer and the second b PE layer is independently, preferably 1 or more and 4 or less, more preferably 1. .5 or more and 3 or less. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.

The content ratio of the high-density polyethylene in the PE layer of the second a and the PE layer of the second b is independently, preferably more than 50% by mass, more preferably 55% by mass or more, still more preferably 60% by mass or more. Thereby, the heat resistance of the multilayer base material can be further improved.

The total content of the high-density polyethylene and the low-density polyethylene in the PE layer of the second a and the PE layer of the second b is independently, preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass. % Or more. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.

In another embodiment, the second PE layer may contain medium density polyethylene and linear low density polyethylene, and the second PE layer may contain medium density polyethylene and linear low density polyethylene. It may be contained. By adjusting the amount ratio of medium-density polyethylene and linear low-density polyethylene, for example, the indentation elastic modulus and the indentation hardness can be adjusted. These layers contribute to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

The mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) in the second PE layer and the second b PE layer is independently and preferably 0.25, respectively. It is 4 or more, more preferably 0.4 or more and 2.4 or less. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.

The total content of the medium-density polyethylene and the linear low-density polyethylene in the PE layer of the second a and the PE layer of the second b is independently, preferably 80% by mass or more, more preferably 90% by mass or more, still more preferable. Is 95% by mass or more. This makes it possible to further improve the stretchability of the laminate which is the precursor.

The thickness of each of the first PE layer and the third PE layer is independently, preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, and further preferably 1 μm or more and 5 μm or less. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

The thickness of each of the first PE layer and the third PE layer is a combination of the second PE layer, the second PE layer and the second PE layer (hereinafter, the second a, second and second b layers). It is preferable that the thickness is smaller than the total thickness of the "multilayer intermediate layer"). The ratio of the respective thicknesses of the first PE layer and the third PE layer to the total thickness of the multilayer intermediate layers (first PE layer or third PE layer / multilayer intermediate layer) is preferably 0.05. It is 0.8 or more, more preferably 0.1 or more and 0.7 or less, and further preferably 0.1 or more and 0.4 or less. Thereby, the rigidity, strength and heat resistance of the multilayer base material can be further improved.

The thickness of the second PE layer is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 40 μm or less, and further preferably 5 μm or more and 30 μm or less. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.

The thickness of each of the second PE layer and the second b PE layer is independently, preferably 0.5 μm or more and 15 μm or less, more preferably 1 μm or more and 10 μm or less, and further preferably 1 μm or more and 8 μm or less. Thereby, the heat resistance of the multilayer base material or the stretchability of the laminate as a precursor can be further improved.

The ratio of the total thickness of the second PE layer and the second PE layer to the thickness of the second PE layer (total thickness of the second PE layer and the second PE layer / thickness of the second PE layer) S) is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. Thereby, the rigidity, strength and heat resistance of the multilayer base material can be further improved.
The thickness of each of the above layers is the thickness after the stretching treatment.

Each layer constituting the multilayer base material may independently contain an additive. Examples of the additive include a cross-linking agent, an antioxidant, an anti-blocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment and a resin for modification. Be done.

At least one layer selected from the first PE layer, the second PE layer, and the third PE layer in the multilayer substrate of the first aspect and the second aspect of the present disclosure, specifically, the first. At least one layer selected from the PE layer, the second PE layer, the second PE layer, the second PE layer, and the third PE layer may contain a slip agent. Thereby, for example, the processability of the multilayer base material can be improved. For example, the second PE layer may contain a slip agent, and all of the above layers may contain a slip agent.

Examples of the slip agent include amide-based lubricants, fatty acid esters such as glycerin fatty acid esters, hydrocarbon-based waxes, higher fatty acid-based waxes, metal soaps, hydrophilic silicones, silicone-modified (meth) acrylic resins, silicone-modified epoxy resins, and silicones. Examples thereof include modified polyethers, silicone-modified polyesters, block-type silicone (meth) acrylic copolymers, polyglycerol-modified silicones and paraffins.

Among the lubricants, amide-based lubricants are preferable. Examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides and aromatic bisamides.

Examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide and hydroxystearic acid amide. Examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Examples of the substituted amide include N-oleyl palmitate amide, N-stearyl stearyl amide, N-stearyl oleate amide, N-oleyl stealic acid amide and N-stearyl erucate amide. Examples of the methylolamide include methylolstearic acid amide. Examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstearic acid. Examples thereof include amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-distealyl adipic acid amides and N, N'-distealyl sebasic acid amides. Examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amides, ethylene biserukaic acid amides, hexamethylene bisoleic acid amides, N, N'-diorail adipic acid amides and N, N'-diorail sevacinic acid amides. Can be mentioned. Examples of the fatty acid ester amide include stearoamide ethyl stearate. Examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide and N, N'-distearylisophthalic acid amide.
Among the slip agents, erucic acid amide is preferable.

In order to increase the dispersibility of the slip agent in the resin composition forming each layer, a master batch containing the slip agent and polyethylene may be used. The content ratio of the slip agent in the masterbatch is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and further preferably 3% by mass or more and 10% by mass or less. Examples of polyethylene include the above-mentioned specific examples. The preferable physical properties (density, MFR, etc.) filled with polyethylene are also as described above.

In the multilayer substrate of the first aspect and the second aspect of the present disclosure, the content ratio of the slip agent in the layer containing the slip agent may be, for example, 0.01% by mass or more and 3% by mass or less, and 0.03% by mass. It may be% or more and 1% by mass or less. Thereby, the processability of the multilayer base material can be further improved.

When one layer contains a plurality of types of polyethylene having different densities (n types; n is an integer of 2 or more), the density of the polyethylene constituting the layer may be measured in accordance with the above JIS K7112. , The average density _Dav calculated according to the following formula (F1) may be used as the density of the polyethylene constituting the layer.

D _av ₌ ΣW _i × Di… (F1)
In equation (F1), Σ means to take the sum of Wi x _Di for _i from 1 to n, n is an integer of 2 or more, and Wi is the mass fraction of the _i -th polyethylene. Shown, Di indicates the density of the _i -th polyethylene (g / cm ³ ).

Since the multilayer substrate of the first aspect and the second aspect of the present disclosure is stretch-treated and has unique physical properties, it is excellent in rigidity, strength and heat resistance as compared with the conventional polyethylene film. It also has excellent ink adhesion. Therefore, the polyethylene multilayer base material of the present disclosure can be used, for example, as a base material for a packaging material, and a clear image can be formed on the surface of the multilayer base material.

Hereinafter, specific embodiments of the multilayer base material of the first aspect and the second aspect will be described.
The polyethylene multilayer base material of the first embodiment has a thickness of a first PE layer, a second PE layer, a second PE layer, a second PE layer, and a third PE layer. The first PE layer contains medium-density polyethylene and high-density polyethylene, and the second PE layer contains high-density polyethylene and optionally low-density polyethylene. The second PE layer contains linear low density polyethylene, the second PE layer contains high density polyethylene and optionally low density polyethylene, and the third PE layer contains medium density polyethylene and high density. Contains polyethylene.

The polyethylene multilayer base material of the second embodiment has a thickness of a first PE layer, a second PE layer, a second PE layer, a second PE layer, and a third PE layer. The first PE layer contains medium-density polyethylene and high-density polyethylene, and the second PE layer contains medium-density polyethylene and linear low-density polyethylene. , The second PE layer contains linear low density polyethylene, the second PE layer contains medium density polyethylene and linear low density polyethylene, and the third PE layer contains medium density polyethylene and Contains high density polyethylene.

The medium-density polyethylene contained in the first PE layer and the medium-density polyethylene contained in the third PE layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.
The high-density polyethylene contained in the first PE layer and the high-density polyethylene contained in the third PE layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.

In the first embodiment, the high-density polyethylene contained in the PE layer of the second a and the high-density polyethylene contained in the PE layer of the second b may be the same or different, and a multilayer base material can be easily used. From the viewpoint of being able to be manufactured, they are preferably the same.

In the second embodiment, the linear low-density polyethylene contained in the second PE layer and the linear low-density polyethylene contained in the second PE layer and the second PE layer are the same. May also be different.
In the second embodiment, the medium-density polyethylene contained in the PE layer of the second a and the medium-density polyethylene contained in the PE layer of the second b may be the same or different, and a multilayer base material can be easily used. From the viewpoint of being able to be manufactured, they are preferably the same.
In the second embodiment, the linear low-density polyethylene contained in the PE layer of the second a and the linear low-density polyethylene contained in the PE layer of the second b may be the same or different. From the viewpoint that the multilayer base material can be easily produced, it is preferable that they are the same.
In the second embodiment, the medium-density polyethylene contained in the second PE layer and the second PE layer and the medium-density polyethylene contained in the first PE layer and the third PE layer are the same. May also be different.

[Polyethylene multilayer base material of the third aspect]
As shown in FIG. 1, the polyethylene multilayer base material 10 of the third aspect of the present disclosure is as shown in FIG.
Layer (A) 12 containing medium-density polyethylene and
Two or more multilayer intermediate layers (B) 16 each containing polyethylene, and
A layer (C) 14 containing medium-density polyethylene is provided in this order in the thickness direction.
The polyethylene multilayer substrate of the third aspect of the present disclosure has been stretched.

When printing an image on a base material, a surface treatment such as a corona discharge treatment is usually performed on the base material as a pretreatment. The layer containing medium-density polyethylene tends to have higher durability against surface treatment than the layer containing only high-density polyethylene as polyethylene. Therefore, the layer containing medium-density polyethylene is excellent in ink adhesion at the time of printing after surface treatment. The layer containing medium-density polyethylene also has the heat resistance required for printing and heat sealing. Further, the layer containing medium-density polyethylene contributes to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

In one embodiment, the surface layer on one side of the multilayer substrate of the third aspect is the layer (A), and the surface layer on the other side of the multilayer substrate of the third aspect is the layer (C).

When the polyethylene-containing layers arbitrarily adjacent to each other in the thickness direction in the multilayer substrate of the third aspect are described as the layer (1) and the layer (2), the density of the polyethylene constituting the layer (1) and the density of the polyethylene constituting the layer (1). The absolute value of the difference from the density of the polyethylene constituting the layer (2) is 0.030 g / cm ³ or less, preferably 0.025 g / cm ³ or less, and more preferably 0.020 g / cm ³ or less. .. Hereinafter, this requirement is also referred to as a "density difference requirement". That is, any set of polyethylene-containing layers adjacent in the thickness direction contained in the multilayer substrate of the third aspect satisfies the above-mentioned density difference requirement.
In the following, when the density difference is described, it means the absolute value of the difference.

For example, a first layer containing medium density polyethylene (a), a second layer containing high density polyethylene (b), and a third layer containing medium density polyethylene (c) and high density polyethylene (d). , A fourth layer containing the high-density polyethylene (e), and a fifth layer containing the medium-density polyethylene (f) will be described in this order in the thickness direction. For convenience, a symbol is added to each polyethylene.

The above density difference requirement is, in one embodiment,
Density difference between medium density polyethylene (a) and high density polyethylene (b),
Difference between the density of high-density polyethylene (b) and the average density of medium-density polyethylene (c) and high-density polyethylene (d),
Either the difference between the average density of the medium-density polyethylene (c) and the high-density polyethylene (d) and the density of the high-density polyethylene (e), or the difference in density between the high-density polyethylene (e) and the medium-density polyethylene (f). It means that the polyethylene is 0.030 g / cm ³ or less.

When one layer contains a plurality of types of polyethylene having different densities (n types; n is an integer of 2 or more), the density of the polyethylene constituting the layer may be measured in accordance with the above JIS K7112. The average density _Dav calculated according to the above formula (F1) may be used as the density of the polyethylene constituting the layer.

In the multilayer substrate of the third aspect of the present disclosure, the density difference between the polyethylene-containing layers is small as described above. Therefore, the multilayer substrate of the third aspect of the present disclosure exhibits high interlayer strength. Further, the multilayer base material of the third aspect of the present disclosure has excellent ink adhesion as described above, heat resistance and transparency, and is a multilayer used for producing a packaging material or the like. It has sufficient rigidity, strength and rigidity as a base material. Therefore, the multilayer substrate of the third aspect of the present disclosure is useful as a substrate on which a printed layer is formed.

The melt flow rate (MFR) of polyethylene contained in the multilayer substrate of the third aspect of the present disclosure is preferably 0.1 g / 10 minutes or more and 50 g / from the viewpoint of film forming property and processability of the multilayer substrate. It is 10 minutes or less, more preferably 0.3 g / 10 minutes or more and 30 g / 10 minutes or less. In the present disclosure, the MFR is measured in accordance with ASTM D1238 under the conditions of a temperature of 190 ° C. and a load of 2.16 kg.

<Third aspect: layer (A) and layer (C)>
Layer (A) contains one or more medium density polyethylenes.
The layer (C) contains one or more medium density polyethylenes.

The medium-density polyethylene contained in the layer (A) and the medium-density polyethylene contained in the layer (C) may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.

The layer (A) and the layer (C) may independently contain only medium-density polyethylene as polyethylene.
The layer (A) and the layer (C) may each independently contain the medium-density polyethylene and further polyethylene other than the medium-density polyethylene. Examples of polyethylene other than medium-density polyethylene include high-density polyethylene, low-density polyethylene (high-pressure method low-density polyethylene), linear low-density polyethylene, and ultra-low-density polyethylene. Among these, high-density polyethylene is preferable from the viewpoint of further improving heat resistance and scratch resistance. That is, in one embodiment, the layer (A) and the layer (C) independently contain medium-density polyethylene and high-density polyethylene, respectively.

In this case, the mass ratio of the medium-density polyethylene in the layers (A) and (C) to other polyethylene such as high-density polyethylene (medium-density polyethylene / other polyethylene) is independently and preferably 0.25. It is 4 or more, more preferably 0.4 or more and 2.4 or less. Thereby, the ink adhesion of the multilayer base material, the durability against the surface treatment, and the heat resistance can be further improved.

The densities of the polyethylene constituting the layer (A) and the layer (C) are independently, preferably more than 0.925 g / cm ³ and 0.960 g / cm ³ or less, more preferably 0.925 g / cm ³ . It is more than 0.955 g / cm ³ or less, more preferably 0.925 g / cm ³ or more and 0.945 g / cm ³ or less. When two or more kinds of polyethylene are contained in the same layer, the density of polyethylene means the above-mentioned average density. Thereby, the ink adhesion of the multilayer base material, the durability against the surface treatment, and the heat resistance can be further improved.

The content ratio of polyethylene in the layer (A) and the layer (C) is independently, preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.

The layer (A) and the layer (C) may independently contain one or more additives. Examples of the additive include a cross-linking agent, an antioxidant, an anti-blocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment and a resin for modification. Be done.

The thickness of each of the layer (A) and the layer (C) in the multilayer substrate of the third aspect is independently, preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, and further preferably 1 μm. It is 5 μm or less. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

It is preferable that the thickness of each of the layer (A) and the layer (C) is smaller than the total thickness of the multilayer intermediate layer (B). The ratio of the respective thicknesses of the layers (A) and (C) to the total thickness of the multilayer intermediate layer (B) (layer (A) or layer (C) / multilayer intermediate layer (B)) is preferably 0. It is 0.05 or more and 0.8 or less, more preferably 0.1 or more and 0.7 or less, and further preferably 0.1 or more and 0.4 or less. Thereby, the rigidity, strength and heat resistance of the multilayer base material can be further improved.

<Third aspect: Multilayer intermediate layer (B)>
The multilayer intermediate layer (B) includes two or more layers containing one or more types of polyethylene.

Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene (high-pressure method low-density polyethylene), linear low-density polyethylene, and ultra-low-density polyethylene.

For example, when the layer (A) and the layer (C) do not contain high-density polyethylene, it is preferable that the multilayer intermediate layer (B) includes a layer containing high-density polyethylene. This makes it possible to improve the heat resistance and rigidity of the multilayer base material.

For example, when the layer (A) and the layer (C) contain high-density polyethylene, it is preferable that the multilayer intermediate layer (B) includes a layer containing medium-density polyethylene and linear low-density polyethylene. This makes it possible to improve the balance between the heat resistance and the stretchability of the multilayer base material.

The content ratio of polyethylene in each layer constituting the multilayer intermediate layer (B) is independently, preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.

Each layer constituting the multilayer intermediate layer (B) may independently contain one or more additives. Examples of the additive include a cross-linking agent, an antioxidant, an anti-blocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment and a resin for modification. Be done.

The total thickness of the multilayer intermediate layer (B) is preferably 1 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less, and further preferably 10 μm or more and 30 μm or less. Thereby, the heat resistance of the multilayer base material can be further improved.

The number of layers of the multilayer intermediate layer (B) is two or more, preferably three or more, and more preferably three or more and five or less, from the viewpoint of rigidity, strength, and ease of manufacture of the multilayer base material.

As a specific example of the multilayer intermediate layer (B), the first to fourth embodiments will be described.
The multilayer intermediate layer of the first embodiment is
A layer containing high density polyethylene and
With a layer containing medium density polyethylene and high density polyethylene,
A layer containing high-density polyethylene is provided in this order in the thickness direction.
The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the layer containing medium-density polyethylene and high-density polyethylene is preferably 0.25 or more and 4 or less, more preferably 0.4. It is 2.4 or less.

The multilayer base material provided with the multilayer intermediate layer of the first embodiment has, for example, a first layer (layer (A)) containing medium-density polyethylene, a second layer containing high-density polyethylene, and a medium density. A third layer containing polyethylene and high-density polyethylene, a fourth layer containing high-density polyethylene, and a fifth layer (layer (C)) containing medium-density polyethylene are formed in the thickness direction. It is prepared in order and is stretched.

The multilayer intermediate layer of the second embodiment is
With a layer containing medium density polyethylene,
A layer containing medium density polyethylene and linear low density polyethylene,
A layer containing medium-density polyethylene is provided in this order in the thickness direction.
The mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) in the layer containing medium-density polyethylene and linear low-density polyethylene is preferably 0.25 or more. It is 4 or less, more preferably 0.4 or more and 2.4 or less.

The multilayer base material provided with the multilayer intermediate layer of the second embodiment is, for example, a first layer (layer (A)) containing medium-density polyethylene, a second layer containing medium-density polyethylene, and a medium density. A third layer containing polyethylene and linear low-density polyethylene, a fourth layer containing medium-density polyethylene, and a fifth layer (layer (C)) containing medium-density polyethylene have a thickness. It is prepared in this order in the direction and is stretched.

The multilayer intermediate layer of the third embodiment is
A layer containing medium density polyethylene and linear low density polyethylene,
With a layer containing linear low density polyethylene,
A layer containing medium-density polyethylene and linear low-density polyethylene is provided in this order in the thickness direction.
The mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) in the layer containing medium-density polyethylene and linear low-density polyethylene is preferably 0.25 or more. It is 4 or less, more preferably 0.4 or more and 2.4 or less.

The multilayer base material provided with the multilayer intermediate layer of the third embodiment includes, for example, a first layer (layer (A)) containing medium-density polyethylene and high-density polyethylene, and medium-density polyethylene and linear low-density polyethylene. A second layer containing, a third layer containing linear low density polyethylene, a fourth layer containing medium density polyethylene and linear low density polyethylene, medium density polyethylene and high density polyethylene. A fifth layer (layer (C)) containing the above-mentioned material is provided in this order in the thickness direction, and is stretched.

The multilayer intermediate layer of the fourth embodiment is
With a layer containing medium density polyethylene,
Layers containing linear low density polyethylene and medium density polyethylene,
A layer containing medium-density polyethylene is provided in this order in the thickness direction.
The mass ratio of the linear low-density polyethylene to the medium-density polyethylene (linear low-density polyethylene / medium-density polyethylene) in the layer containing the linear low-density polyethylene and the medium-density polyethylene is preferably 0.25 or more. It is 4 or less, more preferably 0.4 or more and 2.4 or less.

The multilayer base material provided with the multilayer intermediate layer of the fourth embodiment is, for example, a first layer (layer (A)) containing high-density polyethylene and medium-density polyethylene, and a second layer containing medium-density polyethylene. And a third layer containing linear low-density polyethylene and medium-density polyethylene, a fourth layer containing medium-density polyethylene, and a fifth layer (layer (layer) containing high-density polyethylene and medium-density polyethylene. C)) are provided in this order in the thickness direction and are stretched.

