JP2024054203A - Film, packaging bag made of said film, laminate including said film, and packaging bag made of said laminate - Google Patents

Abstract

[Problem] To provide a film having sufficient strength and heat resistance, which enables the production of packaging bags and the like that are also excellent in recyclability and content concealment. [Solution] The film of the present invention is characterized in that it is made of polyethylene or polypropylene, contains a white pigment, and has been subjected to at least one of a stretching treatment and an electron beam irradiation treatment. [Selected Figure] Figure 1

Description

The present invention relates to a film, a packaging bag made of the film, a laminate including the film, and a packaging bag made of the laminate.

Conventionally, resin films made of resin materials have been used as materials for making packaging bags. For example, resin films made of polyolefins have moderate flexibility and transparency, as well as excellent heat sealability, and are therefore widely used for packaging bags.

Normally, resin films made of polyolefins are inferior in terms of strength and heat resistance and cannot be used as a base material for constructing packaging bags, etc., and are used by laminating them with resin films made of polyester, polyamide, etc. For this reason, normal packaging bags are composed of a laminate in which the base material and the sealant layer are made of different types of resin materials (for example, Patent Document 1).

In recent years, with the growing demand for a recycling-oriented society, there is a demand for packaging bags and other items with high recyclability. However, as mentioned above, conventional packaging bags are made up of different resin materials, and because it is difficult to separate the individual resin materials, they are not currently recycled.

In addition, such packaging bags are filled with various contents, but depending on the contents, such as detergent, the color of the contents can be seen through the packaging bag, causing the image formed on the surface of the substrate to become unclear, which is a problem.
In order to solve such problems, a background layer is formed between the substrate and the sealant layer using an ink containing a white pigment to conceal the contents.
However, when a background layer is formed, new problems arise, such as a decrease in the lamination strength between the substrate and the heat seal and a decrease in the hand-tearability of the packaging bag.

JP 2009-202519 A

The inventors have discovered that by subjecting a polyethylene film or a polypropylene film to at least one of a stretching treatment and an electron beam irradiation treatment, the strength and heat resistance of the film can be significantly improved, making it possible to use the film as a base material for laminates used in the production of packaging bags, etc.
The inventors also discovered that by forming the sealant layer from a polyolefin, like the substrate, the recyclability of the laminate can be significantly improved.

The inventors also discovered that by irradiating one side of a polyethylene film or polypropylene film with an electron beam, it is possible to harden or crosslink the polyethylene or polypropylene in the vicinity of the film surface irradiated with the electron beam, thereby realizing a film having different physical properties on the front and back sides. Furthermore, they discovered that if such a film with different physical properties on the front and back sides is used, a packaging bag can be produced using this film alone.

Furthermore, the inventors have discovered that by incorporating a white pigment into a polyethylene film or polypropylene film, the contents can be effectively concealed without reducing the laminate strength between the layers or the ease with which the packaging bag can be torn by hand.

The present invention was made in light of the above findings, and the problem it aims to solve is to provide a film that has sufficient strength and heat resistance, and that enables the production of packaging bags and the like that are also highly recyclable and capable of concealing the contents.

The problem that the present invention aims to solve is to provide a packaging bag made of the film, a laminate including the film, and a packaging bag made of this laminate.

The film of the present invention is characterized in that it is made of polyethylene or polypropylene, contains a white pigment, and has been subjected to at least one of a stretching treatment and an electron beam irradiation treatment.

In one embodiment, the content of the white pigment in the film of the present invention is 2% by mass or more and 20% by mass or less.

The packaging bag of the present invention is made of the above-mentioned film, and the film is characterized in that only one side of the film is subjected to electron beam irradiation treatment, and the surface not irradiated with the electron beam is arranged on the inside.

The laminate of the present invention comprises the above-mentioned film and a sealant layer, and the sealant layer is made of the same material as the film, which is polyethylene or polypropylene.

The packaging bag of the present invention is characterized by being made of the above laminate.

According to the present invention, it is possible to provide a film that has sufficient strength and heat resistance, and that enables the production of packaging bags and the like that are also excellent in recyclability and content concealment properties.
Furthermore, according to the present invention, it is possible to provide a packaging bag made of the film, a laminate including the film, and a packaging bag made of this laminate.

1 is a cross-sectional schematic diagram showing one embodiment of a film of the present invention. 1 is a cross-sectional schematic diagram showing one embodiment of a film of the present invention. 1 is a perspective view showing one embodiment of a packaging bag of the present invention. 1 is a front view showing one embodiment of a packaging bag of the present invention. 1 is a front view showing one embodiment of a packaging bag of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention. 1 is a schematic cross-sectional view showing one embodiment of a laminate of the present invention.

(film)
The film of the present invention is characterized in that it is made of polyethylene or polypropylene, contains a white pigment, and has been subjected to at least one of a stretching treatment and an electron beam irradiation treatment.
By subjecting the material to at least one of the stretching treatment and the electron beam irradiation treatment, its heat resistance and strength can be significantly improved, making it suitable for use as a material for forming packaging bags and the like.

As polyethylene, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene and very low density polyethylene can be used.

In the present invention, the high-density polyethylene may be polyethylene having a density of 0.945 g/ ^cm3 or more, the medium-density polyethylene may be polyethylene having a density of 0.925 g/ ^cm3 or more and less than 0.945 g/ ^cm3 , the low-density polyethylene may be polyethylene having a density of 0.900 g/ ^cm3 or more and less than 0.925 g/ ^cm3 , the linear low-density polyethylene may be polyethylene having a density of 0.900 g/ ^cm3 or more and less than 0.925 g/ ^cm3 , and the very low-density polyethylene may be polyethylene having a density less than 0.900 g/ ^cm3 .

In addition, as long as the characteristics of the present invention are not impaired, copolymers of ethylene and other monomers can also be used as the polyethylene. Examples of ethylene copolymers include copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, and examples of α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene. In addition, as long as the objective of the present invention is not impaired, copolymers with vinyl acetate or acrylic esters may also be used.

The film of the present invention preferably contains biomass-derived polyethylene. Biomass-derived polyethylene is a material that uses biomass-derived ethylene instead of ethylene obtained from fossil fuels as a raw material. Since such biomass-derived polyethylene is a carbon-neutral material, it is possible to reduce the environmental impact of film production. Such biomass-derived polyethylene can be produced, for example, by a method such as that described in JP 2013-177531 A. Commercially available biomass-derived polyethylene (such as Green PE available from Braskem) may also be used.

It is also possible to use polyethylene that has been recycled through mechanical recycling. Mechanical recycling generally refers to a method in which collected polyethylene film is crushed and washed with an alkali to remove dirt and foreign matter from the film surface, and then dried at high temperature and reduced pressure for a certain period of time to diffuse and decontaminate the contaminants remaining inside the film, removing dirt from the polyethylene film and returning it to polyethylene.

The polypropylene may be a homopolymer, a random copolymer or a block copolymer.
A polypropylene homopolymer is a polymer of propylene alone, a polypropylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene (e.g., ethylene, butene-1, 4-methyl-1-pentene, etc.), and a polypropylene block copolymer is a copolymer having a polymer block of propylene and a polymer block of the above-mentioned α-olefin other than propylene.

It is also possible to use polypropylene derived from biomass or polypropylene recycled through mechanical recycling.

The film of the present invention contains a white pigment. This makes it possible to improve the visibility of an image formed on the film. In addition, it makes it possible to conceal the contents filled in a packaging bag produced using the film of the present invention. In addition, it makes it possible to improve the light-shielding property of the film.
Furthermore, the film of this construction does not require a background layer to be formed from an ink containing a white pigment, which is preferable because it does not cause a decrease in the lamination strength between layers when used as a laminate, or a decrease in the ease of tearing the film by hand.

Examples of white pigments include titanium white (titanium(IV) oxide), zinc oxide (zinc oxide), lithopone, calcium carbonate, barium sulfate, and aluminum hydroxide. Among these, titanium oxide is preferred because it has no specific absorption in the visible range and a high refractive index. The substrate may contain two or more of these white pigments.

