JP7579520B2 - Polyethylene sealant film, laminate and packaging bag - Google Patents

Description

The present invention relates to a sealant film, a laminate, and a packaging bag.

Traditionally, packaging bags have been used to fill and package contents such as food, medicines, chemicals, and cosmetics. The laminate that constitutes the packaging bag includes one that has a base layer such as a stretched film and a sealant film that has sealing properties. The packaging bag is manufactured by heat-sealing the sealant film that is provided in the laminate.

In recent years, with growing calls for the creation of a recycling-oriented society, there is a desire to move away from fossil fuels in the materials sector, just as there is in the energy sector, and the use of biomass has attracted attention. Biomass is an organic compound produced by photosynthesis from carbon dioxide and water, and by using it, it becomes carbon dioxide and water again, making it a so-called carbon-neutral renewable energy. Recently, the practical application of biomass plastics made from these biomass raw materials has progressed rapidly, and attempts are also being made to produce various resins from biomass raw materials.

As for biomass-derived resins, polylactic acid (PLA), which is manufactured via lactic acid fermentation, was the first to be commercially produced; however, since its performance as a plastic differs significantly from current general-purpose plastics, including its biodegradability, there are limitations to its product applications and manufacturing methods, and it has not yet come into widespread use. Furthermore, a life cycle assessment (LCA) is being carried out on PLA, and discussions are being held on the energy consumption during PLA manufacturing and its equivalence as an alternative to general-purpose plastics.

Here, various types of polymers such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyester are used as general-purpose plastics. In particular, polyethylene is molded into films, sheets, bottles, etc. and used for various purposes such as packaging materials, and since it is used in large quantities worldwide, using conventional polyethylene derived from fossil fuels places a large burden on the environment. Therefore, it is desirable to use biomass-derived raw materials in the production of polyethylene to reduce the amount of fossil fuels used. For example, research has been conducted to date on the production of ethylene and butylene, the raw materials for polyolefin resins, from renewable natural raw materials (see Patent Document 1).

Special Publication No. 2011-506628

It is desirable to use biomass-derived raw materials for sealant films as well, thereby reducing the amount of fossil fuel used and the burden on the environment. In addition to sealing properties, sealant films are also required to have lamination strength with other layers and blocking resistance when rolled up.

The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a polyethylene sealant film that is excellent in reducing the environmental load, as well as in sealing properties, lamination strength, and blocking resistance.
An object of the present invention is to provide a laminate comprising the polyethylene sealant film.
An object of the present invention is to provide a packaging bag including the laminate.

The present invention provides a polyethylene sealant film comprising at least a laminate layer and a seal layer,
The biomass content of the polyethylene sealant film is 50% or more,
the sealing layer comprises linear low-density polyethylene and high-pressure low-density polyethylene, the linear low-density polyethylene being a main component of the sealing layer;
The laminate layer is a polyethylene sealant film containing an oligomer having 18 to 36 carbon atoms, and the content of the oligomer in the entire laminate layer is 350 ppm or less.

The polyethylene sealant film according to the present invention comprises at least one copolymer selected from the group consisting of ethylene-1-octene copolymers and ethylene-1-hexene copolymers,
The total content of the ethylene-1-octene copolymer and the ethylene-1-hexene copolymer may be 30% by mass or less based on the entire polyethylene sealant film.

In the polyethylene sealant film according to the present invention, the laminate layer may contain, as a main component, at least one type of polyethylene selected from the group consisting of fossil fuel linear low density polyethylene, fossil fuel high pressure process low density polyethylene, and biomass high pressure process low density polyethylene.

The polyethylene sealant film according to the present invention may further include an intermediate layer between the laminate layer and the seal layer.

In the polyethylene sealant film according to the present invention, the intermediate layer may contain biomass polyethylene as a main component.

The present invention provides a laminate comprising at least a base layer, an adhesive layer, and a sealant layer in this order,
The sealant layer comprises the polyethylene sealant film according to any one of claims 1 to 5, and is adjacent to the adhesive layer;
The laminate layer of the polyethylene sealant film is located on the base layer side,
The sealing layer of the polyethylene sealant film may be one surface layer of the laminate.

In the laminate according to the present invention, the substrate layer may be a stretched film.

The present invention is a packaging bag comprising the laminate.

According to the present invention, it is possible to provide a polyethylene sealant film which is excellent in reducing the environmental load, as well as excellent in sealing properties, lamination strength, and blocking resistance.
An object of the present invention is to provide a laminate comprising the polyethylene sealant film.
An object of the present invention is to provide a packaging bag including the laminate.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a polyethylene sealant film according to the present invention. FIG. 1 is a schematic cross-sectional view showing one embodiment of a polyethylene sealant film according to the present invention. FIG. 2 is a plan view showing a test piece for evaluating impact strength. FIG. 2 is a schematic diagram showing a method for measuring impact strength. FIG. 2 is a schematic diagram showing an example of a method for measuring puncture strength. 1 is a schematic cross-sectional view showing one embodiment of a laminate according to the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate according to the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate according to the present invention. FIG. 2 is a schematic diagram showing a method for measuring laminate strength. FIG. 2 is a schematic diagram showing a method for measuring laminate strength. FIG. 13 is a diagram showing the measurement results of laminate strength. FIG. 2 is a schematic diagram showing a method for measuring seal strength. 1 is a schematic diagram showing one embodiment of a packaging bag according to the present invention. 1 is a schematic diagram showing one embodiment of a packaging bag according to the present invention.

The following describes an embodiment of the present invention. Note that in the drawings accompanying this specification, the scale and aspect ratios have been appropriately altered and exaggerated from those of the actual product for the sake of ease of illustration and understanding.

In addition, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "orthogonal" and "same," as well as values of length and angle, are not limited to their strict meanings, but are interpreted to include the range within which similar functions can be expected.

[Polyethylene sealant film]
First, in this specification, polyethylene includes ethylene homopolymers and copolymers of ethylene and α-olefins (hereinafter also referred to as ethylene-α-olefin copolymers). The content of α-olefin units in the ethylene-α-olefin copolymers is, for example, 10 mol % or less, and may be 5 mol % or less.

Examples of the homopolymer of ethylene include high density polyethylene (HDPE), medium density polyethylene (MDPE), and high pressure low density polyethylene (LDPE).
In this specification, high density polyethylene means polyethylene having a density of 0.942 g/cm3 or ^more , and medium density polyethylene means polyethylene having a density of 0.930 g/cm3 ^or more and less than 0.942 g/ ^cm3 . High pressure low density polyethylene means polyethylene having a density of 0.910 g/cm3 ^or more and less than 0.930 g/ ^cm3 . High pressure low density polyethylene can be obtained, for example, by polymerizing ethylene under high pressure of 1000 atmospheres or more and less than 2000 atmospheres.
In this specification, the density of the resin, layer, film, etc. is measured in accordance with Method B (pycnometer method) or Method D (density gradient tube method) of JIS K7112:1999. Method B or Method D is selected appropriately depending on the shape and mass of the test piece to be measured. In Method D, the measurement temperature (liquid temperature) is 23°C.

The ethylene-α-olefin copolymer may also be called linear polyethylene. Linear polyethylene will now be described.
Linear polyethylene is a copolymer of ethylene and an α-olefin polymerized using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst. It is therefore distinguished from a homopolymer of ethylene. The α-olefins that serve as monomers for linear polyethylene have 3 or more carbon atoms, and examples of such α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene, 3,3-dimethylbutene, and mixtures thereof.
Linear polyethylene having a density less than 0.930 g/ ^cm3 may be referred to as linear low density polyethylene (LLDPE).

The single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene transition metal compound or a nonmetallocene transition metal compound with an activation cocatalyst. Compared to multi-site catalysts, single-site catalysts have a uniform active site structure, and therefore can polymerize polymers with high molecular weight and highly uniform structures. Particularly preferred examples of single-site catalysts include metallocene catalysts. Metallocene catalysts are catalysts that contain a transition metal compound of Group IV of the periodic table that contains a ligand having a cyclopentadienyl skeleton, a cocatalyst, and if necessary, an organometallic compound and each of the catalyst components of the carrier.

In the above-mentioned transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, or the like. Examples of the substituted cyclopentadienyl group include those having at least one substituent selected from a hydrocarbon group having 1 to 30 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, a haloalkyl group, a halosilyl group, and the like. The substituted cyclopentadienyl group may have two or more substituents, and the substituents may be bonded to each other to form a ring, such as an indenyl ring, a fluorenyl ring, an azulenyl ring, or a hydrogenated product thereof. The rings formed by bonding the substituents to each other may further have substituents.

In the transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the transition metal may be zirconium, titanium, hafnium, etc., and is particularly preferably zirconium and/or hafnium. The transition metal compound preferably has two ligands having a cyclopentadienyl skeleton, and each ligand having a cyclopentadienyl skeleton is bonded to each other by a bridging group. Examples of the bridging group include alkylene groups having 1 to 4 carbon atoms, silylene groups, substituted silylene groups such as dialkylsilylene groups and diarylsilylene groups, and substituted germylene groups such as dialkylgermylene groups and diarylgermylene groups. The bridging group is preferably a substituted silylene group.

In transition metal compounds of Group IV of the periodic table, examples of ligands other than those having a cyclopentadienyl skeleton include hydrogen, hydrocarbon groups having 1 to 20 carbon atoms (alkyl groups, alkenyl groups, aryl groups, alkylaryl groups, aralkyl groups, polyenyl groups, etc.), halogens, metaalkyl groups, metaaryl groups, etc.

The above-mentioned transition metal compounds of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton can be used as a catalyst component, either alone or in a mixture of two or more kinds.

The co-catalyst refers to a catalyst that can effectively use the above-mentioned transition metal compound of Group IV of the periodic table as a polymerization catalyst, or can balance the ionic charge in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxanes of organoaluminum oxy compounds and benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of cations with or without active hydrogen groups and non-coordinating anions, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing fluoro groups.

The transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used supported on an inorganic or organic carrier, preferably an inorganic or organic porous oxide, specifically montmorillonite or other ion-exchangeable layered _silicate , _SiO2 , _Al2O3 , MgO, _ZrO2 , _TiO2 , _B2O3 , CaO, ZnO, BaO, _{ThO2 ,} or mixtures thereof.

Examples of organometallic compounds that may be used as needed include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum compounds are preferably used.

The polyethylene sealant film according to the present invention includes a laminate layer and a seal layer. The polyethylene sealant film may include an intermediate layer between the laminate layer and the seal layer.
In the following, the polyethylene sealant film will also be simply referred to as "sealant film".