In the multilayer intermediate layer of the first to fourth embodiments, the ratio of the total thickness of the outer two layers to the thickness of the central layer (total thickness of the outer two layers / thickness of the central layer) is preferable. Is 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. Thereby, the rigidity, strength and heat resistance of the multilayer base material can be further improved. For example, in the case of the first embodiment, the outer two layers in the multilayer intermediate layer refer to the layer containing high-density polyethylene, and the central layer refers to the layer containing medium-density polyethylene and high-density polyethylene. ..

[Polyethylene multilayer base material of the fourth aspect]
The polyethylene multilayer substrate of the fourth aspect of the present disclosure is directly composed of a first layer containing medium density polyethylene and high density polyethylene, and a second layer containing medium density polyethylene and linear low density polyethylene. A third layer containing chain low density polyethylene, a fourth layer containing medium density polyethylene and linear low density polyethylene, and a fifth layer containing medium density polyethylene and high density polyethylene. It is prepared in this order in the thickness direction and is stretched.

In one embodiment, the surface layer on one side of the multilayer substrate of the fourth aspect is the first layer, and the surface layer on the other side of the multilayer substrate of the fourth aspect is the fifth layer. The multilayer base material of the fourth aspect may be provided with another layer between the first to fifth layers, but in one embodiment, the multilayer base material of the fourth aspect is the first to fifth layers. Consists of only.

Hereinafter, each layer constituting the multilayer base material of the fourth aspect will be described.

<Fourth aspect: first layer and fifth layer>
The first layer contains one or more types of medium density polyethylene and one or more types of high density polyethylene.
The fifth layer contains one or more types of medium density polyethylene and one or more types of high density polyethylene.
When printing an image on a substrate, a surface treatment such as a corona discharge treatment is usually performed on the substrate as a pretreatment. The layer containing medium-density polyethylene tends to have higher durability against surface treatment than the layer containing only high-density polyethylene as polyethylene. Therefore, the layer containing medium-density polyethylene is excellent in ink adhesion at the time of printing after surface treatment. The layer containing medium-density polyethylene also has the heat resistance required for printing and heat sealing. Further, the layer containing medium-density polyethylene contributes to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

The medium-density polyethylene contained in the first layer and the medium-density polyethylene contained in the fifth layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.
The high-density polyethylene contained in the first layer and the high-density polyethylene contained in the fifth layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.

The first layer and the fifth layer may independently contain medium-density polyethylene and high-density polyethylene, as well as polyethylene other than these polyethylenes. Examples of polyethylene other than medium-density polyethylene and high-density polyethylene include low-density polyethylene (high-pressure method low-density polyethylene), linear low-density polyethylene, and ultra-low-density polyethylene. The first layer preferably contains only medium-density polyethylene and high-density polyethylene as polyethylene from the viewpoint of further improving the ink adhesion and heat resistance of the multilayer base material. The fifth layer preferably contains only medium-density polyethylene and high-density polyethylene as polyethylene from the viewpoint of further improving the ink adhesion and heat resistance of the multilayer base material.

The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the first layer and the fifth layer is independently, preferably 1.1 or more and 5 or less, more preferably 1. .5 or more and 3 or less. This makes it possible to further improve the balance between ink adhesion and heat resistance.
The total content of the medium-density polyethylene and the high-density polyethylene in the first layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.
The total content of the medium-density polyethylene and the high-density polyethylene in the fifth layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

The thickness of each of the first layer and the fifth layer is independently, preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, and further preferably 1 μm or more and 5 μm or less. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

The thickness of each of the first layer and the fifth layer is referred to as a second layer, a third layer, and a fourth layer (hereinafter, the second to fourth layers are collectively referred to as a "multilayer intermediate layer". ) Is preferably smaller than the total thickness. The ratio of the thickness of each of the first layer and the fifth layer to the total thickness of the multilayer intermediate layer (first layer or fifth layer / multilayer intermediate layer) is preferably 0.05 or more and 0.8. Below, it is more preferably 0.1 or more and 0.7 or less, and further preferably 0.1 or more and 0.4 or less. Thereby, the rigidity, strength and heat resistance of the multilayer base material can be further improved.

<Fourth aspect: second layer and fourth layer>
The second layer contains one or more medium density polyethylenes and one or more linear low density polyethylenes.
The fourth layer contains one or more medium density polyethylenes and one or more linear low density polyethylenes.
Each of the second layer and the fourth layer contributes to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

The medium-density polyethylene contained in the second layer and the medium-density polyethylene contained in the fourth layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.
The linear low-density polyethylene contained in the second layer and the linear low-density polyethylene contained in the fourth layer may be the same or different, and a multilayer base material can be easily produced. From the viewpoint, it is preferable that they are the same.
The medium-density polyethylene contained in the second layer and the fourth layer and the medium-density polyethylene contained in the first layer and the fifth layer may be the same or different.

The second layer and the fourth layer may independently contain medium-density polyethylene and linear low-density polyethylene, as well as polyethylene other than these polyethylenes. Examples of polyethylene other than medium-density polyethylene and linear low-density polyethylene include high-density polyethylene, low-density polyethylene (high-pressure method low-density polyethylene), and ultra-low-density polyethylene. The second layer preferably contains only medium-density polyethylene and linear low-density polyethylene as polyethylene from the viewpoint of further improving the stretchability of the laminate which is the precursor of the multilayer base material. The fourth layer preferably contains only medium-density polyethylene and linear low-density polyethylene as polyethylene from the viewpoint of further improving the stretchability of the laminate which is the precursor of the multilayer base material.

The mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) in the second layer and the fourth layer is independently, preferably 0.25 or more. Below, it is more preferably 0.4 or more and 2.4 or less. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.
The total content of the medium-density polyethylene and the linear low-density polyethylene in the second layer is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more. This makes it possible to further improve the stretchability of the laminate which is the precursor.
The total content of the medium-density polyethylene and the linear low-density polyethylene in the fourth layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the stretchability of the laminate which is the precursor.

The thickness of each of the second layer and the fourth layer is independently, preferably 0.5 μm or more and 15 μm or less, more preferably 1 μm or more and 10 μm or less, and further preferably 1 μm or more and 8 μm or less. This makes it possible to further improve the stretchability of the laminate which is the precursor.

<Fourth aspect: third layer>
The third layer contains one or more linear low density polyethylenes. The third layer contributes to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

The linear low-density polyethylene contained in the third layer and the linear low-density polyethylene contained in the second layer and the fourth layer may be the same or different.

The third layer may further contain polyethylene other than the linear low-density polyethylene as well as the linear low-density polyethylene. Examples of polyethylene other than linear low-density polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene (high-pressure method low-density polyethylene), and ultra-low-density polyethylene. The third layer preferably contains only linear low-density polyethylene as polyethylene from the viewpoint of further improving the stretchability of the laminate which is the precursor of the multilayer base material.

The content ratio of the linear low-density polyethylene in the third layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.

The thickness of the third layer is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 40 μm or less, and further preferably 5 μm or more and 30 μm or less. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.

The ratio of the total thickness of the second and fourth layers to the thickness of the third layer (total thickness of the second and fourth layers / thickness of the third layer) is preferably. It is 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. Thereby, the rigidity, strength and heat resistance of the multilayer base material can be further improved.

The first to fifth layers constituting the multilayer substrate of the fourth aspect of the present disclosure may independently contain one or more additives. Examples of the additive include a cross-linking agent, an antioxidant, an anti-blocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment and a resin for modification. Be done.

In one embodiment, in the multilayer substrate of the fourth aspect of the present disclosure, the density of polyethylene in the second layer is lower than the density of polyethylene in the first layer, and the density of polyethylene in the second layer is higher than the density of polyethylene in the second layer. Also, the density of polyethylene in the third layer is lower, the density of polyethylene in the fourth layer is higher than the density of polyethylene in the third layer, and the density of polyethylene in the fourth layer is higher than the density of polyethylene in the fifth layer. The density of polyethylene in the layer is higher. The multilayer base material having such a structure is excellent in the balance between ink adhesion, heat resistance and manufacturability (stretchability of the laminate which is a precursor).

When any adjacent layer selected from the first to fifth layers in the multilayer substrate of the fourth aspect is described as a layer (1) and a layer (2), the polyethylene constituting the layer (1) is described. The absolute value of the difference between the density of the above and the density of the polyethylene constituting the layer (2) is preferably 0.030 g / cm ³ or less, more preferably 0.025 g / cm ³ or less, still more preferably 0. It is 020 g / cm ³ or less. Hereinafter, this requirement is also referred to as a "density difference requirement". That is, any set (for example, a set of a first layer and a second layer, which is adjacent to each other in the thickness direction selected from the first to fifth layers, which is included in the multilayer substrate of the fourth aspect, the first layer. It is preferable that the pair of the second layer and the third layer, the pair of the third layer and the fourth layer, and the pair of the fourth layer and the fifth layer) also satisfy the above-mentioned density difference requirement.
In the following, when the density difference is described, it means the absolute value of the difference.

In the multilayer base material satisfying the above density difference requirement, the density difference between the first to fifth layers is small as described above. Therefore, a multilayer substrate that meets the above density difference requirements exhibits high interlayer strength.

[Polyethylene multilayer base material of the fifth aspect]
The polyethylene multilayer substrate of the fifth aspect of the present disclosure is
A first layer containing medium density polyethylene and high density polyethylene,
A second layer containing high density polyethylene and
A third layer containing linear low density polyethylene,
A fourth layer containing high density polyethylene,
A fifth layer containing medium-density polyethylene and high-density polyethylene is provided in this order in the thickness direction and is stretched.

In one embodiment, the surface layer on one side of the multilayer substrate of the fifth aspect is the first layer, and the surface layer on the other side of the multilayer substrate of the fifth aspect is the fifth layer. The multilayer base material of the fifth aspect may be provided with another layer between the first to fifth layers, but in one embodiment, the multilayer base material of the fifth aspect is the first to fifth layers. Consists of only.

Hereinafter, each layer constituting the multilayer base material of the fifth aspect will be described.

<Fifth aspect: first layer and fifth layer>
The first layer contains one or more types of medium density polyethylene and one or more types of high density polyethylene.
The fifth layer contains one or more types of medium density polyethylene and one or more types of high density polyethylene.

When printing an image on a base material, a surface treatment such as a corona discharge treatment is usually performed on the base material as a pretreatment. The layer containing medium-density polyethylene tends to have higher durability against surface treatment than the layer containing only high-density polyethylene as polyethylene. Therefore, the layer containing medium-density polyethylene is excellent in ink adhesion at the time of printing after surface treatment. The layer containing medium-density polyethylene and high-density polyethylene also has heat resistance required for printing and heat sealing. Further, the layer containing medium-density polyethylene contributes to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

The first layer and the fifth layer may independently contain medium-density polyethylene and high-density polyethylene, as well as polyethylene other than these polyethylenes. Examples of polyethylene other than medium-density polyethylene and high-density polyethylene include low-density polyethylene (high-pressure method low-density polyethylene), linear low-density polyethylene, and ultra-low-density polyethylene. The first layer may contain only medium-density polyethylene and high-density polyethylene as polyethylene from the viewpoint of further improving the ink adhesion and heat resistance of the multilayer base material. The fifth layer may contain only medium-density polyethylene and high-density polyethylene as polyethylene from the viewpoint of further improving the ink adhesion and heat resistance of the multilayer base material.

The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the first layer and the fifth layer is independently, preferably 1.1 or more and 5 or less, more preferably 1. .5 or more and 3 or less. This makes it possible to further improve the balance between ink adhesion and heat resistance.

The total content of the medium-density polyethylene and the high-density polyethylene in the first layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

The total content of the medium-density polyethylene and the high-density polyethylene in the fifth layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the ink adhesion and heat resistance of the multilayer base material.

<Fifth aspect: second layer and fourth layer>
The second layer contains one or more high density polyethylenes.
The fourth layer contains one or more high density polyethylenes.
The second layer and the fourth layer each contribute to improving the heat resistance of the multilayer base material. That is, by incorporating high-density polyethylene in the second layer and the fourth layer in addition to the first layer and the fifth layer, the heat resistance of the multilayer base material can be further improved.

The high-density polyethylene contained in the second layer and the high-density polyethylene contained in the fourth layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.

The second layer may further contain one or more low density polyethylenes. The fourth layer may further contain one or more low density polyethylenes. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.
The low-density polyethylene contained in the second layer and the low-density polyethylene contained in the fourth layer may be the same or different, and are the same from the viewpoint that a multilayer base material can be easily produced. Is preferable.

The second layer and the fourth layer may independently contain high-density polyethylene and low-density polyethylene, as well as polyethylene other than these polyethylenes. Examples of polyethylene other than high-density polyethylene and low-density polyethylene include medium-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. The second layer may contain only high-density polyethylene and low-density polyethylene as polyethylene from the viewpoint of further improving the heat resistance of the multilayer base material. The fourth layer may contain only high-density polyethylene and low-density polyethylene as polyethylene from the viewpoint of further improving the heat resistance of the multilayer base material.

The mass ratio of high-density polyethylene to low-density polyethylene (high-density polyethylene / low-density polyethylene) in the second layer and the fourth layer is independently, preferably 1 or more and 4 or less, more preferably 1.5. More than 3 or less. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.

The content ratio of the high-density polyethylene in the second layer is preferably more than 50% by mass, more preferably 55% by mass or more, and further preferably 60% by mass or more. Thereby, the heat resistance of the multilayer base material can be further improved.

The content ratio of the high-density polyethylene in the fourth layer is preferably more than 50% by mass, more preferably 55% by mass or more, and further preferably 60% by mass or more. Thereby, the heat resistance of the multilayer base material can be further improved.

The total content of the high-density polyethylene and the low-density polyethylene in the second layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.

The total content of the high-density polyethylene and the low-density polyethylene in the fourth layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to further improve the balance between heat resistance, rigidity and workability of the multilayer base material.

The thickness of each of the second layer and the fourth layer is independently, preferably 0.5 μm or more and 15 μm or less, more preferably 1 μm or more and 10 μm or less, and further preferably 1 μm or more and 8 μm or less. Thereby, the heat resistance of the multilayer base material can be further improved.

<Fifth aspect: third layer>
The third layer contains one or more linear low density polyethylenes. The third layer contributes to the improvement of the stretchability of the laminate which is the precursor of the multilayer base material.

The third layer may further contain polyethylene other than the linear low-density polyethylene as well as the linear low-density polyethylene. Examples of polyethylene other than linear low-density polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene (high-pressure method low-density polyethylene), and ultra-low-density polyethylene.

The third layer may further contain one or more low density polyethylenes.

The content of the linear low-density polyethylene in the third layer is preferably more than 50% by mass, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, 90% by mass. % Or more, or 95% by mass or more. Thereby, the balance between heat resistance, rigidity and stretchability can be further improved.

When the third layer contains low-density polyethylene, the content ratio of the low-density polyethylene is preferably less than 50% by mass, more preferably 5% by mass or more and 40% by mass or less, and further preferably 10% by mass or more and 30% by mass. It is as follows.

<Additives>
The first to fifth layers constituting the multilayer substrate of the fifth aspect of the present disclosure may independently contain one or more additives. Examples of the additive include a cross-linking agent, an antioxidant, an anti-blocking agent, a slip agent, an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment and a resin for modification. Be done.

At least one layer selected from the first layer, the second layer, the third layer, the fourth layer and the fifth layer in the multilayer substrate of the fifth aspect of the present disclosure contains a slip agent. You may. Thereby, for example, the processability of the multilayer base material can be improved. For example, the third layer may contain a slip agent, and all of the first to fifth layers may contain a slip agent.

Among the lubricants, amide-based lubricants are preferable. Examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides and aromatic bisamides. Specific examples of these are as described in the column of [Polyethylene multilayer base material of the first aspect and the second aspect].

Among the slip agents, erucic acid amide is preferable.
One type or two or more types of slip agents can be used.

In the multilayer substrate of the fifth aspect of the present disclosure, the content ratio of the slip agent in the layer containing the slip agent may be, for example, 0.01% by mass or more and 3% by mass or less, and 0.03% by mass or more and 1% by mass. It may be as follows. Thereby, the processability of the multilayer base material can be further improved.

In one embodiment, in the multilayer substrate of the fifth aspect of the present disclosure, the density of polyethylene in the first layer and the density of polyethylene in the second layer are similar, and the density of polyethylene in the second layer. The density of polyethylene in the third layer is lower than that of the third layer, the density of polyethylene in the fourth layer is higher than the density of polyethylene in the third layer, and the density of polyethylene in the fourth layer and the fifth. The density of polyethylene in the layer is similar. The multilayer base material having such a structure is excellent in the balance between ink adhesion, heat resistance and manufacturability (stretchability of the laminate which is a precursor). The absolute value of the difference between the density of polyethylene in the first layer and the density of polyethylene in the second layer may be, for example, 0.020 g / cm ³ or less, or 0.010 g / cm ³ or less. The absolute value of the difference between the density of polyethylene in the fourth layer and the density of polyethylene in the fifth layer may be, for example, 0.020 g / cm ³ or less, or 0.010 g / cm ³ or less.

[Manufacturing method of polyethylene multilayer base material]
The polyethylene multilayer base material of the present disclosure can be produced, for example, by forming a film of a plurality of polyethylene materials by an inflation method or a T-die method to form a laminate, and stretching the obtained laminate. By the stretching treatment, the transparency, rigidity, strength and heat resistance of the multilayer base material can be improved, and the multilayer base material can be suitably used as a base material for, for example, a packaging material.

The multilayer base material is, for example, a laminate in which a layer containing medium-density polyethylene, two or more multilayer intermediate layers each containing polyethylene, and a layer containing medium-density polyethylene are provided in this order in the thickness direction. (Precursor) is obtained by stretching treatment.

Specifically, from the outside, a layer containing medium-density polyethylene, two or more multilayer intermediate layers each containing polyethylene, and a layer containing medium-density polyethylene are co-extruded into a tubular shape to form a film. And the laminate can be manufactured. Alternatively, a laminate is manufactured by co-extruding a layer containing medium-density polyethylene and a layer containing polyethylene in a tube shape from the outside, and then pressure-bonding the layers containing opposite polyethylene with a rubber roll or the like. can. By manufacturing the laminate by such a method, the number of defective products can be remarkably reduced and the production efficiency can be improved.

The multilayer substrate includes, for example, a layer containing medium-density polyethylene and high-density polyethylene, a layer containing medium-density polyethylene and linear low-density polyethylene, or a layer containing high-density polyethylene, and linear low-density. A layer containing polyethylene, a layer containing medium-density polyethylene and linear low-density polyethylene, or a layer containing high-density polyethylene, and a layer containing medium-density polyethylene and high-density polyethylene are formed in the thickness direction. The laminate (precursor) prepared in this order is obtained by stretching treatment.

Specifically, from the outside, a layer containing medium-density polyethylene and high-density polyethylene, a layer containing medium-density polyethylene and linear low-density polyethylene, or a layer containing high-density polyethylene, and a linear low A layer containing density polyethylene, a layer containing medium density polyethylene and linear low density polyethylene, or a layer containing high density polyethylene, and a layer containing medium density polyethylene and high density polyethylene are formed into a tube shape. It can be co-extruded to form a film to produce a laminate. Alternatively, from the outside, a layer containing medium-density polyethylene and high-density polyethylene, a layer containing medium-density polyethylene and linear low-density polyethylene, or a layer containing high-density polyethylene, and a linear low-density polyethylene. A laminate can be produced by co-extruding the containing layer into a tube shape and then pressure-bonding the opposing layers containing the linear low-density polyethylene with a rubber roll or the like. By manufacturing the laminate by such a method, the number of defective products can be remarkably reduced and the production efficiency can be improved.

Other polyethylene multilayer base materials can also be manufactured by, for example, the above-mentioned method.

FIG. 2 shows an embodiment of the multilayer substrate of the present disclosure. The multilayer base material 10 of FIG. 2 includes a layer 12, a layer 18, a layer 20, a layer 22, and a layer 14 in this order in the thickness direction.

In the case of the polyethylene multilayer base material of the first aspect and the second aspect, for example, the layer 12 is the first PE layer, the layer 18 is the second PE layer, and the layer 20 is the second PE layer. The layer 22 is the second PE layer, and the layer 14 is the third PE layer. The second PE layer and the second PE layer may be omitted.

