JP2023145482A - Film, packaging bag constituted of film, laminate comprising film and packaging bag constituted of laminate - Google Patents

Abstract

To provide a film having sufficient strength and heat resistance and capable of preparing a packaging bag or the like having excellent recyclability and an excellent concealability of contents.SOLUTION: There is provided a film which is constituted of polyethylene or polypropylene, contains a white pigment, is subjected to at least one of stretching treatment and electron beam irradiation treatment and contains polyethylene derived from biomass or polypropylene derived from biomass.SELECTED DRAWING: 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, a resin film made of a resin material has been used as a material constituting a packaging bag. For example, resin films made of polyolefins have appropriate flexibility and transparency, and have excellent heat-sealing properties, so they are widely used for packaging bags.

Resin films made of polyolefin usually have poor strength and heat resistance, so they cannot be used as a base material for making packaging bags, etc., and can be pasted with resin films made of polyester, polyamide, etc. Therefore, a typical packaging bag is composed of a laminate in which the base material and the sealant layer are made of different resin materials (for example, Patent Document 1).

In recent years, as calls for building a recycling-oriented society have increased, packaging bags and other materials are required to be highly recyclable. However, as described above, conventional packaging bags are made of different types of resin materials, and it is difficult to separate them into different resin materials, so they are currently not recycled.

In addition, such packaging bags are filled with various contents, but depending on the contents, such as detergent, the color may be visible through the packaging bag, and images formed on the surface of the base material may be visible. There was a problem that the image became unclear.
In order to solve such problems, a background layer is formed using ink containing a white pigment between the base material and the sealant layer to hide the contents.
However, when a background layer is formed, new problems have arisen, such as a decrease in the strength of the laminate between the base material and the heat seal, and a decrease in the ease with which the packaging bag can be cut by hand.

Japanese Patent Application Publication No. 2009-202519

The present inventors have found that by subjecting polyethylene film or polypropylene film to at least one of stretching treatment and electron beam irradiation treatment, the strength and heat resistance of the film can be significantly improved, and the film can be used for making packaging bags, etc. We have obtained the knowledge that it can be used as a base material for a laminate.
The inventors have also found that, like the base material, by forming the sealant layer from polyolefin, the recyclability of the laminate can be significantly improved.

The present inventors also discovered that by irradiating one side of a polyethylene film or a polypropylene film with an electron beam, the polyethylene or polypropylene near the surface of the film irradiated with the electron beam can be cured or crosslinked, and as a result, It was found that a film with different physical properties on the front and back sides could be realized. Furthermore, we have found that by using such a film with different physical properties on the front and back sides, it is possible to produce packaging bags using only the film instead of the laminates conventionally used for packaging.

Furthermore, the present inventors have found that by incorporating a white pigment into a polyethylene film or a polypropylene film, the contents can be effectively hidden without reducing the lamination strength between the layers and the ease with which the packaging bag can be cut by hand. We obtained the following knowledge.

The present invention has been made in view of the above findings, and an object of the present invention is to provide a film having sufficient strength and heat resistance, which is also excellent in recyclability and content concealment properties, such as packaging bags. An object of the present invention is to provide a film that can be produced.

Moreover, the problem to be solved by the present invention is to provide a packaging bag made of the film, a laminate including the film, and a packaging bag made of the laminate.

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

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 composed of the above-mentioned film, and the film is characterized in that only one surface of the film is subjected to electron beam irradiation treatment, and the film is arranged so that the non-electron beam irradiated surface is on the inside. do.

The laminate of the present invention is characterized in that it includes the above film and a sealant layer, the sealant layer is made of the same material as the film, and the same material is polyethylene or polypropylene.

In one embodiment, the sealant layer comprises biomass-derived polyethylene or biomass-derived polypropylene.

The packaging bag of the present invention is characterized by being constructed from the above-mentioned 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.
Further, 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 the laminate.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the film of the present invention. FIG. 1 is a schematic cross-sectional view showing one embodiment of the film of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view showing one embodiment of the packaging bag of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a front view showing one embodiment of the packaging bag of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a front view showing one embodiment of the packaging bag of this 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 composed of polyethylene or polypropylene, contains biomass-derived polyethylene or biomass-derived polypropylene, and a white pigment, and is characterized by being subjected to at least one of a stretching treatment and an electron beam irradiation treatment. .
By subjecting it to at least one of the stretching treatment and electron beam irradiation treatment, its heat resistance and strength can be significantly improved, and it can be suitably used as a material constituting packaging bags and the like.
Moreover, since the film of the present invention contains biomass-derived polyethylene or biomass-derived polypropylene, the environmental load of a packaging bag produced using this film can be reduced.

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, polyethylene with a density of 0.945 g/cm ³ or more can be used as the high-density polyethylene, and polyethylene with a density of 0.925 g/cm ³ or more and less than 0.945 g/cm ³ can be used as the medium-density polyethylene. Polyethylene with a density of 0.900 g/cm ³ or more and less than 0.925 g/cm ³ can be used as the low-density polyethylene, and as the linear low-density polyethylene, a polyethylene with a density of Polyethylene with a density of 0.900 g/cm ³ or more and less than 0.925 g/cm ³ can be used, and as the ultra-low density polyethylene, polyethylene with a density of less than 0.900 g/cm 3 can be used.

Further, as the polyethylene, a copolymer of ethylene and other monomers can also be used as long as the characteristics of the present invention are not impaired. 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- Examples include 1-heptene. Furthermore, a copolymer with vinyl acetate or acrylic acid ester may be used as long as it does not impair the purpose of the present invention.

In one embodiment, the film of the invention comprises biomass-derived polyethylene. This is made by polymerizing monomers containing ethylene derived from biomass. Since such biomass-derived polyethylene is a carbon neutral material, the environmental impact of film production can be reduced.
Since biomass-derived ethylene is used as the raw material monomer, the polymerized polyethylene is biomass-derived. Note that the raw material monomer for polyethylene does not need to contain 100% by mass of ethylene derived from biomass.

When the film contains biomass-derived polyethylene, the content thereof is preferably 5% by mass or more and 100% by mass or less, and more preferably 10% by mass or more and 70% by mass or less.

The monomer that is the raw material for biomass-derived polyethylene may further contain fossil fuel-derived ethylene and/or α-olefin, or may further contain biomass-derived α-olefin.

The concentration of biomass-derived ethylene in the polyethylene contained in the film (hereinafter sometimes referred to as "biomass degree") is preferably 10% or more.
"Biomass degree" is a value obtained by measuring the content of carbon derived from biomass by radiocarbon (C14) measurement.
Since carbon dioxide in the atmosphere contains C14 at a certain rate (105.5 pMC), the C14 content in plants that grow by taking in atmospheric carbon dioxide, such as corn, is also around 105.5 pMC. It is known. It is also known that fossil fuels contain almost no C14.
Therefore, by measuring the proportion of C14 contained in all carbon atoms in polyethylene, the proportion of carbon derived from biomass can be calculated. In the present invention, the biomass-derived carbon content Pbio, where the C14 content in polyethylene is PC14, can be determined as follows.
Pbio (%) = PC14/105.5×100

In the present invention, theoretically, if all biomass-derived ethylene is used as a raw material for polyethylene, the biomass-derived ethylene concentration is 100%, and the biomass degree of biomass-derived polyethylene is 100%.
Furthermore, the biomass-derived ethylene concentration in fossil fuel-derived polyethylene produced only from fossil fuel-derived raw materials is 0%, and the biomass degree of fossil fuel-derived polyethylene is 0%.

Biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use fermented ethanol derived from biomass obtained from plant materials. The plant raw material is not particularly limited, and conventionally known plants can be used. For example, corn, sugar cane, beets and manioc may be mentioned.

In the present invention, fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from a plant material with a product derived from an ethanol-producing microorganism or its crushed product, and then purified. Conventionally known methods such as distillation, membrane separation, and extraction can be applied to purify ethanol from the culture solution. For example, methods include adding benzene, cyclohexane, etc. and azeotropically distilling the mixture, or removing water by membrane separation or the like.

A catalyst is usually used to obtain ethylene through the dehydration reaction of ethanol, but this catalyst is not particularly limited, and conventionally known catalysts can be used. A fixed bed flow reaction is advantageous in terms of process because it allows easy separation of the catalyst and the product, and for example, γ-alumina is preferred.

Since this dehydration reaction is an endothermic reaction, it is usually carried out under heating conditions. The heating temperature is not limited as long as the reaction proceeds at a commercially useful reaction rate, but a temperature of preferably 100°C or higher, more preferably 250°C or higher, and still more preferably 300°C or higher is suitable. The upper limit is also not particularly limited, but from the viewpoint of energy balance and equipment, it is preferably 500°C or less, more preferably 400°C or less.

The reaction pressure is also not particularly limited, but a pressure higher than normal pressure is preferred in order to facilitate subsequent gas-liquid separation. Industrially, a fixed bed flow reaction is preferred because it allows easy separation of the catalyst, but a liquid phase suspension bed, a fluidized bed, etc. may also be used.

In the dehydration reaction of ethanol, the yield of the reaction is influenced by 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 in consideration of water removal efficiency. However, it has been found that in the case of ethanol dehydration using a solid catalyst, the amount of other olefins, especially butene, tends to increase in the absence of water. This is probably because ethylene dimerization after dehydration cannot be suppressed unless a small amount of water is present. The lower limit of the allowable water content is 0.1% or more, preferably 0.5% or more. The upper limit is not particularly limited, but from the viewpoint of material balance and heat balance, it is preferably 50% by weight or less, more preferably 30% or less, and still more preferably 20% or less.

By performing the dehydration reaction of ethanol in this way, a mixed portion of ethylene, water and a small amount of unreacted ethanol is obtained, but since ethylene is a gas at room temperature and below about 5 MPa, gas-liquid separation is performed from this mixed portion. Ethylene can be obtained by excluding water and ethanol. This method may be performed by a known method.

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

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 the decomposition product thereof, and enzyme decomposition products. Contains extremely small amounts of impurities such as nitrogen-containing compounds such as amines and amino acids, as well as ammonia, which is a decomposition product thereof. Depending on the use of ethylene, these minute amounts of impurities may pose a problem, so they may be removed by purification. The purification method is not particularly limited, and can be performed by a conventionally known method. As a suitable purification operation, for example, an adsorption purification method can be mentioned. The adsorbent used is not particularly limited, and conventionally known adsorbents can be used. For example, a material with a high surface area is preferable, and the type of adsorbent is selected depending on the type and amount of impurities in ethylene obtained by the dehydration reaction of biomass-derived ethanol.

Note that caustic water treatment may be used in combination as a method for purifying impurities in ethylene. If caustic water treatment is to be performed, it is desirable to perform it before adsorption purification. In that case, it is necessary to perform water removal treatment after caustic treatment and before adsorption purification.

Moreover, the film of the present invention can also contain polyethylene recycled by mechanical recycling. Mechanical recycling generally involves pulverizing recovered polyethylene film, washing it with alkali to remove dirt and foreign matter from the film surface, and then drying it at high temperature and reduced pressure for a certain period of time to remain inside the film. This method involves decontaminating the film by diffusing contaminants, removing dirt from the polyethylene film, and then returning it to polyethylene.

Polypropylene may be a homopolymer, a random copolymer or a block copolymer.
A polypropylene homopolymer is a polymer of only propylene, and a polypropylene random copolymer is a polymer of propylene and other α-olefins other than propylene (for example, ethylene, butene-1, 4-methyl-1-pentene, etc.). It is a random copolymer, and the polypropylene block copolymer is a copolymer having a polymer block made of propylene and a polymer block made of other α-olefins other than the above-mentioned propylene.
Among these polypropylenes, homopolymers can be used when the rigidity and heat resistance of the packaging bag are important, and random copolymers can be used when impact resistance and the like are important.

In one embodiment, the film also includes biomass-derived polypropylene.

When the film contains polypropylene derived from biomass, the content thereof is preferably 5% by mass or more and 95% by mass or less, and more preferably 10% by mass or more and 70% by mass or less.
Further, the biomass degree of the biomass-derived polypropylene is preferably 10% or more.

The film can also include polypropylene recycled by mechanical recycling.

The film of the present invention contains a white pigment. Thereby, when an image is formed on the film, the visibility of the image can be improved. Moreover, the contents filled in the packaging bag produced using the film of the present invention can be hidden. Moreover, the light-shielding properties of the film can be improved.
Furthermore, in a film having such a structure, there is no need to form a background layer using ink containing a white pigment. Therefore, it is preferable because it does not cause a decrease in the lamination strength between the layers in the case of forming a laminate or a decrease in the manual tearability of the film.

Examples of white pigments include titanium white (titanium (IV) oxide), zinc white (zinc oxide), lithopone, calcium carbonate, barium sulfate, and aluminum hydroxide. Titanium oxide is preferable because it does not have a high refractive index and has a high refractive index. The base material may contain two or more types of these white pigments.

The content of the white pigment in the film is preferably 2% by mass or more and 20% by mass or less, more preferably 4% by mass or more and 15% by mass or less.
By setting the content of the white pigment in the film to 4% by mass or more, when an image is formed on the film, the visibility of the image can be further improved. Moreover, the light-shielding properties of the film can be further improved. Moreover, the contents filled in the packaging bag produced using the film of the present invention can be further hidden.
In addition, by controlling the content of white pigment in the film to 20% by mass or less, it is possible to form a film with a stable thickness during film formation, and maintain processing suitability comparable to transparent film during printing and lamination processing. It is possible to maintain the physical properties of the product after processing, and it is possible to suppress unnecessary increases in film prices.

The film may contain additives within a range that does not impair the characteristics of the present invention, such as crosslinking agents, antioxidants, anti-blocking agents, slip agents, ultraviolet absorbers, light stabilizers, and fillers. , reinforcing agents, antistatic agents, pigments, and modifying resins.

In one embodiment, the film has a multilayer structure.
Further, in a film having a multilayer structure, the white pigment may be contained in at least one layer. In this case, the white pigment is preferably contained in the intermediate layer from the viewpoint of suitability for printing on the film.

In one embodiment, the film includes a layer made of high-density polyethylene (hereinafter referred to as a high-density polyethylene layer), a layer made of medium-density polyethylene (hereinafter referred to as a medium-density polyethylene layer), and a layer made of high-density polyethylene (hereinafter referred to as a medium-density polyethylene layer). (hereinafter referred to as a high-density polyethylene layer).
With such a configuration, the strength and heat resistance of the film can be further improved. Further, it is possible to prevent the film from curling. Moreover, the stretching suitability of the film can also be improved.
At this time, 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. Further, 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 stretching suitability of the film can be further improved.