The content of the white pigment in the film is preferably from 2% by mass to 20% by mass, and more preferably from 4% by mass to 15% by mass.
By making the content of the white pigment in the film 4% by mass or more, it is possible to further improve the visibility of an image formed on the film, to further improve the light-shielding property of the film, and to further conceal the contents filled in the packaging bag produced using the film of the present invention.
Furthermore, by setting the white pigment content in the film to 20 mass % or less, a film with a stable thickness can be produced during film formation, processing suitability comparable to that of transparent films can be maintained during printing and lamination, physical properties can be maintained in the product state after processing, and unnecessary increases in film prices can be suppressed.

The film may contain additives to the extent that they do not impair the properties of the present invention, such as crosslinking agents, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

In one embodiment, the film has a multi-layer structure. In a film having a multi-layer structure, the white pigment may be contained in at least one layer. In this case, from the viewpoint of suitability for printing on the film, it is preferable that the white pigment be contained in an intermediate layer.

In one embodiment, the film has a multilayer structure including a layer made of high density polyethylene (hereinafter referred to as high density polyethylene layer), a layer made of medium density polyethylene (hereinafter referred to as medium density polyethylene layer), and a layer made of high density polyethylene (hereinafter referred to as high density polyethylene layer).
By adopting such a constitution, it is possible to further improve the strength and heat resistance of the film, prevent the film from curling, and improve the stretchability of the film.
In this case, the thickness of the high density polyethylene layer is preferably thinner than the thickness of the medium density polyethylene layer.
The ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer is preferably 1/10 or more and 1/1 or less, and more preferably 1/5 or more and 1/2 or less.
By setting the ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer to 1/10 or more, the strength and heat resistance of the film can be further improved, while by setting the ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer to 1/1 or less, the stretchability of the film can be further improved.

In one embodiment, the film comprises a high density polyethylene layer, a medium density polyethylene layer, a low density polyethylene layer, a linear low density polyethylene layer or an ultra low density polyethylene layer (collectively referred to as a low density polyethylene layer in this paragraph for the sake of simplicity), a medium density polyethylene layer and a high density polyethylene layer.
By adopting such a constitution, it is possible to improve the stretchability of the film, improve the strength and heat resistance of the film, prevent the occurrence of curling in the substrate, and improve the production efficiency of the film.
In this case, the thickness of the high density polyethylene layer is preferably thinner than the thickness of the medium density polyethylene layer.
The ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer is preferably 1/10 or more and 1/1 or less, and more preferably 1/5 or more and 1/2 or less.
By setting the ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer to 1/10 or more, the strength and heat resistance of the film can be improved, while by setting the ratio of the thickness of the high density polyethylene layer to the thickness of the medium density polyethylene layer to 1/1 or less, the stretchability of the film can be improved.
In addition, the thickness of the high density polyethylene layer is preferably the same as or greater than the thickness of the low density polyethylene layer.
The ratio of the thickness of the high density polyethylene layer to the thickness of the low density polyethylene layer is preferably 1/0.25 or more and 1/2 or less, and more preferably 1/0.5 or more and 1/1 or less.
By setting the ratio of the thickness of the high density polyethylene layer to the thickness of the low density polyethylene layer to be 1/0.25 or more, the heat resistance of the film can be improved, and by setting the ratio of the thickness of the high density polyethylene layer to the thickness of the low density polyethylene layer to be 1/1 or less, the adhesion between the medium density polyethylene layers can be improved.
The thickness of each high-density polyethylene layer is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less. By making the thickness of the high-density polyethylene layer 1 μm or more, the strength and heat resistance of the film of the present invention can be further improved. In addition, by making the thickness of the high-density polyethylene layer 20 μm or less, the processability of the film of the present invention can be further improved.
The thickness of the medium-density polyethylene layer is preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. By making the thickness of the medium-density polyethylene layer 1 μm or more, the stretchability of the film can be further improved. In addition, by making the thickness of the medium-density polyethylene layer 30 μm or less, the processability of the film of the present invention can be further improved.
The thickness of the low-density polyethylene layer is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 5 μm or less. By making the thickness of the low-density polyethylene layer 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved. In addition, by making the thickness of the low-density polyethylene layer 5 μm or less, the processability of the film of the present invention can be further improved.
In one embodiment, a film of this configuration can be produced, for example, by an inflation process.
Specifically, the film can be produced by co-extruding, from the outside, a high-density polyethylene layer, a medium-density polyethylene layer, and a low-density polyethylene layer, a linear low-density polyethylene layer, or an ultra-low-density polyethylene layer into a tubular shape, and then pressing the opposing low-density polyethylene layers, linear low-density polyethylene layers, or ultra-low-density polyethylene layers together using a rubber roll or the like.
By using such a method, the number of defective products during manufacturing can be significantly reduced, and ultimately, production efficiency can be improved.
In addition, the stretching can also be carried out in the inflation film forming machine, which can further improve the production efficiency.

In one embodiment, the seven-layer co-extruded film may be configured to include, from the outside, a high-density polyethylene layer, a blend resin layer of high-density polyethylene and medium-density polyethylene, a medium-density polyethylene layer, a low-density polyethylene layer, a linear low-density polyethylene layer or an ultra-low-density polyethylene layer (in this paragraph, for the sake of simplicity, these are collectively referred to as low-density polyethylene layers), a medium-density polyethylene layer, a blend resin layer of high-density polyethylene and medium-density polyethylene, and a high-density polyethylene layer.
By adopting such a constitution, it is possible to improve the adhesion between the high density polyethylene layer and the medium density polyethylene layer, and also to improve the processability of the film of the present invention.
The thickness of each high-density polyethylene layer is preferably 1 μm or more and 20 μm or less, and more preferably 2 μm or more and 10 μm or less. By making the thickness of the high-density polyethylene layer 1 μm or more, the strength and heat resistance of the film of the present invention can be further improved. In addition, by making the thickness of the high-density polyethylene layer 20 μm or less, the processability of the film of the present invention can be further improved.
The thickness of each blend resin layer of high density polyethylene and medium density polyethylene is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 10 μm or less. This can improve the adhesion between the high density polyethylene layer and the medium density polyethylene layer. Also, the processability of the film of the present invention can be improved.
The thickness of the medium-density polyethylene layer is preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. By making the thickness of the medium-density polyethylene layer 1 μm or more, the stretchability of the film can be further improved. In addition, by making the thickness of the medium-density polyethylene layer 30 μm or less, the processability of the film of the present invention can be further improved.
The thickness of the low-density polyethylene layer is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 5 μm or less.
By making the thickness of the low-density polyethylene layer 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved, and by making the thickness of the low-density polyethylene layer 5 μm or less, the processability of the film of the present invention can be further improved.
In one embodiment, the stretched polyethylene film having such a configuration can be produced by the inflation method described above.
By using such a method, the number of defective products during manufacturing can be significantly reduced, and ultimately, production efficiency can be improved.
In addition, the stretching can also be carried out in the inflation film forming machine, which can further improve the production efficiency.

When the film is subjected to a stretching treatment, the stretching may be uniaxial or biaxial.
The stretching ratio in the machine direction (MD) of the film is preferably 2 to 10 times, and more preferably 3 to 7 times.
By making the stretching ratio in the longitudinal direction (MD) of the film 2 times or more, the strength and heat resistance of the film can be improved. Furthermore, the printability of the film can be improved. On the other hand, the upper limit of the stretching ratio in the longitudinal direction (MD) of the film is not particularly limited, but it is preferably 10 times or less from the viewpoint of the breaking limit of the film.
The stretching ratio in the transverse direction (TD) of the film is preferably 2 to 10 times, more preferably 3 to 7 times.
By making the stretching ratio in the transverse direction (TD) of the film 2 times or more, the strength and heat resistance of the film can be improved. Furthermore, the printability of the film can be improved. On the other hand, the upper limit of the stretching ratio in the transverse direction (TD) of the film is not particularly limited, but it is preferably 10 times or less from the viewpoint of the breaking limit of the film.