In the case of the multilayer substrate including the multilayer intermediate layer of the first embodiment in the polyethylene multilayer substrate of the third aspect, for example, the layer 12 is the first layer (layer (A)) containing the medium density polyethylene. The layer 18 is a second layer containing high-density polyethylene, the layer 20 is a third layer containing medium-density polyethylene and high-density polyethylene, and the layer 22 contains high-density polyethylene. The fourth layer is a fifth layer (layer (C)) containing medium-density polyethylene.

In the case of the polyethylene multilayer base material of the fourth aspect, for example, the layer 12 is the first layer containing the medium density polyethylene and the high density polyethylene, and the layer 18 is the medium density polyethylene and the linear low density polyethylene. A second layer containing, layer 20 is a third layer containing linear low density polyethylene, and layer 22 is a fourth layer containing medium density polyethylene and linear low density polyethylene. It is a layer, and layer 14 is a fifth layer containing medium-density polyethylene and high-density polyethylene.

In the case of the polyethylene multilayer base material of the fifth aspect, for example, the layer 12 is the first layer containing the medium density polyethylene and the high density polyethylene, and the layer 18 is the second layer containing the high density polyethylene. Layer 20 is a third layer containing linear low density polyethylene, layer 22 is a fourth layer containing high density polyethylene, and layer 14 is medium density polyethylene and high density. A fifth layer containing polyethylene.

When the laminate is manufactured by the T-die method, the melt flow rate (MFR) of the polyethylene constituting each layer is preferably 3 g / 10 minutes or more and 20 g / 10 from the viewpoint of film forming property and processability of the multilayer base material. Less than a minute.

When the laminate is manufactured by the inflation method, the MFR of the polyethylene constituting each layer is preferably 0.2 g / 10 minutes or more and 5 g / 10 minutes or less from the viewpoint of film forming property and processing suitability of the multilayer base material. It is preferably 0.5 g / 10 minutes or more and 5 g / 10 minutes or less.

The multilayer base material of the present disclosure is obtained, for example, by stretching the above-mentioned laminate. In the inflation film forming machine, stretching of the laminate can also be performed. As a result, the multilayer base material can be manufactured, so that the production efficiency can be further improved.

The multilayer base material of the present disclosure may be a uniaxially stretched film or a biaxially stretched film. The multilayer base material is, in one embodiment, a uniaxially stretched film, and more specifically, a uniaxially stretched film that has been stretched in the longitudinal direction (MD).

The elongation ratio in the longitudinal direction (MD) of the multilayer substrate of the present disclosure is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less in one embodiment. The stretch ratio in the lateral direction (TD) of the multilayer substrate of the present disclosure is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less in one embodiment.

When the draw ratio is 2 times or more, for example, the rigidity, strength and heat resistance of the multilayer substrate can be improved, the ink adhesion to the multilayer substrate can be improved, and the transparency of the multilayer substrate can be improved. When the draw ratio is 10 times or less, the laminate can be satisfactorily stretched.

The haze value of the multilayer substrate of the present disclosure is preferably 25% or less, more preferably 15% or less, still more preferably 10% or less. The smaller the haze value is, the more preferable it is, but in one embodiment, the lower limit value may be 0.1% or 1%. The haze value of the multilayer base material is measured according to JIS K7136.

The content ratio of polyethylene in the multilayer substrate of the present disclosure is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the multilayer base material.

It is preferable that the laminate or the multilayer base material is surface-treated. This makes it possible to improve the adhesion between the surface layer of the multilayer base material and the layer laminated on the multilayer base material. Surface treatment methods include, for example, corona discharge treatment, ozone treatment, low temperature plasma treatment using gases such as oxygen gas and nitrogen gas, physical treatment such as glow discharge treatment; and oxidation treatment using chemicals. Chemical treatment can be mentioned.

An anchor coat layer may be formed on the surface of the laminate or the multilayer base material by using a conventionally known anchor coat agent.

The total thickness of the multilayer substrate of the present disclosure is preferably 10 μm or more and 60 μm or less, and more preferably 15 μm or more and 50 μm or less. When the thickness of the multilayer substrate is 10 μm or more, the rigidity and strength of the multilayer substrate can be improved. When the thickness of the multilayer substrate is 60 μm or less, the processability of the multilayer substrate can be improved. Within the range where the above-mentioned effects can be obtained, it is preferable that the thickness of the multilayer base material is small, for example, from the viewpoint of cost reduction.

[Printing substrate]
The printed substrate of the present disclosure includes the polyethylene multilayer substrate of the present disclosure and a printing layer formed on the multilayer substrate. The printed layer is formed, for example, on the first PE layer or the third PE layer in the multilayer substrate of the first aspect and the second aspect. The printed layer is formed, for example, in the layer (A) or the layer (C) in the multilayer substrate of the third aspect. The printed layer is formed, for example, in the first layer or the fifth layer in the multilayer substrate of the fourth aspect and the fifth aspect. Since the multilayer base material has excellent ink adhesion, a good image can be formed. The multilayer substrate of the present disclosure is suitable for printing because it has excellent heat resistance such as heat shrinkage in one embodiment.

The print layer contains, for example, an image. Examples of the image include characters, figures, symbols, and combinations thereof. Examples of the method for forming the print layer include a gravure printing method, an offset printing method, and a flexographic printing method. In one embodiment, the flexographic printing method is preferable from the viewpoint of reducing the environmental load. Further, from the viewpoint of reducing the environmental load, a printing layer may be formed on the surface of the multilayer base material using an ink derived from biomass.

The printed layer contains a colorant in one embodiment. Examples of the colorant include pigments such as inorganic pigments and organic pigments; dyes such as acid dyes, direct dyes, disperse dyes, oil-soluble dyes, metal-containing oil-soluble dyes and sublimation dyes. Examples of the colorant include an ultraviolet light emitting material that emits fluorescence by absorbing ultraviolet rays, and a fluorescent light emitting material such as an infrared light emitting material that emits fluorescence by absorbing infrared rays.

The printed layer may contain a resin material in one embodiment. Examples of the resin material include cellulose resin, (meth) acrylic resin, urethane resin, alkyd resin, polyester, polycarbonate, polyolefin, polystyrene, norbornene-based resin, polyvinyl chloride, polyvinyl acetate and vinyl chloride-vinyl acetate copolymer. Can be mentioned.

[Laminate]
The laminate of the first to fourth aspects of the present disclosure includes a polyethylene multilayer base material and a heat seal layer containing polyethylene as a main component. The laminate of the fifth aspect of the present disclosure includes a base material and a heat seal layer. The laminate of another aspect of the present disclosure comprises the polyethylene multilayer substrate of the present disclosure and a heat seal layer.

[Laminates of the first to fourth aspects and other embodiments]
Hereinafter, the laminates of the first to fourth aspects and the laminates of other embodiments will be described, but when referring to the laminates with respect to the matters common to the laminates of these embodiments, "the laminates of the present disclosure" will be described. Also described.

As shown in FIG. 3, the laminate 30 of the present disclosure includes a polyethylene multilayer base material 10 and a heat seal layer 32. The polyethylene multilayer base material 10 may be the polyethylene multilayer base material of the present disclosure described above, or may be another polyethylene multilayer base material. In FIG. 3, in the case of the laminated body of the first to fourth aspects, or in the case of the multilayer base material of the first and second aspects, the second polyethylene layer and, if necessary, the second a and the second b. The intermediate layer including the polyethylene layer becomes the multilayer intermediate layer 16. In FIG. 3, in the case of the multilayer base material of the fourth and fifth aspects, the intermediate layer including the second layer, the third layer and the fourth layer becomes the multilayer intermediate layer 16.

In one embodiment, the laminate 30 further includes a print layer (not shown) on the multilayer substrate 10. The printed layer is usually on the surface layer provided with the heat seal layer in the multilayer substrate, for example, on the first polyethylene layer in the multilayer substrate of the first and second embodiments described above, and the multilayer substrate of the third aspect. It is formed on the layer (A) in the above, or on the first layer in the multilayer substrate of the fourth and fifth aspects. The details of the print layer are as described in the [Printing substrate] column, and the description in this column is omitted.

In one embodiment, as shown in FIG. 4, the laminate 30 includes a barrier layer 34 and an adhesive layer 36 between the multilayer base material 10 and the heat seal layer 32. In this embodiment, the barrier layer 34 is formed on the surface of the multilayer base material 10.

In one embodiment, as shown in FIG. 5, the laminate 30 includes an adhesive layer 36 and a barrier layer 34 between the multilayer base material 10 and the heat seal layer 32. In this embodiment, the barrier layer 34 is formed on the surface of the heat seal layer 32.

In one embodiment, as shown in FIG. 6, the laminate 30 includes an adhesive layer 36 between the multilayer base material 10 and the heat seal layer 32.

In the laminate of the present disclosure, the content ratio of polyethylene is preferably 90% by mass or more. This makes it possible to improve the recyclability of the laminated body. The polyethylene content ratio in the laminate means the ratio of the polyethylene content to the sum of the content of the resin material in each layer constituting the laminate.

The laminate of the first to fourth aspects of the present disclosure is
Polyethylene multilayer base material and
A laminate provided with a heat-sealed layer containing polyethylene as a main component.
Polyethylene multilayer base material,
The first PE layer and
The second PE layer and
A third PE layer is provided in this order in the thickness direction, and is stretched.

The laminate of the first aspect of the present disclosure satisfies the following requirement (C). The laminate of the second aspect of the present disclosure satisfies the following requirement (D). The laminate of the first aspect may further satisfy the following requirement (D).
Requirement (C): The indentation elastic modulus of the first PE layer is 3.5 times or more the indentation elastic modulus of the second PE layer, and the indentation elastic modulus of the third PE layer is the second PE layer. It is 3.5 times or more of the indentation elastic modulus of.
Requirement (D): The indentation hardness of the first PE layer is 2.0 times or more the indentation hardness of the second PE layer, and the indentation hardness of the third PE layer is the indentation hardness of the second PE layer. It is more than 2.0 times.

The laminate of the third aspect of the present disclosure satisfies the following requirement (E). The laminate of the fourth aspect of the present disclosure satisfies the following requirement (F). The laminate of the third aspect may further satisfy the following requirement (F).
Requirement (E): The indentation elastic modulus of the first PE layer is 1.0 GPa or more, and the indentation elastic modulus of the third PE layer is 1.0 GPa or more.
Requirement (F): The indentation hardness of the first PE layer is 45 MPa or more, and the indentation hardness of the third PE layer is 45 MPa or more.

The polyethylene multilayer substrate further includes a second PE layer between the first PE layer and the second PE layer, and a second PE layer between the second PE layer and the third PE layer. You may prepare. In this case, the multilayer base material has a first PE layer, a second PE layer, a second PE layer, a second PE layer, and a third PE layer in this order in the thickness direction. Be prepared. The second PE layer, the second PE layer, and the second PE layer form an intermediate layer (multilayer intermediate layer) in the multilayer substrate.

The polyethylene multilayer base material constituting the laminate of the first to fourth aspects of the present disclosure has, in one embodiment, the first aspect and the second aspect of the present disclosure described above except for the indentation elastic modulus and the indentation hardness. Since it is the same as the polyethylene multilayer base material of the above, and the laminated structure and the composition and thickness of each layer are as described above, detailed description in this column will be omitted. The indentation elastic modulus and indentation hardness in the polyethylene multilayer base material constituting the laminate of the first to fourth aspects of the present disclosure will be described below.

<Laminated body of the first aspect>
In the laminate of the first aspect of the present disclosure, the indentation elastic modulus of the first PE layer is 3.5 times or more the indentation elastic modulus of the second PE layer, and the indentation elastic modulus of the third PE layer. However, it is characterized in that it is 3.5 times or more the indentation elastic modulus of the second PE layer. As a result, the heat resistance of the laminated body can be improved, and for example, heat shrinkage of the laminated body at the time of heat application such as heat sealing can be suppressed.

The ratio (elastic modulus 1 / elastic modulus 2) and the ratio (elastic modulus 3 / elastic modulus 2) in the laminated body of the first aspect are independently 3.5 or more, preferably 4.0 or more, and more. It is preferably 4.5 or more, more preferably 5.0 or more, still more preferably 5.5 or more; preferably 16.0 or less, more preferably 14.0 or less, still more preferably 12.0 or less, and more. It is more preferably 10.0 or less, and particularly preferably 9.0 or less. The range of the ratio (modulus of elasticity 1 / elastic modulus 2) and the range of the ratio (modulus of elasticity 3 / elastic modulus 2) may be any combination of the above lower limit value and upper limit value, for example, 3.5. It may be 16.0 or less.

In the laminated body of the first aspect of the present disclosure, the indentation elastic modulus of the second PE layer is preferably 2.0 times or more the indentation elastic modulus of the second PE layer, and is more than 2.0 times the indentation elastic modulus of the second PE layer. The indentation elastic modulus is preferably 2.0 times or more the indentation elastic modulus of the second PE layer. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed.

The ratio (elastic modulus 2a / elastic modulus 2) and the ratio (elastic modulus 2b / elastic modulus 2) in the laminated body of the first aspect are independently, preferably 2.0 or more, more preferably 2.5 or more, respectively. It is more preferably 3.0 or more; preferably 14.0 or less, more preferably 12.0 or less, still more preferably 10.0 or less, still more preferably 9.0 or less, and particularly preferably 8.5 or less. be. The range of the ratio (elastic modulus 2a / elastic modulus 2) and the range of the ratio (elastic modulus 2b / elastic modulus 2) may be independently any combination of the above lower limit value and upper limit value, for example, 2.0. It may be 14.0 or less.

The indentation elastic modulus 1 and the indentation elastic modulus 3 in the laminated body of the first aspect are independently, preferably 1.0 GPa or more, more preferably 1.05 GPa or more, still more preferably 1.1 GPa or more, still more preferably 1.1 GPa or more. 1.15 GPa or more, particularly preferably 1.3 GPa or more; preferably 4.5 GPa or less, more preferably 4.0 GPa or less, still more preferably 3.5 GPa or less, still more preferably 3.0 GPa or less, particularly preferably. It is 2.5 GPa or less, 2.0 GPa or less, or 1.8 GPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The ranges of the indentation elastic modulus 1 and the indentation elastic modulus 3 may be independently arbitrary combinations of the above lower limit value and upper limit value, and may be, for example, 1.0 GPa or more and 4.5 GPa or less.

The indentation elastic modulus 2 in the laminate of the first aspect is preferably 0.03 GPa or more, more preferably 0.05 GPa or more, still more preferably 0.1 GPa or more, still more preferably 0.13 GPa or more, and particularly preferably 0. It is .15 GPa or more; preferably 0.7 GPa or less, more preferably 0.6 GPa or less, still more preferably 0.5 GPa or less, still more preferably 0.4 GPa or less, and particularly preferably 0.3 GPa or less. With such a design, for example, the stretchability of the pre-stretched laminate tends to be more excellent. The range of the indentation elastic modulus 2 may be any combination of the above lower limit value and upper limit value, and may be, for example, 0.03 GPa or more and 0.7 GPa or less.

The indentation elastic modulus 2a and the indentation elastic modulus 2b in the laminated body of the first aspect are independently, preferably 0.3 GPa or more, more preferably 0.4 GPa or more, still more preferably 0.5 GPa or more, still more preferably 0.5 GPa or more. It is 0.6 GPa or more; preferably 3.5 GPa or less, more preferably 3.0 GPa or less, still more preferably 2.5 GPa or less, still more preferably 2.0 GPa or less, and particularly preferably 1.5 GPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The ranges of the indentation elastic modulus 2a and the indentation elastic modulus 2b may be independently arbitrary combinations of the above lower limit value and upper limit value, and may be, for example, 0.3 GPa or more and 3.5 GPa or less.

In the laminated body of the first aspect, the magnitude of the indentation elastic modulus of each PE layer preferably satisfies the relationship of indentation elastic modulus 1> indentation elastic modulus 2a> indentation elastic modulus 2, and indentation elastic modulus 3> indentation elastic modulus. It is preferable to satisfy the relationship of rate 2b> indentation elastic modulus 2. This tends to further improve the balance between the heat resistance of the multilayer base material and the stretchability (processability, productivity), for example.

In the laminate of the first aspect, the ratio (elastic modulus 1 / elastic modulus 3) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0.8. It is 1.2 or more, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the laminate of the first aspect, the ratio (elastic modulus 2a / elastic modulus 2b) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, still more preferably 0.8. It is 1.2 or more, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

<Laminated body of the second aspect>
In the laminate of the second aspect of the present disclosure, the indentation hardness of the first PE layer is 2.0 times or more the indentation hardness of the second PE layer, and the indentation hardness of the third PE layer is the second. It is characterized in that it is 2.0 times or more the indentation hardness of the PE layer of 2. As a result, the heat resistance of the laminated body can be improved, and for example, heat shrinkage of the laminated body at the time of heat application such as heat sealing can be suppressed.

The ratio (hardness 1 / hardness 2) and the ratio (hardness 3 / hardness 2) in the laminate of the second aspect are independently 2.0 or more, preferably 2.2 or more, and more preferably 2. 4 or more, more preferably 2.6 or more, even more preferably 2.8 or more; preferably 6.0 or less, more preferably 5.5 or less, still more preferably 5.0 or less, still more preferably 4 It is 5.5 or less, particularly preferably 4.0 or less or 3.5 or less. The range of the ratio (hardness 1 / hardness 2) and the range of the ratio (hardness 3 / hardness 2) may be independently any combination of the above lower limit value and upper limit value, for example, 2.0 or more and 6.0. It may be as follows. The laminate of the first aspect may further satisfy the above requirements relating to the ratio (hardness 1 / hardness 2) and the ratio (hardness 3 / hardness 2).

In the laminated body of the second aspect of the present disclosure, the indentation hardness of the second PE layer is preferably 1.5 times or more the indentation hardness of the second PE layer, and the indentation hardness of the second PE layer. Is preferably 1.5 times or more the indentation hardness of the second PE layer. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed.

The ratio (hardness 2a / hardness 2) and the ratio (hardness 2b / hardness 2) in the laminate of the second aspect are independently, preferably 1.5 or more, more preferably 1.7 or more, still more preferably 1. 9.9 or more; preferably 6.0 or less, more preferably 5.5 or less, still more preferably 5.0 or less, even more preferably 4.5 or less, particularly preferably 4.0 or less or 3.5 or less. Is. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The range of the ratio (hardness 2a / hardness 2) and the range of the ratio (hardness 2b / hardness 2) may be independently any combination of the above lower limit value and upper limit value, for example, 1.5 or more and 6.0. It may be as follows. The laminate of the first aspect may further satisfy the above requirements relating to the ratio (hardness 2a / hardness 2) and the ratio (hardness 2b / hardness 2).

The indentation hardness 1 and the indentation hardness 3 in the laminate of the second aspect are independently, preferably 45 MPa or more, more preferably 48 MPa or more, still more preferably 50 MPa or more, still more preferably 52 MPa or more; preferably 110 MPa or more. Below, it is more preferably 90 MPa or less, further preferably 80 MPa or less, still more preferably 75 MPa or less, and particularly preferably 70 MPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The range of the indentation hardness 1 and the indentation hardness 3 may be any combination of the above lower limit value and the upper limit value independently, and may be, for example, 45 MPa or more and 110 MPa or less. The laminate of the first aspect may further satisfy the above requirements relating to the indentation hardness 1 and the indentation hardness 3.

The indentation hardness 2 in the laminate of the second aspect is preferably 1 MPa or more, more preferably 3 MPa or more, still more preferably 7 MPa or more, still more preferably 10 MPa or more, particularly preferably 15 MPa or more; preferably 40 MPa or less, It is more preferably 35 MPa or less, further preferably 30 MPa or less, still more preferably 26 MPa or less, and particularly preferably 23 MPa or less. With such a design, for example, the stretchability of the pre-stretched laminate tends to be more excellent. The range of the indentation hardness 2 may be any combination of the above lower limit value and the upper limit value, and may be, for example, 1 MPa or more and 40 MPa or less. The laminate of the first aspect may further satisfy the above requirement relating to the indentation hardness 2.

The indentation hardness 2a and the indentation hardness 2b in the laminate of the second aspect are independently, preferably 20 MPa or more, more preferably 30 MPa or more, still more preferably 35 MPa or more, still more preferably 37 MPa or more; preferably 100 MPa or more. Below, it is more preferably 80 MPa or less, further preferably 70 MPa or less, still more preferably 65 MPa or less, and particularly preferably 60 MPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The range of the indentation hardness 2a and the indentation hardness 2b may be independently any combination of the above lower limit value and the upper limit value, and may be, for example, 20 MPa or more and 100 MPa or less. The laminate of the first aspect may further satisfy the above requirements relating to the indentation hardness 2a and the indentation hardness 2b.

