Sealant film, laminate, packaging material, and packaging bag

Abstract

Provided is a sealant film 1a comprising: a recycled material-containing layer 2 that contains a recycled material containing two or more types of resin; and a sealant layer 3 that is laminated on one principal surface of the recycled material-containing layer, wherein the arithmetic surface roughness of a surface S3a of the sealant layer 3 on the side opposite to the recycled material-containing layer 2 side is 0.5-5 μm.

Description

Sealant films, laminates, packaging materials and packaging bags

[0001] The present invention relates to a sealant film, a laminate, a packaging material, and a packaging bag.

[0002] In general, plastic films have properties such as light weight, chemical stability, ease of processing, flexibility and strength, and the ability to be mass-produced, and are therefore used in a wide variety of applications. Their applications are diverse, including packaging materials for food products, pharmaceuticals, etc., intravenous drip packs, shopping bags, posters, tapes, optical films used in LCD televisions, etc., protective films, window films attached to windows, greenhouses, building materials, etc. Specific materials include thermoplastic resins such as polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polycarbonate, polyamide, polyethylene terephthalate, and polybutylene terephthalate, and thermosetting resins such as epoxy resin, polyurethane, and polyimide.

[0003] Appropriate plastic materials are selected depending on the application, and multiple types of plastic materials are sometimes layered together to form laminates. In addition, multiple plastic materials can be mixed in one layer to compensate for the shortcomings of a single material.

[0004] Recycling plastic products is expected to be a key part of addressing recent environmental issues, and various recycling methods are being considered. For example, PET bottles can be recycled by cleaning and crushing them, and then reused as raw materials, and chemical recycling technology has been established to convert them into monomers.

[0005] Furthermore, as a means of recycling polyethylene materials, the use of recycled polyethylene for applications such as films has been considered. For example, Patent Document 1 below proposes a sealant film containing recycled polyethylene resin.

[0006] International Publication No. 2022 / 124229

[0007] Some recycled materials contain different types of resins. The present inventors have investigated the possibility of recycling such recycled materials as raw materials for sealant films, and have found that a sealant film having a layer containing recycled materials may have reduced reliability during heat sealing.

[0008] On the other hand, film products such as sealant films are required to have the property of being able to be molded without the occurrence of folds or wrinkles from the film formation to the winding up (hereinafter also referred to as "film formability"). If the film has insufficient film formability, the film after winding is likely to have poor appearance due to folds or wrinkles.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a sealant film, a laminate, a packaging material, and a packaging bag that contain recycled materials containing two or more types of resins and have sufficient reliability during heat sealing and film-forming properties.

[0010] In order to solve the above problems, the present inventors have investigated the factors that reduce reliability during heat sealing, and have found that when different types of resins are mixed in a layer containing recycled material, aggregates are formed by resin components other than the resin with the highest content ratio, and when these aggregates cause excessively large protrusions on the surface of the sealant film, air entrapment occurs during heat sealing. Based on this finding, the present inventors have conducted further investigations and found that a sealant film prepared so that the surface roughness of the sealant layer meets specific conditions can solve the above problems, leading to the completion of the present invention.

[0011] One aspect of the present invention relates to the following [1] to

[15] .

[0012] [1] A sealant film comprising a recycled material-containing layer containing recycled materials containing two or more resins, and a sealant layer laminated on one main surface of the recycled material-containing layer, wherein the arithmetic surface roughness of the surface of the sealant layer opposite the recycled material-containing layer is 0.5 μm or more and 5 μm or less. [2] The sealant film according to [1], wherein at least one of the recycled material-containing layer and the sealant layer contains a chemically recycled resin. [3] The sealant film according to [1] or [2], wherein the sealant film contains a biomass-derived polyethylene resin. [4] The sealant film according to any of [1] to [3], wherein the sealant film has been subjected to electron beam irradiation treatment. [5] The sealant film according to any of [1] to [4], wherein the sealant film contains inorganic particles. [6] The sealant film according to any of [1] to [5], wherein the sealant layer has a thickness of 5 μm or more and 70 μm or less. [7] The sealant film according to any one of [1] to [6], wherein the maximum height H of the convex portions on the surface of the sealant layer is 0.5 μm or more and 10 μm or less, and the ratio [W / H] of the width W at half the maximum height H to the maximum height H of the convex portions having the maximum height H is 20 or less. [8] The sealant film according to any one of [1] to [7], wherein the resin with the largest content ratio among the two or more resins contained in the recycled material is a polyethylene-based resin or a polypropylene-based resin. [9] The sealant film according to any one of [1] to [8], further comprising an auxiliary layer laminated on the other main surface of the recycled-material-containing layer.

[10] The sealant film according to [9], wherein the auxiliary layer contains the same type of virgin resin as the resin with the largest content ratio in the recycled-material-containing layer.

[11] A laminate comprising the sealant film according to any one of [1] to

[10] , and a gas barrier layer provided on the surface of the sealant film opposite to the sealant layer side.

[12] A laminate comprising the sealant film according to any one of [1] to

[10] , an adhesive layer, and a base film, in this order.

[13] A packaging material comprising the sealant film according to any one of [1] to

[10] .

[14] The packaging material according to

[13] , wherein the content of plastic material contained in the recycled material is 10 mass% or more based on the total amount of plastic material in the packaging material.

[15] A packaging bag made from the packaging material according to

[13] or

[14] .

[0013] According to the present invention, it is possible to provide a sealant film, a laminate, a packaging material, and a packaging bag that contain recycled materials containing two or more types of resins and that have sufficient reliability during heat sealing and film-forming properties.

[0014] FIG. 1 is a schematic cross-sectional view showing one embodiment of a sealant film according to the present invention. FIG. 2 is a schematic view for explaining the aspect ratio of a low transmittance lightness region. FIG. 3 is a schematic cross-sectional view showing another embodiment of a sealant film according to the present invention. FIG. 4 is a schematic cross-sectional view showing one embodiment of a laminate according to the present invention. FIG. 5 is a schematic cross-sectional view showing another embodiment of a laminate according to the present invention. FIG. 6 is a schematic cross-sectional view showing another embodiment of a laminate according to the present invention. FIG. 7 is a schematic cross-sectional view showing another embodiment of a laminate according to the present invention. FIG. 8 is a schematic cross-sectional view showing one embodiment of a packaging material according to the present invention. FIG. 9 is a schematic cross-sectional view showing another embodiment of a packaging material according to the present invention. FIG. 10 is a schematic cross-sectional view showing another embodiment of a packaging material according to the present invention.

[0015] Hereinafter, embodiments of the present invention will be described in detail. Note that Figures 1 to 10 are schematic views, and the size and shape of each part are appropriately exaggerated for ease of understanding. Furthermore, the embodiments shown below are merely examples of configurations that embody the technical concept of the present invention, and the technical concept of the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims.

[0016] <Sealant Film> The sealant film of the present embodiment includes a recycled material-containing layer containing a recycled material that includes two or more types of resin, and a sealant layer laminated on one main surface of the recycled material-containing layer.

[0017] Fig. 1 is a schematic cross-sectional view showing one embodiment of a sealant film. The sealant film 1a shown in Fig. 1 includes a recycled material-containing layer 2 and a sealant layer 3 laminated on one main surface of the recycled material-containing layer 2.

[0018] In the sealant film of the present embodiment, at least one of the recycled material-containing layer and the sealant layer may contain a chemically recycled resin.

[0019] With growing awareness of the need to prevent global warming and reduce the use of petroleum, a finite resource, efforts are underway to replace conventional petroleum-derived plastic materials with carbon-neutral plant-derived plastic materials. Products that meet the standard of a plant-derived plastic mass ratio of 10% or more are certified with the Biomass Mark by the Japan Organics Recycling Association, and those that meet the standard of 25% or more are certified with the BiomassPla Mark by the Japan Bioplastics Association. To increase the biomass content of plastic-containing products such as packaging materials, there is a demand for sealant films that contain plant-derived plastics.

[0020] The sealant film of the present embodiment may contain a polyethylene resin derived from biomass. Such a sealant film contains a recycled material containing two or more resins, yet has sufficient reliability during heat sealing and film formability, and can also increase the biomass content of plastic-containing products.