In the sealant film according to the present invention, the laminate layer contains an oligomer having 18 to 36 carbon atoms (hereinafter also referred to as "C ₁₈ -C ₃₆ oligomer"). The content of the C ₁₈ -C ₃₆ oligomer is 350 ppm or less based on the entire laminate layer.
The _C18 - _C36 oligomer present in the film is a wax component. Such a wax component reduces the laminate strength between the sealant film and other layers, particularly between the sealant film and a layer adjacent to the sealant film via an adhesive layer (hereinafter also referred to as "adjacent layer"). By setting the content of the _C18 - _C36 oligomer in the laminate layer to 350 ppm or less, a sealant film having excellent laminate strength with other layers can be realized.

In the sealant film according to the present invention, the seal layer contains linear low-density polyethylene and high-pressure low-density polyethylene, and the linear low-density polyethylene is the main component of the seal layer. In this specification, the term "main component" means a component contained in an amount of 50% by mass or more.
Low density polyethylene has high sealing properties, and among them, linear low density polyethylene has a low heat fusion temperature and is particularly excellent in sealing properties. When the sealing layer contains linear low density polyethylene as a main component, the heat fusion temperature of the sealant film can be lowered, and a sealant film with excellent sealing properties can be realized. On the other hand, linear low density polyethylene has excellent sealing properties but is poor in blocking resistance. That is, when the sealing layer is made of only linear low density polyethylene, blocking occurs when the sealant film is wound up. When the sealing layer contains high pressure low density polyethylene, which has better blocking resistance than linear low density polyethylene, together with linear low density polyethylene, a sealant film with excellent sealing properties and excellent blocking resistance can be realized.

As described above, since the sealing layer contains linear low density polyethylene and high-pressure low density polyethylene, the sealant film according to the present invention contains linear low density polyethylene and high-pressure low density polyethylene.
The content of the linear low-density polyethylene in the sealant film is, for example, 15% by mass or more, or may be 20% by mass or more, or 30% by mass or more, based on the entire sealant film, while the content of the linear low-density polyethylene in the sealant film is, for example, 70% by mass or less, or may be 50% by mass or less, based on the entire sealant film.

The content of high-pressure low-density polyethylene in the sealant film is, for example, 45% by mass or more, and may be 25% by mass or more, based on the entire sealant film. On the other hand, the content of high-pressure low-density polyethylene in the sealant film is, for example, 80% by mass or less, and may be 75% by mass or less, or may be 65% by mass or less, based on the entire sealant film.

The ratio of the content of linear low-density polyethylene to high-pressure low-density polyethylene in the sealant film is, for example, 0.05 or more, or may be 0.1 or more, or may be 0.3, on a mass basis. On the other hand, the ratio is, for example, 15 or less, or may be 5 or less, or may be 1 or less, on a mass basis.

In one embodiment, the sealant film contains at least one copolymer selected from the group consisting of an ethylene-1-octene copolymer and an ethylene-1-hexene copolymer, and the total content of the ethylene-1-octene copolymer and the ethylene-1-hexene copolymer is 30% by mass or less based on the entire sealant film. This can improve the tearability of the sealant film. The content is preferably 20% by mass or less, more preferably 15% by mass or less.
On the other hand, from the viewpoint of the impact resistance of the sealant film, the content is preferably 1 mass % or more, more preferably 5 mass % or more, and even more preferably 10 mass % or more.

The sealant film may contain high density polyethylene (HDPE) and/or medium density polyethylene (MDPE) as long as the purpose of the present invention is not impaired.

In one embodiment, the sealant film may contain biomass polyethylene. By containing biomass polyethylene in the sealant film, the environmental load reduction of the sealant film can be improved. The content of biomass polyethylene in the sealant film is preferably 50% by mass or more, more preferably 60% by mass or more, based on the entire sealant film. On the other hand, the content of biomass polyethylene in the sealant film may be, for example, 90% by mass or less, or 80% by mass or less, based on the entire sealant film.
As used herein, biomass polyethylene refers to a polymer of a monomer composition containing ethylene derived from biomass. The monomer composition may also contain ethylene derived from conventional fossil fuels.
An example of a method for producing ethylene derived from biomass will be described below.

Biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use biomass-derived fermented ethanol obtained from plant raw materials. The plant raw material is not particularly limited, and any conventionally known plant can be used. Examples include corn, sugarcane, beet, and manioc.

Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from plant raw materials with an ethanol-producing microorganism or a product derived from the crushed microorganism, and then purifying the ethanol. Conventional methods such as distillation, membrane separation, and extraction can be used to purify ethanol from the culture solution. For example, methods include adding benzene, cyclohexane, etc., and performing azeotropic distillation, or removing water by membrane separation, etc.

To obtain the above ethylene, further advanced purification may be carried out at this stage, such as reducing the total amount of impurities in the ethanol to 1 ppm or less.

A catalyst is usually used when obtaining ethylene by the dehydration reaction of ethanol, but there are no particular limitations on the catalyst, and any conventionally known catalyst can be used. From a process standpoint, a fixed-bed flow reaction is advantageous because it is easy to separate the catalyst from the product; for example, gamma-alumina is preferred.

Since this dehydration reaction is an endothermic reaction, it is usually carried out under heating conditions. As long as the reaction proceeds at a commercially useful reaction rate, the heating temperature is not limited, but a temperature of 100°C or higher is preferable, 250°C or higher is more preferable, and 300°C or higher is even more preferable. There is no particular upper limit, but from the viewpoint of energy balance and equipment, it is preferably 500°C or lower, and more preferably 400°C or lower.

In the dehydration reaction of ethanol, the yield of the reaction depends on the amount of water contained in the ethanol supplied as a raw material. In general, when performing a dehydration reaction, it is preferable to have no water, considering the efficiency of removing water. However, in the case of the dehydration reaction of ethanol using a solid catalyst, it has been found that the production amount of other olefins, especially butene, tends to increase if water is not present. This is probably because the presence of a small amount of water makes it difficult to suppress ethylene dimerization after dehydration. The lower limit of the allowable water content is 0.1 mass% or more, and preferably 0.5 mass% or more. There is no particular limit to the upper limit, but from the viewpoint of material balance and heat balance, it is preferably 50 mass% or less, more preferably 30 mass% or less, and even more preferably 20 mass% or less.

By carrying out the dehydration reaction of ethanol in this way, a mixture of ethylene, water, and a small amount of unreacted ethanol is obtained. However, since ethylene is in a gaseous state at room temperature and below about 5 MPa, water and ethanol can be removed from this mixture by gas-liquid separation to obtain ethylene. This can be done by any known method.

The ethylene obtained by gas-liquid separation is further distilled. There are no particular restrictions on the distillation method, operating temperature, residence time, etc., except that the operating pressure is normal pressure or higher.

When the raw material is biomass-derived ethanol, the obtained ethylene contains carbonyl compounds such as ketones, aldehydes, and esters, which are impurities mixed in during the ethanol fermentation process, as well as carbon dioxide gas, which is their decomposition product, and nitrogen-containing compounds such as amines and amino acids, which are enzyme decomposition products and impurities, as well as ammonia, which is their decomposition product. These impurities are desirably removed because they may affect the polymerization catalyst when ethylene is polymerized. On the other hand, although it is possible to reduce the content of these impurities contained in ethylene by a conventionally known purification method, it is difficult to completely remove the impurities from the cost and technical standpoints. Therefore, ethylene obtained from biomass-derived ethanol contains extremely small amounts of impurities. As a result, biomass polyethylene, which is a polymer of a monomer composition containing biomass-derived ethylene, also contains extremely small amounts of impurities. Note that biomass polyethylene may also contain low molecular weight compounds such as monomers and oligomers, which are unreacted components resulting from these impurities.

The inclusion of biomass polyethylene in the sealant film of the present invention can be determined by measuring the biomass content of the sealant film. If the sealant film contains biomass polyethylene, the biomass content of the sealant film will be greater than 0%.

Here, the biomass degree will be described.
Carbon dioxide in the atmosphere contains a certain percentage of C14 (105.5 pMC), so it is known that the C14 content in plants that grow by absorbing carbon dioxide from the atmosphere, such as corn, is also about 105.5 pMC. It is also known that fossil fuels contain very little C14. Therefore, by measuring the percentage of C14 in the total carbon atoms, the percentage of carbon derived from biomass can be calculated.
The term "biomass degree" refers to the weight ratio of biomass-derived components. For example, in the case of polyethylene terephthalate, polyethylene terephthalate is a polymer of ethylene glycol containing two carbon atoms and terephthalic acid containing eight carbon atoms in a molar ratio of 1:1. Therefore, when only biomass-derived ethylene glycol is used, the weight ratio of biomass-derived components in the polyester is 31.25%, so the theoretical value of the biomass degree is 31.25%. Specifically, the mass of polyethylene terephthalate is 192, of which the mass derived from biomass-derived ethylene glycol is 60, so 60÷192×100=31.25. In addition, the weight ratio of biomass-derived components in the fossil fuel polyester produced using ethylene glycol derived from fossil fuel and dicarboxylic acid derived from fossil fuel is 0%, and the biomass degree of the fossil fuel polyester is 0%. Hereinafter, unless otherwise specified, "biomass degree" refers to the weight ratio of biomass-derived components.

Theoretically, if only biomass-derived raw materials are used as raw materials for polyethylene, the concentration of biomass-derived ethylene will be 100%, and therefore the biomass content of biomass polyethylene will be 100%.
The concentration of biomass-derived ethylene in fossil fuel polyethylene produced only from raw materials derived from fossil fuels is 0%, so the biomass content of fossil fuel-derived polyethylene is 0%.

In the sealant film according to the present invention, the biomass degree is 50% or more. This allows for a sealant film with excellent environmental load reduction properties to be realized. The biomass degree is more preferably 60% or more. On the other hand, the biomass degree of the sealant film is, for example, 90% or less, and may be 80% or less.

The thickness of the sealant film is, for example, 20 μm or more, may be 70 μm or more, or may be 100 μm or more. On the other hand, the thickness of the sealant film is, for example, 300 μm or less, may be 200 μm or less, or may be 150 μm or less.

The sealant film may contain one or more additives as long as the object of the present invention is not impaired. Examples of additives include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, friction reducers, slip agents, antiblocking agents, antioxidants, ion exchange agents, and color pigments. The sealant film preferably contains a slip agent and/or an antiblocking agent.