In the laminate of the second aspect, the magnitude of the indentation hardness of each PE layer preferably satisfies the relationship of indentation hardness 1> indentation hardness 2a> indentation hardness 2, and indentation hardness 3> indentation hardness 2b> indentation hardness 2 It is preferable to satisfy the relationship of. This tends to further improve the balance between the heat resistance of the multilayer base material and the stretchability (processability, productivity), for example.

In the laminate of the second aspect, the ratio (hardness 1 / hardness 3) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, still more preferably 0.8 or more and 1 It is .2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the laminate of the second aspect, the ratio (hardness 2a / hardness 2b) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0.8 or more and 1 It is .2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

<Laminated body of the third aspect>
The laminate of the third aspect of the present disclosure is characterized in that the indentation elastic modulus of the first PE layer is 1.0 GPa or more and the indentation elastic modulus of the third PE layer is 1.0 GPa or more. And. As a result, the heat resistance of the laminated body can be improved, and for example, heat shrinkage of the laminated body at the time of heat application such as heat sealing can be suppressed.

The indentation elastic modulus 1 and the indentation elastic modulus 3 in the laminated body of the third aspect are independently 1.0 GPa or more, preferably 1.05 GPa or more, more preferably 1.1 GPa or more, and further preferably 1. 15 GPa or more, particularly preferably 1.3 GPa or more; preferably 4.5 GPa or less, more preferably 4.0 GPa or less, still more preferably 3.5 GPa or less, still more preferably 3.0 GPa or less, particularly preferably 2. It is 5 GPa or less, 2.0 GPa or less, or 1.8 GPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The ranges of the indentation elastic modulus 1 and the indentation elastic modulus 3 may be independently arbitrary combinations of the above lower limit value and upper limit value, and may be, for example, 1.0 GPa or more and 4.5 GPa or less.

The indentation elastic modulus 2 in the laminate of the third aspect is preferably 0.03 GPa or more, more preferably 0.05 GPa or more, still more preferably 0.1 GPa or more, still more preferably 0.13 GPa or more, and particularly preferably 0. It is .15 GPa or more; preferably 0.7 GPa or less, more preferably 0.6 GPa or less, still more preferably 0.5 GPa or less, still more preferably 0.4 GPa or less, and particularly preferably 0.3 GPa or less. With such a design, for example, the stretchability of the pre-stretched laminate tends to be more excellent. The range of the indentation elastic modulus 2 may be any combination of the above lower limit value and upper limit value, and may be, for example, 0.03 GPa or more and 0.7 GPa or less.

The indentation elastic modulus 2a and the indentation elastic modulus 2b in the laminated body of the third aspect are independently, preferably 0.3 GPa or more, more preferably 0.4 GPa or more, still more preferably 0.5 GPa or more, still more preferably 0.5 GPa or more. It is 0.6 GPa or more; preferably 3.5 GPa or less, more preferably 3.0 GPa or less, still more preferably 2.5 GPa or less, still more preferably 2.0 GPa or less, and particularly preferably 1.5 GPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The ranges of the indentation elastic modulus 2a and the indentation elastic modulus 2b may be independently arbitrary combinations of the above lower limit value and upper limit value, and may be, for example, 0.3 GPa or more and 3.5 GPa or less.

In the laminated body of the third aspect, the magnitude of the indentation elastic modulus of each PE layer preferably satisfies the relationship of indentation elastic modulus 1> indentation elastic modulus 2a> indentation elastic modulus 2, and indentation elastic modulus 3> indentation elastic modulus. It is preferable to satisfy the relationship of rate 2b> indentation elastic modulus 2. This tends to further improve the balance between the heat resistance of the multilayer base material and the stretchability (processability, productivity), for example.

In the laminated body of the third aspect, the indentation elastic modulus of the first PE layer is preferably 3.5 times or more the indentation elastic modulus of the second PE layer, and the indentation elastic modulus of the third PE layer. Is preferably 3.5 times or more the indentation elastic modulus of the second PE layer. As a result, the heat resistance of the laminated body can be improved, and for example, the thermal shrinkage of the laminated body at the time of heat application such as heat sealing can be further suppressed.

The ratio (elastic modulus 1 / elastic modulus 2) and the ratio (elastic modulus 3 / elastic modulus 2) in the laminated body of the third aspect are independently, preferably 3.5 or more, more preferably 4.0 or more, respectively. More preferably 4.5 or more, even more preferably 5.0 or more, particularly preferably 5.5 or more; preferably 16.0 or less, more preferably 14.0 or less, still more preferably 12.0 or less, It is even more preferably 10.0 or less, and particularly preferably 9.0 or less. The range of the ratio (modulus of elasticity 1 / elastic modulus 2) and the range of the ratio (modulus of elasticity 3 / elastic modulus 2) may be any combination of the above lower limit value and upper limit value, for example, 3.5. It may be 16.0 or less.

In the laminated body of the third aspect, the indentation elastic modulus of the second PE layer is preferably 2.0 times or more the indentation elastic modulus of the second PE layer, and the indentation elastic modulus of the second PE layer. Is preferably 2.0 times or more the indentation elastic modulus of the second PE layer. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed.

The ratio (elastic modulus 2a / elastic modulus 2) and the ratio (elastic modulus 2b / elastic modulus 2) in the laminated body of the third aspect are independently, preferably 2.0 or more, more preferably 2.5 or more, respectively. It is more preferably 3.0 or more; preferably 14.0 or less, more preferably 12.0 or less, still more preferably 10.0 or less, still more preferably 9.0 or less, and particularly preferably 8.5 or less. be. The range of the ratio (elastic modulus 2a / elastic modulus 2) and the range of the ratio (elastic modulus 2b / elastic modulus 2) may be independently any combination of the above lower limit value and upper limit value, for example, 2.0. It may be 14.0 or less.

In the laminate of the third aspect, the ratio (elastic modulus 1 / elastic modulus 3) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0.8. It is 1.2 or more, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the laminate of the third aspect, the ratio (elastic modulus 2a / elastic modulus 2b) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, still more preferably 0.8. It is 1.2 or more, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

<Laminated body of the fourth aspect>
The laminate of the fourth aspect of the present disclosure is characterized in that the indentation hardness of the first PE layer is 45 MPa or more, and the indentation hardness of the third PE layer is 45 MPa or more. As a result, the heat resistance of the laminated body can be improved, and for example, heat shrinkage of the laminated body at the time of heat application such as heat sealing can be suppressed.

The indentation hardness 1 and the indentation hardness 3 in the laminate of the fourth aspect are independently 45 MPa or more, preferably 48 MPa or more, more preferably 50 MPa or more, still more preferably 52 MPa or more; preferably 110 MPa or less, respectively. It is more preferably 90 MPa or less, further preferably 80 MPa or less, still more preferably 75 MPa or less, and particularly preferably 70 MPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The range of the indentation hardness 1 and the indentation hardness 3 may be any combination of the above lower limit value and the upper limit value independently, and may be, for example, 45 MPa or more and 110 MPa or less. The laminate of the third aspect may further satisfy the above requirements relating to the indentation hardness 1 and the indentation hardness 3.

The indentation hardness 2 in the laminate of the fourth aspect is preferably 1 MPa or more, more preferably 3 MPa or more, further preferably 7 MPa or more, still more preferably 10 MPa or more, particularly preferably 15 MPa or more; preferably 40 MPa or less, It is more preferably 35 MPa or less, further preferably 30 MPa or less, still more preferably 26 MPa or less, and particularly preferably 23 MPa or less. With such a design, for example, the stretchability of the pre-stretched laminate tends to be more excellent. The range of the indentation hardness 2 may be any combination of the above lower limit value and the upper limit value, and may be, for example, 1 MPa or more and 40 MPa or less. The laminate of the third aspect may further satisfy the above requirement relating to the indentation hardness 2.

The indentation hardness 2a and the indentation hardness 2b in the laminate of the fourth aspect are independently, preferably 20 MPa or more, more preferably 30 MPa or more, still more preferably 35 MPa or more, still more preferably 37 MPa or more; preferably 100 MPa or more. Below, it is more preferably 80 MPa or less, further preferably 70 MPa or less, still more preferably 65 MPa or less, and particularly preferably 60 MPa or less. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The range of the indentation hardness 2a and the indentation hardness 2b may be independently any combination of the above lower limit value and the upper limit value, and may be, for example, 20 MPa or more and 100 MPa or less. The laminate of the third aspect may further satisfy the above requirements relating to the indentation hardness 2a and the indentation hardness 2b.

In the laminate of the fourth aspect, the magnitude of the indentation hardness of each PE layer preferably satisfies the relationship of indentation hardness 1> indentation hardness 2a> indentation hardness 2, and indentation hardness 3> indentation hardness 2b> indentation hardness 2 It is preferable to satisfy the relationship of. This tends to further improve the balance between the heat resistance of the multilayer base material and the stretchability (processability, productivity), for example.

In the laminated body of the fourth aspect, the indentation hardness of the first PE layer is preferably 2.0 times or more the indentation hardness of the second PE layer, and the indentation hardness of the third PE layer is the second. It is preferably 2.0 times or more the indentation hardness of the PE layer of 2. As a result, the heat resistance of the laminated body can be improved, and for example, the thermal shrinkage of the laminated body at the time of heat application such as heat sealing can be further suppressed.

The ratio (hardness 1 / hardness 2) and the ratio (hardness 3 / hardness 2) in the laminate of the fourth aspect are independently, preferably 2.0 or more, more preferably 2.2 or more, still more preferably 2. It is 4.4 or more, more preferably 2.6 or more, particularly preferably 2.8 or more; preferably 6.0 or less, more preferably 5.5 or less, still more preferably 5.0 or less, still more preferably. It is 4.5 or less, particularly preferably 4.0 or less or 3.5 or less. The range of the ratio (hardness 1 / hardness 2) and the range of the ratio (hardness 3 / hardness 2) may be independently any combination of the above lower limit value and upper limit value, for example, 2.0 or more and 6.0. It may be as follows. The laminate of the third aspect may further satisfy the above requirements relating to the ratio (hardness 1 / hardness 2) and the ratio (hardness 3 / hardness 2).

In the laminated body of the fourth aspect, the indentation hardness of the second PE layer is preferably 1.5 times or more the indentation hardness of the second PE layer, and the indentation hardness of the second PE layer is the first. It is preferably 1.5 times or more the indentation hardness of the PE layer of 2. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed.

The ratio (hardness 2a / hardness 2) and the ratio (hardness 2b / hardness 2) in the laminate of the fourth aspect are independently, preferably 1.5 or more, more preferably 1.7 or more, still more preferably 1. 9.9 or more; preferably 6.0 or less, more preferably 5.5 or less, still more preferably 5.0 or less, even more preferably 4.5 or less, particularly preferably 4.0 or less or 3.5 or less. Is. Thereby, for example, there is a tendency that the heat shrinkage of the laminated body at the time of heat sealing can be further suppressed. The range of the ratio (hardness 2a / hardness 2) and the range of the ratio (hardness 2b / hardness 2) may be independently any combination of the above lower limit value and upper limit value, for example, 1.5 or more and 6.0. It may be as follows. The laminate of the third aspect may further satisfy the above requirements relating to the ratio (hardness 2a / hardness 2) and the ratio (hardness 2b / hardness 2).

In the laminate of the fourth aspect, the ratio (hardness 1 / hardness 3) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, still more preferably 0.8 or more and 1 It is .2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

In the laminate of the fourth aspect, the ratio (hardness 2a / hardness 2b) is preferably 0.6 or more and 1.7 or less, more preferably 0.7 or more and 1.4 or less, and further preferably 0.8 or more and 1 It is .2 or less, more preferably 0.9 or more and 1.1 or less. Thereby, for example, the symmetry of the layer structure of the multilayer base material can be improved, and therefore the curl of the multilayer base material can be suppressed, and the processability of printing and laminating tends to be improved.

The laminate of the present disclosure exhibits the following heat shrinkage in one embodiment. For example, the laminated body of the first to fourth aspects of the present disclosure and the laminated body provided with the multilayer base material of the first to fifth aspects show the following heat shrinkage rate in one embodiment. MD refers to the longitudinal direction or flow direction of the laminated body, and TD refers to the direction perpendicular to MD.

The heat shrinkage (MD) of the MD of the laminated body is, for example, 15% or less, preferably 13% or less, more preferably 11% or less, still more preferably 10% or less, still more preferably 8% or less, and particularly preferably. Is less than 7%. The lower the lower limit of the heat shrinkage (MD) is preferable, but it may be, for example, 0.5%, 1%, 2% or 3%. A laminate having such a small heat shrinkage rate (MD) is excellent in, for example, printability and bag making suitability when manufacturing a packaging bag by heat sealing.

The heat shrinkage (TD) of the TD of the laminate is, for example, 15% or less, preferably 13% or less, more preferably 11% or less, still more preferably 10% or less, still more preferably 8% or less, particularly preferably. Is less than 7%. The lower the lower limit of the heat shrinkage (MD) is preferable, but it may be, for example, 0.5%, 1%, 2% or 3%. A laminate having such a small heat shrinkage rate (TD) is excellent in, for example, printability and bag making suitability when manufacturing a packaging bag by heat sealing.

The ratio (MD / TD) of the heat shrinkage rate (MD) to the heat shrinkage rate (TD) of the laminate is preferably 0.5 or more and 2.0 or less, more preferably 0.7 or more and 1.4 or less, and further. It is preferably 0.8 or more and 1.2 or less, and particularly preferably 0.9 or more and 1.1 or less. When the ratio (MD / TD) is in such a range, the laminate shrinks relatively uniformly to MD and TD even after being heat-treated, so that distortion of the image in the print layer of the laminate can be suppressed, for example. ..

The heat shrinkage rate of the laminated body is measured as follows. The laminate is cut into 10 cm × 10 cm to prepare three sample pieces. Fold each sample piece in half parallel to MD or TD so that the heat seal layer side is on the inside, and use a heat seal tester at a temperature of 120 ° C, pressure of 1 kgf / cm ² , and 1.5 cm x for 1 second. A 10 cm area is heat-sealed (see FIG. 7). In FIG. 7, the shaded area indicates the heat-sealed part. After heat sealing, the seal width of the sample is measured, and the shrinkage rate of MD (see FIG. 7A) and the shrinkage rate of TD (see FIG. 7B) are calculated. The average value of the three sample pieces is taken as each heat shrinkage rate.

Each heat shrinkage rate is calculated by the following formula.
Heat shrinkage rate (MD) (%) = {(Length of the heat-sealed part of the laminated body in the MD direction (1.5 cm) -Length of the heat-sealed part of the laminated body after heat-sealing in the MD direction) / Laminating Length of the planned heat seal part of the body in the MD direction (1.5 cm)} x 100
Heat shrinkage rate (TD) (%) = {(Length of the heat-sealed part of the laminated body in the TD direction (1.5 cm) -Length of the heat-sealed part of the laminated body after heat-sealing in the TD direction) / Laminating Length of the planned heat seal part of the body in the TD direction (1.5 cm)} x 100

As an example, when the laminate is sealed with a 1.5 cm heat seal bar, if the seal width of the sample is 1.4 cm, the heat shrinkage rate is (1.5-1.4) /. It becomes 1.5 × 100 = 6.7%.

<Heat seal layer>
The laminate of the present disclosure comprises a heat seal layer.
The heat seal layer is preferably made of polyethylene. In one embodiment, the heat seal layer is a layer containing polyethylene as a main component, that is, a layer containing polyethylene in a range of more than 50% by mass. The content ratio of polyethylene in the heat seal layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more. .. With such a configuration, a laminate for packaging materials having sufficient rigidity, strength, heat resistance, and excellent recyclability can be obtained.

Hereinafter, the recyclability will be described.
Compared with other thermoplastic resin films, polyethylene films are inferior in heat resistance, so when used as a base material for packaging materials, they may be deformed during heat sheets. Further, since the polyethylene film has poor rigidity, its printability is low, and a clear image cannot be formed on the surface thereof. In addition, the polyethylene film does not have high strength and cannot meet the durability required as an outer layer of the packaging material. Therefore, a laminated body is obtained by laminating a resin film (base material) having excellent rigidity, strength and heat resistance such as a polyester film and a nylon film and a polyethylene film (heat seal layer), and the polyethylene film of the laminated body is obtained. The packaging material is manufactured by heat-sealing the end of the laminate so that the side is on the inside.

In recent years, with the growing demand for the construction of a sound material-cycle society, attempts have been made to recycle and use packaging materials. However, when a laminate is produced by laminating different types of resin films as described above, it is difficult to separate the resin films from each other. Therefore, such a laminate is not suitable for recycling.

On the other hand, since the polyethylene multilayer base material of the present disclosure is stretched as described above and has a unique layer structure in one embodiment, it has, for example, rigidity, as compared with the conventional polyethylene film. It has excellent strength and heat resistance, and also has excellent ink adhesion. Therefore, the polyethylene multilayer base material of the present disclosure can be used, for example, as a base material for a packaging material, and a clear image can be formed on the surface of the multilayer base material.

In one embodiment, the laminate of the present disclosure includes the above-mentioned polyethylene multilayer base material and a heat-sealing layer containing polyethylene as a main component (hereinafter, also referred to as “heat-sealing polyethylene layer”). In one embodiment, a print layer (image) is formed on at least one surface of the multilayer substrate. Since deterioration of the image over time can be prevented, it is preferable that the printing layer is formed on the side of the multilayer base material on which the heat-sealing polyethylene layer is provided.

In one embodiment, the first polyethylene layer or the third polyethylene layer in the multilayer substrate of the first aspect and the second aspect constitutes a surface layer on one side of the laminate, and the heat seal layer is laminated. It constitutes the surface layer on the other side of the body.

In the laminated body including the polyethylene multilayer base material and the heat-sealing polyethylene layer, the resin layer contained in the laminated body is a polyethylene layer in one embodiment, and the laminated body is a polyester film and a nylon film. It does not have a different kind of resin film such as. Further, the polyethylene multilayer base material satisfies the rigidity, strength, heat resistance and the like required for the outer layer film of the packaging material, and the heat-sealable polyethylene layer enables packaging. Therefore, the laminate is suitable as a material for constituting a packaging material that is required to be recyclable.

In one embodiment, the laminate of the present disclosure comprises only the polyethylene multilayer base material on which a printed layer is formed, if necessary, and a heat seal layer made of polyethylene. As a result, in the laminate of the present disclosure, since each resin layer is made of polyethylene, which is the same material, recyclability can be particularly improved.

The heat seal layer is usually a layer that is not stretched. For example, a heat-sealed layer is formed by laminating an unstretched polyethylene film on a multilayer base material or the like via an adhesive layer as needed, or by melt-extruding a resin material containing polyethylene onto a multilayer base material or the like. Can be formed. Examples of the adhesive layer include an adhesive layer described later.

Examples of the polyethylene constituting the heat-sealing layer include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. Linear low density polyethylene and ultra low density polyethylene are preferable. From the viewpoint of reducing the environmental load, polyethylene derived from biomass or recycled polyethylene may be used.

The content ratio of polyethylene in the heat seal layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.
The heat seal layer may contain one or more of the above additives.

The heat seal layer may be one layer or two or more layers. In one embodiment, the number of heat seal layers is 1 or more and 3 or less.
The thickness of the heat seal layer is, for example, 10 μm or more and 300 μm or less.
The thickness of the heat-sealed layer may be appropriately changed from the viewpoint of the strength of the heat-sealed layer and the processability of the laminated body, depending on the mass of the contents to be filled in the packaging material produced by the laminated body of the present disclosure, for example. preferable.

For example, when the packaging material is a pouch, the thickness of the heat seal layer is preferably 20 μm or more and 60 μm or less. In this case, for example, the contents of 1 g or more and 200 g or less are well filled in the pouch.

For example, when the packaging material is a stand pouch, the thickness of the heat seal layer is preferably 50 μm or more and 200 μm or less. In this case, for example, the contents of 50 g or more and 2000 g or less are well filled in the stand pouch.

<Barrier layer>
In one embodiment, the laminate of the present disclosure comprises a barrier layer between the multilayer substrate and the heat seal layer. Thereby, the gas barrier property of the laminated body, specifically, the oxygen barrier property and the water vapor barrier property can be improved. The barrier layer may be formed on the surface of the multilayer base material or may be formed on the surface of the heat seal layer.