When the film is irradiated with electron beams, the crosslink density of the polyethylene or polypropylene contained in the film is improved by the electron beam irradiation, and the heat resistance and strength of the film can be significantly improved. This embodiment is particularly suitable when the film is made of polyethylene.

When the film has been subjected to electron beam irradiation treatment, the film 10 may have polyethylene on only one side thereof whose crosslink density has been improved by electron beam irradiation, as shown in FIG. 1, or may have polyolefin crosslink density improved throughout the film, as shown in FIG. 2.
By crosslinking only the polyethylene on one side by electron beam irradiation, the strength and heat resistance of that side can be improved, while the heat sealability of the other side is maintained, so that packaging bags can be produced using only the film of the present invention.

When the film has a multi-layer structure, it is sufficient that the crosslink density of at least the polyethylene in the outermost layer is improved by electron beam irradiation.
From the viewpoint of strength and heat resistance, it is preferable that the crosslink density of the polyethylene as a whole is improved by electron beam irradiation.

The reason why the crosslink density of polyethylene differs with and without electron beam irradiation is unclear, but it is thought to be as follows. That is, when polyethylene is irradiated with an electron beam, the molecular chain of the carbon-hydrogen bond in the polyethylene near the film surface is broken, and radicals are generated at the ends of the molecular chains of the broken bonds. The generated radicals come into contact with other polyethylene molecular chains due to the molecular motion of the molecular chains, extract hydrogen atoms and bond with carbon atoms in the polyethylene molecular chains, resulting in the formation of a crosslinked structure.

Polyethylene films usually tend to shrink when heated, but as the crosslinking density increases, the dimensional stability tends to improve. Therefore, if the crosslinking density is different between the front and back of a polyethylene film, it will curl like a bimetal when heated. Therefore, a simple way to confirm that the crosslinking density is different between the front and back of a polyethylene film is to heat the resulting polyethylene film.

As an apparatus that can be used to irradiate the film with an electron beam, a conventionally known apparatus can be used, such as a curtain-type electron beam irradiation apparatus (LB1023, manufactured by I-Electron Beam Co., Ltd.), a line-type low-energy electron beam irradiation apparatus (EB-ENGINE, manufactured by Hamamatsu Photonics K.K.), and a drum roll-type electron beam irradiation apparatus (EZ-CURE, manufactured by I-Electron Beam Co., Ltd.).

The dose of the electron beam irradiated to the film is preferably in the range of 10 kGy to 2000 kGy, more preferably in the range of 20 kGy to 1000 kGy, and even more preferably in the range of 150 kGy to 500 kGy.
The acceleration voltage of the electron beam is preferably in the range of 30 kV or more and 300 kV or less, more preferably in the range of 50 kV or more and 300 kV or less, and even more preferably in the range of 50 kV or more and 250 kV or less.
The irradiation energy of the electron beam is preferably in the range of 20 keV to 750 keV, more preferably in the range of 25 keV to 500 keV, even more preferably in the range of 30 keV to 400 keV, and particularly preferably in the range of 20 keV to 200 keV.

The oxygen concentration in the electron beam irradiation device is preferably 500 ppm or less, and more preferably 100 ppm or less. By performing electron beam irradiation under such conditions, it is possible to suppress the generation of ozone and to suppress the deactivation of radicals generated by electron beam irradiation by oxygen in the atmosphere. Such conditions can be achieved, for example, by creating an inert gas (nitrogen, argon, etc.) atmosphere inside the device.

In one embodiment, the electron beam irradiation can be performed simultaneously with cooling using a cooling drum or the like.

The film may also be subjected to a surface treatment, which can improve the adhesion between adjacent layers.
The method of the surface treatment is not particularly limited, and examples thereof include physical treatments such as corona discharge 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.
Furthermore, an anchor coat layer may be formed on the film surface using a conventionally known anchor coat agent.

The film may have a printed layer on its surface. The image formed on the printed layer is not particularly limited, and may be a letter, a pattern, a symbol, or a combination thereof.
From the viewpoint of environmental impact, it is preferable that the printing layer is formed on the film using ink derived from biomass.
The method for forming the printed layer is not particularly limited, and examples of the method include conventionally known printing methods such as gravure printing, offset printing, flexographic printing, etc. Among these, flexographic printing is preferred from the viewpoint of environmental load.

The thickness of the film is preferably from 10 μm to 50 μm, and more preferably from 15 μm to 30 μm.
By making the thickness of the film 10 μm or more, the strength and heat resistance of the film can be further improved. In addition, when an image is formed on the film, the visibility of the image can be further improved. In addition, the contents filled in the packaging bag produced using the film of the present invention can be more concealed. Furthermore, the light-shielding property of the film can be further improved.
Furthermore, by making the thickness of the film 50 μm or less, the processability can be improved.

In one embodiment, the film may have a vapor-deposited film on its surface. This can improve the gas barrier properties, specifically the oxygen barrier properties and water vapor barrier properties.

Examples of vapor-deposited films include those composed of metals such as aluminum, and inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

The thickness of the evaporated film is preferably 1 nm or more and 150 nm or less, more preferably 5 nm or more and 60 nm or less, and even more preferably 10 nm or more and 40 nm or less.
By making the thickness of the vapor-deposited film 1 nm or more, the oxygen barrier property and water vapor barrier property of the film can be further improved. Also, by making the thickness of the vapor-deposited film 150 nm or less, the occurrence of cracks in the vapor-deposited film can be prevented. Also, the recyclability of the film when it is made into a laminate described later can be maintained.

In one embodiment, the film has a barrier coat layer on the surface, which can improve the oxygen barrier property and water vapor barrier property.
When the film includes a vapor-deposited film, the barrier coat layer may be provided on or under the vapor-deposited film.

In one embodiment, the barrier coat layer contains a gas barrier resin such as an ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, polyamides such as nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6), polyester, polyurethane, and (meth)acrylic resin. Among these, polyvinyl alcohol is preferred from the viewpoints of oxygen barrier property and water vapor barrier property.
Furthermore, when the vapor-deposited film is made of an inorganic oxide, the occurrence of cracks in the vapor-deposited film can be effectively prevented by including polyvinyl alcohol in the barrier coat layer.

The content of the gas barrier resin in the barrier coat layer is preferably 50% by mass or more and 95% by mass or less, and more preferably 75% by mass or more and 90% by mass or less. By making the content of the gas barrier resin in the barrier coat layer 50% by mass or more, the oxygen barrier property and water vapor barrier property of the film can be further improved.

The barrier coat layer may contain the above additives as long as they do not impair the properties of the present invention.

The thickness of the barrier coat layer is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less.
By making the thickness of the barrier coat layer 0.01 μm or more, it is possible to further improve the oxygen barrier property and the water vapor barrier property, and by making the thickness of the barrier coat layer 10 μm or less, it is possible to maintain the recyclability when made into a laminate described later.

The barrier coat layer can be formed by dissolving or dispersing the above-mentioned materials in water or a suitable solvent, applying the solution, and drying the solution. The barrier coat layer can also be formed by applying a commercially available barrier coat agent and drying the solution.

In another embodiment, the barrier coat layer is a gas barrier coating film containing at least one resin composition such as a hydrolysate of a metal alkoxide or a hydrolysis condensate of a metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method in the presence of a sol-gel catalyst, water, an organic solvent, etc.
When the film has a vapor-deposited film made of an inorganic oxide, by providing a barrier coat layer of this type adjacent to the vapor-deposited film, it is possible to effectively prevent the occurrence of cracks in the vapor-deposited film.

In one embodiment, the metal alkoxide is represented by the following general formula:
R1nM(OR2)m
(In the formula, R1 and R2 each 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.)

As the metal atom M, for example, silicon, zirconium, titanium, aluminum, etc. can be used.
Examples of the organic groups represented by R1 and R2 include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and an i-butyl group.