In one embodiment, the film includes a high-density polyethylene layer, a medium-density polyethylene layer, a low-density polyethylene layer, a linear low-density polyethylene layer, or a very low-density polyethylene layer (in this paragraph, for the sake of brevity, ), a medium density polyethylene layer, and a high density polyethylene layer.
With such a configuration, the stretching suitability of the film can be improved. Moreover, the strength and heat resistance of the film can be improved. Further, it is possible to prevent curling in the base material. Furthermore, film production efficiency can be improved.
At this time, 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. Furthermore, 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 stretching suitability of the film can be improved.
Moreover, the thickness of the high-density polyethylene layer is preferably the same as or thicker 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, more preferably 1/0.5 or more and 1/1 or less. preferable.
By setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer to 1/0.25 or more, the heat resistance of the film can be improved. Furthermore, by setting the ratio of the thickness of the high-density polyethylene layer to the thickness of the low-density polyethylene layer to 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, more preferably 2 μm or more and 10 μm or less. By setting the thickness of the high-density polyethylene layer to 1 μm or more, the strength and heat resistance of the film of the present invention can be further improved. Further, by setting the thickness of the high-density polyethylene layer to 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, more preferably 5 μm or more and 20 μm or less. By setting the thickness of the medium density polyethylene layer to 1 μm or more, the stretching suitability of the film can be further improved. Further, by setting the thickness of the medium density polyethylene layer to 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, more preferably 2 μm or more and 5 μm or less. By setting the thickness of the low-density polyethylene layer to 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved. Further, by setting the thickness of the low-density polyethylene layer to 5 μm or less, the processability of the film of the present invention can be further improved.
In one embodiment, a film with such a configuration can be produced, for example, by an inflation method.
Specifically, from the outside, high-density polyethylene, a medium-density polyethylene layer, and a low-density polyethylene layer, a linear low-density polyethylene layer, or a very low-density polyethylene layer are coextruded into a tube shape, and then facing each other. It can be produced by pressing low-density polyethylene layers, linear low-density polyethylene layers, or very low-density polyethylene layers together using a rubber roll or the like.
By manufacturing using such a method, the number of defective products during manufacturing can be significantly reduced, and ultimately production efficiency can be improved.
Further, in the inflation film forming machine, stretching can also be performed, thereby further improving production efficiency.

In one embodiment, 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 a very low density polyethylene layer. layer (in this paragraph, to simplify the description, they are collectively referred to as a low-density polyethylene layer), a medium-density polyethylene layer, a blend resin layer of high-density polyethylene and medium-density polyethylene, and a high-density polyethylene layer. It is also possible to have a structure of a seven-layer co-pressed film.
With such a configuration, it is possible to improve the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer. Further, the processing suitability of the film of the present invention can be improved.
The thickness of each high-density polyethylene layer is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 10 μm or less. By setting the thickness of the high-density polyethylene layer to 1 μm or more, the strength and heat resistance of the film of the present invention can be further improved. Further, by setting the thickness of the high-density polyethylene layer to 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. Further, the processing suitability 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, more preferably 5 μm or more and 20 μm or less. By setting the thickness of the medium density polyethylene layer to 1 μm or more, the stretching suitability of the film can be further improved. Further, by setting the thickness of the medium density polyethylene layer to 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, more preferably 2 μm or more and 5 μm or less.
By setting the thickness of the low-density polyethylene layer to 1 μm or more, the adhesion between the high-density polyethylene layer and the medium-density polyethylene layer can be further improved. Further, by setting the thickness of the low-density polyethylene layer to 5 μm or less, the processability of the film of the present invention can be further improved.
In one embodiment, a stretched polyethylene film having such a structure can be produced by the above-described inflation method.
By manufacturing using such a method, the number of defective products during manufacturing can be significantly reduced, and ultimately production efficiency can be improved.
Further, in the inflation film forming machine, stretching can also be performed, thereby further improving production efficiency.

When the film is subjected to stretching treatment, the stretching may be uniaxial or biaxial stretching.
The stretching ratio in the longitudinal direction (MD) of the film is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less.
By setting the stretching ratio in the longitudinal direction (MD) of the film to 2 times or more, the strength and heat resistance of the film can be improved. Furthermore, the suitability for printing onto films can be improved. Moreover, the transparency 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 from the viewpoint of the breaking limit of the film, it is preferably 10 times or less.
Further, the stretching ratio of the film in the transverse direction (TD) is preferably 2 times or more and 10 times or less, and preferably 3 times or more and 7 times or less.
By setting the stretching ratio of the film in the transverse direction (TD) to 2 times or more, the strength and heat resistance of the film can be improved. Furthermore, the suitability for printing onto films can be improved. Moreover, the transparency 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 from the viewpoint of the breaking limit of the film, it is preferably 10 times or less.

When a film is subjected to electron beam irradiation, the crosslinking density of 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. Note that 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 be made of polyethylene on only one side whose crosslinking density has been improved by electron beam irradiation, as shown in FIG. As shown in FIG. 2, the polyolefin may have an improved crosslinking density throughout.
By crosslinking only the polyethylene on one side by electron beam irradiation, the strength and heat resistance of that side can be improved, and the heat sealability of the other side is maintained, so packaging can be achieved using only the film of the present invention. Bags can be made.

When the film has a multilayer structure, it is sufficient that the crosslinking density of the polyethylene in the outermost layer has been improved by at least electron beam irradiation.
From the viewpoint of strength and heat resistance, it is preferable that the overall crosslinking density of the polyethylene is improved by electron beam irradiation.

The reason why the crosslinking density of polyethylene differs depending on the presence or absence of electron beam irradiation is not clear, but it is thought to be as follows. That is, when polyethylene is irradiated with an electron beam, molecular chains of carbon-hydrogen bonds in the polyethylene near the film surface are cut, and radicals are generated at the ends of the cut bond-terminated molecular chains. It is thought that the generated radicals come into contact with other polyethylene molecular chains due to the molecular movement 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 typically tend to shrink when heated, but higher crosslink density tends to improve dimensional stability. Therefore, if a polyethylene film has different crosslink densities on the front and back sides, it will curl like a bimetal when heated. Therefore, a simple way to confirm that the crosslink density is different on the front and back sides of a polyethylene film is to heat the obtained polyethylene film.

Conventionally known devices can be used to irradiate the film with electron beams, such as curtain type electron irradiation device (LB1023, manufactured by I-Electron Beam Co., Ltd.), line irradiation type low energy electron beam An irradiation device (EB-ENGINE, manufactured by Hamamatsu Photonics Co., Ltd.), a drum roll type electron beam irradiation device (EZ-CURE, manufactured by I-Electron Beam Co., Ltd.), and the like can be suitably used.

The dose of the electron beam irradiated to the film is preferably in the range of 10 kGy or more and 2000 kGy or less, more preferably 20 kGy or more and 1000 kGy or less, and more preferably 150 kGy or more and 500 kGy or less.
Further, the accelerating 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.
Further, the irradiation energy of the electron beam is preferably in the range of 20 keV or more and 750 keV or less, more preferably in the range of 25 keV or more and 500 keV or less, even more preferably in the range of 30 keV or more and 400 keV or less, and even more preferably in the range of 20 keV or more and 200 keV or less. The following ranges are particularly preferred.