A barrier layer may be provided between the multilayer base material and the heat seal layer via an adhesive or the like. For example, a barrier film provided with a second base material and a barrier layer formed on the second base material between the multilayer base material and the heat seal layer is provided, if necessary, via an adhesive or the like. It may be provided. In this aspect, from the viewpoint of recyclability, the second base material in the barrier film is preferably made of polyethylene. The content ratio of polyethylene in the second base material is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

In one embodiment, the barrier layer is a thin-film deposition layer. The vapor-filmed layer is composed of, for example, a metal such as aluminum and an inorganic oxide such as aluminum oxide, silicon oxide, magsium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide and barium oxide. Among these, the aluminum vapor deposition layer is preferable.

The thickness of the barrier layer is preferably 1 nm or more and 150 nm or less, more preferably 5 nm or more and 60 nm or less, and further preferably 10 nm or more and 40 nm or less. By setting the thickness of the barrier layer to 1 nm or more, the oxygen barrier property and the water vapor barrier property of the laminated body can be further improved. By setting the thickness of the barrier layer to 150 nm or less, it is possible to suppress the occurrence of cracks in the barrier layer and improve the recyclability of the laminated body.

Examples of the method for forming the barrier layer include a physical vapor deposition method (PVD method) such as a vacuum vapor deposition method, a sputtering method and an ion plating method; and a plasma chemical vapor deposition method, a thermochemical vapor deposition method and a photochemical vapor deposition method. Examples thereof include a chemical vapor deposition method (CVD method) such as a phase growth method. The barrier layer may be a composite film containing two or more barrier layers of different kinds of inorganic oxides, which are formed by using both the physical vapor deposition method and the chemical vapor deposition method in combination.

The degree of vacuum of the vapor deposition chamber is preferably about ^10-2 to ^10-8 mbar before the introduction of oxygen, and preferably about 10-1 to ^10-6 ^mbar after the introduction of oxygen. The amount of oxygen introduced depends on the size of the vapor deposition machine. As the introduced oxygen, an inert gas such as argon gas, helium gas and nitrogen gas may be used as the carrier gas within a range that does not hinder. The transport speed of the multilayer base material is, for example, about 10 to 800 m / min.

It is preferable that the surface of the barrier layer is subjected to the above-mentioned surface treatment. This makes it possible to improve the adhesion between the barrier layer and the adjacent layer.

When the vapor-deposited layer is composed of an inorganic oxide such as aluminum oxide and silicon oxide, a barrier coat layer may be provided on the surface of the vapor-deposited layer to form a barrier layer having the vapor-deposited layer and the barrier coat layer. In one embodiment, the laminate of the present disclosure includes a multilayer base material, an inorganic oxide-deposited layer, a barrier coat layer, and a heat seal layer in this order in the thickness direction. With such a configuration, for example, the oxygen barrier property and the water vapor barrier property of the laminated body can be improved, and the generation of cracks in the inorganic oxide vapor-deposited layer can be effectively suppressed.

In one embodiment, the barrier coat layer is composed of a gas barrier resin. Examples of the gas barrier resin include polyamide resins such as ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, nylon 6, nylon 6,6 and polymethoxylylen adipamide (MXD6), and polyester resins. Examples include polyurethane resin and (meth) acrylic resin.

The thickness of the barrier coat layer is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less. By setting the thickness of the barrier coat layer to 0.01 μm or more, the gas barrier property can be further improved. By setting the thickness of the barrier coat layer to 10 μm or less, the processability of the laminated body can be improved. Further, it can be a laminate that can be suitably used for manufacturing a monomaterial packaging container.

The barrier coat layer can be formed by dissolving or dispersing a material such as a gas barrier resin in water or an appropriate organic solvent, and applying and drying the obtained coating liquid.

In another embodiment, the barrier coat layer is a hydrolyzed metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer in the presence of a sol-gel method catalyst, water, an organic solvent, or the like by a sol-gel method. A gas barrier coating film formed from a composition containing a decomposition product or a hydrolyzed condensate of a metal alkoxide.
By providing such a barrier coat layer on the thin-film deposition layer, it is possible to effectively prevent the occurrence of cracks in the thin-film deposition layer.

In one embodiment, the metal alkoxide is represented by the following general formula.
R ¹ _n M (OR ² ) _m
In the above formula, R ¹ and R ² independently represent an organic group having 1 or more carbon atoms and 8 or less carbon atoms, M represents a metal atom, n represents an integer of 0 or more, and m represents an integer of 1 or more. , N + m represent the valence of M.

Examples of the organic group represented by R ¹ and R ² include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples of the metal atom M include silicon, zirconium, titanium and aluminum.

Examples of the metal alkoxide satisfying the above general formula include tetramethoxysilane (Si (OCH ₃ ) ₄ ), tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ), and tetrapropoxysilane (Si (OC ₃ H ₇ ) ₄ ). ), And tetrabutoxysilane (Si (OC ₄ H ₉ ) ₄ ).

It is preferable to use a silane coupling agent together with the above metal alkoxide. As the silane coupling agent, known organic reactive group-containing organoalkoxysilanes can be used.

As the water-soluble polymer, polyvinyl alcohol and ethylene-vinyl alcohol copolymer are preferable. Either one of polyvinyl alcohol and ethylene-vinyl alcohol copolymer may be used, or both may be used in combination, depending on desired physical properties such as oxygen barrier property, water vapor barrier property, water resistance and weather resistance. Further, a gas barrier coating film obtained by using polyvinyl alcohol and a gas barrier coating film obtained by using an ethylene-vinyl alcohol copolymer may be laminated.

As the sol-gel method catalyst, an acid or amine compound is suitable.

The above composition may further contain an acid. The acid is used as a sol-gel catalyst, mainly as a catalyst for hydrolysis of metal alkoxides and silane coupling agents. Examples of the acid include mineral acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as acetic acid and tartaric acid.

The above composition may contain an organic solvent. Examples of the organic solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol and n-butanol.

The thickness of the gas barrier coating film is preferably 0.01 μm or more and 100 μm or less, and more preferably 0.1 μm or more and 50 μm or less. Thereby, the gas barrier property can be further improved. By setting the thickness of the gas barrier coating film to 0.01 μm or more, the oxygen barrier property and the water vapor barrier property of the laminated body can be improved, and the generation of cracks in the thin-film deposition layer can be prevented. By setting the thickness of the gas barrier coating film to 100 μm or less, a laminate that can be suitably used for producing a monomaterial packaging container can be obtained.

The gas barrier coating film is prepared by applying a composition containing the above materials by a conventionally known means such as a roll coat such as a gravure roll coater, a spray coat, a spin coat, a dipping, a brush, a bar coat and an applicator. The composition can be formed by polycondensing by the sol-gel method.

An embodiment of a method for forming a gas barrier coating film will be described below. First, a composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel method catalyst, water, an organic solvent and, if necessary, a silane coupling agent. The polycondensation reaction gradually proceeds in the composition. Next, the composition is applied and dried on the thin-film deposition layer by the conventionally known means. By this drying, the polycondensation reaction of the metal alkoxide and the water-soluble polymer (and the silane coupling agent when the above composition contains a silane coupling agent) further proceeds, and a layer of the composite polymer is formed. Finally, by heating, a gas barrier coating film can be formed.

<Adhesive layer>
In one embodiment, the laminate of the present disclosure is any layer (eg, between a multilayer substrate and a barrier layer, between a barrier layer and a heat seal layer, or between a multilayer substrate and a heat seal layer). Also provided with an adhesive layer. Thereby, the adhesion between the layers contained in the laminated body can be improved.

The adhesive layer contains one or more adhesives. Examples of the adhesive include a one-component curable adhesive, a two-component curable adhesive, and a non-curable adhesive.

The adhesive may be a solvent-free adhesive or a solvent-type adhesive, and a solvent-free adhesive is preferable from the viewpoint of environmental load. Examples of the solvent-free adhesive include a polyether adhesive, a polyester adhesive, a silicone adhesive, an epoxy adhesive and a urethane adhesive. Examples of the solvent-based adhesive include rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, olefin-based adhesives, and urethane-based adhesives. Among these, a two-component curing type urethane adhesive is preferable.

The adhesive layer may contain one or more additives. Additives include, for example, pigments, dyes, lubricants, colorants, wetting agents, thickeners, coagulants, gelling agents, antioxidants, softeners, hardeners, plasticizers, leveling agents, antioxidants, etc. Examples include UV absorbers, light stabilizers and flame retardants.

In the case of an adhesive layer adjacent to a barrier layer such as an aluminum vapor-deposited layer, it is preferable to form the adhesive layer with a cured product of a resin composition containing a polyester polyol, an isocyanate compound and a phosphoric acid-modified compound. By having such a structure of the adhesive layer, the oxygen barrier property and the water vapor barrier property of the laminate of the present disclosure can be further improved.

The thickness of the adhesive layer is preferably 0.5 μm or more and 6 μm or less, more preferably 0.8 μm or more and 5 μm or less, and further preferably 1 μm or more and 4.5 μm or less, from the viewpoint of the adhesiveness of the adhesive layer and the processability of the laminated body. Is.

The adhesive layer is formed by applying and drying an adhesive on a multilayer substrate or the like by, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a fonten method, a transfer roll coating method, or the like. It can be formed by doing.

[Laminate of the fifth aspect]
The laminate of the fifth aspect of the present disclosure includes a base material and a heat seal layer.
In the laminate of the fifth aspect of the present disclosure, the base material and the heat seal layer are made of the same kind of resin material. That is, the base material is made of a resin material, and the heat seal layer is made of a resin material of the same type as the resin material constituting the base material. By using a laminate having such a structure, for example, a packaging material having excellent recyclability can be produced.

The same type of resin material means a resin material having a common basic structure, and is not limited to the completely same resin material. The same type of resin material includes a resin material having a common main monomer among the monomers forming the resin material. For example, when the main monomer is described as Monomer A, the homopolymer of Monomer A, the copolymer of Monomer A and Monomer B, and the copolymer of Monomer A, Monomer B, and Monomer C are of the same type. Classified as a resin material.

Examples of polyethylene include high-density polyethylene and linear low-density polyethylene, which are classified into the same type of resin material. For example, examples of polyester include polyethylene terephthalate and polyethylene naphthalate, which are classified into the same type of resin material.

The content ratio of the same type of resin material in the entire laminate of the fifth aspect of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more. Since such a laminate uses the same type of resin material, it can be classified as a so-called monomaterial material, and the recyclability of the laminate can be improved.

In one embodiment, the same kind of resin material is polyolefin. In this case, the content ratio of the polyolefin in the entire laminate of the fifth aspect is preferably 80% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass or more. In one embodiment, the content ratio of polyethylene or polypropylene in the entire laminate of the fifth aspect is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more.

In one embodiment, the same kind of resin material is polyester. In this case, the content ratio of the polyester in the entire laminate of the fifth aspect is preferably 80% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass or more.

In one embodiment, the laminate 30 of the fifth aspect of the present disclosure includes a base material 10a and a heat seal layer 32 as shown in FIG. In one embodiment, the laminate 30 of the fifth aspect of the present disclosure further comprises a printing layer (not shown) on the substrate 10a. The print layer is usually formed on a surface layer provided with a heat seal layer on the substrate. In one embodiment, the laminate 30 of the fifth aspect of the present disclosure includes an adhesive layer 36 between the base material 10a and the heat seal layer 32, as shown in FIG. The base material 10a has a multi-layer structure, but the multi-layer structure is not shown.

<Base material>
The base material constituting the laminate of the fifth aspect of the present disclosure is a base material that has been stretched and has a multi-layer structure. Hereinafter, such a base material is also referred to as a “stretched multilayer base material”.

By the stretching treatment, the heat resistance and strength of the base material can be improved, and such a stretched multilayer base material can satisfy the physical properties required as an outer layer such as a packaging material. The stretching may be uniaxial stretching or biaxial stretching.

In one embodiment, the stretching ratio in the longitudinal direction (MD) of the stretched multilayer substrate is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less. In one embodiment, the stretching ratio in the lateral direction (TD) of the stretched multilayer substrate is preferably 2 times or more and 10 times or less, and more preferably 3 times or more and 7 times or less.

When the draw ratio is 2 times or more, for example, the rigidity, strength and heat resistance of the base material can be improved, the printability on the base material can be improved, and the transparency of the base material can be improved. When the draw ratio is 10 times or less, for example, good stretching can be performed without causing breakage of the film.

The stretched multilayer base material constituting the laminated body of the fifth aspect of the present disclosure is a uniaxially stretched film in one embodiment, and more specifically, a uniaxially stretched film stretched in the longitudinal direction (MD). be.

The stretched multilayer base material has a multilayer structure of two or more layers. In one embodiment, the number of layers of the stretched multilayer base material is preferably 2 layers or more and 7 layers or less, and more preferably 3 layers or more and 5 layers or less. When the stretched multilayer base material has a multi-layer structure, the balance between rigidity, strength, heat resistance, printability and stretchability of the base material can be improved. Each layer of the stretched multilayer base material is also composed of the same type of resin material.

Examples of the resin material constituting the stretched multilayer base material include polyolefins such as polyethylene, polypropylene and polymethylpentene; and polyester. Among these, polyolefins are preferable, and polyethylene and polypropylene are more preferable.

Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. Among these, high-density polyethylene and medium-density polyethylene are preferable from the viewpoint of strength and heat resistance of the base material, and medium-density polyethylene is more preferable from the viewpoint of stretchability.

The melt flow rate (MFR) of polyethylene is preferably 0.1 g / 10 minutes or more and 50 g / 10 minutes or less, more preferably 0.3 g / 10 minutes or more and 30 g, from the viewpoint of film forming property and processing suitability of the base material. / 10 minutes or less. In the present disclosure, the polyethylene MFR is measured in accordance with ASTM D1238 under the conditions of a temperature of 190 ° C. and a load of 2.16 kg.

Polypropylene may be any of propylene homopolymer, propylene random copolymer and propylene block copolymer. Propylene homopolymer is a polymer containing only propylene. The propylene random copolymer is a random copolymer of propylene and an ethylenically unsaturated monomer other than propylene (for example, α-olefin such as ethylene, 1-butene and 4-methyl-1-pentene). The propylene block copolymer is a polymer block made of propylene and a polymer block made of an ethylenically unsaturated monomer other than propylene (for example, α-olefin such as ethylene, 1-butene and 4-methyl-1-pentene). It is a copolymer having. For example, it is preferable to use a homopolymer when the rigidity and heat resistance of the packaging material are important, and to use a random copolymer when the impact resistance of the packaging material is important.

The polypropylene MFR is preferably 0.1 g / 10 minutes or more and 50 g / 10 minutes or less, more preferably 0.3 g / 10 minutes or more and 30 g / 10 minutes or less, from the viewpoint of film forming property and processing suitability of the base material. be. In the present disclosure, the polypropylene MFR is measured in accordance with ASTM D1238 under the conditions of a temperature of 230 ° C. and a load of 2.16 kg.

Examples of the polyolefin include a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene, and a polymer of propylene and an ethylenically unsaturated monomer other than propylene (however, in the above-mentioned polyethylene and polypropylene). Excluding applicable copolymers).

Examples of the ethylenically unsaturated monomer include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-octadecene. Α-olefins having 2 or more and 20 or less carbon atoms such as 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene and 6-methyl-1-heptene; vinyl acetate and vinyl propionate. Monomers; and (meth) acrylic acid esters such as methyl (meth) acrylate and ethyl (meth) acrylate.

Polyolefins having different densities or branches can be obtained by appropriately selecting a polymerization method. For example, using a multisite catalyst such as a Cheegler-Natta catalyst or a single site catalyst such as a metallocene catalyst as the polymerization catalyst, one step is carried out by any of gas phase polymerization, slurry polymerization, solution polymerization and high pressure ion polymerization. Alternatively, it is preferable to carry out the polymerization in multiple stages of two or more stages. Details of the single-site catalyst are as described above.

As the polyolefin, a polyolefin derived from biomass may be used. That is, as a raw material for obtaining a polyolefin, a biomass-derived olefin may be used instead of the olefin obtained from fossil fuel. Since the polyolefin derived from biomass is a carbon-neutral material, the environmental load of the packaging material can be reduced. Biomass-derived polyolefins (for example, polyethylene) can be produced, for example, by the method described in JP2013-177531A. Commercially available biomass-derived polyolefins (eg, green PE commercially available from Braskem) may be used.

As the polyolefin, a polyolefin recycled by mechanical recycling may be used. Mechanical recycling generally means that the recovered polyolefin film or the like is crushed and alkaline-cleaned to remove stains and foreign substances on the film surface, and then dried under high temperature and reduced pressure for a certain period of time to stay inside the film. This is a method in which a contaminant is diffused and decontaminated to remove stains on a film made of polyolefin, and the film is returned to polyolefin again.

Examples of the polyester as the resin material constituting the stretched multilayer base material include a copolymer of a dicarboxylic acid compound and a diol compound. As the monomer forming the copolymer, a monomer other than the dicarboxylic acid compound and the diol compound may be used, if necessary.

Examples of the dicarboxylic acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecandionic acid, eicosandionic acid, pimelliic acid, azelaic acid, methylmalonic acid and ethylmalonic acid, and adamantan. Dicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodium sulfoisophthalic acid, phenylendandicarboxylic acid, anthracendicarboxylic acid, phenanthrangecarboxylic acid, 9,9'-bis Examples thereof include (4-carboxyphenyl) fluorenic acid and ester derivatives thereof.

Examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentylglycol, cyclohexanedimethanol, and cyclohexane. Diethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanedimethanol, norbornandiethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindiethanol, decalindiethanol, 5 -Methylol-5-ethyl-2- (1,1-dimethyl-2-hydroxyethyl) -1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis (4-hydroxy) Cyclohexylpropane), 2,2-bis (4- (2-hydroxyethoxy) cyclohexyl) propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamandiol , Paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane and pentaerythritol.

Among the above, polyethylene terephthalate, which is a copolymer of terephthalic acid and its ester derivative and ethylene glycol, is preferable.

As the polyester, biomass-derived polyester may be used. In this polyester, the diol compound which is a copolymerization component is derived from biomass, the amount of fossil fuel used can be significantly reduced, and the environmental load for producing a laminate can be effectively reduced.

Biomass-derived diol compounds, for example, biomass-derived ethylene glycol, are made from ethanol (biomass ethanol) produced from biomass as a raw material. Biomass-derived ethylene glycol can be obtained by a method of producing biomass ethanol via ethylene oxide or the like by a conventionally known method. Further, the biomass ethylene glycol sold may be used, and for example, the biomass ethylene glycol sold by India Glycol Co., Ltd. can be preferably used.

As the polyester, recycled polyester may be used. Examples of the recycled polyester include chemical recycled polyester and mechanical recycled polyester. The chemical recycled polyester means a polyester obtained by decomposing a polyester container to the monomer level and polymerizing the monomer again. Mechanically recycled polyester is a polyester container that is sorted, crushed, and washed to remove contaminants and foreign substances, and flakes are obtained. The flakes are further treated at high temperature and under reduced pressure for a certain period of time to remove contaminants inside the resin. Means the polyester obtained by doing so.

The content ratio of the same type of resin material in each layer constituting the stretched multilayer base material is independently, preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

The content ratio of the same type of resin material in the stretched multilayer base material is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

The stretched multilayer base material may contain one or more additives. Additives include, for example, cross-linking agents, anti-blocking agents, slip agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, dyes and modifying resins. Can be mentioned. Each layer constituting the stretched multilayer base material can independently contain the above-mentioned additive.

The haze value of the stretched multilayer base material is preferably 25% or less, more preferably 15% or less, still more preferably 10% or less. The smaller the haze value is, the more preferable it is, but in one embodiment, the lower limit value may be 0.1% or 1%. The haze value of the stretched multilayer base material is measured according to JIS K7136.

The total thickness of the stretched multilayer base material is preferably 10 μm or more and 60 μm or less, and more preferably 15 μm or more and 50 μm or less. When the thickness of the stretched multilayer base material is 10 μm or more, the rigidity and strength of the laminated body can be improved. When the thickness of the stretched multilayer base material is 60 μm or less, the processability of the laminated body can be improved.