Below, one embodiment of the polyethylene sealant film according to the present invention will be described with reference to the drawings.

In one embodiment, the polyethylene sealant film 10 is composed of a laminate layer 11 and a seal layer 12, as shown in FIG. 1. As shown in FIG. 1, the seal layer 12 is one surface layer of the polyethylene sealant film 10, and the laminate layer 11 is the other surface layer of the polyethylene sealant film 10.

In one embodiment, the polyethylene-based sealant film 10 is composed of a laminate layer 11, an intermediate layer 13, and a seal layer 12, as shown in FIG. 2. As shown in FIG. 2, the seal layer 12 is one surface layer of the polyethylene-based sealant film 10, and the laminate layer 11 is the other surface layer of the polyethylene-based sealant film 10. As shown in FIG. 2, the polyethylene-based sealant film 10 has an intermediate layer 13 between the laminate layer 11 and the seal layer 12.

The layer structure of the polyethylene sealant film 10 can be combined as desired.

Below, we will explain each layer that the polyethylene sealant film of the present invention may have.

<Laminate layer>
The laminate layer is a layer that constitutes one of the surface layers of the sealant film, and is a layer that is located on the base layer side of the laminate when the sealant film is used in the laminate.
In the sealant film according to the present invention, the laminate layer contains the C ₁₈ -C ₃₆ oligomer as described above, and the content of the C ₁₈ -C ₃₆ oligomer is 350 ppm or less based on the entire laminate layer.

The content of C ₁₈ -C ₃₆ oligomers can be measured by the following method.
First, a calibration curve is created using standard substances.
A sample (eg, 1 g) is then scraped off from the laminate layer provided with the sealant film.
Next, this sample is placed in 10 ml of chloroform at 50° C., and the oligomer components are extracted by shaking for 6 hours.
Then, pyrolysis GC-MS analysis is carried out to measure the content of oligomer components.
As the pyrolysis GCMS device, 7890B (GC) 5977B (MS) manufactured by Agilent Technologies, Inc. can be used. As the pyrolysis device, AS-1020E/PY-3030D manufactured by Frontier Labs, Inc. can be used. The measurement conditions are, for example, as follows.
(Measurement conditions)
・Inlet temperature: 320℃
Column oven: 50°C (5 min hold) -10°C/min -320°C (3 min hold)
Column: UA-5 (length: 30 m, inner diameter: 0.25 mm, film thickness: 0.25 μm)
Interface temperature: 320°C
・SCAN range: 33 to 600 (m / z)
Ion source temperature: 230° C.

The content of C ₁₈ -C ₃₆ oligomers in the laminate layer is preferably 260 ppm or less, more preferably 200 ppm or less, based on the entire laminate layer.
The content of the oligomer is, for example, 10 ppm or more, or may be 50 ppm or more, or may be 100 ppm or more, based on the entire laminate layer.

In one embodiment, the laminate layer contains linear low density polyethylene. This improves the impact resistance of the sealant film. In addition, the laminate layer contains linear low density polyethylene, which improves the laminate strength with other layers. The linear low density polyethylene contained in the laminate layer may contain at least one copolymer selected from the group consisting of ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer.

From the viewpoint of the impact resistance of the sealant film and adhesion to other layers, the content of linear low-density polyethylene in the laminate layer is preferably 15% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 70% by mass or more, based on the entire laminate layer. On the other hand, the content of linear low-density polyethylene in the laminate layer is, for example, 95% by mass or less, or may be 90% by mass or less, or may be 85% by mass or less, based on the entire laminate layer.

In one embodiment, the laminate layer contains high-pressure low-density polyethylene, which improves the tearability of the sealant film.

From the viewpoint of tearability of the sealant film, the content of high-pressure low-density polyethylene in the laminate layer is preferably 3% by mass or more, more preferably 8% by mass or more, and even more preferably 13% by mass or more, based on the entire laminate layer. On the other hand, the content of high-pressure low-density polyethylene in the laminate layer is, for example, 83% by mass or less, and may be 45% by mass or less, 35% by mass or less, or 25% by mass or less, based on the entire laminate layer.

In one embodiment, the laminate layer contains at least one polyethylene selected from the group consisting of fossil fuel linear low-density polyethylene, fossil fuel high-pressure process low-density polyethylene, and biomass high-pressure process low-density polyethylene as a main component. Fossil fuel linear low-density polyethylene, fossil fuel high-pressure process low-density polyethylene, and biomass high-pressure process low-density polyethylene tend to have a low content of low-molecular-weight compounds, which are unreacted components generated when these are polymerized. Therefore, by containing at least one polyethylene selected from the group consisting of fossil fuel linear low-density polyethylene, fossil fuel high-pressure process low-density polyethylene, and biomass high-pressure process low-density polyethylene as a main component, it is possible to suppress a decrease in laminate strength caused by low-molecular-weight compounds.

In the laminate layer, the content of at least one type of polyethylene selected from the group consisting of fossil fuel linear low density polyethylene, fossil fuel high pressure low density polyethylene, and biomass high pressure low density polyethylene is more preferably 60% by mass, and even more preferably 70% by mass or more, based on the entire laminate layer, from the viewpoint of the laminate strength with other layers of the sealant film. On the other hand, the content of linear low density polyethylene in the laminate layer is, for example, 95% by mass or less, may be 90% by mass or less, or may be 85% by mass or less, based on the entire laminate layer.

The thickness of the laminate layer is, for example, 5 μm or more, may be 10 μm or more, or may be 15 μm or more. On the other hand, the thickness of the laminate layer is, for example, 70 μm or less, may be 50 μm or less, or may be 35 μm or less.

The laminate layer may contain high density polyethylene (HDPE) and/or medium density polyethylene (MDPE) as long as it does not impair the objectives of the present invention.

In one embodiment, the laminate layer may include biomass polyethylene.

The laminate layer may contain one or more additives, provided that the purpose of the present invention is not impaired. Examples of additives include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, friction reducers, slip agents, antiblocking agents, antioxidants, ion exchange agents, and color pigments. The laminate layer preferably contains a slip agent.

The surface of the sealant film on the laminate layer side may be subjected to a surface treatment, which can improve adhesion to other layers.
The method of the surface treatment is not particularly limited, and examples thereof include physical treatments such as corona treatment, flame treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and/or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

<Sealing layer>
The sealing layer is a layer that constitutes the other surface layer of the sealant film. In addition, when the sealant film is used in a laminate, the sealing layer is a layer that constitutes one surface layer of the laminate or both surface layers of the laminate, and is a layer that is fused by heat.

In the sealant film according to the present invention, the sealing layer contains linear low-density polyethylene and high-pressure low-density polyethylene as described above, and the linear low-density polyethylene is the main component of the sealing layer.

The linear low-density polyethylene contained in the sealing layer may contain at least one copolymer selected from the group consisting of ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer.

From the viewpoint of the impact resistance and sealability of the sealant film, the content of linear low-density polyethylene in the seal layer is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. On the other hand, the content of linear low-density polyethylene in the seal layer is, for example, 95% by mass or less, or may be 90% by mass or less, or may be 85% by mass or less, based on the entire seal layer.

From the viewpoint of tearability of the sealant film, the content of the later-developed low-density polyethylene in the seal layer is preferably 3% by mass or more, more preferably 8% by mass or more, and even more preferably 13% by mass or more, based on the entire seal layer. On the other hand, the content of the high-pressure low-density polyethylene in the laminate layer is, for example, 45% by mass or less, or may be 35% by mass or less, or may be 25% by mass or less, based on the entire seal layer.
For the entire seal layer,

The ratio of the content of high-pressure low-density polyethylene to linear low-density polyethylene in the seal layer is, by mass, preferably 1.1 or more, more preferably 1.5 or more, even more preferably 3 or more, and particularly preferably 4 or more. On the other hand, the ratio, by mass, is, for example, 30 or less, or may be 15 or less, or 5 or less.

The thickness of the sealing layer is, for example, 5 μm or more, may be 10 μm or more, or may be 15 μm or more. On the other hand, the thickness of the sealing layer is, for example, 70 μm or less, may be 50 μm or less, or may be 35 μm or less.

The thickness ratio of the laminate layer to the seal layer is preferably 0.5 to 2, more preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1. This thickness ratio can suppress the warping of the sealant film, or the so-called curling phenomenon.

The sealing layer may contain high density polyethylene (HDPE) and/or medium density polyethylene (MDPE) as long as it does not impair the objective of the present invention.

In one embodiment, the sealing layer may include biomass polyethylene.

The sealing layer may contain one or more additives as long as the object of the present invention is not impaired. Examples of additives include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, friction reducers, slip agents, antiblocking agents, antioxidants, ion exchange agents, and color pigments. The sealing layer preferably contains a slip agent and/or an antiblocking agent.

<Middle class>
The intermediate layer is a layer located between the seal layer and the laminate layer. The intermediate layer may be a single layer or multiple layers. When the intermediate layer is a multiple layer, the composition of each intermediate layer may be the same or different.

In one embodiment, the intermediate layer contains biomass polyethylene as a main component. This makes it possible to realize a sealant film that is excellent in reducing the environmental impact.

From the viewpoint of reducing the environmental load, the content of biomass polyethylene in the intermediate layer is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the entire intermediate layer.

The intermediate layer may contain linear low density polyethylene and/or high pressure low density polyethylene. From the viewpoint of the impact resistance of the sealant film, the intermediate layer preferably contains linear low density polyethylene. On the other hand, from the viewpoint of the tearability of the sealant film, the intermediate layer preferably contains high pressure low density polyethylene.

In the intermediate layer, the biomass polyethylene is preferably at least one type of polyethylene selected from the group consisting of linear low-density polyethylene and high-pressure low-density polyethylene.

The thickness of the intermediate layer is, for example, 10 μm or more, may be 50 μm or more, or may be 70 μm or more. On the other hand, the thickness of the intermediate layer is 160 μm or less, may be 100 μm or less, or may be 80 μm or less.

The thickness of the intermediate layer is preferably greater than that of the laminate layer. This can suppress curling of the sealant film. The ratio of the thickness of the intermediate layer to the thickness of the laminate layer is preferably 1 to 10, more preferably 2 to 5.
The thickness of the intermediate layer is preferably thicker than the thickness of the seal layer. This can suppress curling of the sealant film. The ratio of the thickness of the intermediate layer to the thickness of the seal layer is preferably 1 to 10, more preferably 2 to 5.