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

In one embodiment, electron beam irradiation can be performed simultaneously with cooling, such as using a cooling drum.

Further, the film may be subjected to surface treatment. Thereby, adhesion between adjacent layers can be improved.
The surface treatment method is not particularly limited, and includes physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and/or nitrogen gas, glow discharge treatment, and oxidation using chemicals. Examples include chemical treatments such as treatment.
Alternatively, an anchor coat layer may be formed on the surface of the film using a conventionally known anchor coat agent.

The film may have a printing layer on its surface, and the images formed on the printing layer are not particularly limited, and may include characters, patterns, symbols, and combinations thereof.
From the viewpoint of environmental impact, it is preferable that the printing layer is formed on the film using biomass-derived ink.
The method for forming the printed layer is not particularly limited, and conventionally known printing methods such as gravure printing, offset printing, and flexographic printing can be used. Among these, flexographic printing is preferred from the viewpoint of environmental impact.

The thickness of the film is preferably 10 μm or more and 50 μm or less, more preferably 15 μm or more and 30 μm or less.
By setting the thickness of the film to 10 μm or more, its strength and heat resistance can be further improved. Furthermore, when an image is formed on a film, the visibility of the image can be further improved. Moreover, the contents filled in the packaging bag produced using the film of the present invention can be further hidden. Furthermore, the light-shielding properties of the film can be further improved.
Moreover, by setting the thickness of the film to 50 μm or less, its processing suitability can be improved.

In one embodiment, the film may include a deposited film on its surface. Thereby, gas barrier properties, specifically oxygen barrier properties and water vapor barrier properties, can be improved.

The vapor-deposited film is 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. can be mentioned.

Further, the thickness of the deposited 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 setting the thickness of the deposited film to 1 nm or more, the oxygen barrier properties and water vapor barrier properties of the film can be further improved. Furthermore, by setting the thickness of the deposited film to 150 nm or less, it is possible to prevent the occurrence of cracks in the deposited film. Moreover, recyclability can be maintained when a laminate is formed as described below.

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

In one embodiment, the barrier coat layer comprises polyamides, polyesters, such as ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol, polyacrylonitrile, nylon 6, nylon 6,6, and polymethaxylylene adipamide (MXD6), Contains gas barrier resins such as polyurethane and (meth)acrylic resins. Among these, polyvinyl alcohol is preferred from the viewpoint of oxygen barrier properties and water vapor barrier properties.
Further, when the vapor deposited film is composed of an inorganic oxide, the occurrence of cracks in the vapor deposited film can be effectively prevented by containing 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, more preferably 75% by mass or more and 90% by mass or less. By setting the content of the gas barrier resin in the barrier coat layer to 50% by mass or more, the oxygen barrier properties and water vapor barrier properties of the film can be further improved.

The barrier coat layer can contain the above-mentioned additives within a range that does not impair the characteristics of the present invention.

The thickness of the barrier coat layer is preferably 0.01 μm or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less.
By setting the thickness of the barrier coat layer to 0.01 μm or more, oxygen barrier properties and water vapor barrier properties can be further improved. By setting the thickness of the barrier coat layer to 10 μm or less, it is possible to maintain recyclability when forming a laminate as described below.

The barrier coat layer can be formed by dissolving or dispersing the above material in water or an appropriate solvent, applying the solution, and drying the solution. The barrier coat layer can also be formed by applying and drying a commercially available barrier coat agent.

In another embodiment, the barrier coat layer is 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 method catalyst, water, an organic solvent, etc. It is a gas barrier coating film containing at least one resin composition such as a hydrolyzate of or a hydrolyzed condensate of a metal alkoxide.
When the film includes a deposited film made of an inorganic oxide, by providing a barrier coat layer of this type adjacent to the deposited film, it is possible to effectively prevent the occurrence of cracks in the deposited film. .

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

As the metal atom M, silicon, zirconium, titanium, aluminum, etc. can be used, for example.
Examples of the organic group represented by R ¹ and R ² include alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, and i-butyl group. I can do it.

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

Moreover, it is preferable that a silane coupling agent is used together with the metal alkoxide.
As the silane coupling agent, known organoalkoxysilanes containing organic reactive groups can be used, but organoalkoxysilanes containing epoxy groups are particularly preferred. Examples of the organoalkoxysilane having an epoxy group include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. It will be done.

Two or more types of silane coupling agents as described above may be used, and the silane coupling agents are used in an amount of about 1 to 20 parts by mass based on 100 parts by mass of the total amount of the alkoxides. It is preferable.

As the water-soluble polymer, polyvinyl alcohol and ethylene-vinyl alcohol copolymer 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 based on 100 parts by mass of the metal alkoxide.
By setting the content of water-soluble polymer in the gas barrier coating film to 5 parts by mass or more based on 100 parts by mass of metal alkoxide, oxygen barrier properties and water vapor barrier properties can be further improved. Further, by controlling the content of the water-soluble polymer in the gas barrier coating film to 500 parts by mass or less based on 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 0.01 μm or more and 100 μm or less, more preferably 0.1 μm or more and 50 μm or less.
By setting the thickness of the gas barrier coating film to 0.01 μm or more, oxygen barrier properties and water vapor barrier properties can be improved. Moreover, when it is provided adjacent to a deposited film made of an inorganic oxide, it is possible to prevent cracks from occurring in the deposited film. Further, by setting the thickness of the gas barrier coating film to 100 μm or less, recyclability can be maintained when forming a laminate as described below.

The gas barrier coating film is prepared by applying a composition containing the above-mentioned materials by conventionally known means such as roll coating with a gravure roll coater, spray coating, spin coating, dipping, brush, barcode, applicator, etc. It can be formed by polycondensing products by a sol-gel method.
As the sol-gel method catalyst, acid or amine compounds are suitable. As the amine compound, tertiary amines that are substantially insoluble in water and soluble in organic solvents are suitable, such as N,N-dimethylbenzylamine, tripropylamine, tributylamine, tripentyl Examples include amines. Among these, N,N-dimethylbenzylamine is preferred.
The sol-gel method catalyst is preferably used in a range of 0.01 parts by mass or more and 1.0 parts by mass or less, and 0.03 parts by mass or more and 0.3 parts by mass or less, per 100 parts by mass of metal alkoxide. It is more preferable.
By setting the amount of the sol-gel method catalyst to be 0.01 parts by mass or more per 100 parts by mass of metal alkoxide, the catalytic effect can be improved. Further, by controlling the amount of the sol-gel method catalyst to be 1.0 parts 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. Acids are used as catalysts in the sol-gel process, mainly for the hydrolysis of alkoxides, silane coupling agents, and the like.
As the acid, mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as acetic acid and tartaric acid are used. The amount of 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 (for example, silicate portion) of the silane coupling agent.
The catalytic effect can be improved by setting the amount of the acid used to be 0.001 mol or more based on the total molar amount of the alkoxide and the alkoxide portion (eg, silicate portion) of the silane coupling agent. In addition, by setting the total molar amount of the alkoxide and the alkoxide component (for example, silicate portion) of the silane coupling agent to 0.05 mole or less, the thickness of the gas barrier coating film formed can be made uniform. can.

Further, the above composition may contain water in a proportion of preferably 0.1 mol or more and 100 mols or less, more preferably 0.8 mol or more and 2 mols or less, per 1 mol of the total molar amount of the alkoxide. preferable.
By setting the water content to 0.1 mol or more per 1 mol of the total molar amount of alkoxide, oxygen barrier properties and water vapor barrier properties can be improved. Furthermore, by setting the water content to 100 mol or more per 1 mol of the total molar amount of alkoxide, the hydrolysis reaction can be carried out quickly.