It is preferable that the stretched multilayer base material is surface-treated. This makes it possible to improve the adhesion between the surface layer of the stretched multilayer base material and the layer laminated on the stretched multilayer base material. Surface treatment methods include, for example, corona discharge treatment, ozone treatment, low temperature plasma treatment using gases such as oxygen gas and nitrogen gas, physical treatment such as glow discharge treatment; and oxidation treatment using chemicals. Chemical treatment can be mentioned. Further, an anchor coat layer may be formed on the surface of the stretched multilayer base material by using a conventionally known anchor coat agent.

The stretched multilayer base material can be produced by, for example, forming a laminate by forming a film of a plurality of resin materials or resin compositions by an inflation method or a T-die method, and stretching the obtained laminate. By the stretching treatment, the transparency, rigidity, strength and heat resistance of the base material can be improved, and the base material can be suitably used as a base material for, for example, a packaging material.

The stretched multilayer base material is obtained by stretching a laminate (precursor) having a multilayer structure in one embodiment. Specifically, each layer can be co-extruded into a tube to form a film, and a laminate can be produced. Alternatively, a laminate can be produced by co-extruding each layer into a tube shape and then pressure-bonding the opposing layers with a rubber roll or the like. By manufacturing the laminate by such a method, the number of defective products can be remarkably reduced and the production efficiency can be improved.

For example, when the stretched multilayer substrate is made of polyethylene and the multilayer substrate is manufactured by the T-die method, the melt flow rate (MFR) of polyethylene constituting each layer of the multilayer substrate has a film-forming property. From the viewpoint of processing suitability of the multilayer substrate, it is preferably 3 g / 10 minutes or more and 20 g / 10 minutes or less.

For example, when the stretched multilayer base material is composed of polyethylene and the multilayer base material is manufactured by the inflation method, the MFR of polyethylene constituting each layer of the multilayer base material has film-forming properties and processing of the multilayer base material. From the viewpoint of suitability, it is preferably 0.5 g / 10 minutes or more and 5 g / 10 minutes or less.

The stretched multilayer base material is obtained, for example, by stretching the above-mentioned laminate. The preferred draw ratio is as described above. In the inflation film forming machine, stretching of the laminate can also be performed. As a result, the stretched multilayer base material can be manufactured, so that the production efficiency can be further improved.

Hereinafter, some examples of the embodiments of the stretched multilayer base material will be described. Hereinafter, the layer made of polyethylene is described as "polyethylene layer".
The stretched multilayer base material of the first embodiment has a thickness of a medium-density polyethylene layer, a high-density polyethylene layer, a blend layer of medium-density polyethylene and high-density polyethylene, a high-density polyethylene layer, and a medium-density polyethylene layer. Prepare in this order in the vertical direction. With such a configuration, the printability of the base material can be improved, the strength and heat resistance can be improved, and the stretchability of the pre-stretched laminate can be improved.

The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the above-mentioned blend layer of medium-density polyethylene and high-density polyethylene is preferably 0.25 or more and 4 or less, more preferably 0.4. It is 2.4 or less.

The stretched multilayer base material of the second embodiment includes a medium-density polyethylene layer, a medium-density polyethylene layer, a blend layer of medium-density polyethylene and linear low-density polyethylene, a medium-density polyethylene layer, and a medium-density polyethylene layer. Are provided in this order in the thickness direction. With such a configuration, the printability of the base material can be improved, the strength and heat resistance can be improved, and the stretchability of the pre-stretched laminate can be improved.

The mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) in the above-mentioned blend layer of medium-density polyethylene and linear low-density polyethylene is preferably 0.25 or more. It is 4 or less, more preferably 0.4 or more and 2.4 or less.

The stretched multilayer base material of the third embodiment includes a blend layer of medium-density polyethylene and high-density polyethylene, a blend layer of medium-density polyethylene and linear low-density polyethylene, a linear low-density polyethylene layer, and medium density. A blend layer of polyethylene and linear low-density polyethylene and a blend layer of medium-density polyethylene and high-density polyethylene are provided in this order in the thickness direction. With such a configuration, the printability of the base material can be improved, the strength and heat resistance can be improved, and the stretchability of the pre-stretched laminate can be improved.

The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the above-mentioned blend layer of medium-density polyethylene and high-density polyethylene is independently, preferably 0.25 or more and 4 or less, more preferably. Is 0.4 or more and 2.4 or less.
The mass ratio of medium-density polyethylene to linear low-density polyethylene (medium-density polyethylene / linear low-density polyethylene) in the above-mentioned blend layer of medium-density polyethylene and linear low-density polyethylene is preferably 0.25 or more. It is 4 or less, more preferably 0.4 or more and 2.4 or less.

The stretched multilayer base material of the fourth embodiment includes a blend layer of high-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, a blend layer of linear low-density polyethylene and medium-density polyethylene, and a medium-density polyethylene layer. , High-density polyethylene and a blend layer of medium-density polyethylene are provided in this order in the thickness direction. With such a configuration, the printability of the base material can be improved, the strength and heat resistance can be improved, and the stretchability of the pre-stretched laminate can be improved.

The mass ratio of medium-density polyethylene to high-density polyethylene (medium-density polyethylene / high-density polyethylene) in the above-mentioned blend layer of high-density polyethylene and medium-density polyethylene is independently, preferably 0.25 or more and 4 or less, more preferably. Is 0.4 or more and 2.4 or less.
The mass ratio of the linear low-density polyethylene to the medium-density polyethylene (linear low-density polyethylene / medium-density polyethylene) in the blend layer of the linear low-density polyethylene and the medium-density polyethylene is preferably 0.25 or more 4 Below, it is more preferably 0.4 or more and 2.4 or less.

In the stretched multilayer substrate of the first to fourth embodiments, the thickness of each of the two surface layers is independently, preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, still more preferably. It is 1 μm or more and 5 μm or less. Thereby, the heat resistance and printability of the base material can be further improved.

In the stretched multilayer base material of the first to fourth embodiments, the thickness of each of the two surface layers is preferably smaller than the total thickness of the inner three layers (multilayer intermediate layer). The ratio of the thickness of each of the two surface layers to the total thickness of the multilayer intermediate layer (surface layer / multilayer intermediate layer) is preferably 0.05 or more and 0.8 or less, more preferably 0.1 or more and 0.7. Below, it is more preferably 0.1 or more and 0.4 or less. Thereby, the rigidity, strength and heat resistance of the base material can be further improved.

The stretched multilayer base material of the fifth embodiment includes a high-density polyethylene layer and a medium-density polyethylene layer in this order in the thickness direction. Since the surface layer of the base material is a high-density polyethylene layer, the strength and heat resistance of the base material can be improved. By providing the base material with a medium-density polyethylene layer, the stretchability of the pre-stretched laminate can be improved.

The stretched multilayer base material of the sixth embodiment includes a high-density polyethylene layer, a medium-density polyethylene layer, and a high-density polyethylene layer in this order in the thickness direction. With such a configuration, the strength and heat resistance of the base material can be improved, the generation of curl in the base material can be suppressed, and the stretchability of the pre-stretched laminate can be improved.

In the stretched multilayer base material of the fifth to sixth embodiments, the thickness of the high-density polyethylene layer is preferably less than or equal to the thickness of the medium-density polyethylene layer. The ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer is preferably 0.1 or more and 1 or less, and more preferably 0.2 or more and 0.5 or less.

The stretched multilayer substrate of the seventh embodiment includes a high-density polyethylene layer, a medium-density polyethylene layer, a low-density polyethylene layer, a linear low-density polyethylene layer, or an ultra-low-density polyethylene layer (for simplification of description, these are used. 3 layers are collectively referred to as "low density polyethylene layer or the like"), a medium density polyethylene layer, and a high density polyethylene layer are provided in this order in the thickness direction. With such a configuration, the stretchability of the pre-stretched laminate can be improved, the strength and heat resistance of the base material can be improved, and the generation of curl in the base material can be suppressed.

In the stretched multilayer base material of the seventh embodiment, the thickness of the high-density polyethylene layer is preferably less than or equal to the thickness of the medium-density polyethylene layer. The ratio of the thickness of the high-density polyethylene layer to the thickness of the medium-density polyethylene layer is preferably 0.1 or more and 1 or less, and more preferably 0.2 or more and 0.5 or less.

In the stretched multilayer base material of the seventh embodiment, the thickness of the high-density polyethylene layer is preferably greater than or equal to the thickness of the low-density polyethylene layer or the like. The ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer is preferably 1 or more and 4 or less, and more preferably 1 or more and 2 or less.

As the stretched multilayer base material of another embodiment, a high-density polyethylene layer, a high-density polyethylene layer, a blend layer of medium-density polyethylene and high-density polyethylene, a high-density polyethylene layer, and a high-density polyethylene are provided in the thickness direction. Base material provided in this order; a base material provided with a medium-density polyethylene layer, a high-density polyethylene layer, a linear low-density polyethylene layer, a high-density polyethylene layer, and a medium-density polyethylene layer in this order in the thickness direction. Can also be mentioned.

The stretched multilayer base material may be the polyethylene multilayer base material of the first to fifth aspects of the present disclosure described above.

<Barrier layer>
In one embodiment, the laminate of the fifth aspect of the present disclosure comprises a barrier layer between the stretched multilayer substrate and the heat seal layer. Thereby, the gas barrier property of the laminated body, specifically, the oxygen barrier property and the water vapor barrier property can be improved. The barrier layer may be formed on the surface of the stretched multilayer base material or may be formed on the surface of the heat seal layer.

A barrier layer may be provided between the stretched multilayer base material and the heat seal layer via an adhesive or the like. For example, a barrier film provided with a second base material and a barrier layer formed on the second base material between the stretched multilayer base material and the heat seal layer is provided with an adhesive or the like, if necessary. May be provided. In this aspect, from the viewpoint of recyclability, it is preferable that the second base material in the barrier film is made of a resin material of the same type as the resin material constituting the stretched multilayer base material. The content ratio of the same kind of resin material in the second base material is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

The details of the barrier layer are as described in the <Barrier layer> column of [Laminates of the first to fourth aspects and other embodiments], and the description in this column is omitted.

<Print layer>
The laminate of the fifth aspect of the present disclosure further comprises, in one embodiment, a printing layer formed on the stretched multilayer substrate described above. In one embodiment, it is preferable that the printed layer is formed on the side of the stretched multilayer substrate on which the heat seal layer is provided, because deterioration of the image over time can be suppressed. When the laminate of the fifth aspect has a barrier layer on the stretched multilayer base material, for example, a printing layer may be provided on the barrier layer. In this case, the laminate of the fifth aspect of the present disclosure includes, for example, a stretched multilayer base material, a barrier layer, a printing layer, and a heat seal layer in this order in the thickness direction. The details of the print layer are as described in the [Printing substrate] column, and the description in this column is omitted.

<Heat seal layer>
The laminate of the fifth aspect of the present disclosure includes a heat seal layer. The heat seal layer in the laminate of the fifth aspect is a layer that has not been stretched. The heat seal layer is made of a resin material of the same type as the resin material constituting the stretched multilayer base material. The laminate having such a structure has both heat-sealing property and recyclability.

For example, when the stretched multilayer substrate is composed of polyolefin, the heat seal layer is composed of polyolefin, which is a resin material of the same type as the stretched multilayer substrate. Among the above-mentioned polyolefins, polyethylene and polypropylene are preferable.

In the embodiment in which the stretched multilayer base material is made of polyethylene, examples of the polyethylene constituting the heat seal layer include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. From the viewpoint of heat-sealing property, low-density polyethylene, linear low-density polyethylene and ultra-low-density polyethylene are preferable. From the viewpoint of reducing the environmental load, polyethylene derived from biomass and / or recycled polyethylene may be used.

In the embodiment in which the stretched multilayer base material is made of polyethylene, the content ratio of polyethylene in the heat seal layer is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

In the embodiment in which the stretched multilayer substrate is made of polypropylene, examples of polypropylene constituting the heat seal layer include propylene homopolymers, propylene random copolymers, and propylene block copolymers. From the viewpoint of heat-sealing property, the density of polypropylene is preferably 0.88 g / cm ³ or more and 0.92 g / cm ³ or less, and more preferably 0.90 g / cm ³ or more and 0.91 g / cm ³ or less. From the viewpoint of reducing the environmental load, polypropylene derived from biomass and / or recycled polypropylene may be used.

In the embodiment in which the stretched multilayer base material is made of polypropylene, the content ratio of polypropylene in the heat seal layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

For example, when the stretched multilayer base material is composed of polyester, the heat seal layer is composed of polyester, which is a resin material of the same type as the stretched multilayer base material. Among the polyesters described above, polyethylene terephthalate is preferable. From the viewpoint of reducing the environmental load, biomass-derived polyester and / or recycled polyester may be used.

In the embodiment in which the stretched multilayer base material is made of polyester, the heat seal layer is preferably made of low crystalline or amorphous polyester from the viewpoint of heat sealability. The crystallinity of the polyester constituting the heat seal layer is preferably 12% or less, more preferably 10% or less. This makes it possible to further improve the heat sealability.

The crystallinity of the polyester is the value obtained by dividing the calorific value of melting when the low crystalline or amorphous polyester is melted by the calorific value of melting of the complete crystal (polyethylene terephthalate is 140 J / g) using a differential scanning calorimeter. Obtained by multiplying by 100.

The glass transition temperature (Tg) of the polyester constituting the heat seal layer is preferably 60 ° C. or higher and 90 ° C. or lower, more preferably 63 ° C. or higher and 80 ° C. or lower. When Tg is 90 ° C. or lower, the heat sealability of the heat seal layer can be improved. When Tg is 60 ° C. or higher, the occurrence of blocking can be suppressed. Tg is a value obtained by differential scanning calorimetry in accordance with JIS K7121.

In the embodiment in which the stretched multilayer base material is made of polyester, the content ratio of polyester in the heat seal layer is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. This makes it possible to improve the recyclability of the laminated body.

The heat seal layer may contain one or more additives. Additives include, for example, cross-linking agents, anti-blocking agents, slip agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, dyes and modifying resins. Can be mentioned. Each layer constituting the heat seal layer can independently contain the above-mentioned additive.

The heat seal layer may be a single layer or may have a multi-layer structure of two or more layers. In one embodiment, the number of layers of the heat seal layer is 2 or more and 7 or less in the case of a multilayer structure. Each layer of the heat seal layer is also composed of the same type of resin material.

In one embodiment, the heat seal layer is a resin film made of a resin material of the same type as the resin material constituting the stretched multilayer base material. This resin film is an unstretched resin film. As a result, excellent heat-sealing properties can be obtained. This resin film may have a multilayer structure. The resin film can be produced, for example, by using a casting method, a T-die method, an inflation method, or the like.

In one embodiment, the heat seal layer is a melt extrusion layer made of a resin material of the same type as the resin material constituting the stretched multilayer base material. This melt extruded layer may have a multi-layer structure.

For example, a heat-sealing layer can be formed by laminating an unstretched film on a stretched multilayer base material via an adhesive layer as needed, or by melt-extruding a heat-sealing resin material onto a stretched multilayer base material. .. Examples of the adhesive layer include an adhesive layer described later.

The thickness of the heat seal layer is preferably 10 μm or more and 300 μm or less, and more preferably 15 μm or more and 250 μm or less. The thickness of the heat-sealed layer is appropriately determined according to the mass of the contents to be filled in the packaging material produced by the laminated body of the fifth aspect of the present disclosure from the viewpoint of the strength of the heat-sealed layer and the processability of the laminated body. It is preferable to change it.

For example, when the packaging material is a stand pouch, the thickness of the heat seal layer is preferably 40 μm or more and 200 μm or less. In this case, for example, the contents of 50 g or more and 2000 g or less are well filled in the stand pouch.

In the laminate of the fifth aspect of the present disclosure, the stretched multilayer base material satisfies the rigidity, strength and heat resistance required for the outer layer film of the packaging material, and the heat seal layer enables packaging. Further, the stretched multilayer base material and the heat seal layer are made of the same kind of resin material. Therefore, the laminate is suitable as a material for constituting a packaging material that is required to be recyclable.

In one embodiment, the laminate of the fifth aspect of the present disclosure comprises only a stretched multilayer base material on which a printed layer is formed, if necessary, and a heat seal layer. In one embodiment, the laminate of the fifth aspect of the present disclosure comprises only a stretched multilayer base material on which a printed layer is formed, an adhesive layer, and a heat seal layer, if necessary. As a result, in the laminate of the fifth aspect of the present disclosure, since each resin layer is composed of the same type of resin material, recyclability can be particularly improved.
<Adhesive layer>
In one embodiment, the laminate of the fifth aspect of the present disclosure is between a stretched multilayer base material and a heat seal layer, between a stretched multilayer base material and a barrier film, and between a barrier film and a heat seal layer. An adhesive layer is provided between any layers such as. This makes it possible to improve the adhesion between the stretched multilayer base material and the heat seal layer and the adhesion between other layers.

The details of the adhesive layer are as described in the <Adhesive layer> column of [Laminates of the first to fourth aspects and other embodiments], and the description in this column is omitted.

In one embodiment, from the viewpoint of recyclability, when the stretched multilayer base material and the heat seal layer constituting the laminate of the fifth aspect of the present disclosure are each composed of polyolefin, the adhesive layer is an olefin adhesive. It may be configured by.

In one embodiment, from the viewpoint of recyclability, when the stretched multilayer base material and the heat seal layer constituting the laminate of the fifth aspect of the present disclosure are each made of polyester, the adhesive layer is a polyester adhesive. It may be configured by.

[Use]
The polyethylene multilayer base material, the printed base material and the laminate described above in the present disclosure can be suitably used for packaging material applications such as packaging bags. The packaging material of the present disclosure comprises the polyethylene multilayer base material, the printed base material or the laminate described above in the present disclosure, respectively.

For example, a packaging material can be manufactured by folding the laminated body in half so that the multilayer base material is located on the outside and the heat-sealing layer on the inside, and stacking them on top of each other, and heat-sealing the ends thereof. Further, a packaging material can be manufactured by superimposing a plurality of the above-mentioned laminated bodies so that the heat-sealing layers face each other and heat-sealing the end portions thereof. The entire packaging material may be composed of the above-mentioned laminate, or a part of the packaging material may be composed of the above-mentioned laminate.

The form of the heat seal in the packaging material is, for example, a side seal type, a two-way seal type, a three-way seal type, a four-way seal type, an envelope sticker type, a gassho sticker type (pillow seal type), a fold seal type, and a flat bottom. Examples include a seal type, a square bottom seal type, and a gusset type. In addition, a self-supporting packaging bag (stand pouch) is also possible. Examples of the heat sealing method include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing.

For example, a stand pouch having a body and a bottom can be manufactured as follows. First, the body is formed by heat-sealing one or more of the above laminated bodies into a cylindrical shape so that the heat-sealing layer is on the inside. Next, the further laminated body is folded into a V shape so that the heat seal layer is on the outside. The bottom is formed by sandwiching the V-shaped laminate at one end of the body and heat-sealing.

In the stand pouch, only the body portion may be formed by the above-mentioned laminate, only the bottom portion may be formed by the above-mentioned laminate, or both the body portion and the bottom portion may be formed by the above-mentioned laminate. good.

Examples of the contents to be filled in the packaging material include liquids, powders and gels, which may be foods or non-foods. After filling the contents in the packaging material, the opening of the packaging material is heat-sealed to obtain a package.