[0021] There is also a demand for sealant films to have properties other than sealant properties. For example, blending inorganic particles into a resin film can be expected to impart a hiding function, and such sealant films can contribute to the diversification of packaging materials.

[0022] The sealant film of the present embodiment may contain inorganic particles, the recycled material-containing layer may contain inorganic particles, or an auxiliary layer may further be provided that contains inorganic particles. Such a sealant film contains a recycled material containing two or more resins, yet has sufficient reliability during heat sealing and film formability, and can also be imparted with functionality by the inorganic particles.

[0023] (Recycled Material-Containing Layer) Examples of recycled materials that can be contained in the recycled material-containing layer include post-consumer recycled (PCR) products such as bottles and packaging bags for beverages, detergents, and seasonings that have been collected from the market, food containers for lunch boxes and instant noodles, packaging bags for food and garbage bags, and plastic products such as hangers, stationery, daily necessities, home appliances, and toys; and post-industry recycled (PIR) products such as defective products that cannot be made into products discharged from factories, scraps generated in the process of making products, and plastic products used for transportation and packaging.

[0024] When the recycled material is a material recycled material, the material recycled material may be washed and crushed as necessary. Material recycled material has the advantage that less energy is required for recycling compared to resins obtained by chemical recycling, which involves chemical recycling such as thermal decomposition. Therefore, the greater the proportion of material recycled material in the recycled material-containing layer, the smaller the environmental impact can be.

[0025] In the sealant film of this embodiment, from the viewpoint of material recycling of plastic films, a laminate (packaging material) made by bonding together multiple types of resin sheets, a packaging bag made from such a laminate, a laminate (packaging material) made from the same types of resin sheets, or a packaging bag made from such a laminate, or a mixture of these may be used. Examples of packaging bags include refill pouches for toiletries.

[0026] The recycled material contained in the recycled material-containing layer includes two or more resins. Examples of the two or more resins include thermoplastic resins, thermosetting resins, and cured products thereof (including crosslinked products). The two or more resins also include, for example, resin components constituting adhesives (e.g., thermosetting resins) and their cured products.

[0027] Examples of thermoplastic resins include polyolefin resins, acrylic resins, polycarbonate resins, polyester resins, polyamide resins, etc. Examples of thermosetting resins include epoxy resins, polyurethane resins, polyimide resins, etc.

[0028] Examples of polyolefin resins include polyethylene-based resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and ethylene-α-olefin copolymers, as well as polypropylene-based resins such as homopolypropylene (PP), block polypropylene, random polypropylene, and propylene-α-olefin copolymers.

[0029] Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polylactic acid.

[0030] An example of the polyamide resin is nylon 6.

[0031] The two or more resins may include a first resin that has the largest content in the recycled material and a second resin that is incompatible with the first resin or that can form aggregates in the first resin. The type of resin contained in the recycled material-containing layer can be confirmed using a microscopic infrared spectrophotometer or the like.

[0032] The first resin and the second resin may be any of the following combinations: (a) a thermoplastic resin, a thermosetting resin, and a cured product thereof; (b) a hydrocarbon resin and a heteroatom-containing resin; or (c) a resin that dissolves in a predetermined solvent and a resin that does not dissolve in the predetermined solvent.

[0033] Examples of the hydrocarbon resin in (b) include polyolefin resins and polystyrene resins, and examples of the heteroatom-containing resin include acrylic resins, polyester resins, and polyamide resins.

[0034] Examples of the predetermined solvent in (c) include aromatic hydrocarbons, chlorinated hydrocarbons, etc. Examples of resins that dissolve in the predetermined solvent include uncrosslinked resins, etc. Examples of resins that do not dissolve in the predetermined solvent include crosslinked resins, cured thermosetting resins, etc.

[0035] The first resin having the highest content in the recycled material may be a polyethylene resin or a polypropylene resin from the viewpoint of recycling packaging bags for pouch products, etc. In this case, the second resin may be, for example, at least one of a polyester resin, a polyamide resin, and a resin component constituting an adhesive and its cured product.

[0036] The content of the first resin in the recycled material-containing layer may be 75 to 98 mass %, 75 to 95 mass %, or 80 to 90 mass %, based on the total mass of the recycled material-containing layer.

[0037] The content of the second resin in the recycled material-containing layer may be 2 to 33 parts by mass, 5 to 33 parts by mass, or 11 to 25 parts by mass per 100 parts by mass of the first resin.

[0038] The content of recycled material in the recycled material-containing layer may be 13% by mass or more, 33% by mass or more, 50% by mass or more, or 100% by mass, based on the total mass of the recycled material-containing layer.

[0039] The resin having the highest content in the recycled material-containing layer may be the same as the resin having the highest content in the recycled material, for example, at least one polyethylene resin selected from the group consisting of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0040] The recycled material-containing layer may contain a virgin material such as a virgin resin. The virgin material may be blended so that the resin with the highest content in the recycled material is the same as the resin with the highest content in the recycled material-containing layer. The virgin material may be, for example, the same as the polyolefin resin described above, or may be at least one polyethylene resin selected from the group consisting of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0041] The virgin resin may be a petroleum-derived resin or a biomass-derived resin, but from the viewpoint of increasing the biomass content, a biomass-derived resin is preferred.

[0042] The recycled material-containing layer may contain a polyethylene-based resin derived from biomass. By containing a polyethylene-based resin derived from biomass in the recycled material-containing layer, it is possible to achieve both a high recycling rate and a high biomass content, thereby further reducing the environmental impact.

[0043] Examples of biomass-derived polyethylene resins include homopolymers of plant-derived ethylene derived from bioethanol obtained from plant raw materials, and copolymers of the plant-derived ethylene with other monomers.

[0044] Plant-derived ethylene can be obtained by fermenting sugar liquid or starch obtained from plants such as sugarcane, corn, and sweet potato using microorganisms such as yeast to produce bioethanol, and then heating this in the presence of a catalyst.

[0045] Plant-derived ethylene may be obtained by fermenting sugar solution or starch obtained from non-edible plants such as rice straw, sorghum, thinned wood, waste mushroom beds, and coffee grounds using microorganisms such as yeast to produce bioethanol, which is then heated in the presence of a catalyst. Using non-edible plants as raw materials does not compete with food resources, making it possible to produce a more sustainable and environmentally friendly film.

[0046] Furthermore, commercially available polyethylene resins derived from biomass (for example, Green PE available from Braskem) may be used.

[0047] The polyethylene resins having different densities and branching levels can be obtained by appropriately selecting a polymerization method. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as a polymerization catalyst, and to carry out the polymerization in one stage or in two or more stages by any of gas phase polymerization, slurry polymerization, solution polymerization, and high pressure ionic polymerization.

[0048] The single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene transition metal compound or a non-metallocene transition metal compound with an activating co-catalyst. Single-site catalysts are preferred because they have a more uniform active site structure than multi-site catalysts, making it possible to polymerize polymers with high molecular weights and highly uniform structures. Metallocene catalysts are particularly preferred as single-site catalysts. Metallocene catalysts are catalysts containing the following catalytic components: a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a co-catalyst, and optionally an organometallic compound and a carrier.

[0049] In the above-mentioned transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, or the like. The substituted cyclopentadienyl group has at least one substituent selected from a hydrocarbon group having 1 to 30 carbon atoms, a silyl group, a silyl-substituted alkyl group, a silyl-substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group, a haloalkyl group, a halosilyl group, and the like. The substituted cyclopentadienyl group may have two or more substituents, and the substituents may be bonded to each other to form a ring, such as an indenyl ring, a fluorenyl ring, an azulenyl ring, or a hydrogenated product thereof. The rings formed by bonding the substituents to each other may further have substituents.

[0050] In the transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the transition metal can be zirconium, titanium, hafnium, etc., with zirconium and hafnium being particularly preferred. The transition metal compound typically contains two ligands having a cyclopentadienyl skeleton, and the cyclopentadienyl ligands are preferably bonded to each other via a bridging group. Examples of the bridging group include alkylene groups having 1 to 4 carbon atoms, silylene groups, substituted silylene groups such as dialkylsilylene groups and diarylsilylene groups, and substituted germylene groups such as dialkylgermylene groups and diarylgermylene groups, with substituted silylene groups being preferred. The above-mentioned transition metal compounds of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton can be used as a catalyst component, either alone or in combination.