Further, the above composition may contain an organic solvent. As the organic solvent, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol, etc. can be used.

An embodiment of a method for forming a gas barrier coating film will be described below.
First, a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and if necessary a silane coupling agent are mixed to prepare a composition. A polycondensation reaction gradually proceeds in the composition.
Next, the composition is applied onto the film by the conventionally known method described above and dried. By this drying, the polycondensation reaction of the alkoxide and the water-soluble polymer (and the silane coupling agent if the composition includes the silane coupling agent) further proceeds, and a composite polymer layer is formed.
Finally, a gas barrier coating film can be formed by heating the composition at a temperature of 20 to 250°C, preferably 50 to 220°C, for 1 second to 10 minutes.

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 using a T-die method, an inflation method, or the like, and then stretching and/or irradiating the film with an electron beam.
By forming the film by the inflation method, the stretching process can be performed simultaneously.
When stretching and electron beam irradiation are performed together, either may be performed first, but it is preferable to perform stretching first for the reason of suitability for stretching processing.

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

When producing a film by the inflation method, the MFR of the resin composition is preferably 0.5 g/10 minutes or more and 5 g/10 minutes or less.
By setting the MFR of the resin composition to 0.5 g/10 minutes or more, the processability of the film can be improved. Further, by controlling the MFR of the resin composition to 5 g/10 minutes or less, film formability can be improved.

Formation of a vapor deposition film on a film can be performed using a conventionally known method, for example, a physical vapor deposition method (PVD method) such as a vacuum evaporation method, a sputtering method, an ion plating method, etc. ), as well as chemical vapor deposition methods (CVD methods) such as plasma chemical vapor deposition methods, thermal chemical vapor deposition methods, and photochemical vapor deposition methods.

Furthermore, for example, a composite film consisting of two or more layers of vapor-deposited films of different types of inorganic oxides can be formed and used by using both physical vapor deposition and chemical vapor deposition. The degree of vacuum in the deposition chamber is preferably about 10 ^-2 to 10 ^-8 mbar before introducing oxygen, and preferably about 10 ^-1 to 10 ^-6 mbar after introducing oxygen. Note that 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 within a range that does not cause any problem. The transport speed of the film can be approximately 10 to 800 m/min.

The surface of the deposited film is preferably subjected to the above surface treatment. Thereby, adhesion between adjacent layers can be improved.

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

The shape of the packaging bag 20 is not particularly limited, and as shown in FIG. 3, it may be a stand pouch having a bag-like shape.
In one embodiment, the packaging bag 30 of the present invention has a dispensing nozzle part 31 as shown in FIG. It may be a stand-up pouch.
Further, from the viewpoint of ease of opening, the packaging bag 30 may include a curved portion 32 curved inward as shown in FIG. 4.
Furthermore, a cutout portion 33 formed by a laser beam or the like may be provided.

In one embodiment, the packaging bag 40 of the present invention may be a stand-up pouch including a spout 42 interposed by an upper edge seal portion 41, as shown in FIG. Further, a lid plug 43 is screwed onto the upper end of the spout 42.

Note that in FIGS. 3 to 5, the shaded area represents the heat-sealed area. Further, in FIGS. 3 to 5, a stand pouch is illustrated as an example of the packaging bag, but the present invention is not limited to this.

In one embodiment, the packaging bag can be manufactured by folding the film of the present invention in two and stacking them on top of each other so that the non-electron beam irradiation side faces inside, and then heat-sealing the ends.
In another embodiment, the packaging bag can also be manufactured by stacking two films such that their non-irradiated surfaces face each other and heat-sealing the ends.

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

In one embodiment, the packaging bag is formed by stacking two of the above-mentioned films so that the non-electron beam irradiation surfaces face each other, heat-sealing one side to form the bottom, and then placing two more films together. The body can be manufactured by folding the laminate into a V-shape so that the non-electron beam irradiation surface faces outward, sandwiching the facing films from both ends, and heat sealing. .

The method of heat sealing is not particularly limited, and for example, known methods such as bar sealing, rotating roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing can be used.

The contents filled in the packaging bag are not particularly limited, and the contents may be liquid, powder, or gel. Moreover, it may be food or non-food.
According to the packaging bag of the present invention, even if the contents are colored detergents or the like, the bag can be suitably filled because it does not affect the image formed on the base material.

(laminate)
As shown in FIG. 6, the laminate 50 of the present invention includes the film 10 and a sealant layer 51 as base materials.
In addition, when only one surface of the film 10 is subjected to electron beam irradiation treatment, the base material is provided so that the electron beam irradiated surface of the film 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, thereby improving the recyclability of the laminate.

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

(Sealant layer)
In one embodiment, the sealant layer is characterized in that it is composed of the same material as the film (substrate), namely polyethylene or polypropylene. Thereby, the recyclability of the laminate can be improved.

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

Moreover, in order to improve the hand-tearability of the packaging bag produced using the laminate of the present invention, it is preferable that the sealant layer contains low-density polyethylene.
Further, in order to improve the drop strength of the packaging bag produced using the laminate of the present invention, the sealant layer preferably contains linear low-density polyethylene. Linear low density polyethylenes 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 improved drop strength, C-6LLDPE is preferred.
Preferably, the sealant layer includes both C-4LLDPE and C-6LLDPE.

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

In one embodiment, the sealant layer comprises polyethylene or polypropylene derived from the biomass described above.

When the sealant layer contains biomass-derived polyethylene or polypropylene, the content thereof is preferably 5% by mass or more and 100% by mass or less, and more preferably 10% by mass or more and 70% by mass or less.

The sealant layer can also include mechanically recycled polyethylene, polypropylene, and the like.

In one embodiment, the sealant layer includes the white pigment described above.
The content of the white pigment in the sealant layer is preferably 2% by mass or more and 15% by mass or less, more preferably 4% by mass or more and 10% by mass or less.
By setting the content of the white pigment in the sealant layer to 2% by mass or more, when an image is formed on a film (substrate), the visibility of the image can be further improved. Moreover, the contents filled in the packaging bag produced using the laminate of the present invention can be further hidden. Moreover, the light-shielding properties of the laminate can be further improved.
Further, by controlling 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 suppresses an increase in cost.

The sealant layer can contain the above-mentioned additives within a range that does not impair the characteristics of the present invention.

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

In one embodiment, the intermediate sealant layer included in the multilayer sealant layer includes at least one of medium density polyethylene and high density polyethylene. Thereby, the strength of the laminate of the present invention can be further improved.
Specific examples of a layer containing at least one of medium-density polyethylene and high-density polyethylene as the intermediate layer include a layer containing at least one of low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene; Examples include a configuration including a layer containing at least one of 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.
It can be configured as follows.
With the above configuration, the bag-making suitability and strength of the laminate of the present invention can be further improved while maintaining heat-sealability.

The thickness of the sealant layer is preferably 40 μm or more and 180 μm or less, more preferably 80 μm or more and 150 μm or less. Thereby, the heat sealability of the laminate of the present invention can be further improved. Furthermore, when the sealant layer contains a white pigment, the visibility of the image formed on the film (substrate) can be further improved. Moreover, the contents filled in the packaging bag produced using the laminate of the present invention can be further hidden. Moreover, the light-shielding properties of the laminate can be further improved.