The present disclosure relates to, for example, the following [1] to [19].
[1] The first polyethylene layer, the second polyethylene layer, and the third polyethylene layer are provided in this order in the thickness direction and are stretched, and the following requirements (A) and / or the following requirements (B) are provided. ) Is filled with a polyethylene multilayer base material:
Requirement (A): The indentation elastic modulus of the first polyethylene layer is 3.0 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the third polyethylene layer is the second polyethylene layer. It is more than 3.0 times the indentation modulus of
Requirement (B): The indentation hardness of the first polyethylene layer is 2.0 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the third polyethylene layer is the indentation hardness of the second polyethylene layer. It is more than 2.0 times.
[2] The polyethylene multilayer substrate has a second polyethylene layer between the first polyethylene layer and the second polyethylene layer, and a second polyethylene layer between the second polyethylene layer and the third polyethylene layer. , The indentation elasticity of the second polyethylene layer is 2.0 times or more the indentation elasticity of the second polyethylene layer, and the indentation elasticity of the second polyethylene layer is the second polyethylene layer. The indentation elasticity of the second polyethylene layer is 2.0 times or more, and / or the indentation hardness of the second polyethylene layer is 1.4 times or more of the indentation hardness of the second polyethylene layer. The indentation hardness is 1.4 times or more the indentation hardness of the second polyethylene layer.
The polyethylene multilayer base material according to the above [1].
[3] A layer (A) containing medium-density polyethylene, two or more multilayer intermediate layers (B) each containing polyethylene, and a layer (C) containing medium-density polyethylene are formed in the thickness direction. It is a polyethylene multilayer base material provided in this order, and the multilayer base material is stretch-treated, and any polyethylene-containing layers adjacent to each other in the thickness direction in the multilayer base material are described as layers (1) and (2). In this case, the absolute value of the difference between the density of the polyethylene constituting the layer (1) and the density of the polyethylene constituting the layer (2) is 0.030 g / cm ³ or less, which is a polyethylene multilayer base material.
[4] A first layer containing medium-density polyethylene and high-density polyethylene, a second layer containing medium-density polyethylene and linear low-density polyethylene, and a third layer containing linear low-density polyethylene. A fourth layer containing medium-density polyethylene and linear low-density polyethylene, and a fifth layer containing medium-density polyethylene and high-density polyethylene are provided in this order in the thickness direction, and are stretched. Polyethylene multilayer base material.
[5] A first layer containing medium-density polyethylene and high-density polyethylene, a second layer containing high-density polyethylene, a third layer containing linear low-density polyethylene, and high-density polyethylene. A polyethylene multilayer base material in which a fourth layer containing the polyethylene and a fifth layer containing the medium-density polyethylene and the high-density polyethylene are provided in this order in the thickness direction and subjected to a stretching treatment.
[6] The polyethylene multilayer base material according to any one of the above [1] to [5], wherein the polyethylene content in the polyethylene multilayer base material is 80% by mass or more.
[7] A printing substrate comprising the polyethylene multilayer substrate according to any one of [1] to [6] above and a printing layer formed on the polyethylene multilayer substrate.
[8] A laminate including a polyethylene multilayer base material and a heat seal layer containing polyethylene as a main component, wherein the polyethylene multilayer base material includes a first polyethylene layer, a second polyethylene layer, and a third. The polyethylene layers of the above are provided in this order in the thickness direction and are stretched, and the laminate meets the following requirements (C) and / or the following requirements (D).
Requirement (C): The indentation elastic modulus of the first polyethylene layer is 3.5 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the third polyethylene layer is the second polyethylene layer. It is more than 3.5 times the indentation modulus of
Requirement (D): The indentation hardness of the first polyethylene layer is 2.0 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the third polyethylene layer is the indentation hardness of the second polyethylene layer. It is more than 2.0 times.
[9] The polyethylene multilayer substrate has a second polyethylene layer between the first polyethylene layer and the second polyethylene layer, and a second polyethylene layer between the second polyethylene layer and the third polyethylene layer. , The indentation elasticity of the second polyethylene layer is 2.0 times or more the indentation elasticity of the second polyethylene layer, and the indentation elasticity of the second polyethylene layer is the second polyethylene layer. The indentation elasticity of the second polyethylene layer is 2.0 times or more, and / or the indentation hardness of the second polyethylene layer is 1.5 times or more of the indentation hardness of the second polyethylene layer. The laminate according to the above [8], wherein the indentation hardness is 1.5 times or more the indentation hardness of the second polyethylene layer.
[10] A laminate including a polyethylene multilayer base material and a heat-sealed layer containing polyethylene as a main component, wherein the polyethylene multilayer base material includes a first polyethylene layer, a second polyethylene layer, and a third. The polyethylene layers of the above are provided in this order in the thickness direction and are stretched, and the laminate meets the following requirements (E) and / or the following requirements (F).
Requirement (E): The indentation elastic modulus of the first polyethylene layer is 1.0 GPa or more, and the indentation elastic modulus of the third polyethylene layer is 1.0 GPa or more.
Requirement (F): The indentation hardness of the first polyethylene layer is 45 MPa or more, and the indentation hardness of the third polyethylene layer is 45 MPa or more.
[11] The polyethylene multilayer substrate has a second polyethylene layer between the first polyethylene layer and the second polyethylene layer, and a second polyethylene layer between the second polyethylene layer and the third polyethylene layer. , And the indentation elasticity of the second polyethylene layer is 0.03 GPa or more and 0.7 GPa or less, and the indentation elasticity of the second polyethylene layer and the indentation elasticity of the second polyethylene layer are, respectively. Independently, it is 0.3 GPa or more and 3.5 GPa or less, and / or the indentation hardness of the second polyethylene layer is 1 MPa or more and 40 MPa or less, the indentation hardness of the second polyethylene layer, and the polyethylene layer of the second b. The laminate according to the above [10], wherein the indentation hardness of each is independently 20 MPa or more and 100 MPa or less.
[12] A laminate comprising the polyethylene multilayer substrate according to any one of the above [1] to [6] and a heat seal layer.
[13] The heat shrinkage rate in the longitudinal direction (MD) of the laminated body is 15% or less, and the heat shrinkage rate in the vertical direction (TD) with respect to the MD of the laminated body is 15% or less. ] The laminate according to any one of.
[14] A laminate including a base material and a heat seal layer, wherein the base material and the heat seal layer are made of the same type of resin material, and the base material has a multi-layer structure. However, the laminated body is a base material that has been subjected to a stretching treatment, and the heat seal layer is a layer that has not been subjected to a stretching treatment.
[15] The laminate according to the above [14], wherein the same type of resin material is polyolefin or polyester.
[16] The laminate according to the above [14], wherein the same type of resin material is polyethylene.
[17] The laminate according to any one of the above [14] to [16], wherein the heat seal layer has a multilayer structure.
[18] The laminate according to any one of [8] to [17] above, further comprising a barrier layer formed on the surface of the base material or the surface of the heat seal layer.
[19] The polyethylene multilayer base material according to any one of the above [1] to [6], the printing base material according to the above [7], or the laminate according to any one of the above [8] to [18]. The packaging material.

[Evaluation methods]
[Ink adhesion evaluation]
An image by a gravure printing method using an oil-based gravure ink (manufactured by DIC Graphics Co., Ltd., trade name: Finato) on the corona discharge-treated surface side of the stretched multilayer base material and the polyethylene film obtained in each of the following examples. Formed. The images formed on the stretched multilayer substrate and the polyethylene film were visually observed and evaluated based on the following evaluation criteria.

(Evaluation criteria)
AA: When cellophane tape (registered trademark) is attached to the image-forming surface side of the stretched multilayer substrate or polyethylene film and peeled off, the ink adheres well to the stretched multilayer substrate or polyethylene film, and it adheres to the cellophane tape (registered trademark). No ink peeling occurred.
BB: When cellophane tape (registered trademark) is attached to the image forming surface side of the stretched multilayer substrate or polyethylene film and peeled off, the ink adhesion to the stretched multilayer substrate or polyethylene film is weak, and the ink on the cellophane tape (registered trademark) is weak. Peeling occurred.

[Shrinkage evaluation]
The laminates obtained in each of the following examples were cut into 10 cm × 10 cm to prepare three sample pieces. Fold each sample piece in half so that the heat seal layer side is on the inside, and use a heat seal tester to heat seal the area of 1.5 cm x 10 cm under the conditions of temperature 120 ° C, pressure 1 kgf / cm ² , and 1 second. bottom. After heat sealing, the seal width of the sample was measured, and the shrinkage rates of MD and TD were calculated. The average value of the three sample pieces was taken as each heat shrinkage rate.

[Heat resistance evaluation]
The heat resistance was evaluated according to the following criteria.
AA: During printing, dry laminating, and heat sealing of the laminates produced in each of the following examples, there was no large shrinkage of the base material (stretched multilayer base material or polyethylene film), and the desired product could be produced neatly.
BB: During printing, dry laminating, and heat sealing of the laminates produced in each of the following examples, large shrinkage of the base material (stretched multilayer base material or polyethylene film) occurred, and the target product could not be produced neatly.

[Haze evaluation]
The haze values of the stretched multilayer base material and the polyethylene film obtained in each of the following examples were measured according to JIS K7136.

[Rigidity evaluation]
The stretched multilayer base material and polyethylene film obtained in each of the following examples are cut into test pieces having a width of 10 mm, and the rigidity of the test pieces is measured by a loop stiffness measuring tester (manufactured by Toyo Seiki Seisakusho, trade name: loop stiff nestester). Was measured. The length of the loop was 60 mm.

[Strength evaluation]
A dumbbell-shaped test piece having a width of 10 mm was cut out from the stretched multilayer base material and the polyethylene film obtained in each of the following examples. The tensile strength of this test piece in the MD direction was measured by a tensile tester (RTC-1310A, manufactured by Orientec). The distance between the chucks was 10 mm, and the tensile speed was 300 mm / min.

[Evaluation of stretchability]
Stretchability was evaluated according to the following criteria.
AA: The base material (polyethylene film) does not break during stretching, and the base material (polyethylene film) does not break.
It was able to be stretched stably.
BB: The base material (polyethylene film) breaks during stretching,
It could not be stretched stably.

[Recyclability evaluation]
The content ratio of polyethylene in the whole laminate obtained in each of the following examples was determined, and its recyclability was evaluated based on the following evaluation criteria.

(Evaluation criteria)
AA: The content ratio of polyethylene in the entire laminate is
It was 90% by mass or more.
BB: The content ratio of polyethylene in the entire laminate is
It was 80% by mass or more and less than 90% by mass.
CC: The content ratio of polyethylene in the entire laminate is
It was less than 80% by mass.

[Heat sealability evaluation]
The laminates obtained in each of the following examples were cut into a size of 220 mm in length × 130 mm in width. The two laminates cut in this way were laminated so that the heat seal layers face each other, and the laminates obtained in each of the following examples were folded into a V shape so that the heat seal layer was on the outside. I put something in one end of the body. Next, two vertical sides and a side sandwiching the V-shaped laminate were heat-sealed (140 ° C., 1 kgf, 1 second). The obtained packaging bag was filled with 300 mL of liquid detergent, and the remaining side was heat-sealed (140 ° C., 1 kgf, 1 second) to obtain a package.

The above package was freely dropped from a height of 100 cm onto a hard floor 10 times with the body of the package level with the ground. The test was carried out for each of 10 bags, the presence or absence of damage was visually observed, and the heat sealability was evaluated based on the following evaluation criteria.

(Evaluation criteria)
AA: No damage was confirmed in all 10 bags.
NG: Damage was confirmed in 1 or more of the 10 bags, and there was a problem in practical use.

[Evaluation of delamination]
The laminates obtained in each of the following examples were cut into 10 cm × 10 cm to prepare three sample pieces. Each sample piece was folded in half so that the heat seal layer side was on the inside, and a 1 cm × 10 cm area was heat-sealed using a heat seal tester under the conditions of a temperature of 140 ° C., a pressure of 1 kgf / cm ² , and 1 second.

The sample piece after heat sealing is cut into strips with a width of 15 mm, both ends that have not been heat sealed are grasped by a tensile tester, and a tensile test is performed under the conditions of a speed of 300 mm / min and a load range of 50 N. It was confirmed whether or not delamination of the base material or the polyethylene film occurred.
AA: Delamination of the stretched multilayer base material or polyethylene film did not occur during the tensile test.
BB: Delamination of the stretched multilayer base material or polyethylene film occurred during the tensile test.
[Example A]
The multilayer base material of the first aspect and the second aspect of the present disclosure, and the laminate of the first to fourth aspects will be described more specifically based on Examples, but the multilayer substrate and the laminate of the present disclosure will be described in more detail. Is not limited by the examples. Hereinafter, "parts by mass" is simply referred to as "parts".

The polyethylene used in the following examples and comparative examples will be described.
・ Medium density polyethylene:
Product name Allow4002MC
Density: 0.940 g / cm ³ , Melting point: 128 ° C,
MFR: 0.25 g / 10 minutes, ExxonMobil high-density polyethylene (1):
Product name Elite5960G
Density: 0.960 g / cm ³ , Melting point: 134 ° C,
MFR: 0.8g / 10 minutes, Dowchemical High Density Polyethylene (2):
Product name H619F
Density: 0.965 g / cm ³ , Melting point: 135 ° C,
MFR: 0.7g / 10 minutes, SCG linear low density polyethylene:
Product name Exceed XP8656ML
Density: 0.916 g / cm ³ , Melting point: 121 ° C,
MFR: 0.5g / 10 minutes, ExxonMobil low density polyethylene:
Product name LD2420F
Density: 0.922 g / cm ³ , Melting point: 112 ° C,
MFR: 0.75g / 10 minutes, manufactured by PTT Public Company Limited, containing slip agent: MB:
Product name SLIP61 10061-K
Density: 0.910 g / cm ³ , MFR: 10 g / 10 minutes,
Polyethylene base, containing 5% by mass of erucic acid amide slip agent,
Made by Ampcate

In the column of Example A, the medium density polyethylene (Enable4002MC) is referred to as "MDPE", the high density polyethylene (1) (Elite5960G) is referred to as "HDPE (1)", and the high density polyethylene (2) (H619F) is referred to as "HDPE (1)". HDPE (2) ”, the linear low density polyethylene (Exceed XP8656ML) is also referred to as“ LLDPE ”, and the low density polyethylene (LD2420F) is also referred to as“ LDPE ”.

<Making blended polyethylene>
・ Blended polyethylene A1
Blended polyethylene A1 having an average density of 0.948 g / cm ³ by mixing 70 parts of MDPE and 30 parts of HDPE (1) (hereinafter referred to as "blended PE (A1)" in the column of Example A). Got
・ Blended polyethylene B1
Blended polyethylene B1 having an average density of 0.950 g / cm ³ by mixing 70 parts of HDPE (2) and 30 parts of LDPE (hereinafter referred to as "blended PE (B1)" in the column of Example A). Got
・ Blended polyethylene B2
50 parts of MDPE and 50 parts of LLDPE were mixed to obtain a blended polyethylene B2 having an average density of 0.929 g / cm ³ (hereinafter referred to as "blended PE (B2)" in the column of Example A). ..
・ Blended polyethylene C1
98 parts of LLDPE and 2 parts of slip agent-containing MB are mixed and blended polyethylene C1 having an average density of 0.916 g / cm ³ (hereinafter referred to as "blended PE (C1)" in the column of Example A). Got

[Example 1A]
Blended PE (A1), blended PE (B1) and blended PE (C1) are blended PE (A1) layer (15 μm) / blended PE (B1) layer (22.5 μm) / blended PE (C1) by the inflation molding method. ) Layer (50 μm) / Blend PE (B1) layer (22.5 μm) / Blend PE (A1) layer (15 μm) 5 layers are co-extruded with a layer thickness ratio to form a tube-like film, and the total thickness is 125 μm. The polyethylene film of No. 1 was obtained, and the tubular film was folded at the nip site to form two layers. The numbers in parentheses indicate the layer thickness.

The polyethylene film produced above is stretched in the longitudinal direction (MD) at a draw ratio of 5 times, and further, the blended PE (A1) layer (surface layer) on one side is subjected to a corona discharge treatment, and then the end portion is formed. The slit was made and divided into two pieces to obtain a polyethylene multilayer base material (stretched multilayer base material) having a thickness of 25 μm.

[Example 2A and Comparative Example 1A]
A polyethylene film and a stretched multilayer base material were obtained in the same manner as in Example 1A except that the layer structure was changed as shown in Table 5.

[Preparation of laminated body]
First linear low density polyethylene (Prime Polymer, SP2520, density: 0.925 g / cm ³ , melting point: 122 ° C) and second linear low density polyethylene (Prime Polymer, SP0510, A density: 0.903 g / cm ³ , melting point: 98 ° C.) was extruded in multiple layers by an inflation molding method, and a first linear low-density polyethylene layer with a thickness of 20 μm and a second layer with a thickness of 20 μm were formed. An unstretched polyethylene film provided with the linear low-density polyethylene layer of the above was prepared. This unstretched polyethylene film was used as a heat seal layer as described below.

The first linear low-density polyethylene layer side of the unstretched polyethylene film (heat-sealed layer) produced above and the corona discharge-treated surface side of the stretched multilayer base material obtained in Examples and Comparative Examples are 2 A laminated body was obtained by dry laminating via a liquid-curable urethane adhesive (Ru-77T / H-7 manufactured by Rock Paint Co., Ltd.). The thickness of the adhesive layer was 3.0 μm.

[Indentation elastic modulus, indentation hardness evaluation]
With respect to the stretched multilayer base material and the laminated body obtained in Examples and Comparative Examples, the TD direction of each polyethylene layer of the stretched multilayer base material using a nanoindenter (“TI950 TriboIndenter” manufactured by HYSITRON). The indentation elastic modulus and the indentation hardness were obtained by averaging the elastic modulus values and the hardness values obtained by measuring at five points in the same cross section with the cross section parallel to the measuring surface. As the indenter of the nanoindenter, a Berkovich indenter (triangular pyramid indenter) was used for the measurement.

The measurement conditions are as follows. An indenter was pushed into the polyethylene layer from a cross section parallel to the TD direction of the stretched multilayer substrate and the laminate to a pushing depth of 200 nm over 10 seconds, and held in that state for 5 seconds. Then, the load was removed over 10 seconds. As a result, the maximum load Pmax, the contact projected area A at the maximum depth, and the load-displacement curve could be obtained, and the elastic modulus and the hardness were calculated from the obtained load-displacement curve. The measurement was carried out in a room temperature (25 ° C.) environment. The cross section was prepared by cutting the stretched multilayer base material and the laminate in parallel with the TD direction in an environment of -100 ° C using a cryoultra microtome. Finishing was done with a diamond knife. The thickness of each layer can also be measured by observing the above cross section.

The above evaluation results are shown in Tables 1 to 5. In the polyethylene multilayer base materials of Examples and Comparative Examples, the indentation elastic modulus of the first PE layer and the third PE layer is about the same, and the indentation elastic modulus of the second PE layer and the second PE layer is about the same. Since the elastic moduli are about the same, the description of the indentation elastic modulus of the second PE layer and the third PE layer is omitted. The same applies to the indentation hardness.

[Example B]
The multilayer base material of the third aspect and the fourth aspect of the present disclosure will be described more specifically based on the examples, but the multilayer base material of the present disclosure is not limited by the examples. Hereinafter, "parts by mass" is simply referred to as "parts".

The polyethylene used in the following examples and comparative examples will be described.
・ Medium density polyethylene:
Product name Elite5538G
Density: 0.941 g / cm ³ , Melting point: 129 ° C,
MFR: 1.3g / 10 minutes, Dowchemical High Density Polyethylene:
Product name Elite5960G
Density: 0.960 g / cm ³ , Melting point: 134 ° C,
MFR: 0.8 g / 10 minutes, manufactured by Dowchemical, linear low-density polyethylene:
Product name Elite5400G
Density: 0.916 g / cm ³ , Melting point: 123 ° C,
MFR: 1.3g / 10 minutes, manufactured by Dowchemical

In the column of Example B, the medium density polyethylene (Elite5538G) is also referred to as "MDPE", the high density polyethylene (Elite5960G) is referred to as "HDPE", and the linear low density polyethylene (Elite5400G) is also referred to as "LLDPE".

<Making blended polyethylene>
・ Blended polyethylene A
50 parts of MDPE and 50 parts of HDPE were mixed to obtain a blended polyethylene A having an average density of 0.951 g / cm ³ (hereinafter referred to as "blended PE (A)" in the column of Example B). ..
・ Blended polyethylene B
50 parts of MDPE and 50 parts of LLDPE were mixed to obtain a blended polyethylene B having an average density of 0.929 g / cm ³ (hereinafter referred to as "blended PE (B)" in the column of Example B). ..
・ Blended polyethylene B1
70 parts of MDPE and 30 parts of LLDPE were mixed to obtain a blended polyethylene B1 having an average density of 0.934 g / cm ³ (hereinafter referred to as "blended PE (B1)" in the column of Example B). ..
・ Blended polyethylene C
70 parts of MDPE and 30 parts of HDPE were mixed to obtain a blended polyethylene C having an average density of 0.947 g / cm ³ (hereinafter referred to as "blended PE (C)" in the column of Example B). ..
・ Blended polyethylene D
30 parts of MDPE and 70 parts of HDPE were mixed to obtain a blended polyethylene D having an average density of 0.954 g / cm ³ (hereinafter referred to as "blended PE (D)" in the column of Example B). ..

[Example 1B]
MDPE, HDPE and blend PE (A) are subjected to MDPE layer (15 μm) / HDPE layer (22.5 μm) / blend PE (A) layer (50 μm) / HDPE layer (22.5 μm) / MDPE layer by inflation molding method. Five layers were co-extruded at a layer thickness ratio of (15 μm) to form a tubular film, a polyethylene film having a total thickness of 125 μm was obtained, and the tubular film was folded at the nip site to form two layers. The numbers in parentheses indicate the layer thickness.