The intermediate layer may contain high density polyethylene (HDPE) and/or medium density polyethylene (MDPE) as long as the objective of the present invention is not impaired.

The intermediate layer may contain one or more additives as long as the object of the present invention is not impaired. Examples of additives include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, friction reducers, slip agents, antiblocking agents, antioxidants, ion exchange agents, and color pigments. The intermediate layer preferably contains a slip agent.

<Characteristics of sealant film>
In the sealant film according to the present invention, the value I obtained by dividing the impact strength by the thickness of the sealant film is, for example, 0.0018 J/μm or more, or may be 0.0022 J/μm or more, or may be 0.0028 J/μm or more. On the other hand, the value I is, for example, 0.01 J/μm or less, or may be 0.006 J/μm or less.
In this specification, the impact strength of the sealant film is measured in accordance with ASTM D3420. For example, a film impact tester BU-302 manufactured by Tester Sangyo Co., Ltd. can be used as a measuring instrument. In this specification, unless otherwise specified, the environment during the measurement of the impact strength is a temperature of 23° C. and a relative humidity of 90% RH.

The method for measuring impact strength will be described with reference to Figures 3 and 4. First, as shown in Figure 3, the test piece 20 is clamped and fixed between ring-shaped jigs 21 and 22. Next, as shown in Figure 4, the fixed test piece 20 is placed, and the arm 24 is swung down around the fulcrum 23, so that the conical indenter 25 at the tip of the arm 24 breaks through the test piece 20, and the strength at the time of breakthrough is measured. Measurements are carried out on five test pieces, and the average value is taken as the impact strength. The diameter of the indenter 25 is about 1 inch (about 25.4 mm), the load is about 30 kg cm, and the lifting angle of the arm is about 90°.

In the sealant film according to the present invention, the value T obtained by dividing the tear strength by the thickness of the sealant film is, for example, 0.01 N/μm or more, and may be 0.03 N/μm or more, in at least one direction, while the value T is, for example, 0.15 N/μm or less, and may be 0.1 N/μm or less, or may be 0.07 N/μm or less, in at least one direction.
In one embodiment, the value T is, for example, 0.01 N/μm or more, and may be 0.03 N/μm or more in the machine direction (MD) of the sealant film. On the other hand, the value T is, for example, 0.01 N/μm or more, and may be 0.03 N/μm or more in the machine direction (MD) of the sealant film.
In this specification, the tear strength of the sealant film is measured in accordance with the Elmendorf tear method of JIS K7128-2:1998. For example, an Elmendorf tear tester IM-701 manufactured by Tester Sangyo Co., Ltd. can be used as the measuring device. Measurement is performed on five test pieces, and the average value is taken as the tear strength. In this specification, unless otherwise specified, the environment during the measurement of tear strength is a temperature of 23°C and a relative humidity of 90% RH.

The breaking strength of the sealant film according to the present invention is, for example, 10 MPa or more, and may be 20 MPa or more, in at least one direction, whereas the breaking strength of the sealant film is, for example, 50 MPa or less, and may be 30 MPa or less, in at least one direction.
In one embodiment, the breaking strength of the sealant film in the MD is, for example, 10 MPa or more, and may be 20 MPa or more, whereas the breaking strength of the sealant film in the MD is, for example, 50 MPa or less, and may be 30 MPa or less.
In one embodiment, the breaking strength of the sealant film in the direction perpendicular to the machine direction (TD) of the sealant film is, for example, 10 MPa or more, and may be 20 MPa or more, whereas the breaking strength of the sealant film in the TD is, for example, 50 MPa or less, and may be 30 MPa or less.

The breaking elongation of the sealant film according to the present invention is, for example, 400% or more, and may be 500% or more, in at least one direction, while the breaking elongation of the sealant film is, for example, 900% or less, and may be 800% or less, in at least one direction.
In one embodiment, the breaking elongation of the sealant film in the MD is, for example, 400% or more, and may be 500% or more, whereas the breaking elongation of the sealant film in the MD is, for example, 900% or less, and may be 800% or less.
In one embodiment, the breaking elongation of the sealant film in the TD is, for example, 400% or more, and may be 500% or more, whereas the breaking elongation of the sealant film in the TD is, for example, 900% or less, and may be 800% or less.

In this specification, the breaking strength and breaking elongation of the sealant film are measured in accordance with JIS Z1702:1994. For example, a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd. can be used as a measuring instrument. A sealant film cut into a dumbbell shape can be used as a test piece. The measurement width of the test piece is 5 mm, the distance between the pair of chucks holding the test piece at the start of the measurement is 80 mm, and the tensile speed is 500 mm/min. Measurements are performed on five test pieces, and the average values are taken as the breaking strength and breaking elongation. The length of the test piece can be changed as long as the test piece can be held by the pair of chucks. In this specification, unless otherwise specified, the environment during measurement of the breaking strength and breaking elongation is a temperature of 23°C and a relative humidity of 90% RH.

In the sealant film according to the present invention, the value P obtained by dividing the puncture strength by the thickness of the sealant film is, for example, 0.02 N/μm or more, and may be 0.03 N/μm or more, while the value P is, for example, 0.1 N/μm or less, and may be 0.05 N/μm or less.
In this specification, the puncture strength of the sealant film is measured in accordance with JIS Z1707:2019. For example, a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd. can be used as a measuring instrument. In this specification, unless otherwise specified, the environment during the measurement of the puncture strength is a temperature of 23°C and a relative humidity of 90% RH.

The method for measuring the puncture strength will be described with reference to Figure 5. As shown in Figure 5, a semicircular needle 31 with a diameter of 1.0 mm and a tip radius of 0.5 mm is pierced into a fixed test piece 30 at a speed of 50 mm/min, and the maximum stress until the needle 31 penetrates the test piece 30 is measured. The maximum stress is measured for five test pieces, and the average value is taken as the puncture strength of the sealant film.

[Method of manufacturing sealant film]
The sealant film according to the present invention can be produced by a conventionally known method, and the laminate layer provided in the sealant film can be formed by appropriately selecting the types of monomers and oligomers that are raw materials and/or by appropriately adjusting the contents of the monomers and oligomers that are raw materials.

The method for producing the sealant film according to the present invention is not particularly limited, and the film can be produced by a conventionally known method. The sealant film is preferably co-extruded, and more preferably, the co-extrusion is performed by the T-die method or the inflation method. An example of a method for producing a sealant film by the T-die method and the inflation method is described below.

In the T-die method, first, the materials constituting each layer are dried, and then supplied to a melt extruder heated to a temperature above the melting point (Tm) to a temperature of Tm+100°C, where they are melted and extruded into a sheet from the T-die. The extruded sheet is then quenched and solidified on a rotating cooling drum or the like to form a sealant film.
As the melt extruder, a single screw extruder, a twin screw extruder, a vent extruder, a tandem extruder, etc. can be used depending on the purpose.

In the inflation method, the materials constituting each layer are first dried, and then fed into a melt extruder heated to a temperature above the melting point (Tm) to Tm+100°C, where they are melted and extruded into a cylindrical shape through an annular die. At this time, air is fed into the cylindrical molten resin from below to expand the diameter of the cylinder to a predetermined size, and cooling air is fed from below to the outside of the cylinder. This expanded cylindrical body is called a bubble. Next, the bubble is folded into a film shape by a guide plate and a pinch roll, and wound up in a winding section. The folded film can be wound up as it is in a cylindrical shape, or both ends of the cylinder can be removed with a slitter or the like, cut into two films, and then each can be wound up. This allows the sealant film to be formed.
As the melt extruder, a single screw extruder, a twin screw extruder, a vent extruder, a tandem extruder, etc. can be used depending on the purpose.

[Laminate]
The laminate according to the present invention comprises a base layer, an adhesive layer, and a sealant layer in this order. In the laminate according to the present invention, the sealant layer comprises the sealant film according to the present invention and is adjacent to the adhesive layer. In the laminate according to the present invention, the lamination layer of the sealant film is located on the base layer side, and the seal layer of the sealant film is one surface layer of the laminate. Since the laminate according to the present invention comprises the sealant film according to the present invention, it is excellent in reducing environmental load, and is also excellent in sealing property and laminate strength.
In one embodiment, the laminate may further comprise a support layer located between the substrate layer and the adhesive layer.
In one embodiment, the laminate may include a barrier layer located between the substrate layer and the adhesive layer.

Below, one embodiment of the laminate according to the present invention will be described with reference to the drawings.

In one embodiment, the laminate 40 includes a base layer 41, an adhesive layer 42, and a sealant layer 43 in this order, as shown in FIG. 6. As shown in FIG. 6, the sealant layer 43 is adjacent to the adhesive layer 42. As shown in FIG. 6, the base layer 41 is adjacent to the adhesive layer 42. As shown in FIG. 6, the sealant layer 43 is a sealant film 10 including a laminate layer 11 and a seal layer 12. As shown in FIG. 6, the laminate layer 11 of the sealant film 10 is located on the base layer 42 side. As shown in FIG. 6, the seal layer 12 of the sealant film 10 is one surface layer of the laminate 40.

In one embodiment, the laminate 40 includes a base layer 41, a support layer 44, an adhesive layer 42, and a sealant layer 43 in this order, as shown in FIG. 7. As shown in FIG. 7, the sealant layer 43 is adjacent to the adhesive layer 42. As shown in FIG. 7, the support layer 14 is adjacent to the adhesive layer 12. As shown in FIG. 7, the sealant layer 43 is a sealant film 10 including a laminate layer 11 and a seal layer 12. As shown in FIG. 7, the laminate layer 11 of the sealant film 10 is located on the base layer 42 side. As shown in FIG. 7, the seal layer 12 of the sealant film 10 is one of the surface layers of the laminate 40.

In one embodiment, the laminate 40 includes a base layer 41, a barrier layer 45, an adhesive layer 42, and a sealant layer 43 in this order, as shown in FIG. 8. As shown in FIG. 8, the sealant layer 43 is adjacent to the adhesive layer 42. As shown in FIG. 8, the barrier layer 45 is adjacent to the adhesive layer 42. As shown in FIG. 8, the sealant layer 43 is a sealant film 10 including a laminate layer 11 and a seal layer 12. As shown in FIG. 8, the laminate layer 11 of the sealant film 10 is located on the base layer 42 side. As shown in FIG. 8, the seal layer 12 of the sealant film 10 is one surface layer of the laminate 40. When the laminate 40 includes a support layer 44, the barrier layer 45 may be located between the base layer 41 and the support layer 44, and/or between the support layer 44 and the adhesive layer 42 (not shown).