[0051] The co-catalyst refers to a catalyst that can effectively function as a polymerization catalyst for the above-mentioned transition metal compound of Group IV of the periodic table, or that can balance the ionic charge in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxanes of organoaluminum oxy compounds, benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of a cation with or without an active hydrogen group and a non-coordinating anion, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.

[0052] The transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used by being supported on an inorganic or organic carrier. The carrier is preferably a porous oxide of an inorganic or organic compound, specifically, an ion-exchange layered silicate such as montmorillonite, SiO ２ , Al ２ O ３ , MgO, ZrO ２ , TiO ２ , B ２ O ３ , CaO, ZnO, BaO, ThO ２ and the like, or mixtures thereof. Furthermore, examples of organometallic compounds that may be used as needed include organoaluminum compounds, organomagnesium compounds, organozinc compounds, etc. Of these, organoaluminum compounds are preferably used.

[0053] When the recycled material-containing layer contains a resin derived from biomass, it becomes easy to reduce the Ra, H, and ratio [W / H] in the sealant layer described below.

[0054] The recycled material-containing layer may contain chemically recycled resin. In this specification, chemically recycled resin refers to a resin obtained by chemical recycling, which means a resin produced by first decomposing discarded resin into low-molecular-weight compounds through a process such as gasification or monomerization, and then polymerizing the resulting resin. Chemically recycled resin is produced from raw materials obtained by chemically decomposing waste, thereby reducing the amount of foreign matter.

[0055] The chemically recycled resin can be any resin produced by a chemical recycling method, without any particular limitations. Examples of chemical recycling methods include depolymerization, thermal decomposition, gasification, coke oven chemical recycling, and blast furnace reducing agent methods. The polymerization or repolymerization method is not particularly limited, and known methods can be used.

[0056] The chemically recycled resin may be a polyolefin resin such as chemically recycled polyethylene or chemically recycled polypropylene. Such polyolefin resins can be produced, for example, by pyrolyzing mixed waste plastics containing polyolefin resins under oxygen-free conditions, cracking the resulting pyrolysis oil (such as naphtha) to produce ethylene and propylene, and polymerizing these.

[0057] When the recycled material-containing layer contains a chemically recycled resin, it becomes easy to reduce the Ra, H, and ratio [W / H] in the sealant layer described below.

[0058] When the recycled material-containing layer contains inorganic particles, the inorganic particles can be appropriately selected depending on the function to be imparted. Examples of the function to be imparted include concealing property, moisture absorption property, etc. One type of inorganic particle may be used alone, or two or more types may be used in combination.

[0059] When imparting hiding power to the recycled material-containing layer, white inorganic particles can be used as the inorganic particles, and examples thereof include titanium oxide, zinc oxide, lithopone, calcium carbonate, barium sulfate, and aluminum hydroxide from the viewpoint of interfacial adhesion between the particle surface and the resin. Among these, titanium oxide is preferred because it has no specific absorption in the visible region and has a high refractive index.

[0060] From the viewpoint of dispersibility in the recycled material-containing layer, the average particle size of the inorganic particles may be 0.10 to 0.50 μm, 0.15 to 0.40 μm, or 0.20 to 0.30 μm. The average particle size of the inorganic particles means a value measured by a laser diffraction / scattering method.

[0061] The content of the inorganic particles may be 0.10 to 30.00% by mass, based on the total mass of the recycled material-containing layer. When the recycled material-containing layer is to be imparted with hiding properties, the content of the inorganic particles may be 1.00% by mass or more, 5.00% by mass or more, 7.00% by mass or more, or 10.00% by mass or more, based on the total mass of the recycled material-containing layer, from the viewpoint of achieving better hiding properties. Furthermore, the content of the inorganic particles may be 23.00% by mass or less, 20.00% by mass or less, 15.00% by mass or less, 12.00% by mass or less, or 8.00% by mass or less, from the viewpoint of suppressing a decrease in the cold impact resistance of the sealant film.

[0062] The inorganic particles are preferably dispersed in the recycled material-containing layer. When the recycled material contains a resin having a polar group such as a hydroxyl group, an ester group, or an amide group, the dispersibility of the recycled material and the inorganic particles in the recycled material-containing layer can be improved.

[0063] When imparting hiding power to the sealant film, inorganic particles may be incorporated into the recycled material-containing layer and / or the auxiliary layer described below so that the transmission density of the sealant film is 0.20 or more, 0.40 or more, or 0.50 or more. The transmission density can be measured using an X-RITE portable transmission densitometer (Model No. 341C).

[0064] The recycled material-containing layer may contain aggregates derived from, for example, the second resin, and from the viewpoint of ensuring reliability during heat sealing, the aggregates may have a maximum diameter of 20 μm or less. If the maximum diameter of the aggregates is 20 μm or less, it becomes easier to prevent the formation of convex portions having a height of more than 10 μm or convex portions having a height of 0.5 μm to 10 μm and a width-to-height ratio at half the height of more than 20 on the surface of the sealant layer.

[0065] The recycled material-containing layer may include agglomerates having a maximum diameter of 40 μm to 100 μm, 50 μm to 90 μm, or 60 μm to 80 μm.

[0066] The aggregates and their maximum diameters can be confirmed by the following method. The aggregates contained in the recycled material-containing layer can be confirmed as domains (hereinafter also referred to as "low-transmission brightness regions") with lower transmission brightness than the surrounding area when the sealant film is observed through transmission from a planar view direction. The maximum diameter of the low-transmission brightness regions can be obtained by the following procedure. (i) Using a stereo microscope system SZX16 (manufactured by Olympus Corporation, product name), 10 random observation images (image size: 243 μm × 851 μm) of the sealant film in the planar direction are obtained. (ii) The 10 obtained images are subjected to image analysis using WinROOF2021 (manufactured by Mitani Corporation, product name). In the image analysis, the low-transmission brightness regions and the surrounding high-transmission brightness regions are binarized to calculate the maximum diameter of each low-transmission brightness region. Note that during binarization, the visual shape of the low-transmission brightness regions and the colored range can be matched by appropriately combining the following operations. (a) Highlight low-transmission brightness areas by adjusting brightness and contrast. (b) Adjust the threshold to match the visible low-transmission brightness areas with the colored range. (c) If there are areas where adjacent low-transmission brightness areas are recognized as a single area or where perforated low-transmission brightness areas are recognized as multiple areas, perform division or integration processing as necessary.

[0067] The maximum diameter of the aggregates in the recycled material-containing layer can be reduced by, for example, the following adjustment means: (a) Reducing the content of recycled material in the recycled material-containing layer; (b) Increasing the content of the first resin in the recycled material; (c) Increasing the screw rotation speed when extruding the recycled material-containing layer; (d) Avoiding narrowing of the flow path as much as possible when extruding the recycled material-containing layer to create a mechanism that is less susceptible to elongation stress; (e) Using a twin-screw extruder to mix the recycled material with repellent or virgin resin to form a masterbatch.

[0068] The recycled material-containing layer may have a thickness of 20 to 100 μm.

[0069] (Sealant Layer) The surface of the sealant layer opposite to the recycled material-containing layer has an uneven shape. ３ａ The arithmetic surface roughness Ra of the film, as defined in JIS B 0601:2001, is 0.5 μm or more and 5 μm or less. When Ra is 5 μm or less, it is possible to prevent a decrease in reliability (e.g., a decrease in low-temperature heat sealability) due to air entrapment when overlapping sealant films and heat sealing them. In addition, it is less likely that the thickness of the recessed portions will be locally thin, resulting in problems such as a decrease in impact resistance and puncture resistance. On the other hand, when Ra is 0.5 μm or more, the coefficient of friction will not be too large, allowing for appropriate slip properties and making it less likely that wrinkles will occur during film formation.

[0070] From the above viewpoint, the Ra may be 0.5 μm or more and 4 μm or less, 0.5 μm or more and 3 μm or less, 0.5 μm or more and 2 μm or less, 0.5 μm or more and 1.5 μm or less, 1.0 μm or more and 4 μm or less, 1.0 μm or more and 3 μm or less, or 1.0 μm or more and 2 μm or less.