The polyethylene film produced above is stretched in the longitudinal direction (MD) at a draw ratio of 5 times, and further, the MDPE layer (surface layer) on one side is subjected to a corona discharge treatment, and then the end portion is slit and 2 The sheets were divided into sheets to obtain a stretched multilayer substrate having a thickness of 25 μm.

[Reference Example 1B and Example 3B]
LLDPE, blended PE (B) and blended PE (C) are blended PE (C) layer (15 μm) / blended PE (B) layer (22.5 μm) / LLDPE layer (50 μm) / blended PE by the inflation molding method. Five layers were co-extruded at a layer thickness ratio of (B) layer (22.5 μm) / blended PE (C) layer (15 μm) to form a tube-like film, and a polyethylene film with a total thickness of 125 μm was obtained. The shape of the film was folded at the nip and two layers were stacked. The numbers in parentheses indicate the layer thickness.

The polyethylene film produced above is stretched in the longitudinal direction (MD) at a draw ratio of 5 times, and further, the blended PE (C) layer (surface layer) on one side is subjected to a corona discharge treatment, and then the end portion is formed. The slit was made and divided into two pieces to obtain a stretched multilayer base material (Example 3B) having a thickness of 25 μm. Further, the blended PE (C) layer (surface layer) on one side of the polyethylene film produced above was subjected to a corona discharge treatment (Reference Example 1B).

[Examples 2B, 4B to 5B and Comparative Examples 1B to 2B]
A polyethylene film and a stretched multilayer base material were obtained in the same manner as in Example 1B except that the layer structure was changed as described in Tables 6 and 7.

[Preparation of laminated body]
First linear low density polyethylene (Prime Polymer, SP2520, density: 0.925 g / cm ³ , melting point: 122 ° C) and second linear low density polyethylene (Prime Polymer, SP1520, A density: 0.913 g / cm ³ , melting point: 116 ° C.) was extruded in multiple layers by an inflation molding method, and a first linear low-density polyethylene layer with a thickness of 20 μm and a second layer with a thickness of 20 μm were formed. An unstretched polyethylene film provided with the linear low-density polyethylene layer of the above was prepared. This unstretched polyethylene film was used as a heat seal layer as described below.

The first linear low-density polyethylene layer side of the unstretched polyethylene film (heat-sealed layer) produced above, the stretched multilayer base material obtained in Examples and Comparative Examples, or the polyethylene film obtained in Reference Example. Was dry-laminated via a two-component curable urethane adhesive (Ru-77T / H-7, manufactured by Rock Paint Co., Ltd.) to obtain a laminated body.

The laminate prepared above was cut into 10 cm × 10 cm to prepare three sample pieces. Each sample piece was folded in half so that the heat seal layer side was on the inside, and a 1 cm × 10 cm area was heat-sealed using a heat seal tester under the conditions of a temperature of 140 ° C., a pressure of 1 kgf / cm ² , and 1 second.
The above evaluation results are shown in Tables 6 and 7.

[Example C]
The multilayer base material of the fifth aspect of the present disclosure will be described in more detail based on Examples, but the multilayer base material of the present disclosure is not limited to the examples. Hereinafter, "parts by mass" is simply referred to as "parts".

In the column of Example C, the medium density polyethylene (Enable4002MC) is referred to as "MDPE", the high density polyethylene (1) (Elite5960G) is referred to as "HDPE (1)", and the high density polyethylene (2) (H619F) is referred to as "HDPE (1)". HDPE (2) ”, the linear low density polyethylene (Exceed XP8656ML) is also referred to as“ LLDPE ”, and the low density polyethylene (LD2420F) is also referred to as“ LDPE ”.

<Making blended polyethylene>
・ Blended polyethylene A1
Blended polyethylene A1 having an average density of 0.948 g / cm ³ by mixing 70 parts of MDPE and 30 parts of HDPE (1) (hereinafter referred to as "blended PE (A1)" in the column of Example C). Got
・ Blended polyethylene B1
Blended polyethylene B1 having an average density of 0.950 g / cm ³ by mixing 70 parts of HDPE (2) and 30 parts of LDPE (hereinafter referred to as "blended PE (B1)" in the column of Example C). Got
・ Blended polyethylene C1
98 parts of LLDPE and 2 parts of slip agent-containing MB are mixed and blended polyethylene C1 having an average density of 0.916 g / cm ³ (hereinafter referred to as "blended PE (C1)" in the column of Example C). Got

・ Blended polyethylene A2
69 parts of MDPE, 30 parts of HDPE (1) and 1 part of slip agent-containing MB are mixed and blended polyethylene A2 having an average density of 0.948 g / cm ³ (in the column of Example C, hereinafter "blended". PE (A2) ”) was obtained.
・ Blended polyethylene B2
69 parts of HDPE (2), 30 parts of LDPE, and 1 part of slip agent-containing MB are mixed and blended polyethylene B2 with an average density of 0.949 g / cm ³ (in the column of Example C, hereinafter "blended". PE (B2) ”) was obtained.
・ Blended polyethylene C2
Blended polyethylene C2 having an average density of 0.916 g / cm ³ by mixing 99 parts of LLDPE and 1 part of slip agent-containing MB (hereinafter referred to as "blended PE (C2)" in the column of Example C). Got

・ Blended polyethylene C3
68 parts of LLDPE, 30 parts of LDPE, and 2 parts of slip agent-containing MB are mixed to make a blended polyethylene C3 having an average density of 0.918 g / cm ³ (in the column of Example C, hereinafter, "blended PE (C3)". ) ”) Was obtained.

[Example 1C]
Blended PE (A1), blended PE (B1) and blended PE (C1) are blended PE (A1) layer (15 μm) / blended PE (B1) layer (22.5 μm) / blended PE (C1) by the inflation molding method. ) Layer (50 μm) / Blend PE (B1) layer (22.5 μm) / Blend PE (A1) layer (15 μm) 5 layers are co-extruded with a layer thickness ratio to form a tube-like film, and the total thickness is 125 μm. The polyethylene film of No. 1 was obtained, and the tubular film was folded at the nip site to form two layers. The numbers in parentheses indicate the layer thickness.

The polyethylene film produced above is stretched in the longitudinal direction (MD) at a draw ratio of 5 times, and further, the blended PE (A1) layer (surface layer) on one side is subjected to a corona discharge treatment, and then the end portion is formed. The slit was made and divided into two pieces to obtain a stretched multilayer base material having a thickness of 25 μm.

[Examples 2C and 3C, Comparative Examples 1C and 2C]
A polyethylene film and a stretched multilayer base material were obtained in the same manner as in Example 1C except that the layer structure was changed as shown in Table 8. In Table 8, the slip agent-containing MB is simply referred to as “MB”.

[Example 4C]
Blended PE (A1), blended PE (B1) and blended PE (C1) are blended PE (A1) layer (12 μm) / blended PE (B1) layer (18 μm) / blended PE (C1) layer by an inflation molding method. A polyethylene film having a total thickness of 100 μm was formed by co-extruding 5 layers at a layer thickness ratio of (40 μm) / blend PE (B1) layer (18 μm) / blend PE (A1) layer (12 μm) to form a tube. Obtained, the tubular film was folded at the nip portion, and two sheets were stacked. The numbers in parentheses indicate the layer thickness.

The polyethylene film produced above is stretched in the longitudinal direction (MD) at a draw ratio of 5 times, and further, the blended PE (A1) layer (surface layer) on one side is subjected to a corona discharge treatment, and then the end portion is formed. The slit was made and divided into two pieces to obtain a stretched multilayer base material having a thickness of 20 μm.

[Examples 5C and 6C]
A polyethylene film and a stretched multilayer base material were obtained in the same manner as in Example 4C except that the layer structure was changed as shown in Table 9. In Table 9, the slip agent-containing MB is simply referred to as “MB”.

Two-component curable urethane-based adhesion between the first linear low-density polyethylene layer side of the unstretched polyethylene film (heat seal layer) produced above and the stretched multilayer base material obtained in Examples and Comparative Examples. A laminate was obtained by dry laminating with an agent (Ru-77T / H-7 manufactured by Rock Paint Co., Ltd.).

The laminate prepared above was cut into 10 cm × 10 cm to prepare three sample pieces. Each sample piece was folded in half so that the heat seal layer side was on the inside, and a 1 cm × 10 cm area was heat-sealed using a heat seal tester under the conditions of a temperature of 140 ° C., a pressure of 1 kgf / cm ² , and 1 second.
The above evaluation results are shown in Tables 8 and 9.

[Example D]
The laminate of the fifth aspect of the present disclosure will be described more specifically based on the examples, but the laminate of the fifth aspect of the present disclosure is not limited by the examples. Hereinafter, "parts by mass" is simply referred to as "parts".

The polyethylene used in the following examples will be described.
・ Medium density polyethylene:
Product name Elite5538G
Density: 0.941 g / cm ³ , Melting point: 129 ° C,
MFR: 1.3g / 10 minutes, Dowchemical High Density Polyethylene:
Product name Elite5960G
Density: 0.960 g / cm ³ , Melting point: 134 ° C,
MFR: 0.8 g / 10 minutes, manufactured by Dowchemical, linear low-density polyethylene:
Product name Elite5400G
Density: 0.916 g / cm ³ , Melting point: 123 ° C,
MFR: 1.3g / 10 minutes, manufactured by Dowchemical

In the column of Example D, the medium density polyethylene (Elite5538G) is also referred to as "MDPE", the high density polyethylene (Elite5960G) is referred to as "HDPE", and the linear low density polyethylene (Elite5400G) is also referred to as "LLDPE".

<Making blended polyethylene>
・ Blended polyethylene A
50 parts of MDPE and 50 parts of HDPE were mixed to obtain a blended polyethylene A having an average density of 0.951 g / cm ³ (hereinafter referred to as "blended PE (A)" in the column of Example D). ..
・ Blended polyethylene B
50 parts of MDPE and 50 parts of LLDPE were mixed to obtain a blended polyethylene B having an average density of 0.929 g / cm ³ (hereinafter referred to as "blended PE (B)" in the column of Example D). ..
・ Blended polyethylene B1
70 parts of MDPE and 30 parts of LLDPE were mixed to obtain a blended polyethylene B1 having an average density of 0.934 g / cm ³ (hereinafter referred to as "blended PE (B1)" in the column of Example D). ..
・ Blended polyethylene C
70 parts of MDPE and 30 parts of HDPE were mixed to obtain a blended polyethylene C having an average density of 0.947 g / cm ³ (hereinafter referred to as "blended PE (C)" in the column of Example D). ..
・ Blended polyethylene D
30 parts of MDPE and 70 parts of HDPE were mixed to obtain a blended polyethylene D having an average density of 0.954 g / cm ³ (hereinafter referred to as "blended PE (D)" in the column of Example D). ..

[Example 1D]
MDPE, HDPE and blend PE (A) are subjected to MDPE layer (15 μm) / HDPE layer (22.5 μm) / blend PE (A) layer (50 μm) / HDPE layer (22.5 μm) / MDPE layer by inflation molding method. Five layers were co-extruded at a layer thickness ratio of (15 μm) to form a tubular film, a polyethylene film having a total thickness of 125 μm was obtained, and the tubular film was folded at the nip site to form two layers. The numbers in parentheses indicate the layer thickness.

First linear low density polyethylene (Prime Polymer, SP2520, density: 0.925 g / cm ³ , melting point: 122 ° C) and second linear low density polyethylene (Prime Polymer, SP1520, A density: 0.913 g / cm ³ , melting point: 116 ° C.) was extruded in multiple layers by an inflation molding method, and a first linear low-density polyethylene layer with a thickness of 20 μm and a second layer with a thickness of 20 μm were formed. An unstretched polyethylene film having a multilayer structure including the linear low-density polyethylene layer of the above was prepared. The unstretched polyethylene film having this multilayer structure was used as a heat seal layer as described below.

The first linear low-density polyethylene layer side of the unstretched polyethylene film (heat seal layer) having the multilayer structure produced above and the stretched multilayer substrate prepared above are bonded to a two-component curable urethane adhesive. (Ru-77T / H-7 manufactured by Rock Paint Co., Ltd.) was dry-laminated to obtain a laminated body.

[Examples 2D to 7D]
A laminated body was obtained in the same manner as in Example 1D except that the layer structure of the stretched multilayer base material was changed as shown in Table 10.

The above evaluation results are shown in Table 10. As is clear from the results in Table 10, it can be seen that according to the laminate of the fifth aspect of the present disclosure, it is possible to produce a packaging bag having excellent strength, heat sealability and recyclability.

As those skilled in the art will understand, the multilayer base material and the like of the present disclosure are not limited by the description of the above-mentioned Examples, and the above-mentioned Examples and the specification are merely for explaining the principle of the present disclosure. Various modifications or improvements may be made as long as they do not deviate from the gist and scope of the disclosure, and any of these modifications or improvements are included within the scope of the present disclosure for which protection is claimed. Further, the scope of the claims for protection includes not only the description of the claims but also the equivalent thereof.

10: Polyethylene multilayer base material 10a: Base material (stretched multilayer base material)
12: Layer (A)
14: Layer (C)
16: Multilayer intermediate layer (B)
12, 14, 18, 20, 22: Layers constituting the polyethylene multilayer base material 30: Laminated body 32: Heat seal layer 34: Barrier layer 36: Adhesive layer

Claims

With the first polyethylene layer,
With the second polyethylene layer,
A third polyethylene layer is provided in this order in the thickness direction, and the polyethylene layer is stretched.
Satisfy the following requirements (A) and / or the following requirements (B),
Polyethylene multilayer base material:
Requirement (A): The indentation elastic modulus of the first polyethylene layer is 3.0 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the third polyethylene layer is the first. It is 3.0 times or more the indentation elastic modulus of the polyethylene layer of 2.
Requirement (B): The indentation hardness of the first polyethylene layer is 2.0 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the third polyethylene layer is the second polyethylene. It is 2.0 times or more the indentation hardness of the layer.
The polyethylene multilayer substrate has a second polyethylene layer between the first polyethylene layer and the second polyethylene layer, and a second polyethylene between the second polyethylene layer and the third polyethylene layer. With more layers,
The indentation elastic modulus of the second polyethylene layer is 2.0 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the second polyethylene layer is that of the second polyethylene layer. More than 2.0 times the indentation modulus and / or
The indentation hardness of the second polyethylene layer is 1.4 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the second polyethylene layer is the indentation hardness of the second polyethylene layer. 1.4 times or more,
The polyethylene multilayer base material according to claim 1.
The layer (A) containing medium-density polyethylene and
Two or more layers of the multilayer intermediate layer (B), each containing polyethylene, and
A polyethylene multilayer base material in which a layer (C) containing medium-density polyethylene is provided in this order in the thickness direction.
The multilayer base material has been stretched and has been stretched.
When the polyethylene-containing layers arbitrarily adjacent to each other in the thickness direction in the multilayer substrate are described as the layer (1) and the layer (2), the density of the polyethylene constituting the layer (1) and the layer ( The absolute value of the difference from the density of polyethylene constituting 2) is 0.030 g / cm 3 or less.
Polyethylene multilayer base material.
A first layer containing medium density polyethylene and high density polyethylene,
A second layer containing medium density polyethylene and linear low density polyethylene,
A third layer containing linear low density polyethylene,
A fourth layer containing medium density polyethylene and linear low density polyethylene,
A fifth layer containing medium-density polyethylene and high-density polyethylene is provided in this order in the thickness direction, and is stretched.
Polyethylene multilayer base material.
A first layer containing medium density polyethylene and high density polyethylene,
A second layer containing high density polyethylene and
A third layer containing linear low density polyethylene,
A fourth layer containing high density polyethylene,
A fifth layer containing medium-density polyethylene and high-density polyethylene is provided in this order in the thickness direction, and is stretched.
Polyethylene multilayer base material.
The polyethylene multilayer base material according to any one of claims 1 to 5, wherein the polyethylene content in the polyethylene multilayer base material is 80% by mass or more.
The polyethylene multilayer base material according to any one of claims 1 to 6 and the polyethylene multilayer substrate.
A printing substrate including a printing layer formed on the polyethylene multilayer substrate.
Polyethylene multilayer base material and
A laminate provided with a heat-sealed layer containing polyethylene as a main component.
The polyethylene multilayer base material is
With the first polyethylene layer,
With the second polyethylene layer,
A third polyethylene layer is provided in this order in the thickness direction, and the polyethylene layer is stretched.
The laminate satisfies the following requirement (C) and / or the following requirement (D).
Laminate:
Requirement (C): The indentation elastic modulus of the first polyethylene layer is 3.5 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the third polyethylene layer is the first. It is 3.5 times or more the indentation elastic modulus of the polyethylene layer of 2.
Requirement (D): The indentation hardness of the first polyethylene layer is 2.0 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the third polyethylene layer is the second polyethylene. It is 2.0 times or more the indentation hardness of the layer.
The polyethylene multilayer substrate has a second polyethylene layer between the first polyethylene layer and the second polyethylene layer, and a second polyethylene between the second polyethylene layer and the third polyethylene layer. With more layers,
The indentation elastic modulus of the second polyethylene layer is 2.0 times or more the indentation elastic modulus of the second polyethylene layer, and the indentation elastic modulus of the second polyethylene layer is that of the second polyethylene layer. More than 2.0 times the indentation modulus and / or
The indentation hardness of the second polyethylene layer is 1.5 times or more the indentation hardness of the second polyethylene layer, and the indentation hardness of the second polyethylene layer is the indentation hardness of the second polyethylene layer. 1.5 times or more,
The laminate according to claim 8.
Polyethylene multilayer base material and
A laminate provided with a heat-sealed layer containing polyethylene as a main component.
The polyethylene multilayer base material is
With the first polyethylene layer,
With the second polyethylene layer,
A third polyethylene layer is provided in this order in the thickness direction, and the polyethylene layer is stretched.
The laminate satisfies the following requirement (E) and / or the following requirement (F).
Laminate:
Requirement (E): The indentation elastic modulus of the first polyethylene layer is 1.0 GPa or more, and the indentation elastic modulus of the third polyethylene layer is 1.0 GPa or more.
Requirement (F): The indentation hardness of the first polyethylene layer is 45 MPa or more, and the indentation hardness of the third polyethylene layer is 45 MPa or more.
The polyethylene multilayer substrate has a second polyethylene layer between the first polyethylene layer and the second polyethylene layer, and a second polyethylene between the second polyethylene layer and the third polyethylene layer. With more layers,
The indentation elastic modulus of the second polyethylene layer is 0.03 GPa or more and 0.7 GPa or less, and the indentation elastic modulus of the second polyethylene layer and the indentation elastic modulus of the second polyethylene layer are independent of each other. , 0.3 GPa or more and 3.5 GPa or less, and / or
The indentation hardness of the second polyethylene layer is 1 MPa or more and 40 MPa or less, and the indentation hardness of the second polyethylene layer and the indentation hardness of the second polyethylene layer are independently 20 MPa or more and 100 MPa or less. ,
The laminate according to claim 10.
The polyethylene multilayer base material according to any one of claims 1 to 6 and the polyethylene multilayer substrate.
A laminate with a heat seal layer.
The heat shrinkage rate in the longitudinal direction (MD) of the laminated body is 15% or less, and the heat shrinkage rate is 15% or less.
The heat shrinkage rate of the laminated body in the vertical direction (TD) with respect to MD is 15% or less.
The laminate according to any one of claims 8 to 12.
A laminate comprising a base material and a heat seal layer.
The base material and the heat seal layer are made of the same type of resin material.
The base material has a multi-layer structure and has a multi-layer structure.
The base material is a base material that has been subjected to a stretching treatment.
The heat seal layer is a layer that has not been stretched.
Laminated body.
The laminate according to claim 14, wherein the resin material of the same type is polyolefin or polyester.
The laminate according to claim 14, wherein the resin material of the same type is polyethylene.
The laminate according to any one of claims 14 to 16, wherein the heat seal layer has a multilayer structure.
The laminate according to any one of claims 8 to 17, further comprising a barrier layer formed on the surface of the base material or the surface of the heat seal layer.
A packaging material comprising the polyethylene multilayer base material according to any one of claims 1 to 6, the printing base material according to claim 7, or the laminate according to any one of claims 8 to 18.