In one embodiment, the laminate 40 may include a printed layer (not shown) provided on at least one surface of the base layer 41 and/or the support layer 44 .
In one embodiment, the adhesive layer 42 may further be provided between at least one selected from the group consisting of between the substrate layer 41 and the support layer 44, between the substrate layer 41 and the barrier layer 45, and between the support layer 44 and the barrier layer 45 (not shown).
In one embodiment, the sealant layer 43 may be a sealant film 10 with an intermediate layer 13 between a laminate layer 11 and a sealing layer 12 .

The layer structures of the laminate 40 described above can be combined as appropriate.

Each layer that may be provided in the laminate according to the present invention will be described below. The sealant layer is a layer that includes the sealant film of the present invention, and the sealant film has been described above. Therefore, a description of the sealant layer will be omitted.

<Base layer>
The substrate layer is a layer having a function of supporting the laminate. For example, a paper substrate, a resin film, or a laminate thereof can be appropriately used as the substrate layer.

The paper base material can be one that has printability, flex resistance, rigidity, stiffness, strength, etc., and various types of paper such as kraft paper, roll paper, paperboard, and processed paper can be used.

The resin film contains at least one type of resin material. Examples of resin materials contained in the resin film include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, and terephthalic acid-cyclohexane dimethanol-ethylene glycol copolymers; polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6); polyolefins such as polyethylene (PE), polypropylene (PP), and polymethylpentene; vinyl resins such as polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and polyvinylpyrrolidone (PVP); (meth)acrylic resins such as polyacrylate, polymethacrylate, and polymethyl methacrylate; cellulose resins such as cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB); styrene resins such as polystyrene (PS), and chlorinated resins thereof. Among these, the resin material contained in the resin film is preferably at least one selected from the group consisting of polyolefin, polyester, and polyamide, and more preferably at least one selected from the group consisting of polypropylene, polyethylene terephthalate, nylon 6, and nylon 6,6.

The resin film may be a stretched film or an unstretched film. From the viewpoint of strength, the resin film is preferably a stretched film that is stretched uniaxially or biaxially.

The surface of the resin film may be subjected to a surface treatment. The method of the surface treatment is not particularly limited, and examples include physical treatments such as corona treatment, flame treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and/or nitrogen gas, and glow discharge treatment, as well as chemical treatments such as oxidation treatment using chemicals.

The thickness of the substrate layer is, for example, 5 μm or more, and may be 10 μm. On the other hand, the thickness of the substrate layer is, for example, 200 μm or less, and may be 100 μm or less, or may be 50 μm or less.

<Adhesive Layer>
The adhesive layer is an adhesive layer or an adhesive resin layer formed for bonding two layers by lamination. The adhesive layer is preferably an adhesive layer because it has good adhesion to various layers, particularly to a sealant layer.

The adhesive layer is a layer formed using at least one type of one-part or two-part curable or non-curable laminating adhesive. Therefore, the adhesive layer includes a laminating adhesive. Examples of laminating adhesives include vinyl-based, (meth)acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, and rubber-based solvent-based, water-based, or emulsion-based laminating adhesives.
Examples of methods for coating the adhesive include a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, and a transfer roll coating method.
The coating amount in a dry state is, for example, 0.1 g/m2 or ^more , and may be 1 g/m2 or ^more . On the other hand, the coating amount in a dry state is, for example, 10 g/m2 ^or less, and may be about 5 g/m2 or ^less .

The adhesive resin layer contains at least one thermoplastic resin. Examples of the thermoplastic resin contained in the adhesive resin layer include high-pressure low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-maleic acid copolymer, and ionomer resin. Examples of the thermoplastic resin contained in the adhesive resin layer include resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acid, unsaturated carboxylic acid anhydride, or ester monomer to polyolefin, and resins obtained by graft-modifying maleic anhydride to polyolefin.
The thermoplastic resin may be made of a material derived from a fossil fuel, a material derived from biomass, or a combination of both.

<Support Layer>
The support layer is a layer that supports the laminate together with the base layer and improves the strength characteristics, durability, and the like of the laminate.

The support layer contains one or more resin materials. Examples of resin materials contained in the support layer include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymers; polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6); polyolefins such as polyethylene (PE), polypropylene (PP), and polymethylpentene; vinyl resins such as polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and polyvinylpyrrolidone (PVP); (meth)acrylic resins such as polyacrylate, polymethacrylate, and polymethyl methacrylate; cellulose resins such as cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB); styrene resins such as polystyrene (PS), and chlorinated resins thereof.
The support layer may be a resin film made of the above-mentioned resin material. From the viewpoint of strength, the resin film is preferably a film stretched in a uniaxial or biaxial direction.

The thickness of the support layer is, for example, 5 μm or more, and may be 10 μm. On the other hand, the thickness of the support layer is, for example, 200 μm or less, and may be 100 μm or less, or may be 50 μm or less.

<Barrier layer>
The barrier layer is a layer for imparting excellent gas barrier properties to the laminate. A laminate including a barrier layer has excellent barrier properties against gases such as oxygen and water vapor.

In one embodiment, the barrier layer may include a vapor-deposited film of an inorganic substance or an inorganic oxide, such as one or more inorganic substances such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y), or a vapor-deposited film of an inorganic oxide thereof.
The vapor-deposited film can be formed on the surface of the base layer and/or support layer, etc. Examples of methods for forming the vapor-deposited film include known methods such as vacuum deposition, sputtering, and chemical vapor deposition.

The thickness of the deposited film is, for example, 10 nm or more, and may be 20 nm or more. On the other hand, the thickness of the deposited film is, for example, 200 nm or less, and may be 100 nm or less.

In one embodiment, the barrier layer may comprise a gas barrier coating film located on the surface of the vapor deposition film. By providing the barrier layer with a gas barrier coating film, the gas barrier properties can be further improved.

The gas barrier coating film is obtained from a gas barrier composition which contains at least one alkoxide represented by the general formula R ¹ _n M(OR ² ) _m (wherein R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M) and the above-mentioned polyvinyl alcohol resin and/or ethylene-vinyl alcohol copolymer, and which is further polycondensed by a sol-gel process in the presence of a sol-gel process catalyst, an acid, water, and an organic solvent.

As the alkoxide represented by the above general formula R ¹ _n M(OR ² ) _m , at least one of a partial hydrolyzate of an alkoxide and a condensate of hydrolysis of an alkoxide can be used. As the partial hydrolyzate of an alkoxide, it is not necessary that all of the alkoxy groups are hydrolyzed, and one or more alkoxy groups may be hydrolyzed, or a mixture thereof. As the condensate of hydrolysis of an alkoxide, a dimer or more of a partially hydrolyzed alkoxide, preferably a dimer or more and a hexamer or less, is used.

In the alkoxide represented by the above general formula R ¹ _n M(OR ² ) _m , the metal atom represented by M may be silicon, zirconium, titanium, aluminum, etc. Preferred metals include, for example, silicon, titanium, etc. The alkoxide may be used alone or in the form of a mixture of two or more different metal atoms in the same solution.

In the alkoxides represented by the above general formula R ¹ _n M(OR ² ) _m , specific examples of the organic group represented by R ¹ include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, n-hexyl, n-octyl, etc. In the alkoxides represented by the above general formula R ¹ _n M(OR ² ) _m , specific examples of the organic group represented by R ² include methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, etc. These alkyl groups may be the same or different in the same molecule.

When preparing the gas barrier composition, for example, a silane coupling agent may be added. As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used. In particular, an organoalkoxysilane having an epoxy group can be preferably used. As the organoalkoxysilane having an epoxy group, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane can be mentioned. The silane coupling agent may be used alone or in a mixture of two or more kinds.

In one embodiment, the barrier layer may include a metal foil. The metal foil is a foil containing one or more metal materials. Examples of the metal materials contained in the metal foil include aluminum, gold, silver, copper, stainless steel, titanium, and nickel.
The metal foil can be laminated to the base layer and/or support layer via an adhesive layer.

<Printed layer>
The print layer is an image formed using a conventionally known pigment or dye. Examples of the image include characters, patterns, symbols, and combinations thereof. The print layer can be formed by a conventionally known method.

<Characteristics of the laminate>
The laminate strength between the sealant layer and the adjacent layer in the laminate is, for example, 3.0 N or more, or may be 5.0 N or more, or 6.0 N or more, in a width of 15 mm. On the other hand, the laminate strength between the sealant layer and the adjacent layer is, for example, 30 N or less, or may be 20 N or less, in a width of 15 mm.
In this specification, the laminate strength between the sealant layer and the adjacent layer is measured in accordance with JIS Z1707:2019. For example, a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd. can be used as the measuring instrument. In this specification, unless otherwise specified, the environment during measurement of the laminate strength is a temperature of 23°C and a relative humidity of 90% RH.

Specifically, first, the laminate is cut out, and a strip-shaped test piece 50 is prepared by peeling off the sealant layer 51 and the adjacent layer 52 by 15 mm in the long side direction, as shown in FIG. 9. The width of the test piece 50 is 15 mm. Then, as shown in FIG. 10, the already peeled parts of the sealant layer 51 and the adjacent layer 52 are each held by the gripper 53 of the measuring device. The gripper 53 is pulled at a speed of 50 mm/min in opposite directions perpendicular to the surface direction of the part where the sealant layer 51 and the adjacent layer 52 are still laminated, and the average value of the tensile stress F in the stable region is measured. When the pulling starts, the interval S1 between the grippers 53 is 30 mm, and when the pulling ends, the interval S1 between the grippers 53 is 60 mm. FIG. 11 is a diagram showing the change in the tensile stress F with respect to the interval S1 between the grippers 53. As shown in Figure 11, the change in tensile stress F with respect to the spacing S1 passes through a first region R1 and enters a second region R2 (stable region) where the rate of change is smaller than that of the first region R1. The average value of tensile stress F in the stable region is measured for five test pieces, and this average value is taken as the laminate strength.

The seal strength of the laminate at a width of 15 mm is, for example, 15 N or more, or may be 20 N or more, or may be 30 N or more. On the other hand, the seal strength of the laminate at a width of 15 mm is, for example, 100 N or less, or may be 60 N or less.
In this specification, the seal strength of the laminate is measured in accordance with JIS Z 1707:2019. For example, a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd. In this specification, unless otherwise specified, the environment during the measurement of the seal strength is a temperature of 23°C and a relative humidity of 90% RH.