Examples of metal alkoxides satisfying the above general formula include tetramethoxysilane (Si( _OCH3 ) _{4 )} , tetraethoxysilane (mass %) Si( _{OC2H5 ) 4} ), tetrapropoxysilane (Si( _OC3H7 ) ₄ ), and _{tetrabutoxysilane} (Si( _OC4H9 ) ₄ ).

It is also preferable to use a silane coupling agent together with the metal alkoxide.
As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used, and in particular, an organoalkoxysilane having an epoxy group is preferred. Examples of organoalkoxysilane having an epoxy group include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

Two or more of the above silane coupling agents may be used, and it is preferable to use the silane coupling agent in an amount within the range of about 1 to 20 parts by mass per 100 parts by mass of the total amount of the alkoxide.

As water-soluble polymers, polyvinyl alcohol and ethylene-vinyl alcohol copolymers are preferred, and from the viewpoints of oxygen barrier properties, water vapor barrier properties, water resistance and weather resistance, it is preferable to use these in combination.

The content of the water-soluble polymer in the gas barrier coating film is preferably 5 parts by mass or more and 500 parts by mass or less per 100 parts by mass of the metal alkoxide.
By adjusting the content of the water-soluble polymer in the gas barrier coating film to 5 parts by mass or more per 100 parts by mass of the metal alkoxide, the oxygen barrier property and water vapor barrier property can be further improved. Also, by adjusting the content of the water-soluble polymer in the gas barrier coating film to 500 parts by mass or less per 100 parts by mass of the metal alkoxide, the film formability of the gas barrier coating film can be improved.

The thickness of the gas barrier coating film is preferably from 0.01 μm to 100 μm, and more preferably from 0.1 μm to 50 μm.
By making the thickness of the gas barrier coating film 0.01 μm or more, it is possible to improve the oxygen barrier property and the water vapor barrier property. In addition, when the gas barrier coating film is provided adjacent to a vapor deposition film composed of an inorganic oxide, it is possible to prevent the occurrence of cracks in the vapor deposition film. In addition, by making the thickness of the gas barrier coating film 100 μm or less, it is possible to maintain the recyclability when the gas barrier coating film is made into a laminate described later.

The gas barrier coating film can be formed by applying a composition containing the above-mentioned materials by a conventionally known means such as roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brushing, bar coding, or an applicator, and then polycondensing the composition by a sol-gel method.
The sol-gel catalyst is preferably an acid or an amine compound. As the amine compound, a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is preferable, and examples thereof include N,N-dimethylbenzylamine, tripropylamine, tributylamine, and tripentylamine. Among these, N,N-dimethylbenzylamine is preferable.
The sol-gel catalyst is preferably used in the range of 0.01 to 1.0 part by mass, and more preferably 0.03 to 0.3 part by mass, per 100 parts by mass of the metal alkoxide.
By using a sol-gel catalyst in an amount of 0.01 part by mass or more per 100 parts by mass of the metal alkoxide, the catalytic effect can be improved, and by using a sol-gel catalyst in an amount of 1.0 part by mass or less per 100 parts by mass of the metal alkoxide, the thickness of the gas barrier coating film formed can be made uniform.

The composition may further contain an acid, which is used as a catalyst in the sol-gel process, mainly for the hydrolysis of alkoxides, silane coupling agents, etc.
The acid may be a mineral acid such as sulfuric acid, hydrochloric acid, or nitric acid, or an organic acid such as acetic acid, tartaric acid, etc. The amount of the acid used is preferably 0.001 mol or more and 0.05 mol or less based on the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent.
The amount of acid used is 0.001 mole or more relative to the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent, thereby improving the catalytic effect. Also, the amount of acid used is 0.05 mole or less relative to the total molar amount of the alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent, thereby making the thickness of the gas barrier coating film formed uniform.

The composition preferably contains water in an amount of 0.1 to 100 moles, more preferably 0.8 to 2 moles, per mole of the total amount of alkoxides.
By controlling the water content to 0.1 mole or more per mole of the total molar amount of the alkoxides, the oxygen barrier property and the water vapor barrier property can be improved, and by controlling the water content to 100 moles or more per mole of the total molar amount of the alkoxides, the hydrolysis reaction can be carried out quickly.

The composition may also contain an organic solvent. Examples of the organic solvent that can be used include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butanol.

Hereinafter, one embodiment of the method for forming a gas barrier coating film will be described.
First, a composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and optionally a silane coupling agent, etc. In the composition, a polycondensation reaction gradually proceeds.
Next, the composition is applied onto the film by the above-mentioned conventionally known method and dried. This drying process further advances the polycondensation reaction between the alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains a silane coupling agent) to form a composite polymer layer.
Finally, the composition is heated at a temperature of 20 to 250° C., preferably 50 to 220° C., for 1 second to 10 minutes to form a gas barrier coating film.

The barrier coat layer may have a printed layer formed thereon. The method for forming the printed layer is as described above.

The film can be produced by forming a resin composition containing at least polyethylene into a film using a T-die method, an inflation method or the like, and then stretching and/or irradiating it with electron beams.
By forming the film by the inflation method, a stretching step can be carried out at the same time.
When both stretching and electron beam irradiation are carried out, either one may be carried out first, but from the standpoint of suitability for stretch processing, it is preferable to carry out stretching first.

When a film is produced by the T-die method, the MFR of the resin composition is preferably 3 g/10 min or more and 20 g/10 min or less.
By setting the MFR of the resin composition to 3 g/10 min or more, the processability of the film can be improved, and by setting the MFR of the resin composition to 20 g/10 min or less, the film can be prevented from breaking during stretching.

When the film is produced by an inflation method, the MFR of the resin composition is preferably 0.5 g/10 min or more and 5 g/10 min or less.
By adjusting the MFR of the resin composition to 0.5 g/10 min or more, the processability of the film can be improved, and by adjusting the MFR of the resin composition to 5 g/10 min or less, the film formability can be improved.

The deposition film on the film can be formed by a conventional method, for example, physical vapor deposition methods (PVD method) such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition methods (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

Also, for example, a composite film consisting of two or more layers of vapor-deposited films of different inorganic oxides can be formed and used by combining both physical vapor deposition and chemical vapor deposition. The degree of vacuum in the vapor deposition chamber is preferably about 10 ^-2 to 10 ^-8 mbar before oxygen is introduced, and about 10 ^-1 to 10 ^-6 mbar after oxygen is introduced. The amount of oxygen introduced varies depending on the size of the vapor deposition machine. For the oxygen to be introduced, an inert gas such as argon gas, helium gas, or nitrogen gas may be used as a carrier gas to the extent that no problems occur. The film transport speed can be about 10 to 800 m/min.

It is preferable that the surface of the deposited film is subjected to the above-mentioned surface treatment. This can improve adhesion to adjacent layers.

(Packaging bag)
The packaging bag of the present invention is characterized in that it is made of the above-mentioned film, which has been subjected to electron beam treatment on only one side.

The shape of the packaging bag 20 is not particularly limited, and may be a stand-up pouch having a bag-like shape as shown in FIG.
In one embodiment, when the contents are liquids, viscous materials, or powders such as detergent or shampoo, the packaging bag 30 of the present invention may be a stand-up pouch equipped with a pouring nozzle portion 31 as shown in FIG. 4.
From the viewpoint of ease of opening, the packaging bag 30 may have a curved portion 32 curved inward as shown in FIG.
Additionally, a cutout 33 may be provided, such as by a laser beam.

In one embodiment, the packaging bag 40 of the present invention may be a stand-up pouch having a spout 42 interposed by an upper edge seal portion 41, as shown in FIG. 5. In addition, a cap 43 is screwed to the upper end of the spout 42.

In addition, in Figures 3 to 5, the shaded areas represent the heat-sealed areas. Also, in Figures 3 to 5, a stand-up pouch is shown as an example of the packaging bag, but the packaging bag is not limited to this.

In one embodiment, the packaging bag can be produced by folding the film of the present invention in half, overlapping the film so that the surface not irradiated with electron beam is on the inside, and heat sealing the ends.
In another embodiment, the packaging bag can also be produced by overlapping two films with the surfaces not irradiated with electron beams facing each other, and heat sealing the ends.