(adhesive layer)
The adhesive layer may be formed using a conventionally known adhesive. The adhesive may be a one-component curing type, a two-component curing type, or a non-curing type adhesive.
Further, the adhesive may be a solvent-free adhesive or a solvent-based adhesive, but from the viewpoint of environmental load, a solvent-free adhesive can be preferably used.
Examples of solvent-free adhesives include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, two-component curable urethane adhesives adhesives can be preferably used.
Examples of solvent-based adhesives include rubber adhesives, vinyl adhesives, silicone adhesives, epoxy adhesives, phenolic adhesives, and olefin adhesives.

Further, preferably, the adhesive layer is formed of an adhesive using a raw material derived from biomass. Thereby, the environmental load of the packaging bag produced using the laminate of the present invention can be more effectively reduced.
Examples of such adhesives include Adlock RU-80 manufactured by Rock Paint, ECOAD manufactured by Toyo Ink Co., Ltd., and HA-233B-EM manufactured by DIC Graphics Corporation.

Further, 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 a laminate including a vapor-deposited film is formed into a packaging bag, a bending load is applied to the laminate by a molding machine or the like, which may cause cracks or the like to occur in the aluminum-deposited film. By configuring the adhesive layer as described above, it is possible to prevent the occurrence of cracks in the aluminum vapor-deposited film, and even if cracks occur, it is possible to suppress the deterioration of oxygen barrier properties and water vapor barrier properties ( bending load resistance).

Polyester polyol has two or more hydroxyl groups in one molecule as a functional group. Further, the isocyanate compound has two or more isocyanate groups in one molecule as a functional group. A polyester polyol has, for example, a polyester structure or a polyester polyurethane structure as a main skeleton.

As a specific example of the resin composition (adhesive) containing a polyester polyol and an isocyanate compound, the PASLIM series sold by DIC Corporation can be used.

The resin composition may further contain a plate-like inorganic compound, a coupling agent, a cyclodextrin and/or a derivative thereof, and the like.

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

The polyester polyol according to the first example is selected from the group consisting of a polyhydric carboxylic acid component containing at least one orthophthalic acid and its anhydride, and ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol. It is a polycondensate obtained by polycondensation with a polyhydric alcohol component containing at least one type of alcohol.
Particularly preferred is a polyester polyol in which the content of orthophthalic acid and its anhydride is 70 to 100% by mass based on the total polyhydric carboxylic acid components.

The polyester polyol according to the first example essentially contains orthophthalic acid and its anhydride as a polycarboxylic acid component, but other polycarboxylic acid components may be copolymerized to the extent that the effects of this embodiment are not impaired. It's okay.
Specifically, aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid, unsaturated bond-containing polycarboxylic acids such as maleic anhydride, maleic acid and fumaric acid, 1, Alicyclic polycarboxylic acids such as 3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5- Naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, anhydrides of these dicarboxylic acids, and ester formation of these dicarboxylic acids Examples include aromatic polycarboxylic acids such as dihydroxy derivatives, polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these dihydroxycarboxylic acids. Among these, succinic acid, 1,3-cyclopentanedicarboxylic acid, and isophthalic acid are preferred.
Note that two or more types of the other polyhydric carboxylic acids mentioned above may be used.

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

In formula (2), n represents an integer of 1 to 5, and X is a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, 2, represents an arylene group selected from the group consisting of a 3-anthraquinonediyl group and a 2,3-anthracenediyl group, 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 general formula (2).

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

Further, a compound in which any one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (2), and a compound in which any two of R ₁ , R ₂ , and R ₃ are represented by general formula (2) A mixture of two or more of a compound in which R ₁ , R ₂ , and R ₃ are all groups represented by general formula (2) may be used.

X is selected from the group consisting of 1,2-phenylene group, 1,2-naphthylene group, 2,3-naphthylene group, 2,3-anthraquinonediyl group and 2,3-anthracenediyl group, and has a substituent. represents an optionally substituted arylene 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 radical. Examples of the substituent 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, Examples include phthalimide group, carboxyl group, carbamoyl group, N-ethylcarbamoyl group, phenyl group, and naphthyl group.

In general formula (2), Y is 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. and alkylene groups having 2 to 6 carbon atoms, such as dimethylbutylene groups. Among them, Y is preferably a propylene group or an ethylene group, and most preferably an ethylene group.

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

Examples of the aromatic polycarboxylic acid or its anhydride in which carboxylic acid is substituted at the ortho position include orthophthalic acid or its anhydride, naphthalene 2,3-dicarboxylic acid or its anhydride, and naphthalene 1,2-dicarboxylic acid or its anhydride. Examples include anhydride, anthraquinone 2,3-dicarboxylic acid or its anhydride, and 2,3-anthracenecarboxylic acid or its anhydride.
These compounds may have a substituent on any carbon atom of the aromatic ring. Examples of the substituent 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, Examples include phthalimide group, carboxyl group, carbamoyl group, N-ethylcarbamoyl group, phenyl group, and naphthyl group.

Further, examples of the polyhydric alcohol component include alkylene diols having 2 to 6 carbon atoms. For example, diols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol and dimethylbutanediol can be exemplified.

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

In the general formula (4), n2 represents an integer of 2 to 4, n3 represents an integer of 1 to 5, and X is a 1,2-phenylene group, a 1,2-naphthylene group, a 2,3-naphthylene group, An arylene group selected from the group consisting of 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) represents a group represented by However, at least one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (4).

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

In the general formula (4), n2 represents an integer of 2 to 4, and n3 represents an integer of 1 to 5.
X is selected from the group consisting of 1,2-phenylene group, 1,2-naphthylene group, 2,3-naphthylene group, 2,3-anthraquinonediyl group, and 2,3-anthracenediyl group, and has a substituent. represents an optionally substituted arylene 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 radical. Examples of the substituent 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, Examples include phthalimide group, carboxyl group, carbamoyl group, N-ethylcarbamoyl group, phenyl group, and naphthyl group.
Among the substituents of Most preferred is phenyl.

In general formula (4), Y is 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. and alkylene groups having 2 to 6 carbon atoms, such as dimethylbutylene groups. Among them, Y is preferably a propylene group or an ethylene group, and most preferably an ethylene group.

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

Further, a compound in which any one of R ₁ , R ₂ , and R ₃ is a group represented by general formula (4), and a compound in which any two of R ₁ , R ₂ , and R ₃ are represented by general formula (4) A mixture of two or more of a compound in which R ₁ , R ₂ , and R ₃ are all groups represented by general formula (4) may be used.

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

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 include.

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

Examples of the substituent 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, Examples include phthalimide group, carboxyl group, carbamoyl group, N-ethylcarbamoyl group, phenyl group, and naphthyl group.

Further, examples of the polyhydric alcohol component include alkylene diols having 2 to 6 carbon atoms. For example, diols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol and dimethylbutanediol can be mentioned.
Among these, 1,3,5-tris(2-hydroxyethyl)isocyanuric acid or 1,3,5-tris(2-hydroxypropyl)isocyanuric acid is used as a triol compound having an isocyanuric ring, and the carboxylic acid is in the ortho position. A polyester polyol compound having an isocyanuric ring using an aromatic polycarboxylic acid substituted with orthophthalic anhydride as its anhydride and ethylene glycol as a polyhydric alcohol has particularly excellent oxygen barrier properties and adhesive properties. preferable.