[0071] Methods for adjusting the Ra include, in addition to the method of adjusting the maximum diameter of the aggregates described above, changing the thickness of the sealant layer, incorporating an antiblocking agent into the sealant layer, and forming predetermined irregularities on the surface of the sealant layer (for example, pressing a nip roll against the molten resin when cooling and solidifying it during film formation).

[0072] From the viewpoint of ensuring reliability during heat sealing, the surface of the sealant layer (S shown in FIG. 2) ３ａ ) in the convex portion (P shown in FIG. ３ａ ) is the height (H shown in FIG. ３ａ From the same viewpoint, the width at half the height of the convex portion (W shown in FIG. 2) may be 10 μm or less, 0.5 to 9 μm, or 0.5 to 8 μm. ３ａ) may be 200 μm or less, may be 1 to 150 μm, or may be 1 to 100 μm. FIG. 2 is a schematic cross-sectional view for explaining the shape of the protrusions in the sealant film shown in FIG. 1. As shown in FIG. 2, the protrusions P ３ａ The surface S of the sealant layer 3 is formed by the aggregates 50 generated in the recycled material-containing layer. ３ａ It may also be caused by the uplift of

[0073] The convex portions on the surface of the sealant layer may have a maximum height H of 0.5 μm or more and 10 μm or less, and the ratio [W / H] of the width W at half the maximum height H to the maximum height H of the convex portions having the maximum height H may be 20 or less, or the above H may be 0.5 to 9 μm, and the ratio [W / H] may be 1 to 18. This is advantageous in terms of (a) an increase in the content of recycled material in the recycled material-containing layer, (b) an increase in the content of recycled material in the sealant film by reducing the thickness of the sealant layer, and (c) improved productivity by being able to reduce the pressure applied during cooling or hot pressing during film formation.

[0074] The material for forming the sealant layer may be a thermoplastic resin or other material that has appropriate flexibility and good processability, for example, suitability for processing using an extruder. Examples of such materials include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and polypropylene having a homopolymer, random copolymer, or block copolymer; ethylene-vinyl acetate copolymers obtained by copolymerizing olefins such as low-density polyethylene (LDPE) with vinyl acetate; ethylene-methyl acrylate copolymers (EMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-butyl acrylate copolymers (EBA), and ethylene-methacrylic acid copolymers (EMAA), which are obtained by modifying the side chains of olefins. These materials may be used alone or in combination.

[0075] The resin forming the sealant layer may be a chemically recycled resin, and the chemically recycled resins described above can be used.

[0076] From the viewpoint of reducing the environmental impact, the content of the chemically recycled resin in the sealant layer is preferably 40% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass, based on the total mass of the sealant layer.

[0077] The resin forming the sealant layer may contain a biomass-derived polyethylene resin, and the biomass-derived polyethylene resins described above can be used.

[0078] The biomass content of the biomass-derived polyethylene resin in the sealant layer is preferably 50% to 100%, more preferably 70% to 100%. This increases the biomass content of the sealant film and further reduces the environmental impact. The biomass content refers to the dry weight percentage of the biomass raw material used.

[0079] From the viewpoint of heat sealing properties, the sealant layer may contain the same type of resin as the resin with the highest content in the recycled-material-containing layer, and virgin resin and / or chemically recycled resin may be blended to achieve this. For example, if the resin with the highest content in the recycled-material-containing layer is a polyethylene-based resin, the sealant layer may contain a polyethylene-based resin, or the polyethylene-based resin may be the main component (e.g., the content in the sealant layer is 95% by mass or more). In this case, at least one of the recycled-material-containing layer and the sealant layer, or at least one of the recycled-material-containing layer, the sealant layer, and the auxiliary layer described below, may contain a biomass-derived polyethylene-based resin. Furthermore, if the resin with the highest content in the recycled-material-containing layer is a polypropylene-based resin, the sealant layer may contain a polypropylene-based resin, or the polypropylene-based resin may be the main component (e.g., the content in the sealant layer is 95% by mass or more).

[0080] The sealant layer may contain a polypropylene resin from the viewpoint of reducing the maximum height H and the ratio [W / H].

[0081] From the viewpoint of processability in film formation, the MFR of the polyethylene resin may be 0.05 to 15 g / 10 min, or 0.1 to 8 g / 10 min. The MFR here refers to a value measured in accordance with JIS K7210 (190°C, load 2.16 kg).

[0082] From the viewpoint of processability in film formation, the MFR of the polypropylene resin may be 0.05 to 20 g / 10 min, or 0.1 to 10 g / 10 min. The MFR here refers to a value measured in accordance with JIS K7210 (230°C, load 2.16 kg).

[0083] From the viewpoint of heat sealability and rigidity, the crystallinity of the polypropylene-based resin as measured by the heat of fusion using a differential scanning calorimeter (DSC) may be 25% or more and 60% or less, or 30% or more and 55% or less.

[0084] In this specification, the crystallinity of a polypropylene resin is calculated from the ratio of the heat of fusion ΔHm, calculated by integrating the endothermic peak during melting of the sample, to the heat of fusion ΔH100 of a completely crystalline material with a crystallinity of 100% calculated by theoretical calculation, according to the following formula: Crystallinity [%] = (ΔHm / ΔH100) x 100 The heat of fusion ΔH100 of a completely crystalline material can be the value described in the following document. For example, the ΔH100 of polypropylene can be 207 J / g. Reference: The Society of Plastics Processing: Plastic Materials in Molding, 335 (2011), Morikita Publishing Co., Ltd.

[0085] The sealant layer may contain the above resin as a virgin material, or may contain no recycled material from the viewpoint of the stability of heat sealing performance.

[0086] The thickness of the sealant layer may be 5 μm or more and 70 μm or less. In this case, it is easy to prevent the aggregates contained in the recycled material-containing layer from being exposed from the sealant layer, and it is easy to ensure the rigidity of the entire sealant film and to increase the content of recycled material in the sealant film. This makes it possible to more effectively realize material recycling of recycled materials containing two or more resins in the sealant film. The thickness of the sealant layer may be 5 μm or more and 60 μm or less, 5 μm or more and 55 μm or less, 5 μm or more and 50 μm or less, 5 μm or more and 40 μm or less, 5 μm or more and 30 μm or less, 5 μm or more and 20 μm or less, 10 μm or more and 65 μm or less, 10 μm or more and 60 μm or less, 10 μm or more and 55 μm or less, 10 μm or more and 50 μm or less, 10 μm or more and 40 μm or less, 10 μm or more and 30 μm or less, 15 μm or more and 60 μm or less, or 20 μm or more and 60 μm or less.

[0087] The recycled material-containing layer and the sealant layer may contain additives such as compatibilizers, nucleating agents, reinforcing fillers, antioxidants, heat stabilizers, weathering agents, light stabilizers, plasticizers, ultraviolet absorbers, antistatic agents, flame retardants, flame retardant aids, slip agents, antiblocking agents, antifogging agents, lubricants, pigments, dyes, dispersants, copper inhibitors, neutralizing agents, bubble inhibitors, weld strength improvers, natural oils, synthetic oils, waxes, etc. One type of additive may be used alone, or two or more types may be used in combination.

[0088] Examples of nucleating agents and reinforcing fillers include talc, silica, clay, montmorillonite, calcium carbonate, lithium alumina carbonate, titanium oxide, metals such as aluminum, iron, silver, and copper, hydroxides such as aluminum hydroxide and magnesium hydroxide, celluloses such as cellulose microfibrils and cellulose acetate, fibrous fillers such as glass fibers, polyethylene terephthalate fibers, nylon fibers, polyethylene naphthalate fibers, aramid fibers, vinylon fibers, and polyacrylate fibers, carbons such as carbon nanotubes, and elastomers such as ethylene propylene rubber (EPR).

[0089] Examples of the antioxidant include phenolic compounds, organic phosphite compounds, and thioether compounds.

[0090] Examples of the heat stabilizer and light stabilizer include hindered amine compounds.

[0091] Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, and benzoate compounds.

[0092] Examples of the antistatic agent include nonionic compounds, cationic compounds, and anionic compounds.

[0093] Examples of the flame retardant include halogen-based compounds, phosphorus-based compounds, nitrogen-based compounds, inorganic compounds, boron-based compounds, silicone-based compounds, sulfur-based compounds, and red phosphorus-based compounds.