In one embodiment, the packaging bag can be manufactured by stacking two of the above films with the non-electron beam irradiated surfaces facing each other and heat sealing two sides to form the body, and then folding another film into a V shape with the non-electron beam irradiated surface facing outward, sandwiching it from one end of the body, and heat sealing it to form the bottom.

In one embodiment, the packaging bag can be manufactured by stacking two of the above films with the non-electron beam irradiated surfaces facing each other and heat sealing one side to form the bottom, then folding two more laminates into a V shape with the non-electron beam irradiated surfaces facing outwards, sandwiching both ends of the facing films, and heat sealing to form the body.

The heat sealing method is not particularly limited, and can be performed by known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc.

The contents filled in the packaging bag are not particularly limited, and may be liquid, powder, or gel. In addition, the contents may be food or non-food.
According to the packaging bag of the present invention, even if the contents are colored, such as detergent, the image formed on the base material is not affected, and the contents can be suitably filled.

(Laminate)
As shown in FIG. 6, a laminate 50 of the present invention comprises the above-mentioned film 10 as a substrate, and a sealant layer 51 .
When only one surface of the film 10 is subjected to electron beam irradiation treatment, the substrate is provided so that the surface of the film irradiated with electron beams becomes the outermost surface of the laminate.
In the laminate of the present invention, the sealant layer is made of the same material as the film (substrate), that is, polyethylene or polypropylene, which can improve the recyclability of the laminate.

Furthermore, the laminate 50 of the present invention can include an intermediate layer 52 between the substrate 10 and the sealant layer 51, as shown in FIG.
Furthermore, the laminate 50 of the present invention may include an adhesive layer 53 between any of the layers, for example, between the substrate 10 and the sealant layer 51 as shown in FIG.

(Sealant Layer)
In one embodiment, the sealant layer is made of the same material as the film (substrate), i.e., polyethylene or polypropylene, which can improve the recyclability of the laminate.

From the viewpoint of low-temperature heat sealability and drop resistance, the sealant layer preferably contains polyethylene, and more preferably contains low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene.
From the viewpoint of heat resistance, the sealant layer preferably contains polypropylene.

In order to improve the hand-tearability of a packaging bag produced using the laminate of the present invention, the sealant layer preferably contains low-density polyethylene.
Furthermore, in order to improve the drop strength of a packaging bag produced using the laminate of the present invention, the sealant layer preferably contains linear low density polyethylene. Examples of linear low density polyethylene include C-4LLDPE and C-6LLDPE. From the viewpoint of a balance between tearability and impact strength, C-4LLDPE is preferred, and from the viewpoint of improving drop strength, C-6LLDPE is preferred.
Preferably, the sealant layer comprises both C-4 LLDPE and C-6 LLDPE.

When the sealant layer contains low-density polyethylene and linear low-density polyethylene, the content of the low-density polyethylene is preferably 5% by mass or more and 20% by mass or less, and more preferably 9% by mass or more and 15% by mass or less. By making the content of the low-density polyethylene 5% by mass or more, the hand-tearability of the packaging bag made using the laminate of the present invention can be further improved. By making the content of the low-density polyethylene 20% by mass or less, the drop strength of the packaging bag made using the laminate of the present invention can be maintained.
The content of the linear low density polyethylene is preferably 65% by mass or more and 90% by mass or less, and more preferably 70% by mass or more and 80% by mass or less. By making the content of the linear low density polyethylene 65% by mass or more, the drop strength of the packaging bag produced using the laminate of the present invention can be further improved. By making the content of the linear low density polyethylene 90% by mass or less, additives such as slip agents and antiblocking agents can be added, and a film of excellent quality with excellent processability can be obtained.

The sealant layer may also contain the above-mentioned biomass-derived polyethylene, mechanically recycled polyethylene, polypropylene, etc.

In one embodiment, the sealant layer contains the white pigment. The content of the white pigment in the sealant layer is preferably 2% by mass or more and 15% by mass or less, and more preferably 4% by mass or more and 10% by mass or less.
By making the content of the white pigment in the sealant layer 2% by mass or more, when an image is formed on a film (substrate), the visibility of the image can be further improved. In addition, the contents filled in the packaging bag produced using the laminate of the present invention can be more concealed. In addition, the light-shielding property of the laminate can be further improved.
Furthermore, by setting the content of the white pigment in the sealant layer to 15% by mass or less, a film can be obtained that does not impair the mechanical properties of the film and prevents an increase in costs.

The sealant layer may contain the above additives as long as the properties of the present invention are not impaired.

In one embodiment, the sealant layer has a multi-layer structure.
In the sealant layer having a multi-layer structure, the white pigment may be contained in at least one layer.
From the viewpoint of adhesion to adjacent layers and heat sealability, it is preferable that the intermediate layer contains a white pigment.
For example, it is composed of a lamination layer that is laminated to a film (substrate), an intermediate layer that contains a white pigment, and a heat seal layer.

In one embodiment, the intermediate sealant layer of the multi-layer sealant layer contains at least one of medium density polyethylene and high density polyethylene, which can further improve the strength of the laminate of the present invention.
Specific examples of intermediate layers containing at least one of medium-density polyethylene and high-density polyethylene include a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very-low-density polyethylene, a layer containing at least one of medium-density polyethylene and high-density polyethylene, and a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and very-low-density polyethylene.
The configuration may include:
By adopting the above-mentioned configuration, the bag-making suitability and strength of the laminate of the present invention can be further improved while maintaining the heat sealability.

The thickness of the sealant layer is preferably 40 μm or more and 180 μm or less, and more preferably 80 μm or more and 150 μm or less. This can further improve the heat sealability of the laminate of the present invention. In addition, when the sealant layer contains a white pigment, the visibility of an image formed on a film (substrate) can be further improved. In addition, the contents filled in a packaging bag produced using the laminate of the present invention can be further concealed. In addition, the light blocking property of the laminate can be further improved.

(Adhesive Layer)
The adhesive layer may be formed of a conventionally known adhesive. The adhesive may be a one-component curing type, a two-component curing type, or a non-curing type.
The adhesive may be either a solvent-free adhesive or a solvent-based adhesive, but from the standpoint of environmental impact, a solvent-free adhesive is preferably used.
Examples of solvent-free adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, two-component curing urethane adhesives can be preferably used.
Examples of the solvent-based adhesive include rubber-based adhesives, vinyl-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and olefin-based adhesives.

Furthermore, when the laminate of the present invention includes an aluminum vapor-deposited film, the adhesive layer provided adjacent to the aluminum vapor-deposited film is preferably made of a cured product of a resin composition containing a polyester polyol and an isocyanate compound.
When forming a laminate with a vapor-deposited film into a packaging bag, a bending load is applied to the laminate by a molding machine or the like, which may cause cracks in the aluminum vapor-deposited film. By configuring the adhesive layer as described above, it is possible to prevent cracks from occurring in the aluminum vapor-deposited film, and even if cracks do occur, it is possible to suppress a decrease in the oxygen barrier property and water vapor barrier property (flexural load resistance).

Polyester polyols have two or more hydroxyl groups as functional groups in one molecule. Also, isocyanate compounds have two or more isocyanate groups as functional groups in one molecule. Polyester polyols have, for example, a polyester structure or a polyester polyurethane structure as the main skeleton.

Specific examples of resin compositions (adhesives) containing polyester polyol and isocyanate compounds include the PASLIM series sold by DIC Corporation.

The resin composition may further contain a plate-like inorganic compound, a coupling agent, cyclodextrin and/or its derivatives, etc.

As the polyester polyol having two or more hydroxyl groups in one molecule as a functional group, for example, the following [First Example] to [Third Example] can be used.
[Example 1] Polyester polyol obtained by polycondensation of an ortho-oriented polycarboxylic acid or its anhydride with a polyhydric alcohol. [Example 2] Polyester polyol having a glycerol skeleton. [Example 3] Polyester polyol having an isocyanuric ring. Each polyester polyol will be explained below.