The isocyanuric ring is highly polar and trifunctional, and can increase the polarity of the entire system and the crosslink density. From this point of view, it is preferable that the isocyanuric ring is contained in an amount of 5% by mass or more based on the total solid content of the adhesive resin.

The isocyanate compound has two or more isocyanate groups in the molecule.
Further, the isocyanate compound may be aromatic or aliphatic, and may be a low molecular compound or a high molecular compound.
Furthermore, the isocyanate compound may be a blocked isocyanate compound obtained by addition reaction using a known isocyanate blocking agent by a known and commonly used method.
Among these, from the viewpoint of adhesiveness and retort resistance, polyisocyanate compounds having three or more isocyanate groups are preferred, and from the viewpoint of oxygen barrier properties and water vapor barrier properties, aromatic compounds are preferred.

Specific isocyanate compounds include, for example, tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, metaxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and these isocyanate compounds. and adducts, burettes, and allophanates obtained by reacting these isocyanate compounds with low-molecular active hydrogen compounds or their alkylene oxide adducts, or high-molecular active hydrogen compounds.
Examples of low-molecular active hydrogen compounds include ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, Examples of the molecularly active hydrogen compounds include ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, metaxylylenediamine, and the like, and examples of molecularly active hydrogen compounds include polymeric active hydrogen compounds of 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, such as a compound represented by the following general formula (5) or (6).
In the general formula (5), R ₁ , R ₂ , and R ₃ are a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a (meth)acryloyl group, a phenyl group that may have a substituent, and (meth)acryloyl The group is selected from alkyl groups having 1 to 4 carbon atoms and having an oxy group, at least one of which is a hydrogen atom, and n represents an integer of 1 to 4.
In the formula, R ₄ and R ₅ are 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 a (meth)acryloyloxy group having 1 carbon number. A group selected from ~4 alkyl groups, where n is an integer of 1 to 4, x is an integer of 0 to 30, and y is an integer of 0 to 30, except when x and y are both 0. .

More specifically, 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, butoxy Examples include ethyl 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 0.005% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 1% by mass or less.
By setting the content of the phosphoric acid modified compound to 0.005% by mass or more, the oxygen barrier properties and water vapor barrier properties of the laminate of the present invention can be improved. Further, by controlling 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 a polyester polyol, an isocyanate compound, and a phosphoric acid-modified compound may also contain a plate-like inorganic compound, which can improve the adhesiveness of the adhesive layer. Moreover, the bending load resistance of the laminate of the present invention can be improved.
Examples of platy inorganic compounds include kaolinite-serpentinite clay minerals (halloysite, kaolinite, endellite, dickite, nacrite, antigorite, chrysotile, etc.) and pyrophyllite-talc group (pyrophyllite, talc, Kerolai, etc.).

Examples of the coupling agent include a silane coupling agent represented by the following general formula (7), a titanium coupling agent, and an aluminum coupling agent. Note that these coupling agents may be used alone or in combination of two or more.

Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. - Glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxytrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxy Propylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, ethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyl Examples include trimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane 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(dioctylpyrophosphate) titanate, and tetraoctyl bis (didodecyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyltrioctaynortitanate, isopropyl dimethacrylic isostearoyl titanate , isopropyl isostearoyl diacryl titanate, diisostearoyl ethylene titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and dicumylphenyloxyacetate titanate.

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

The resin composition can contain cyclodextrin and/or a derivative thereof, thereby improving the adhesiveness of the adhesive layer. Moreover, the bending load resistance of the laminate of the present invention can be further improved.
Specifically, for example, cyclodextrins such as cyclodextrins, alkylated cyclodextrins, acetylated cyclodextrins, and hydroxyalkylated cyclodextrins in which the hydrogen atoms of the hydroxyl groups of the glucose units of cyclodextrins are replaced with other functional groups may be used. I can do it. Branched cyclic dextrins can also be used.
In addition, the cyclodextrin skeleton in cyclodextrin and cyclodextrin derivatives includes α-cyclodextrin consisting of 6 glucose units, β-cyclodextrin consisting of 7 glucose units, and γ-cyclodextrin consisting of 8 glucose units. It may be either.
These compounds may be used alone or in combination of two or more. Further, these cyclodextrins and/or their derivatives may be hereinafter 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 the alkylated cyclodextrin 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 the acetylated cyclodextrin 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 the hydroxyalkylated cyclodextrin include hydroxypropyl-α-cyclodextrin, hydroxypropyl-β-cyclodextrin, and hydroxypropyl-γ-cyclodextrin. These compounds may be used alone or in combination of two or more.

To the extent that the characteristics of the present invention are not impaired, the adhesive layer may contain pigments such as titanium oxide, zinc white and carbon black, dyes such as disperse dyes, acid dyes and cationic dyes, antioxidants, lubricants, colorants, stabilizers, etc. Additives such as agents, wetting agents, thickeners, coagulants, gelling agents, antisettling agents, softeners, hardeners, plasticizers, leveling agents, UV absorbers, and flame retardants may be included.

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 includes a layer made of polyethylene or polypropylene as an intermediate layer.

Moreover, in one embodiment, the intermediate layer may contain the above-mentioned white pigment.
The content of the white pigment in the intermediate layer is preferably 2% by mass or more and 15% by mass or less, more preferably 4% by mass or more and 10% by mass or less.
By setting the content of the white pigment in the intermediate layer to 2% by mass or more, when an image is formed on a film (substrate), the visibility of the image can be further improved. Moreover, the contents filled in the packaging bag produced using the laminate of the present invention can be further hidden. Moreover, the light-shielding properties of the laminate can be further improved.
Further, by controlling 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 suppresses an increase in cost.

The intermediate layer may be constituted by a stretched film, and may be a uniaxially stretched film or a biaxially stretched film, and the preferred stretching ratio is as described above.
Further, the intermediate layer may 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, more preferably 15 μm or more and 50 μm or less.
When the intermediate layer contains a white pigment, the visibility of the image formed on the base material can be further improved. Moreover, the contents filled in the packaging bag produced using the laminate of the present invention can be further hidden. Moreover, the light-shielding properties of the laminate can be further improved.

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

Moreover, 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 1% by mass or more and 10% by mass or less, more preferably 2% by mass or more and 8% by mass or less.
By setting the content of the white pigment in the gas barrier layer to 1% by mass or more, when an image is formed on a film (substrate), the visibility of the image can be further improved. Moreover, the contents filled in the packaging bag produced using the laminate of the present invention can be further hidden. Moreover, the light-shielding properties of the laminate can be further improved.
Further, by controlling the content of the white pigment in the gas barrier layer to 10% by mass or less, the whiteness of the gas barrier layer can be improved while maintaining gas barrier properties.

The thickness of the gas barrier layer is preferably 0.01 μm or more and 10 μm or less, 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 properties and water vapor barrier properties of the laminate of the present invention can be further improved. 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.
Furthermore, when the intermediate layer contains a white pigment, the visibility of the image formed on the film (substrate) can be further improved. Moreover, the contents filled in the packaging bag produced using the laminate of the present invention can be further hidden. Moreover, the light-shielding properties of the laminate can be further improved.

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

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

(packaging bag)
The packaging bag of the present invention is characterized in that it is composed of the above-mentioned laminate.
The shape of the packaging bag is not particularly limited, and may be as shown in FIGS. 3 to 5.