A method for measuring the seal strength will be described with reference to FIG. 12. First, the sealant layers of two laminates are heat-sealed to form a seal portion. Then, a portion including the seal portion is cut out to prepare a test piece 60 having a width of 15 mm and a length of 100 mm for measuring the seal strength. Next, as shown in FIG. 12, each of the unsealed portions of the test piece 60 is gripped by a gripper 61 of a measuring device. The length of the seal portion 62 is 15 mm. Next, the grippers 61 are pulled at a speed of 300 mm/min in opposite directions in a direction perpendicular to the surface direction of the seal portion 62 of the test piece 60, and the maximum value of the tensile stress is measured. Measurements are performed on five test pieces, and the average value of the maximum value of the tensile stress is taken as the seal strength. The distance S2 between the grippers 61 when pulling is started is 50 mm.
The seal portion 62 of the test piece 60 is formed by heat-sealing the sealant layers of two laminates at 160° C. for 1 second under a load of 1 kgf/cm ² .

The tear strength of the laminate is, for example, 0.1 N or more, and may be 0.5 N or more, in at least one direction. On the other hand, the tear strength of the laminate is, for example, 2.5 N or less, and may be 1.7 N or less, or may be 1.2 N or less, in at least one direction.
In one embodiment, the tear strength of the laminate in the machine direction (MD) of the sealant film is, for example, 0.1 N or more, and may be 0.5 N or more. On the other hand, the tear strength of the laminate in the MD of the sealant film is, for example, 2.5 N or less, and may be 1.7 N or less, or may be 1.2 N or less.
In one embodiment, the tear strength of the laminate in the direction perpendicular to the machine direction (TD) of the sealant film is, for example, 0.1 N or more, and may be 0.5 N or more. Meanwhile, the tear strength of the laminate in the TD of the sealant film is, for example, 2.5 N or less, and may be 1.7 N or less, or may be 1.2 N or less.
In this specification, the tear strength of the laminate is measured in accordance with the Elmendorf tear method of JIS K7128-2:1998. For example, an Elmendorf tear tester IM-701 manufactured by Tester Sangyo Co., Ltd. can be used as a measuring instrument. Measurement is performed on five test pieces, and the average value is taken as the tear strength. In this specification, unless otherwise specified, the environment during the measurement of tear strength is a temperature of 23°C and a relative humidity of 90% RH.

The piercing strength of the laminate is, for example, 10 N or more, or may be 15 N or more, or may be 18 N or more. On the other hand, the piercing strength of the laminate is, for example, 50 N or less, or may be 30 N or less.
In one embodiment, the piercing strength of the laminate when pierced from the base layer side is, for example, 10 N or more, or may be 15 N or more, or may be 18 N or more. On the other hand, the piercing strength of the laminate when pierced from the base layer side is, for example, 50 N or less, or may be 30 N or less.
In one embodiment, the piercing strength of the laminate when pierced from the sealant layer side is, for example, 10 N or more, and may be 15 N or more. On the other hand, the piercing strength of the laminate when pierced from the sealant layer side is, for example, 50 N or less, and may be 30 N or less.
In this specification, the puncture strength of the laminate is measured in accordance with JIS Z1707:2019. For example, a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd. can be used as a measuring instrument. In this specification, unless otherwise specified, the environment during the measurement of the puncture strength is a temperature of 23°C and a relative humidity of 90% RH.
The puncture strength of the laminate can be measured in the same manner as that of the sealant film.

<Example of Layer Structure of Laminate>
An example of the layer structure of the laminate according to the present invention is shown below. In the following example, the left side means the outside when the laminate is used as a packaging bag, and the right side means the inside (content side). In the following example, the symbol "/" means the boundary between each layer.
(1) Substrate layer/printing layer/adhesive layer/sealant layer (2) Substrate layer/printing layer/adhesive layer/support layer/adhesive layer/sealant layer (3) Substrate layer/printing layer/adhesive layer/barrier layer/adhesive layer/sealant layer (4) Substrate layer/printing layer/adhesive layer/barrier layer/support layer/adhesive layer/sealant layer (5) Substrate layer/printing layer/adhesive layer/support layer/barrier layer/adhesive layer/sealant layer (6) Substrate layer/barrier layer/printing layer/adhesive layer/support layer/adhesive layer/sealant layer (7) Substrate layer/printing layer/adhesive layer/barrier layer/adhesive layer/support layer/adhesive layer/sealant layer (8) Substrate layer/printing layer/adhesive layer/support layer/adhesive layer/support (9) Substrate layer/adhesive layer/sealant layer (10) Substrate layer/adhesive layer/support layer/adhesive layer/sealant layer (11) Substrate layer/adhesive layer/barrier layer/adhesive layer/sealant layer (12) Substrate layer/adhesive layer/barrier layer/support layer/adhesive layer/sealant layer (13) Substrate layer/adhesive layer/support layer/barrier layer/adhesive layer/sealant layer (14) Substrate layer/barrier layer/adhesive layer/support layer/adhesive layer/sealant layer (15) Substrate layer/adhesive layer/barrier layer/adhesive layer/support layer/adhesive layer/sealant layer (16) Substrate layer/adhesive layer/support layer/adhesive layer/support layer/adhesive layer/sealant layer

An example of a more specific layer structure of the laminate according to the present invention is shown below. In the following example, the left side means the outside when the laminate is used as a packaging bag, and the right side means the inside (content side). In the following example, the symbol "/" means the boundary between each layer. In the following, "sealant film" means the polyethylene sealant film according to the present invention, "Ny" means nylon, "PET" means polyethylene terephthalate, "AL" means aluminum, and "SiO" means silicon oxide.
(1) Stretched Ny film/image/laminating adhesive/sealant film (2) Stretched PET film/image/laminating adhesive/sealant film (3) Stretched Ny film/image/laminating adhesive/stretched Ny film/laminating adhesive/sealant film (4) Stretched Ny film/image/laminating adhesive/stretched PET film/laminating adhesive/sealant film (5) Stretched PET film/image/laminating adhesive/stretched Ny film (6) Stretched PET film / Image / Laminating adhesive / Stretched PET film / Laminating adhesive / Sealant film (7) Stretched Ny film / Image / Laminating adhesive / AL foil / Laminating adhesive / Sealant film (8) Stretched PET film / Image / Laminating adhesive / AL foil / Laminating adhesive / Sealant film (9) Stretched Ny film / Image / Laminating adhesive / AL vapor deposition film / Stretched P ET film/laminating adhesive/sealant film (10) Stretched Ny film/image/laminating adhesive/stretched PET film/AL vapor deposition film/laminating adhesive/sealant film (11) Stretched PET film/SiO vapor deposition film/image/laminating adhesive/stretched Ny film/laminating adhesive/sealant film (12) Stretched PET film/SiO vapor deposition film/gas barrier coating film/image/laminating adhesive/stretched Ny film/laminating Adhesive/sealant film (13) Stretched PET film/image/laminating adhesive/AL foil/laminating adhesive/stretched Ny film/laminating adhesive/sealant film (14) Stretched PET film/image/laminating adhesive/AL foil/laminating adhesive/stretched PET film/laminating adhesive/sealant film (15) Stretched PET film/image/laminating adhesive/stretched Ny film/laminating adhesive/stretched PET film/laminating (16) Stretched Ny film / Laminating adhesive / sealant film (17) Stretched PET film / Laminating adhesive / sealant film (18) Stretched Ny film / Laminating adhesive / Stretched Ny film / Laminating adhesive / sealant film (19) Stretched Ny film / Laminating adhesive / Stretched PET film / Laminating adhesive / sealant film (20) Stretched PET film / Laminating adhesive (21) Stretched PET film / Laminating adhesive / Stretched PET film / Laminating adhesive / Sealant film (22) Stretched Ny film / Laminating adhesive / AL foil / Laminating adhesive / Sealant film (23) Stretched PET film / Laminating adhesive / AL foil / Laminating adhesive / Sealant film (24) Stretched Ny film / Laminating adhesive / AL vapor deposition film / Stretched P ET film/laminating adhesive/sealant film (25) Stretched Ny film/laminating adhesive/stretched PET film/AL vapor deposition film/laminating adhesive/sealant film (26) Stretched PET film/SiO vapor deposition film/laminating adhesive/stretched Ny film/laminating adhesive/sealant film (27) Stretched PET film/SiO vapor deposition film/gas barrier coating film/laminating adhesive/stretched Ny film/laminating adhesive/sealant Film (28) Stretched PET film / Laminating adhesive / AL foil / Laminating adhesive / Stretched Ny film / Laminating adhesive / Sealant film (29) Stretched PET film / Laminating adhesive / AL foil / Laminating adhesive / Stretched PET film / Laminating adhesive / Sealant film (30) Stretched PET film / Laminating adhesive / Stretched Ny film / Laminating adhesive / Stretched PET film / Laminating adhesive / Sealant film

[Method for producing laminate]
The method for producing the laminate is not particularly limited, and the laminate can be produced by a conventionally known method such as a dry lamination method, a melt extrusion lamination method, or a sand lamination method.

[Packaging bag]
The packaging bag according to the present invention includes the laminate according to the present invention. The laminate according to the present invention is excellent in reducing the environmental load, and is also excellent in sealing properties and laminate strength, so that a packaging bag including the laminate is excellent in reducing the environmental load, and is also excellent in sealing properties and laminate strength.

Fig. 13 is a schematic diagram showing one embodiment of a packaging bag according to the present invention. As shown in Fig. 13, a packaging bag 70 includes a body 71 and a bottom 72. The body 71 is composed of two side sheets 73, and the bottom 72 is composed of a bottom sheet 74. In the packaging bag 70, the side sheets 73 use the laminate 40 according to the present invention. Therefore, the packaging bag 70 is manufactured such that the seal layer 12 of the sealant film 10 included in the laminate 40 becomes the innermost layer.
In addition, the side sheets 53 and the bottom sheet 54 of the packaging bag 50 may be made of the same material or different materials.

The packaging bag 70 may include a pouring nozzle portion 75 as shown in Fig. 14. Moreover, the packaging bag 70 may include a curved portion 76 that is curved inward from the viewpoint of ease of opening as shown in Fig. 14. Furthermore, the packaging bag 70 may include a cutout portion 77 as shown in Fig. 14 from the viewpoint of ease of opening. The cutout portion 77 can be formed by irradiating a laser beam or the like.
In addition, in Figs. 13 and 14, the hatched areas indicate the heat-sealed areas.