The polyester polyol according to the first example is a polycondensate obtained by polycondensing a polycarboxylic acid component containing at least one or more types of orthophthalic acid and its anhydride, and a polyhydric alcohol component containing at least one type selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol.
In particular, polyester polyols in which the content of orthophthalic acid or its anhydride relative to the total amount of polyvalent carboxylic acids is 70 to 100% by mass are preferred.

The polyester polyol according to the first example essentially contains orthophthalic acid and its anhydride as the polycarboxylic acid component, but may be copolymerized with other polycarboxylic acid components as long as the effect of the present embodiment is not impaired.
Specifically, aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecane dicarboxylic acid, unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid, alicyclic polycarboxylic acids such as 1,3-cyclopentane dicarboxylic acid and 1,4-cyclohexane dicarboxylic acid, aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anhydrides of these dicarboxylic acids, and ester-forming derivatives of these dicarboxylic acids, polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids, etc. are exemplified. Among these, succinic acid, 1,3-cyclopentane dicarboxylic acid, and isophthalic acid are preferred.
Two or more of the above other polyvalent carboxylic acids may be used.

As a polyester polyol according to the second example, a polyester polyol having a glycerol skeleton represented by the general formula (1) can be mentioned.
In general formula (1), R ₁ , R ₂ and R ₃ each independently represent H (hydrogen atom) or a group represented by the following general formula (2).

In formula (2), n represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms.
However, at least one of R ₁ , R ₂ and R ₃ represents a group represented by formula (2).

In general formula (1), at least one of R ₁ , R ₂ and R ₃ must be a group represented by general formula (2). In particular, it is preferable that all of R ₁ , R ₂ and R ₃ are groups represented by general formula (2).

In addition, the compound may be a mixture _of two _{or more of a compound in which any one of R 1 ,} R ₂ , and R ₃ is a group represented by general formula (2), a compound in which any two of R 1, R ₂ , and R _{3 are groups represented by general formula (2), and a compound in which all of R 1, R 2, and R 3 are groups} represented by general formula (2).

X represents an arylene group which may have a substituent and is selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group.
When X is substituted with a substituent, it may be substituted with one or more substituents, and the substituent is bonded to any carbon atom on X that is different from the free radical. The substituents include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, a N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.

In general formula (2), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, a propylene group, a butylene group, a neopentylene group, a 1,5-pentylene group, a 3-methyl-1,5-pentylene group, a 1,6-hexylene group, a methylpentylene group, or a dimethylbutylene group. Of these, a propylene group or an ethylene group is preferable, and an ethylene group is most preferable.

The polyester resin compound having a glycerol skeleton represented by general formula (1) can be synthesized by reacting glycerol, an aromatic polycarboxylic acid or its anhydride in which a carboxylic acid is substituted at the ortho position, and a polyhydric alcohol component as essential components.

Examples of aromatic polycarboxylic acids or anhydrides in which a carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracene carboxylic acid or anhydride.
These compounds may have a substituent at any carbon atom of the aromatic ring, such as a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, or a naphthyl group.

The polyhydric alcohol component may be an alkylene diol having 2 to 6 carbon atoms. Examples of such diols include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol.

The polyester polyol according to the third example is a polyester polyol having an isocyanuric ring represented by the following general formula (3).
In formula (3), R ₁ , R ₂ and R ₃ each independently represent "-(CH ₂ )n1-OH (wherein n1 represents an integer of 2 to 4)" or a structure represented by formula (4).

In general formula (4), n2 represents an integer of 2 to 4, n3 represents an integer of 1 to 5, X represents an arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group, which may have a substituent, and Y represents an alkylene group having 2 to 6 carbon atoms), with the proviso that at least one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (4).

In the general formula (3), the alkylene group represented by -(CH ₂ )n1- may be linear or branched. Among these, n1 is preferably 2 or 3, and most preferably 2.

In formula (4), n2 represents an integer of 2 to 4, and n3 represents an integer of 1 to 5.
X represents an optionally substituted arylene group selected from the group consisting of a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, a 2,3-anthraquinonediyl group, and a 2,3-anthracenediyl group.

When X is substituted with a substituent, it may be substituted with one or more substituents, and the substituent is bonded to any carbon atom on X that is different from the free radical. The substituents include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimido group, a carboxyl group, a carbamoyl group, a N-ethylcarbamoyl group, a phenyl group, and a naphthyl group.
The substituent for X is preferably a hydroxyl group, a cyano group, a nitro group, an amino group, a phthalimido group, a carbamoyl group, an N-ethylcarbamoyl group, or a phenyl group, and most preferably a hydroxyl group, a phenoxy group, a cyano group, a nitro group, a phthalimido group, or a phenyl group.

In general formula (4), Y represents an alkylene group having 2 to 6 carbon atoms, such as an ethylene group, a propylene group, a butylene group, a neopentylene group, a 1,5-pentylene group, a 3-methyl-1,5-pentylene group, a 1,6-hexylene group, a methylpentylene group, or a dimethylbutylene group. Of these, a propylene group or an ethylene group is preferable, and an ethylene group is most preferable.

In formula (3), at least one of R ₁ , R ₂ and R ₃ is a group represented by formula (4). In particular, it is preferred that all of R ₁ , R ₂ and R ₃ are groups represented by formula (4).

In addition, the compound may be a mixture _of two or more _{of a compound in which any one of R 1 ,} R ₂ , and R ₃ is a group represented by general formula (4), a compound in which any two of R 1, R ₂ , and R _{3 are groups represented by general formula (4), and a compound in which all of R 1, R 2, and R 3 are groups} represented by general formula (4).

The polyester polyol having an isocyanuric ring represented by the general formula (3) can be synthesized by reacting a triol having an isocyanuric ring, an aromatic polycarboxylic acid or its anhydride in which a carboxylic acid is substituted at the ortho position, and a polyhydric alcohol component as essential components.

Examples of triols having an isocyanuric ring include alkylene oxide adducts of isocyanuric acid, such as 1,3,5-tris(2-hydroxyethyl)isocyanuric acid and 1,3,5-tris(2-hydroxypropyl)isocyanuric acid.

Examples of aromatic polycarboxylic acids or anhydrides in which the carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracene carboxylic acid or anhydride. These compounds may have a substituent on any carbon atom of the aromatic ring.

Such substituents include chloro, bromo, methyl, ethyl, i-propyl, hydroxyl, methoxy, ethoxy, phenoxy, methylthio, phenylthio, cyano, nitro, amino, phthalimido, carboxyl, carbamoyl, N-ethylcarbamoyl, phenyl, and naphthyl groups.

The polyhydric alcohol component may be an alkylene diol having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, and dimethylbutanediol.
Among these, polyester polyol compounds having an isocyanuric ring, which use 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid as the triol compound having an isocyanuric ring, orthophthalic anhydride as the aromatic polycarboxylic acid or its anhydride in which the carboxylic acid is substituted at the ortho position, and ethylene glycol as the polyhydric alcohol, are particularly excellent in oxygen barrier properties and adhesive properties and are therefore preferred.

Isocyanuric rings are highly polar and trifunctional, and can increase the polarity of the entire system and increase the crosslinking density. From this perspective, it is preferable for the adhesive resin to contain 5% by mass or more of isocyanuric rings based on the total solid content.

The isocyanate compound has two or more isocyanate groups in the molecule.
The isocyanate compound may be either aromatic or aliphatic, and may be either a low molecular weight compound or a high molecular weight compound.
Furthermore, the isocyanate compound may be a blocked isocyanate compound obtained by subjecting a known isocyanate blocking agent to an addition reaction by a known, conventional appropriate method.
Among these, from the viewpoints of adhesiveness and retort resistance, polyisocyanate compounds having three or more isocyanate groups are preferred, and from the viewpoints of oxygen barrier property and water vapor barrier property, aromatic compounds are preferred.