[0094] Examples of the flame retardant aid include antimony compounds, zinc compounds, bismuth compounds, magnesium hydroxide, and clay silicates.

[0095] Examples of the anti-blocking agent include acrylic particles, styrene particles, styrene-acrylic particles and crosslinked products thereof, polyurethane particles, polyester particles, silicon particles, fluorine particles, copolymers thereof, zeolite, pyrophyllite, talc, smectite, vermiculite, mica, chlorite, kaolin minerals, clay compound particles such as sepiolite, silica, titanium oxide, alumina, silica alumina, zirconia, zinc oxide, strontium oxide, aluminum hydroxide, strontium carbonate, strontium chloride, strontium sulfate, strontium nitrate, strontium hydroxide, and glass particles.

[0096] In the sealant film of this embodiment, the ratio Tr / Ts of the thickness Tr of the recycled material-containing layer to the thickness Ts of the sealant layer may be 0.3 to 16, 0.5 to 14, or 0.7 to 12.

[0097] The sealant film of the present embodiment is subjected to electron beam irradiation treatment, which increases the crosslink density of the resin contained in the sealant film by electron beam irradiation, thereby further improving the mechanical strength of the sealant film.

[0098] Packaging bags such as pouches are usually produced by forming a packaging material including a sealant film. However, if pinholes form in the packaging material that constitutes the packaging bag due to friction during transportation, external air or components of the base material layer may enter the packaging bag, potentially affecting the hygiene of the contents. Furthermore, when filling the packaging bag with contents having sharp corners, pinholes may form from the inside to the outside of the packaging bag. Therefore, it is desirable that the sealant film used as a packaging material has excellent puncture strength. When the sealant film of this embodiment has been subjected to electron beam irradiation treatment, it can contain recycled materials containing two or more resins and still have sufficient reliability during heat sealing, puncture strength, and film-forming properties.

[0099] The electron beam irradiation treatment may be carried out from the side opposite to the side of the sealant film where the sealant layer is provided (in the case of a packaging material provided with a sealant film, the side opposite to the surface that comes into contact with the contents or filled material).

[0100] The sealant film of this embodiment may be subjected to electron beam irradiation treatment during or after the formation of the laminate or packaging material described below. For example, an ink layer or an overcoat layer that is cured by electron beam irradiation may be provided on the sealant film, and the electron beam irradiation conditions may be set so that the sealant film is irradiated with a predetermined dose of electron beams when these layers are cured. In particular, in the case of multi-color printing, further strength improvement can be expected by accumulating the EB irradiation of each color. Furthermore, in the case of a packaging material in which a sealant film is laminated with a gas barrier layer, a base film, or the like, the electron beam irradiation conditions may be set so that the sealant film is irradiated with a predetermined dose of electron beams during EB sterilization performed after pouching or filling with contents. From the viewpoint of improving puncture strength, etc., the acceleration voltage and irradiation energy of the electron beam may be adjusted so that the electron beam dose on the sealant film is 10 KGy to 2000 KGy or 20 KGy to 500 KGy. From the same viewpoint, the dose of the electron beam, the acceleration voltage of the electron beam, and the irradiation energy may be adjusted so that the gel fraction of the sealant film falls within the range described below.

[0101] The gel fraction of the sealant film of this embodiment, calculated by the following method, may be 0.5% or more and 85% or less, or 20% or more and 80% or less. The gel fraction can be used as an indicator of crosslink density. A gel fraction within the above range facilitates both improving the mechanical strength of the sealant film by increasing the crosslink density of the recycled material-containing layer and ensuring heat-sealability by preventing excessive crosslinking of the sealant layer. (Method for Calculating Gel Fraction) The gel fraction is calculated by utilizing the insolubility of crosslinked portions in solvents. The sealant film is immersed in an organic solvent such as xylene, and the remaining insoluble film is dried and then weighed. The gel fraction can be calculated from the mass of the sealant film before dissolution and the mass of the insoluble film after drying. Specifically, the gel fraction can be calculated by the following procedure: (i) First, X g of sealant film is wrapped in Y g of stainless steel wire mesh and heated and immersed in a solvent. The heating temperature and immersion time are 120°C and 8 hours, respectively. (ii) Next, the sealant film wrapped in the stainless steel wire mesh is removed from the solvent and vacuum dried. The drying temperature and drying time are 60°C and 3 hours, respectively. (iii) The mass (Zg) of the sealant film wrapped in the stainless steel wire mesh after drying is measured, and the gel fraction is calculated using the following formula (1): Gel fraction (mass%) = [(Z-Y) / X] x 100 ... (1)

[0102] Even if the EB irradiation dose is low, the physical strength may be improved by EB irradiation, and it is estimated that crosslinking has occurred even with only a slight increase in gel fraction. In such cases, a shift in the melting peak intensity to a lower temperature and a change in the melting enthalpy are observed in DSC (differential scanning calorimetry) analysis.

[0103] The sealant film of this embodiment may have a multilayer structure in which desired physical properties are complemented by laminating another layer. Fig. 3 is a schematic cross-sectional view showing another embodiment of the sealant film. The sealant film 1b shown in Fig. 3 comprises a recycled material-containing layer 2, a sealant layer 3 laminated on one main surface of the recycled material-containing layer 2, and an auxiliary layer 4 laminated on the other main surface of the recycled material-containing layer 2. In this case, too, the surface S of the sealant layer 3 opposite to the recycled material-containing layer 2 side is ３ｂ The arithmetic surface roughness Ra defined in JIS B 0601:2001 can satisfy the above-mentioned conditions.

[0104] The auxiliary layer 4 may be configured to contain a high-density resin in order to further increase the rigidity of the sealant film 1b, and may be configured to contain a resin having a density similar to that of the resin constituting the sealant layer 3 (for example, a density difference of 0.1 kg / m) in order to suppress curling due to thermal shrinkage of the sealant film 1b. ３ The resin may contain a compound selected from the group consisting of hydroxybenzoates, ...

[0105] Furthermore, when the auxiliary layer 4 is to function as a laminate layer, it may have the same configuration as the above-described sealant layer 3. From the viewpoint of reducing the environmental load, the auxiliary layer 4 may contain a chemically recycled resin. From the viewpoint of increasing the biomass content, the auxiliary layer 4 may contain a biomass-derived polyethylene resin. Furthermore, the auxiliary layer 4 may contain the same type of resin as the resin with the highest content in the recycled material-containing layer 2. In this case, the higher lamination strength makes it easier to improve adhesion with other layers.

[0106] The auxiliary layer 4 may contain one or more of the above-mentioned additives, if necessary.

[0107] Furthermore, when auxiliary layer 4 is made to function as a laminate layer, the arithmetic surface roughness Ra defined in JIS B 0601:2001 of the surface of auxiliary layer 4 opposite to recycled material-containing layer 2 may be 0.03 μm or more and 5 μm or less, 0.04 μm or more and 3 μm or less, or 0.05 μm or more and 2 μm or less. In this case, when another layer is laminated on the laminate layer via an adhesive, it becomes easy to suppress lamination defects caused by the occurrence of defective areas where the adhesive does not adhere.

[0108] The Ra of the auxiliary layer 4 can be adjusted by changing the thickness of the auxiliary layer 4. In this case, the thickness of the auxiliary layer may be 5 μm or more and 100 μm or less, 10 μm or more and 90 μm or less, or 20 μm or more and 80 μm or less, from the viewpoints of suppressing lamination defects and reducing costs.

[0109] From the viewpoint of reducing the environmental impact, the sealant film of this embodiment may not contain petroleum-derived virgin resin. For example, in the case of the sealant film 1a shown in Fig. 1, the recycled material-containing layer 2 and the sealant layer 3 may not contain petroleum-derived virgin resin, and in the case of the sealant film 1b shown in Fig. 3, the recycled material-containing layer 2, the sealant layer 3, and the auxiliary layer 4 may not contain petroleum-derived virgin resin.

[0110] In the sealant film 1b, the electron beam irradiation treatment may be performed from the side (auxiliary layer side) opposite to the side on which the sealant layer is provided (in the case of a packaging material including a sealant film, the side opposite to the surface that comes into contact with the contents or filled material). The sealant film 1b may have the above-mentioned gel fraction.