The contents of the packaging bag are not particularly limited, but the packaging bag is particularly suitable for packaging liquids such as shampoo, conditioner, and detergent.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the description of the following examples as long as it does not deviate from the gist of the invention.

The materials used in the examples are listed below.
(1) Linear low-density polyethylene (ethylene-1-butene copolymer, 4LLDPE_A)...density: 0.918 g/cm ³ , MFR: 1.0 g/10 min, biomass ratio: 87%, manufactured by Braskem, SLL118
(2) Linear low-density polyethylene (ethylene-1-butene copolymer, 4LLDPE_B)...density: 0.918 g/cm ³ , MFR: 4.0 g/10 min, biomass ratio: 0%, manufactured by Ube Maruzen Polyethylene Co., Ltd., Yumerit 722FT
(3) Linear low density polyethylene (ethylene-1-octene copolymer, 8LLDPE_A)...density: 0.918 g/cm ³ , MFR: 0.85 g/10 min, biomass ratio: 0%, manufactured by Dow, INNATE ST50
(4) Linear low density polyethylene (ethylene-1-octene copolymer, 8LLDPE_B)...density: 0.916 g/cm ³ , MFR: 1.0 g/10 min, biomass ratio: 0%, manufactured by Dow, ELITE 5400G
(5) Linear low-density polyethylene (ethylene-1-hexene copolymer, 6LLDPE)...density: 0.916 g/cm ³ , MFR: 2.3 g/10 min, biomass ratio: 0%, manufactured by Prime Polymer Co., Ltd., Evolu (registered trademark) SP2020
(6) High-pressure low-density polyethylene (LDPE_A)...density: 0.923 g/cm ³ , MFR: 2.7 g/10 min, biomass ratio: 95%, manufactured by Braskem, SEB853
(7) High-pressure low-density polyethylene (LDPE_B)...density: 0.919 g/cm ³ , MFR: 2.0 g/10 min, biomass ratio: 0%, manufactured by Sumitomo Chemical Co., Ltd., G201-F
(8) Masterbatch (MB_A)...Base material: polyethylene, slip agent: erucic acid amide, slip agent content: 2.0 mass%, density: 0.921 g/cm ³ , MFR: 5.4 g/10 min, manufactured by Ube Maruzen Polyethylene Co., Ltd., M425
(9) Masterbatch (MB_B)...Base material: polyethylene, antiblocking agent: talc, slip agent: erucic acid amide, antiblocking agent content: 6.0 mass%, slip agent content: 1.5 mass%, density: 0.959 g/cm ³ , MFR: 2.5 g/10 min, manufactured by Ube Maruzen Polyethylene Co., Ltd., M615S

[Example 1]
A mixture of 80 parts by mass of 4LLDPE_B, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, a mixture of 99 parts by mass of LDPE_A and 1 part by mass of MB_A was used as the intermediate layer, and a mixture of 79 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer. The polyethylene sealant film was obtained by melting and co-extruding the mixture into a film shape. The thickness of the polyethylene sealant film was 130 μm. The thickness ratio of the laminate layer:intermediate layer:seal layer was 1:3:1.

[Example 2]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 80 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer.

[Example 3]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 80 parts by mass of 8LLDPE_B, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer.

[Example 4]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 79 parts by mass of 4LLDPE_B, 19 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the sealing layer.

[Example 5]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 60 parts by mass of 4LLDPE_B, 38 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the sealing layer.

[Example 6]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 50 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 49 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Example 7]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 50 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 30 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 38 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Example 8]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 50 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 50 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_B was used as the seal layer.

[Example 9]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 20 parts by mass of 4LLDPE_A, 50 parts by mass of 4LLDPE_B, 29 parts by mass of 8LLDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 60 parts by mass of 4LLDPE_B, 38 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Example 10]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 50 parts by mass of 4LLDPE_B, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 19 parts by mass of 4LLDPE_A, 60 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Example 11]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 79 parts by mass of 8LLDPE_A, 20 parts by mass of LDPE_B, and 1 part by mass of MB_A was used as the laminate layer, a mixture of 99 parts by mass of 4LLDPE_A and 1 part by mass of MB_A was used as the intermediate layer, and a mixture of 79 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_B, and 2 parts by mass of MB_B was used as the seal layer.

[Example 12]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 79 parts by mass of 8LLDPE_B, 20 parts by mass of LDPE_B, and 1 part by mass of MB_A was used as the laminate layer, a mixture of 99 parts by mass of 4LLDPE_A and 1 part by mass of MB_A was used as the intermediate layer, and a mixture of 79 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_B, and 2 parts by mass of MB_B was used as the seal layer.

[Example 13]
A mixture of 99 parts by mass of LDPE_A and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 80 parts by mass of 6LLDPE, 18 parts by mass of LDPE_B, and 2 parts by mass of MB_B was used as the seal layer, and each was melted and co-extruded into a film to obtain a polyethylene sealant film composed of two layers. The thickness of the polyethylene sealant film is 130 μm. The thickness ratio of the laminate layer to the seal layer is 3:1.

[Example 14]
A polyethylene sealant film was obtained in the same manner as in Example 13, except that a mixture of 20 parts by mass of 4LLDPE_A, 79 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 80 parts by mass of 6LLDPE, 18 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 1]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 50 parts by mass of 4LLDPE_A, 30 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 50 parts by mass of 4LLDPE_B, 29 parts by mass of 8LLDPE_B, 19 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 2]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 30 parts by mass of 4LLDPE_A, 30 parts by mass of 8LLDPE_A, 39 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 50 parts by mass of 4LLDPE_B, 29 parts by mass of 8LLDPE_B, 19 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 3]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 79 parts by mass of 4LLDPE_B, 20 parts by mass of LDPE_B, and 1 part by mass of MB_A was used as the laminate layer, a mixture of 99 parts by mass of 4LLDPE_A and 1 part by mass of MB_A was used as the intermediate layer, and a mixture of 79 parts by mass of 8LLDPE_A, 19 parts by mass of LDPE_B, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 4]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 99 parts by mass of 4LLDPE_B and 1 part by mass of MB_A was used as the laminate layer, a mixture of 99 parts by mass of 4LLDPE_A and 1 part by mass of MB_A was used as the intermediate layer, and a mixture of 20 parts by mass of 8LLDPE_B, 78 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 5]
A polyethylene sealant film was obtained in the same manner as in Example 1, except that a mixture of 99 parts by mass of 4LLDPE_B and 1 part by mass of MB_A was used as the laminate layer, a mixture of 99 parts by mass of 4LLDPE_A and 1 part by mass of MB_A was used as the intermediate layer, and a mixture of 20 parts by mass of 8LLDPE_B, 78 parts by mass of LDPE_B, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 6]
A polyethylene sealant film was obtained in the same manner as in Example 13, except that a mixture of 30 parts by mass of 4LLDPE_A, 69 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 80 parts by mass of 6LLDPE, 18 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 7]
A polyethylene sealant film was obtained in the same manner as in Example 13, except that a mixture of 24 parts by mass of 4LLDPE_A, 75 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 28 parts by mass of 4LLDPE_B, 70 parts by mass of 8LLDPE_B, and 2 parts by mass of MB_B was used as the seal layer.

[Comparative Example 8]
A polyethylene sealant film was obtained in the same manner as in Example 13, except that a mixture of 24 parts by mass of 4LLDPE_A, 75 parts by mass of LDPE_A, and 1 part by mass of MB_A was used as the laminate layer, and a mixture of 28 parts by mass of 4LLDPE_B, 70 parts by mass of LDPE_A, and 2 parts by mass of MB_B was used as the seal layer.

Details of the polyethylene sealant films obtained in the examples and comparative examples are shown in Tables 1 and 2.

<<Measurement of _C18 - _C36 Oligomers in Laminate Layers>>
First, a calibration curve was prepared using standard substances.
Next, a 1 g sample was scraped off from the laminate layer provided with the sealant film.
Next, this sample was placed in 10 ml of chloroform at 50° C., and the oligomer components were extracted by shaking for 6 hours.
Then, pyrolysis GC-MS analysis was carried out to measure the content of oligomer components.
The pyrolysis GCMS device used was a 7890B (GC) 5977B (MS) manufactured by Agilent Technologies, Inc. The pyrolysis device used was an AS-1020E/PY-3030D manufactured by Frontier Labs, Inc. The measurement conditions were as follows:
(Measurement conditions)
・Inlet temperature: 320℃
Column oven: 50°C (5 min hold) -10°C/min -320°C (3 min hold)
Column: UA-5 (length: 30 m, inner diameter: 0.25 mm, film thickness: 0.25 μm)
Interface temperature: 320°C
・SCAN range: 33 to 600 (m / z)
Ion source temperature: 230° C.

<<Measurement of impact strength of sealant film>>
The impact strength of the sealant films of the Examples and Comparative Examples was measured in accordance with ASTM D 3420. The measuring device used was a film impact tester BU-302 manufactured by Tester Sangyo Co., Ltd.
Specifically, first, as shown in FIG. 3, the test piece 20 was fixed by being sandwiched between ring-shaped jigs 21 and 22. Next, as shown in FIG. 4, the fixed test piece 20 was placed, and the arm 24 was swung down around the fulcrum 23, and the conical indenter 25 at the tip of the arm 24 broke through the test piece 20, and the strength at the time of breaking through was measured. Measurements were performed on five test pieces, and the average value was taken as the impact strength. The diameter of the indenter 25 was about 1 inch (about 25.4 mm), the load was about 30 kg cm, and the lifting angle of the arm was about 90°. The environment during the measurement of the impact strength was a temperature of 23° C. and a relative humidity of 90% RH. The measurement results are shown in Table 3.
The impact strength was divided by the thickness of the sealant film to calculate the value I. The calculation results are shown in Table 3.

<<Measurement of tear strength of sealant film>>
The tear strength of the sealant films of the Examples and Comparative Examples was measured in accordance with the Elmendorf tear method of JIS K7128-2:1998. The measuring device used was an Elmendorf tear tester IM-701 manufactured by Tester Sangyo Co., Ltd. Measurements were carried out on five test pieces, and the average value was taken as the tear strength. The impact strength was measured in an environment of a temperature of 23°C and a relative humidity of 90% RH. The measurement results are shown in Table 3. In Table 3, "over" means that measurement was not possible.
The tear strength was divided by the thickness of the sealant film to calculate the value T. The calculation results are shown in Table 3.