In one embodiment, a packaging bag can be manufactured by folding the laminate of the present invention in half and stacking them on top of each other so that the sealant layer is on the inside, and heat-sealing the ends.
In other embodiments, the packaging bag can also be manufactured by stacking two laminates so that the sealant layers face each other and heat sealing the ends.

In one embodiment, the packaging bag is made by stacking two of the above laminates so that the sealant layers face each other, heat-sealing the two sides to form the body, and then adding another layer. The bottom part can be formed and manufactured by folding the laminate into a V-shape with the sealant layer on the outside, sandwiching it from one end of the body, and heat-sealing it.

In one embodiment, the packaging bag is formed by stacking two of the above laminates so that the sealant layers face each other and heat-sealing one side to form the bottom, and then stacking two more laminates. The body can be manufactured by folding the body into a V-shape so that the sealant layer is on the outside, sandwiching the body from both ends of the facing laminate, and heat-sealing the body.

The method of heat sealing is not particularly limited, and for example, known methods such as bar sealing, rotating roll sealing, belt sealing, impulse sealing, high frequency sealing, and ultrasonic sealing can be used.

The contents filled in the packaging bag are not particularly limited, and the contents may be liquid, powder, or gel. Moreover, it may be food or non-food.
According to the packaging bag of the present invention, even if the contents are colored detergents or the like, the bag can be suitably filled because it does not affect the image formed on the base material.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Example 1
A resin composition containing biomass-derived low-density polyethylene (LLDPE, density 0.937 g/m ³ , biomass degree 16%) and titanium oxide was formed into a film using an inflation extruder to obtain a polyethylene film with a thickness of 25 μm. Ta. The content of titanium oxide was adjusted to 4% by mass.
One side of this polyethylene film was irradiated with an electron beam using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics Co., Ltd.) under the following conditions. conditions)
Voltage: 70kV
Irradiation dose: 280kGy
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 a film of the present invention.

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

A two-component curable polyester adhesive was applied at 3.5 g/ ^m2 onto the image forming surface of the film produced as described above, and dry laminated with an 80 μm thick unstretched LLDPE film to form the laminate of the present invention. I got it.

Example 3
A film of the present invention was produced in the same manner as in Example 2.

60.5 parts by mass of C6LLDPE (density: 0.919 g/m ³ , MFR: 2.3 g/10 min),
18.5 parts by mass of biomass-derived polyethylene (density: 0.916 g/m ³ , MFR: 1.0 g/10 min),
20.0 parts by mass of LDPE (density: 0.919 g/m ³ , MFR: 2.0 g/10 min),
1.0 parts by mass of an LDPE-based additive (density: 0.921 g/m ³ , MFR: 5.4 g/10 min) was mixed to form a resin composition, which was then processed using an inflation extruder to reduce the thickness. An unstretched film for a sealant layer having a diameter of 80 μm, a density of 0.918 g/m ³ , and a biomass degree of 16.0% was produced.

The image forming surface of the film and the unstretched film for the sealant layer were bonded using an aromatic polyester polyurethane adhesive (manufactured by Rock Paint Co., Ltd., main agent RU-80, which uses biomass-derived sepacic acid as a part of the main agent). A laminate of the present invention was obtained by laminating using a curing agent H-5 (mixing ratio 15:1).

Comparative example 1
A film was produced in the same manner as in Example 1, except that the electron beam irradiation treatment was not performed.

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

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 produced 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 to hide the contents.

<<Contents concealment test>>
The films produced in Example 1 and Comparative Example 1 were cut into a size of 220 mm long x 130 mm wide.
Two films cut as described above were stacked so that the non-electron beam irradiated surfaces (the film in Comparative Example 1 could be either surface) faced each other. The produced film was folded into a V-shape so that the non-electron beam irradiation surface was on the outside, and the film was sandwiched between the two.
Next, the two vertical sides and the side between which the V-shaped laminate was sandwiched were heat-sealed. Note that the heat sealing temperature was 155°C.
The film of Comparative Example 1 did not have sufficient heat resistance and could not be heat sealed.

The laminates produced in Examples 2 to 3 and Comparative Examples 2 to 4 above were cut into a size of 220 mm long x 130 mm wide.
The two laminates cut as described above are stacked one on top of the other with the sealant layers facing each other, and from one end of the body, the laminates produced in the above Examples and Comparative Examples are placed in a V shape so that the sealant layer is on the outside. I inserted something folded into a letter shape.
Next, the two vertical sides and the side between which the V-shaped laminate was sandwiched were heat-sealed. Note that the heat sealing temperature was 155°C.
In the laminate of Comparative Example 2, the film (base material) did not have sufficient heat resistance and could not be heat sealed.

Next, a carbon dioxide laser (manufactured by Keyence, 3Axis-CO2 Laser Marker ML-Z9520A, output 70%, printing speed 1000 mm/min) is irradiated to form a cutout, and punched out to form a pouring nozzle as shown in Figure 4. A stand-up pouch-like packaging bag having a curved portion and an opening was produced.
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 produced 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 confirmed, and high content hiding property was confirmed.
NG: The color of the contents was confirmed, and the color of the image formed on the base material was affected.

<<Laminate strength test>>
Packaging bags produced using the laminates produced in Examples 2 to 3 and Comparative Examples 2 to 4 above were cut into a width of 15 mm in the film flow direction to obtain test pieces. The film (base material) on this test side is peeled off at the interface between the sealant layer, this peeling is stopped midway, and both ends of the partially peeled test piece are pulled up and down at a test speed of 300 mm/min, and the stress at that time is The laminate strength was evaluated by measuring. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: There was no cohesive failure of the white ink layer, and it peeled off with constant strength.
NG: Peeling of the white ink layer due to cohesive failure was confirmed.

<<Hand tearability test>>
The packaging bag obtained in the content concealment test was 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: I was able to open the package without applying much force.
NG: It was necessary to apply strong force, and there were practical problems such as stretching and tearing.

<<Drop strength test>>
The packaging bag obtained in the content concealment test was allowed to fall freely onto a hard floor from a height of 100 cm 10 times with the body of the packaging bag parallel to the ground. The test was conducted on 10 bags each, and the presence or absence of damage 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 observed in all 10 bags. NG: Breakage was observed in at least 1 bag out of 10 bags, posing a practical problem.

10: film, 20, 30, 40: packaging bag, 31: nozzle section, 32: curved section, 33: cutout section, 41: upper edge seal section, 42: spout, 43: lid plug, 50: laminate, 51 : Sealant layer, 52: Intermediate layer, 53: Adhesive layer

Claims (5)

A single layer film composed of polyethylene,
Contains white pigment
At least one of stretching treatment and electron beam irradiation treatment is applied,
The content of the white pigment is 2% by mass or more and 20% by mass or less,
A film characterized by containing biomass-derived polyethylene. A packaging bag composed of the film according to claim 1,
The film is subjected to electron beam irradiation treatment on only one side thereof,
A packaging bag characterized by being arranged so that the non-electron beam irradiation side is on the inside. A laminate comprising the film according to claim 1 and a sealant layer,
The sealant layer is made of polyethylene.
A laminate characterized by: The laminate according to claim 3, wherein the sealant layer contains biomass-derived polyethylene or biomass-derived polypropylene. A packaging bag comprising the laminate according to claim 3 or 4.