[0111] <Method for producing sealant film> The sealant film of the present embodiment can be produced by a conventionally known method, for example, a method of extrusion laminating a recycled material-containing film formed from a resin composition constituting the recycled material-containing layer with a resin composition constituting the sealant layer, or a method of forming the recycled material-containing layer and the sealant layer by co-extrusion molding can be used.

[0112] In the former method, the recycled material-containing film can be produced by melting the resin composition constituting the recycled material-containing layer in an injection molding machine or an extrusion molding machine (for example, a twin-screw extruder) and then forming the film in a T-die through a feed block or a multi-manifold, or by an inflation method. The recycled material can be produced by collecting, cleaning, and pulverizing various plastic waste materials, melt-molding them in an extruder, and pelletizing them. For extrusion lamination, an extrusion laminating machine or the like can be used.

[0113] In the latter method, for example, a sealant film can be produced by melt-kneading and co-extruding the resin composition constituting the recycled material-containing layer and the resin composition constituting the sealant layer using a multi-layer extrusion molding machine.

[0114] The resin composition constituting the recycled material-containing layer may contain only recycled material, or may further contain virgin resin or additives to impart various desired properties such as viscosity adjustment, mechanical property reinforcement, etc. Furthermore, when the recycled material and virgin resin are mixed, they may be dry-blended in which the virgin resin and the recycled material are simultaneously charged into a hopper and melt-kneaded to form a film, or they may be melt-blended in which the virgin resin and the recycled material are separately melt-kneaded in a twin-screw extruder to form a masterbatch.

[0115] To reduce the size of aggregates in the recycled material-containing layer, the layer may be repelletized using a twin-screw extruder, molded under high shear conditions, or may contain an acid-modified polyolefin resin or the like as a compatibilizer.

[0116] The film can be cooled in a manner appropriate to the molding machine. For example, in the T-die method, air-cooling methods such as an air chamber, a vacuum chamber, or an air knife, or water-cooling methods such as dipping a cooling roll in a cold water pan can be used.

[0117] Furthermore, for example, in the case of the T-die method, in order to adjust the Ra of the sealant layer, a predetermined surface shape can be imparted to the sealant layer by pressing the molten resin with a nip roll when cooling and solidifying it using a cooling roll having a predetermined surface shape. A method for imparting a surface shape by shaping may be a method in which a nip roll made of silicone rubber, NBR rubber, fluororesin, or the like is contacted with a cooling roll and a pressure of 0.1 MPa or more is applied, and the molten resin is then poured into the contact area and cooled. The cooling roll may be one obtained by cutting metal or one shaped by blasting. The surface shape of the cooling roll may be a randomly uneven shape, and the surface roughness can be adjusted by changing the particle size and treatment time (amount) during blasting. The Ra of the auxiliary layer can also be adjusted in the same manner as above.

[0118] The sealant film of this embodiment can also be produced by a heat press method. In the heat press method, a flat film can be molded by compressing it between heated rolls or a heated plate. The thickness of the molded product can be controlled by adjusting the compression pressure. Single-layer films produced by heat press may be stacked and then heat pressed again to form a laminate, or a pre-laminated flat film may be prepared and the film thickness adjusted by heat press. Furthermore, when a predetermined surface shape is to be imparted to the film to adjust the surface roughness, the predetermined surface shape may be formed on the surface of a roll or a flat plate and then transferred. The surface shape may be a randomly uneven shape, and the surface roughness can be adjusted by changing the particle size or treatment time (amount) during blast treatment.

[0119] In this embodiment, the sealant film prepared as described above can be subjected to electron beam irradiation treatment. Electron beam irradiation improves the crosslink density of the resin contained in the sealant film, thereby improving the mechanical strength (particularly puncture strength) of the sealant film. The electron beam irradiation treatment is preferably performed from the side opposite to the side of the sealant film on which the sealant layer is provided (in the case of a packaging material having a sealant film, the side opposite to the surface that comes into contact with the contents or filled material).

[0120] In addition, since the arithmetic surface roughness of the surface of the sealant layer opposite to the recycled material-containing layer side of the sealant film produced as described above satisfies the above-mentioned conditions, the mechanical strength (particularly, puncture strength) can be easily improved by electron beam irradiation treatment. Furthermore, since the maximum height H and ratio [W / H] of the convex portions on the surface of the sealant layer specified by the above-mentioned method satisfy the above-mentioned conditions, the mechanical strength (particularly, puncture strength) can be easily improved by electron beam irradiation treatment.

[0121] As an apparatus that can be used to irradiate a sealant film with an electron beam, a conventionally known low-energy type is preferably used, and examples thereof include a curtain-type electron beam irradiation apparatus (LB1023, manufactured by I-Electron Beam Co., Ltd.), a line-irradiation type low-energy electron beam irradiation apparatus (EB-ENGINE, manufactured by Hamamatsu Photonics K.K.), and a drum-roll type electron beam irradiation apparatus (EZ-CURE, manufactured by I-Electron Beam Co., Ltd.).

[0122] The dose of the electron beam irradiated to the sealant film and the acceleration voltage of the electron beam can be set as appropriate, and may be adjusted as appropriate within a range in which the electron beam does not reach the sealant layer when irradiated to the main surface of the sealant film opposite the sealant layer side. In this case, the crosslink density of the sealant layer is improved by the electron beam, and a decrease in the heat sealability of the sealant layer can be suppressed. In addition, the dose of the electron beam, the acceleration voltage of the electron beam, and the irradiation energy may be adjusted so that the gel fraction of the sealant film falls within the above-mentioned range.

[0123] The dose of the electron beam may be 10 kGy or more and 2000 kGy or less, or 20 kGy or more and 500 kGy or less.

[0124] The acceleration voltage of the electron beam may be 30 kV or more and 300 kV or less, 50 kV or more and 300 kV or less, or 50 kV or more and 250 kV or less.

[0125] The irradiation energy of the electron beam may be 20 keV or more and 750 keV or less, 25 keV or more and 500 keV or less, 30 keV or more and 400 keV or less, or 20 keV or more and 200 keV or less.

[0126] The oxygen concentration in the electron beam irradiation apparatus may be 500 ppm or less, or may be 100 ppm or less. By performing electron beam irradiation under such conditions, it is possible to suppress the generation of ozone and to prevent radicals generated by electron beam irradiation from being deactivated by oxygen in the atmosphere. Such conditions can be achieved, for example, by creating an inert gas (nitrogen, argon, etc.) atmosphere inside the apparatus.

[0127] The sealant film may be subjected to a surface modification treatment to improve suitability for subsequent processes. For example, the surface to be laminated may be subjected to a surface modification treatment to improve printability and lamination suitability when laminating with other layers or substrate films. Examples of surface modification treatments include methods for oxidizing the film surface to express functional groups, such as corona discharge treatment, plasma treatment, and flame treatment, and wet process modifications such as coating with an easy-adhesion layer.

[0128] The method for producing the sealant film is not limited to the above-mentioned method, and the sealant film produced by the molding machine may be subjected to in-line or off-line stretching treatment. There are no limitations on the addition of other necessary steps or additives as appropriate.

[0129] <Laminate> The laminate of the present embodiment includes the sealant film of the present embodiment described above.

[0130] The laminate may include, for example, the sealant film of the present embodiment and a gas barrier layer provided on the surface of the sealant film opposite to the sealant layer side.

[0131] When a film is used as a food packaging material, the film is required to have gas barrier properties. The laminate described above contains a recycled material containing two or more resins, yet has sufficient reliability and film formability during heat sealing, and also has excellent gas barrier properties.

[0132] FIG. 4 is a schematic cross-sectional view showing one embodiment of the laminate of this embodiment. The laminate 10a shown in FIG. 4 includes a sealant film 1a in which a recycled material-containing layer 2 and a sealant layer 3 are laminated, and a gas barrier layer 12 provided on the recycled material-containing layer 2 of the sealant film 1a. FIG. 5 is a schematic cross-sectional view showing another embodiment of the laminate of this embodiment. The laminate 10b shown in FIG. 5 further includes a gas barrier layer 12 on the side of the auxiliary layer 4 in the sealant film 1b shown in FIG. 3 opposite to the recycled material-containing layer 2. The laminates 10a and 10b can have improved gas barrier properties (e.g., oxygen barrier properties and water vapor barrier properties). The gas barrier layer may have a single-layer structure or a laminate structure.