<<Measurement of breaking strength and breaking elongation of sealant film>>
The breaking strength and breaking elongation of the sealant films of the Examples and Comparative Examples were measured in accordance with JIS Z1702: 1994. The measuring instrument used was a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd.
The test pieces used were dumbbell-shaped sealant films. The test piece had a measurement width of 5 mm, and the distance between a pair of chucks holding the test piece at the start of the measurement was 80 mm, and the tensile speed was 300 mm/min. Measurements were performed on five test pieces, and the average values were taken as the breaking strength and breaking elongation. The environment during the measurement of the breaking strength and breaking elongation was a temperature of 23° C. and a relative humidity of 90% RH. The measurement results are shown in Table 3.

<<Measurement of puncture strength of sealant film>>
The puncture strength of the sealant films of the Examples and Comparative Examples was measured in accordance with JIS Z1707: 2019. The measuring instrument used was a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd.
Specifically, as shown in FIG. 5, a semicircular needle 31 with a diameter of 1.0 mm and a tip radius of 0.5 mm was pierced at a speed of 50 mm/min into a test piece 30 in a fixed state, and the maximum value of the stress until the needle 31 penetrated the test piece 30 was measured. The maximum value of the stress was measured for five test pieces, and the average value was taken as the piercing strength of the sealant film. The piercing strength was measured in each case where the sealant film was pierced from the laminate layer side and from the seal layer side. The environment during the piercing strength measurement was a temperature of 23° C. and a relative humidity of 90% RH. The measurement results are shown in Table 3.
The puncture strength was divided by the thickness of the sealant film to calculate the value P. The calculation results are shown in Table 3.

[Preparation of Laminate]
A laminate was produced using each of the sealant films of the examples and comparative examples.

Specifically, first, a biaxially oriented polyethylene terephthalate (PET) film having a thickness of 12 μm (E5100, manufactured by Toyobo Co., Ltd.) and a biaxially oriented nylon (Ny) film having a thickness of 15 μm (Bonyl-QC, manufactured by Kohjin Film & Chemicals Co., Ltd.) were prepared. The PET film and the Ny film were bonded together by the dry lamination method using a urethane-based adhesive (RU-77T/H-7, manufactured by Rock Paint Co., Ltd.).

Then, using a urethane adhesive (RU-77T/H-7, manufactured by Rock Paint Co., Ltd.), the Ny film and the sealant film were bonded together by dry lamination so that the laminate layer of the sealant film was positioned on the Ny film side.

As a result of the above, a laminate was obtained having, in this order, a PET film (base material layer), a urethane-based adhesive (adhesive layer), a Ny film (support layer), a polyurethane adhesive (adhesive layer), and a sealant film (sealant layer).
The lamination layer of the sealant film is located on the PET film. The sealing layer of the sealant film is one of the surface layers of the laminate.
In the sealant films of Comparative Examples 3 and 7, blocking occurred, so that no laminate was produced.

<<Measurement of Laminate Strength in Laminate>>
In the above laminate, the laminate strength between the sealant layer and the adjacent layer was measured in accordance with JIS Z1707: 2019. The measuring instrument used was a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd. In the above laminate, the sealant layer was a sealant film, and the adjacent layer was a Ny film.
Specifically, first, the laminate was cut out, and a strip-shaped test piece 50 was prepared by peeling off the sealant layer 51 and the adjacent layer 52 by 15 mm in the long side direction as shown in FIG. 9. The width of the test piece 50 was 15 mm. Then, as shown in FIG. 10, the already peeled parts of the sealant layer 51 and the adjacent layer 52 were each held by a gripper 53 of a measuring device. The grippers 53 were pulled at a speed of 50 mm/min in opposite directions perpendicular to the surface direction of the part where the sealant layer 51 and the adjacent layer 52 are still laminated, and the average value of the tensile stress F in the stable region was measured. The interval S1 between the grippers 53 when the pulling started was 30 mm, and the interval S1 between the grippers 53 when the pulling ended was 60 mm. FIG. 11 is a diagram showing the change in the tensile stress F with respect to the interval S1 between the grippers 53. As shown in Fig. 11, the change in tensile stress F with respect to the spacing S1 passed through the first region R1 and entered the second region R2 (stable region) where the rate of change was smaller than that of the first region R1. The average value of the tensile stress F in the stable region was measured for five test pieces, and the average value was taken as the laminate strength. The environment during the measurement of the laminate strength was a temperature of 23°C and a relative humidity of 90% RH. The measurement results are shown in Table 4.

<<Measurement of seal strength in laminate>>
The seal strength of the laminate was measured in accordance with JIS Z 1707: 2019. The measuring instrument used was a Tensilon universal material testing machine RTC-1530 manufactured by Orientec Co., Ltd.
Specifically, first, the sealant layers of the two laminates were heat-sealed to form a seal portion. Then, a portion including the seal portion was cut out to prepare a test piece 60 having a width of 15 mm and a length of 100 mm for measuring the seal strength. Next, as shown in FIG. 12, each of the unsealed portions of the test piece 60 was held by a gripper 61 of a measuring device. The length of the seal portion 62 was set to 15 mm. Next, the grippers 61 were pulled at a speed of 300 mm/min in opposite directions in a direction perpendicular to the surface direction of the seal portion 62 of the test piece 60, and the maximum value of the tensile stress was measured. Measurements were performed on five test pieces, and the average value of the maximum value of the tensile stress was taken as the seal strength. The interval S2 between the grippers 61 at the start of pulling was set to 50 mm.
The seal portion 62 of the test piece 60 was formed by heat-sealing the sealant layers of the two laminates at 160° C. for 1 second under a load of 1 kgf/cm ² .
The heat fusion temperature was changed to 130° C., 140° C., 150° C., 170° C., 180° C., 190° C., and 200° C., and the seal strength was measured in the same manner as above. The environment during the seal strength measurement was a temperature of 23° C. and a relative humidity of 90% RH. The measurement results are shown in Table 4.

<<Measurement of tear strength in laminate>>
The tear strength of the laminate was measured in accordance with the Elmendorf tear method of JIS K7128-2:1998. The measuring device used was an Elmendorf tear tester IM-701 manufactured by Tester Sangyo Co., Ltd. Measurements were performed on five test pieces, and the average value was taken as the tear strength. The impact strength was measured in an environment of a temperature of 23°C and a relative humidity of 90% RH. The measurement results are shown in Table 4.

<<Measurement of puncture strength of laminate>>
The puncture strength of the laminate was measured in the same manner as in the measurement of the puncture strength of the sealant film.
The puncture strength of the laminate was measured when pierced from the base layer side and when pierced from the sealant layer side. The puncture strength was measured in an environment of a temperature of 23° C. and a relative humidity of 90% RH. The measurement results are shown in Table 4.

<<Evaluation of environmental impact reduction>>
The sealant films in the examples and comparative examples were evaluated for their ability to reduce environmental impact based on the following evaluation criteria. The evaluation results are shown in Table 5.
Good: The biomass content of the sealant film is 50% or more.
No Good: The biomass content of the sealant film is less than 50%.

<Sealing performance evaluation>>
The sealing properties of the sealant films in the examples and comparative examples were evaluated based on the following evaluation criteria. The evaluation results are shown in Table 5. Good: In the laminate obtained using the sealant film, the seal strength at 160° C. is 15 N or more.
No Good: In the laminate obtained using the sealant film, the seal strength at 160°C is less than 15N.

<Evaluation of Laminate Strength>>
The laminate strength of the sealant films in the examples and comparative examples was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 5. Good: In the laminate obtained using the sealant film, the laminate strength is 3N or more.
No Good: In the laminate obtained using the sealant film, the lamination strength is less than 3N.

<<Evaluation of blocking resistance>>
The front and back surfaces of each sealant film in the examples and comparative examples were overlapped in a permanent deformation tester, and a load of 1 kN was applied and left to stand at 40° C. for 24 hours. After standing, the temperature was returned to normal. The blocking resistance was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 5.
Good: The front and back surfaces of the sealant film can be peeled off without resistance.
No Good: There is resistance when peeling the front and back sides of the sealant film.

The sealant film of the present invention is excellent in reducing the environmental impact, and also has excellent sealing properties, lamination strength, and blocking resistance.

10: Polyethylene sealant film 11: Laminate layer 12: Sealing layer 13: Intermediate layer 20: Test pieces 21, 22: Jig 23: Support part 24: Arm part 25: Indenter 30: Test piece 31: Needle 40: Laminate 40: Laminate 41: Base layer 42: Adhesive layer 43: Sealant layer 44: Support layer 45: Barrier layer 50: Test piece 51: Sealant layer 52: Adjacent layer 53: Grip 60: Test piece 61: Grip 62: Sealing part 70: Packaging bag 71: Body part 72: Bottom part 73: Side sheet 74: Bottom sheet 75: Pouring nozzle part 76: Curved part 77: Cut-out part

Claims (8)

A polyethylene sealant film comprising at least a laminate layer and a seal layer,
The biomass content of the polyethylene sealant film is 50% or more,
the sealing layer comprises linear low-density polyethylene and high-pressure low-density polyethylene, the linear low-density polyethylene being a main component of the sealing layer;
A polyethylene sealant film, wherein the laminate layer contains an oligomer having 18 to 36 carbon atoms, and the content of the oligomer is 350 ppm or less based on the entire laminate layer. At least one copolymer selected from the group consisting of ethylene-1-octene copolymers and ethylene-1-hexene copolymers;
The polyethylene sealant film according to claim 1, wherein the total content of the ethylene-1-octene copolymer and the ethylene-1-hexene copolymer is 30 mass% or less with respect to the entire polyethylene sealant film. The polyethylene sealant film according to claim 1 or 2, wherein the laminate layer contains, as a main component, at least one type of polyethylene selected from the group consisting of fossil fuel linear low density polyethylene, fossil fuel high pressure process low density polyethylene, and biomass high pressure process low density polyethylene. The polyethylene sealant film according to any one of claims 1 to 3, further comprising an intermediate layer between the laminate layer and the seal layer. The polyethylene sealant film according to claim 4, wherein the intermediate layer contains biomass polyethylene as a main component. A laminate including at least a base layer, an adhesive layer, and a sealant layer in this order,
The sealant layer comprises the polyethylene sealant film according to any one of claims 1 to 5, and is adjacent to the adhesive layer;
The laminate layer of the polyethylene sealant film is located on the base layer side,
A laminate, wherein the sealing layer of the polyethylene sealant film is one of the surface layers of the laminate. The laminate according to claim 6, wherein the substrate layer is a stretched film. A packaging bag comprising the laminate according to claim 6 or 7.

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