Specific examples of the isocyanate compound include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, metaxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds, as well as adducts, biurets, and allophanates obtained by reacting these isocyanate compounds with low-molecular-weight active hydrogen compounds or their alkylene oxide adducts, or high-molecular-weight active hydrogen compounds.
Examples of low molecular weight active hydrogen compounds include ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and metaxylylenediamine. Examples of molecular weight active hydrogen compounds include polymeric active hydrogen compounds such as various polyester resins, polyether polyols, and polyamides.

The resin composition may contain a phosphoric acid-modified compound in addition to the polyester polyol and the isocyanate compound, and is, for example, a compound represented by the following general formula (5) or (6).
In general formula (5), R ₁ , R ₂ and R ₃ are groups selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms which has a (meth)acryloyloxy group, at least one of which is a hydrogen atom, and n is an integer of 1 to 4.
In the formula, R ₄ and R ₅ are groups selected from a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group which may have a substituent, and an alkyl group having 1 to 4 carbon atoms and having a (meth)acryloyloxy group, n is an integer from 1 to 4, x is an integer from 0 to 30, and y is an integer from 0 to 30, except for the case where both x and y are 0.

More specifically, examples of such acids include phosphoric acid, pyrophosphoric acid, triphosphoric acid, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, dibutyl phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, isododecyl acid phosphate, butoxyethyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, and polyoxyethylene alkyl ether phosphate, and one or more of these can be used.

The content of the phosphoric acid-modified compound in the resin composition is preferably from 0.005% by mass to 10% by mass, and more preferably from 0.01% by mass to 1% by mass.
By adjusting the content of the phosphoric acid-modified compound to 0.005% by mass or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be improved, and by adjusting the content of the phosphoric acid-modified compound to 10% by mass or less, the adhesiveness of the adhesive layer can be improved.

The resin composition containing the polyester polyol and the isocyanate compound may contain a plate-like inorganic compound, which can improve the adhesiveness of the adhesive layer and the bending load resistance of the laminate of the present invention.
Examples of the plate-like inorganic compounds include kaolinite-serpentine group clay minerals (such as halloysite, kaolinite, endelite, dickite, nacrite, antigorite, and chrysotile) and pyrophyllite-talc group (such as pyrophyllite, talc, and keroli).

Examples of the coupling agent include a silane-based coupling agent, a titanium-based coupling agent, and an aluminum-based coupling agent, which are represented by the following general formula (7). These coupling agents may be used alone or in combination of two or more kinds.

Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxytrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β(a Examples of such silanes include N-(aminoethyl) gamma-aminopropyl methyldimethoxysilane, N-β(aminoethyl) gamma-aminopropyl trimethoxysilane, N-β(aminoethyl) gamma-aminopropyl triethoxysilane, gamma-aminopropyl trimethoxysilane, gamma-aminopropyl triethoxysilane, N-phenyl-gamma-aminopropyl trimethoxysilane, gamma-chloropropyl trimethoxysilane, gamma-mercaptopropyl trimethoxysilane, 3-isocyanatopropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethyl-butylidene).

Examples of titanium-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraoctyl bis(didodecyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctyl nor titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacryl titanate, diisostearoyl ethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and dicumyl phenyl oxyacetate titanate.

Specific examples of aluminum-based coupling agents include acetoalkoxyaluminum diisopropylate, diisopropoxyaluminum ethyl acetoacetate, diisopropoxyaluminum monomethacrylate, isopropoxyaluminum alkyl acetoacetate mono(dioctyl phosphate), aluminum 2-ethylhexanoate oxide trimer, aluminum stearate oxide trimer, and alkyl acetoacetate aluminum oxide trimer.

The resin composition may contain cyclodextrin and/or a derivative thereof, which can improve the adhesiveness of the adhesive layer and the bending load resistance of the laminate of the present invention.
Specifically, for example, cyclodextrin, alkylated cyclodextrin, acetylated cyclodextrin, hydroxyalkylated cyclodextrin, and other cyclodextrins in which the hydrogen atoms of the hydroxyl groups of the glucose units of cyclodextrin are substituted with other functional groups can be used. Branched cyclic dextrins can also be used.
Furthermore, the cyclodextrin skeleton in cyclodextrin and cyclodextrin derivatives may be any of α-cyclodextrin consisting of six glucose units, β-cyclodextrin consisting of seven glucose units, and γ-cyclodextrin consisting of eight glucose units.
These compounds may be used alone or in combination of two or more. Hereinafter, these cyclodextrins and/or their derivatives may be collectively referred to as dextrin compounds.

From the viewpoint of compatibility and dispersibility in the resin composition, it is preferable to use a cyclodextrin derivative as the cyclodextrin compound.

Examples of alkylated cyclodextrins include methyl-α-cyclodextrin, methyl-β-cyclodextrin, and methyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

Examples of acetylated cyclodextrins include monoacetyl-α-cyclodextrin, monoacetyl-β-cyclodextrin, and monoacetyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

Examples of hydroxyalkylated cyclodextrins include hydroxypropyl-α-cyclodextrin, hydroxypropyl-β-cyclodextrin, and hydroxypropyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

As long as the properties of the present invention are not impaired, the adhesive layer may contain additives such as pigments such as titanium oxide, zinc oxide and carbon black, dyes such as disperse dyes, acid dyes and cationic dyes, antioxidants, lubricants, colorants, stabilizers, wetting agents, thickeners, coagulants, gelling agents, anti-settling agents, softeners, hardeners, plasticizers, leveling agents, ultraviolet absorbers and flame retardants.

The thickness of the adhesive layer is not particularly limited and can be, for example, 1 μm or more and 5 μm or less.

(Middle class)
In one embodiment, the laminate of the present invention comprises, as an intermediate layer, a layer composed of polyethylene or polypropylene.

In one embodiment, the intermediate layer may contain the white pigment.
The content of the white pigment in the intermediate layer is preferably from 2% by mass to 15% by mass, and more preferably from 4% by mass to 10% by mass.
By making the content of the white pigment in the intermediate layer 2% by mass or more, when an image is formed on a film (substrate), the visibility of the image can be further improved. In addition, the contents filled in the packaging bag produced using the laminate of the present invention can be more concealed. In addition, the light-shielding property of the laminate can be further improved.
Furthermore, by setting the content of the white pigment in the intermediate layer to 15% by mass or less, a film can be obtained that does not impair the mechanical properties of the film and that prevents an increase in costs.

The intermediate layer may be composed of a stretched film, and may be a uniaxially stretched film or a biaxially stretched film, and the preferred stretch ratio is as described above.
The intermediate layer may also be an extruded resin layer formed by melt extruding polyethylene or polypropylene.

The thickness of the intermediate layer is preferably 10 μm or more and 70 μm or less, and more preferably 15 μm or more and 50 μm or less.
When the intermediate layer contains a white pigment, the visibility of an image formed on a substrate can be improved. In addition, the contents filled in a packaging bag produced using the laminate of the present invention can be more concealed. In addition, the light-shielding property of the laminate can be more improved.

In one embodiment, the laminate of the present invention includes, as an intermediate layer, a gas barrier layer made of a gas barrier resin.
By providing the laminate of the present invention with such an intermediate layer, the oxygen barrier property and water vapor barrier property can be improved.
Examples of gas barrier resins include ethylene-vinyl alcohol copolymers (EVOH), polyvinyl alcohol, polyacrylonitrile, polyamides such as nylon 6, nylon 6,6 and polymetaxylylene adipamide (MXD6), polyesters, polyurethanes, and (meth)acrylic resins.

In one embodiment, the gas barrier layer may contain the above-mentioned white pigment.
The content of the white pigment in the gas barrier layer is preferably from 1% by mass to 10% by mass, and more preferably from 2% by mass to 8% by mass.
By making the content of the white pigment in the gas barrier layer 1% by mass or more, when an image is formed on a film (substrate), the visibility of the image can be further improved. In addition, the contents filled in a packaging bag produced using the laminate of the present invention can be more concealed. In addition, the light-shielding property of the laminate can be further improved.
Furthermore, by setting the content of the white pigment in the gas barrier layer to 10 mass % or less, the whiteness of the gas barrier layer can be improved while maintaining the gas barrier properties.