[0133] In the laminate of this embodiment, the gas barrier layer is provided and the surface of the sealant film (in this embodiment, the surface of the recycled material-containing layer) is smooth, so that the density of the gas barrier layer (particularly the vapor deposition layer) to be formed can be increased, and the gas barrier properties can be improved.

[0134] The gas barrier layer can be formed by a conventional method on the surface of the sealant film obtained above opposite to the sealant layer side (for example, the surface of the recycled material-containing layer or the surface of the auxiliary layer).

[0135] Examples of the gas barrier layer 12 include a vapor-deposited layer (vapor-deposited film) made of a metal or inorganic oxide, a metal foil such as aluminum foil, and a film of an ethylene-vinyl alcohol copolymer, a polyamide resin, a polyvinylidene chloride resin, a polyacrylonitrile resin, or the like.

[0136] The vapor-deposited layer may have a single layer structure or a multilayer structure. Examples of the vapor-deposited layer include a vapor-deposited layer composed of a metal such as aluminum, and an inorganic oxide such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

[0137] The deposition layer can be formed by a conventionally known method, and the formation method can be appropriately selected from physical vapor deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (CVD methods) such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition, depending on the deposition material, etc.

[0138] When the vapor-deposited layer is an aluminum vapor-deposited film, the OD value thereof may be from 2 to 3.5 in terms of productivity, oxygen barrier property, and water vapor barrier property of the laminate. Note that, in this specification, the OD value refers to a value measured in accordance with JIS-K-7361.

[0139] When the vapor-deposited layer is an inorganic oxide layer using silicon oxide, the O / Si ratio of the inorganic oxide layer may be 1.5 or more from the viewpoint of transparency. Furthermore, the O / Si ratio may be 2.0 or less from the viewpoint of barrier properties. To obtain the above-mentioned effects more fully, the O / Si ratio of the inorganic oxide layer may be 1.5 or more and 2.0 or less, or 1.6 or more and 1.8 or less.

[0140] The O / Si ratio of the inorganic oxide layer can be determined by X-ray photoelectron spectroscopy (XPS). For example, the measurement can be performed using an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV) with a non-monochromated MgKα (1253.6 eV) X-ray source and an X-ray output of 100 W (10 kV-10 mA). For quantitative analysis to determine the O / Si ratio, relative sensitivity factors of 2.28 for O1s and 0.9 for Si2p can be used.

[0141] The thickness of the vapor-deposited layer may be 1 nm or more and 150 nm or less, 5 nm or more and 60 nm or less, or 5 nm or more and 40 nm or less. When the thickness of the vapor-deposited layer is 1 nm or more, oxygen barrier property and water vapor barrier property are easily obtained. When the thickness of the vapor-deposited layer is 150 nm or less, cracking in the vapor-deposited layer is easily prevented and the recyclability of the sealant film is easily maintained.

[0142] When the gas barrier layer includes a metal foil, the thickness of the metal foil may be 1 μm or more and 15 μm or less, 3 μm or more and 10 μm or less, or 5 μm or more and 8 μm or less, from the viewpoint of gas barrier properties and durability.

[0143] When the gas barrier layer includes a resin film, the thickness of the resin film may be 100 nm to 50 μm, 500 nm to 10 μm, or 1 μm to 5 μm, from the viewpoint of gas barrier properties.

[0144] The gas barrier layer may be formed by laminating an inorganic material layer formed by a method other than vapor deposition, a laminated film of a metal foil and a plastic film, or a vapor-deposited film having a vapor-deposited layer (vapor-deposited film) made of the above-mentioned metal or inorganic oxide, etc. on a plastic film. Examples of plastic films include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polyethylene and polypropylene, polystyrene, polyamides such as 6-nylon, polycarbonate, polyacrylonitrile, polyimide, etc.

[0145] When the gas barrier layer is a resin layer having gas barrier properties such as EVOH or polyvinyl alcohol resin, the resin layer can be provided by coextrusion or wet coating. When the gas barrier layer is the above-mentioned resin film, laminated film, or vapor-deposited film, these gas barrier layers can be formed by lamination using an adhesive or extrusion lamination, as described below.

[0146] The auxiliary layer 4 provided with the gas barrier layer may have the same configuration as the above-described sealant layer 3. When the auxiliary layer 4 contains a polyolefin resin, the polyolefin resin preferably has high crystallinity from the viewpoints of printability, vapor deposition suitability, strength, and heat resistance. The polyolefin resin may be a virgin resin.

[0147] When the polyolefin resin is polyethylene, high-density polyethylene (HDPE) and medium-density polyethylene (MDPE) are preferred from the viewpoints of vapor deposition suitability, printability, strength, and heat resistance, and medium-density polyethylene is more preferred from the viewpoint of suitability for stretching. When the polyolefin resin is polypropylene, the crystallinity determined by the heat of fusion using a differential scanning calorimeter (DSC) may be 40% or more or 45% or more from the viewpoints of printability, strength, and heat resistance, and may be 60% or less or 55% or less from the viewpoint of impact resistance.

[0148] The content of non-material recycled resin (virgin resin, chemical recycled resin, etc.) in the auxiliary layer 4 on which the gas barrier layer is provided can be higher than the content of non-material recycled resin in the recycled-material-containing layer. In this case, it is possible to smooth out partial swelling caused by aggregates on the surface of the recycled-material-containing layer and to improve the mechanical properties and gas barrier properties of the laminate.

[0149] The thickness of the auxiliary layer 4 on which the gas barrier layer is provided may be 20 μm or more, 40 μm or more, or 80 μm or more from the viewpoint of gas barrier properties and adhesion, and may be 150 μm or less, 120 μm or less, or 100 μm or less from the viewpoint of reducing the total thickness when used as a packaging material.

[0150] The laminate may also include, for example, the sealant film of the present embodiment, an adhesive layer, and a substrate film in this order.

[0151] When producing a packaging material having functions such as design and gas barrier properties, a base film provided with a functional layer such as a printed layer or a vapor deposition layer may be bonded to a sealant film with an adhesive, but if the sealant film has low smoothness, bubbles are likely to occur in the resulting laminate, which is likely to cause poor appearance. The above-mentioned laminate contains recycled materials containing two or more resins, yet has sufficient reliability and film formability during heat sealing and also has excellent appearance.

[0152] Fig. 6 is a schematic cross-sectional view showing an example of the laminate 10c. The laminate 10c shown in Fig. 6 includes a sealant film 1a in which a recycled material-containing layer 2 and a sealant layer 3 are laminated, and a base film 6 laminated on the recycled material-containing layer 2 of the sealant film 1a via an adhesive layer 5.

[0153] Fig. 7 is a schematic cross-sectional view showing another example of the laminate 10d. The laminate 10d shown in Fig. 7 includes the sealant film 1b shown in Fig. 3 and a base film 6 laminated on the auxiliary layer 4 of the sealant film 1b via an adhesive layer 5.

[0154] The auxiliary layer 4 in the laminate may further include a gas barrier layer on the side opposite to the recycled material-containing layer 2. In this case, the laminate may have improved gas barrier properties (e.g., oxygen barrier properties and water vapor barrier properties). The gas barrier layer may have a single-layer structure or a multilayer structure.

[0155] The adhesive layer 5 functions as a layer that bonds the base film 6 and the sealant film. For example, in the laminate 10c, the recycled material-containing layer 2 of the sealant film and the base film 6 are bonded via the adhesive layer 5, and in the laminate 10d, the auxiliary layer 4 of the sealant film and the base film 6 are bonded via the adhesive layer 5.

[0156] The laminate shown in Figures 6 and 7 can be used as a packaging material.

[0157] The base film 6 is not particularly limited as long as it has mechanical strength and dimensional stability, and examples of the base film 6 include plastic film, paper, nonwoven fabric, etc. Examples of materials that can be used for the plastic film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polyethylene and polypropylene, polystyrene, polyamides such as 6-nylon, polycarbonate, polyacrylonitrile, and polyimide.

[0158] The base film 6 is preferably a stretched film from the viewpoint of mechanical strength and dimensional stability.