The thickness of the gas barrier layer is preferably 0.01 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 5 μm or less.
By setting the thickness of the gas barrier layer to 0.01 μm or more, the oxygen barrier property and water vapor barrier property of the laminate of the present invention can be further improved, and by setting the thickness of the gas barrier layer to 10 μm or less, the recyclability of the laminate of the present invention can be maintained.
In addition, when the intermediate layer contains a white pigment, the visibility of an image formed on a film (substrate) can be improved. In addition, the contents filled in a packaging bag produced using the laminate of the present invention can be more concealed. In addition, the light-shielding property of the laminate can be more improved.

In one embodiment, the intermediate layer comprises a vapor-deposited film. The form, preferred thickness, and formation method of the vapor-deposited film that can be used are as described above.

In one embodiment, the intermediate layer comprises a barrier coat layer. The configuration, preferred thickness, and formation method of the barrier coat layer are as described above.

(Packaging bag)
The packaging bag of the present invention is characterized in that it is made of the above-mentioned laminate.
The shape of the packaging bag is not particularly limited, and may be as shown in FIGS.

In one embodiment, the packaging bag can be produced by folding the laminate of the present invention in half, overlapping the laminate so that the sealant layer is on the inside, and heat-sealing the ends.
In another embodiment, the packaging bag can also be produced by overlapping two laminates with their sealant layers facing each other, and heat sealing the ends thereof.

In one embodiment, the packaging bag can be manufactured by stacking two of the above laminates with the sealant layers facing each other and heat sealing two sides to form the body, and then folding yet another laminate into a V shape with the sealant layer facing outward, sandwiching it from one end of the body, and heat sealing it to form the bottom.

In one embodiment, the packaging bag can be manufactured by stacking two of the above laminates with their sealant layers facing each other and heat sealing one side to form the bottom, then folding two more laminates into a V shape with the sealant layers facing outwards, sandwiching both ends of the laminates facing each other, and heat sealing to form the body.

The heat sealing method is not particularly limited, and can be performed by known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc.

The contents filled in the packaging bag are not particularly limited, and may be liquid, powder, or gel. In addition, the contents may be food or non-food.
According to the packaging bag of the present invention, even if the contents are colored, such as detergent, the image formed on the base material is not affected, and the contents can be suitably filled.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

Example 1
A resin composition containing linear low density polyethylene (LLDPE, density 0.937 g/cm ³ ) and titanium oxide was formed into a polyethylene film having a thickness of 25 μm using an inflation extruder. The titanium oxide content was adjusted to 4 mass %.
One surface of this polyethylene film was irradiated with electron beams using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) under the following conditions (irradiation conditions):
Voltage: 70 kV
Exposure dose: 280 kGy
Oxygen concentration in the device: 100 ppm or less Line speed: 25 m/min

An image was formed on the electron beam irradiated surface of this film using a gravure printer to obtain the film of the present invention.

Example 2
The resin composition containing the LLDPE and titanium oxide was extruded using an inflation extruder to produce a polyethylene film having a thickness of 125 μm, which was then uniaxially stretched in the longitudinal direction to obtain a film having a thickness of 25 μm. The titanium oxide content was adjusted to 4% by mass.
An image was formed on one side of this film by a gravure printing machine to obtain the film of the present invention.

A two-component curing polyester adhesive was applied at 3.5 g/m ² to the image-forming surface of the film prepared as described above, and dry-laminated with an unstretched LLDPE film having a thickness of 80 μm to obtain a laminate of the present invention.

Comparative Example 1
A film was prepared in the same manner as in Example 1, except that the electron beam irradiation treatment was not carried out.

Comparative Example 2
A laminate was produced in the same manner as in Example 2, except that the stretching treatment was not carried out.

Comparative Example 3
A laminate was produced in the same manner as in Example 2, except that titanium oxide was not used in the production of the film.

Comparative Example 4
A laminate was prepared in the same manner as in Comparative Example 3, except that a 1 μm-thick white ink layer was provided on the image-forming surface of the film in order to conceal the contents.

<<Content Concealment Test>>
The films prepared in Example 1 and Comparative Example 1 were cut to a size of 220 mm length x 130 mm width.
Two pieces of film cut as described above were stacked together with the non-electron beam irradiated surfaces (either surface was acceptable for the film of Comparative Example 1) facing each other, and a film prepared in the above Examples and Comparative Examples was folded into a V shape from one end of the body so that the non-electron beam irradiated surface was on the outside and sandwiched between the two pieces.
Next, the two vertical sides and the side sandwiching the V-shaped laminate were heat-sealed at a heat-sealing temperature of 155°C.
The film of Comparative Example 1 did not have sufficient heat resistance and could not be heat sealed.

The laminates produced in Example 2 and Comparative Examples 2 to 4 were cut into a size of 220 mm length×130 mm width.
Two of the laminates cut as described above were stacked together with the sealant layers facing each other, and a laminate prepared in the above Examples and Comparative Examples was folded into a V shape at one end of the body so that the sealant layer was on the outside and sandwiched between the laminates.
Next, the two vertical sides and the side sandwiching the V-shaped laminate were heat-sealed at a heat-sealing temperature of 155°C.
The laminate of Comparative Example 2 could not be heat-sealed because the heat resistance of the film (substrate) was insufficient.

Next, a carbon dioxide laser (Keyence Corporation, 3Axis- _CO2 laser marker ML-Z9520A, output 70%, printing speed 1000 mm/min) was irradiated to form a cutout portion, and a pouring nozzle portion and a curved portion as shown in FIG. 4 were formed by punching, thereby producing a stand-up pouch-shaped packaging bag having an opening.
This packaging bag was filled with 300 mL of blue liquid detergent, and the remaining side was heat sealed to form a packaging bag.

The packaging bags prepared as described above were visually observed and evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: The color of the contents was not observed, and high content concealment was confirmed.
NG: The color of the contents was observed, and affected the color of the image formed on the substrate.

<<Laminate strength test>>
The packaging bags made using the laminates made in Example 2 and Comparative Examples 2 to 4 were cut to a width of 15 mm in the machine direction of the film to obtain test pieces. The film (substrate) and the sealant layer on the test side were peeled off at the interface, the peeling was stopped halfway, and both ends of the test piece that had been peeled off halfway were pulled up and down at a test speed of 300 mm/min, and the stress at that time was measured to evaluate the laminate strength. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: The white ink layer did not undergo cohesive failure and was peeled off with a constant strength.
NG: Peeling due to cohesive failure of the white ink layer was observed.

<<Hand tearability test>>
The packaging bags obtained in the above content concealment test were opened by hand, and the ease of opening was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: It was possible to open it with almost no force.
NG: It was necessary to apply a strong force, and there were problems in practical use, such as stretching or tearing.

<<Drop strength test>>
The packaging bag obtained in the above content concealment test was dropped 10 times from a height of 100 cm onto a hard floor with the body of the packaging bag horizontal to the ground. The test was carried out for 10 bags at a time, and the presence or absence of breakage was visually observed, and the strength was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: No damage was found in any of the 10 bags. NG: Damage was found in one or more of the 10 bags, which was problematic for practical use.

10: film, 20, 30, 40: packaging bag, 31: nozzle, 32: curved portion, 33: cut-out portion, 41: upper edge seal portion, 42: spout, 43: cap, 50: laminate, 51: sealant layer, 52: intermediate layer, 53: adhesive layer

Claims (4)

A laminate comprising at least a film made of polyethylene and a sealant layer,
The film has been subjected to at least one of a stretching treatment and an electron beam irradiation treatment,
At least one surface of the film is printed,
the sealant layer is made of polyethylene;
At least one of the film and the sealant layer contains a white pigment;
A laminate comprising: The laminate according to claim 1, wherein the content of the white pigment is 2% by mass or more and 20% by mass or less. The film is subjected to electron beam irradiation treatment on only one surface thereof,
A laminate, characterized in that the surface not irradiated with electron beams is disposed on the sealant layer side. A packaging bag characterized by being formed from the laminate described in any one of claims 1 to 3.