[0159] By containing the same type of resin (also referred to as "the same resin") as the resin with the highest content in the sealant film, the entire packaging material can be made mono-material, improving the recyclability of the packaging material. In this case, all layers constituting the sealant film (for example, the sealant layer, or the sealant layer and the auxiliary layer) may contain the same type of resin as the resin with the highest content in the recycled material-containing layer.

[0160] The content of the same resin in the laminate (or packaging material described below) may be 90% by mass or more, based on the total amount of the laminate (or packaging material). In this case, the laminate (or packaging material) can be said to be a (mono-material) packaging material made of a single material. From the viewpoint of further improving recyclability, the content of the same resin in the laminate (or packaging material) may be 92.5% by mass or more, or may be 95% by mass or more, based on the total amount of the laminate (or packaging material).

[0161] From the viewpoint of transparency, the haze value of the base film 6 may be 30% or less, or may be 20% or less. In this specification, the haze value of the film means a value measured in accordance with JIS K 7105.

[0162] The substrate film 6 may be subjected to a surface treatment. In this case, adhesion to adjacent layers can be improved. The method of the surface treatment is not particularly limited, and examples thereof include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment, and chemical treatments such as oxidation treatment using chemicals.

[0163] An anchor coating layer may be provided on the surface of the base film 6 using a conventionally known anchor coating agent.

[0164] The thickness of the base film 6 may be 10 μm or more and 50 μm or less, or 12 μm or more and 30 μm or less. When the thickness of the base film is 10 μm or more, it is easy to improve the strength of the laminate (or packaging material). Furthermore, when the thickness of the base film is 50 μm or less, it is easy to maintain the processability of the laminate (or packaging material).

[0165] The adhesive constituting the adhesive layer 5 is not particularly limited, but a dry laminating adhesive or a solventless adhesive (also called a "solventless adhesive") can be used. Examples of dry laminating adhesives include two-component curing urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, and epoxy adhesives.

[0166] When the packaging material is used for a packaging bag for retort use, a two-component curing urethane adhesive that is retort resistant can be used.

[0167] Examples of solvent-free adhesives include two-component curing polyurethane adhesives in which a base material such as polyester polyol, polyether polyol, or acrylic polyol is reacted with an aromatic or aliphatic isocyanate compound having two or more functional groups as a curing agent. Such adhesives form an adhesive layer by reacting with heat or the like (for example, the hydroxyl groups of the base material react with the isocyanate groups of the curing agent). In this case, the adhesive layer can also be referred to as an adhesive layer (also referred to as a "solvent-free adhesive layer") made of a reaction-cured product of the solvent-free adhesive.

[0168] From the viewpoint of improving adhesiveness, the solventless adhesive may have, for example, an equivalent ratio (NCO group / OH group molar ratio) of the isocyanate groups of the curing agent to the hydroxyl groups of the main agent of 0.5 to 5. Whether the adhesive layer was formed using a solventless adhesive rather than a solvent-based adhesive can be determined by analysis, for example, by Fourier transform infrared spectroscopy.

[0169] A solvent-free adhesive can be used as the adhesive constituting the adhesive layer from the viewpoint of improving the appearance of the laminate. When a base film and a sealant film are bonded together using a dry laminating adhesive, the adhesive dissolved in a solvent is usually applied to the base film, the solvent is removed in a drying oven, and then the sealant film is bonded. While the dry laminating adhesive after solvent removal is hard and has a low degree of freedom in shape deformation, solvent-free adhesives have a high degree of freedom in shape deformation during bonding, and therefore solvent-free adhesives are more likely to conform to the surface shape of even uneven sealant films. Therefore, a solvent-free adhesive layer formed using a solvent-free adhesive is less likely to generate bubbles due to voids between the base film and the sealant film, and can also improve adhesion.

[0170] Incidentally, solvent-free adhesives have the advantage of having a low environmental impact during the manufacturing process and being able to be applied thinner than solvent-based adhesives. Therefore, adhesive layers formed with solvent-free adhesives tend to be thin. In the laminate of this embodiment, when an adhesive layer formed with a solvent-free adhesive is combined with the sealant film of this embodiment, which has sufficiently small surface irregularities, high adhesive strength can be obtained with a smaller amount of adhesive applied, and a good appearance can be obtained with reduced bubble generation.

[0171] From the viewpoint of environmental consideration, the adhesive layer 5 may satisfy at least one of the following conditions: (1) It does not contain 3-glycidyloxypropyltrimethoxysilane (GPTMS), (2) It contains a biomass material, and (3) It does not contain a solvent.

[0172] The adhesive layer 5 may be chlorine-free from the viewpoint of suppressing discoloration of the recycled resin after recycling and the generation of odors due to heat treatment.

[0173] The thickness of the adhesive layer may be 0.3 μm or more and 5.0 μm or less. From the viewpoint of adhesive strength, the thickness of the adhesive layer may be 0.3 μm or more, 0.5 μm or more, or 1 μm or more, and from the viewpoint of recyclability, the thickness may be 5.0 μm or less, 3.5 μm or less, or 2.5 μm or less. When the thickness of the adhesive layer is equal to or less than the above upper limit, the proportion of monomaterials in the packaging material can be increased.

[0174] <Packaging Material> The packaging material of this embodiment includes the sealant film of this embodiment described above. Fig. 8 is a schematic cross-sectional view showing one embodiment of the packaging material. The packaging material 100 shown in Fig. 8 includes a sealant film 1b including an auxiliary layer 4, and a base film 6 laminated onto the auxiliary layer 4 via an adhesive layer 5.

[0175] The adhesive layer 5 is a layer that bonds the base film 6 and the sealant film. In the packaging material 10, the auxiliary layer 4 of the sealant film and the base film 6 are bonded via the adhesive layer 5.

[0176] The packaging material of the present embodiment may further include a functional layer such as a print layer and a gas barrier layer. These functional layers may be provided on the above-mentioned base film.

[0177] The printed layer may be formed on the surface of the base film on which the sealant film is provided, in which case the printed layer can be prevented from coming into contact with the outside air and from deteriorating over time.

[0178] The print layer may represent letters, patterns, symbols, or a combination thereof.

[0179] From the viewpoint of producing a packaging material with less environmental impact, the printed layer may be formed using ink derived from biomass.

[0180] The method for forming the printed layer is not particularly limited, and any conventionally known printing method such as gravure printing, offset printing, flexographic printing, etc. Among these, flexographic printing may be used from the viewpoint of environmental load.

[0181] The gas barrier layer can be provided on the substrate film and may have the same structure as the gas barrier layer 12 described above.

[0182] Alternatively, the gas barrier layer may be formed by laminating a laminate film of a metal foil and a plastic film, or a vapor-deposited film on a plastic film, the vapor-deposited film being formed on the plastic film with a vapor-deposited layer (vapor-deposited film) made of the above-mentioned metal or inorganic oxide, etc. Examples of plastic films include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polyethylene and polypropylene, polystyrene, polyamides such as 6-nylon, polycarbonate, polyacrylonitrile, and polyimide.

[0183] 9 and 10 are schematic cross-sectional views showing other embodiments of the packaging material.

[0184] The packaging material 101 shown in Figure 9 comprises a sealant film 1b having an auxiliary layer 4, and a base film 6 having a gas barrier layer 12 laminated onto the auxiliary layer 4 via an adhesive layer 5.

[0185] 10 includes a laminate 10b in which a sealant film 1b having a laminated structure of a sealant layer 3, a recycled material-containing layer 2, and an auxiliary layer 4, and a gas barrier layer 12 are laminated in this order, and a base film 6 having a printed layer 7 bonded to the gas barrier layer 12 side of the laminate via an adhesive layer 5. In the packaging material 102, as described above, the printed layer 7 is formed on the surface of the base film 6 on the side where the sealant film is provided.

[0186] Each layer in the packaging material of this embodiment may contain the additives described above.

[0187] The packaging material of the present embodiment can be modified in various ways in addition to the configuration described above, and may have the following configurations: (a) sealant film of the present embodiment / adhesive layer / gas barrier film / adhesive layer / base film (b) sealant film of the present embodiment / adhesive layer / gas barrier film (c) sealant film of the present embodiment / gas barrier layer (e.g., vapor-deposited layer) / adhesive layer / base film The gas barrier film may be the above-mentioned base film provided with a gas barrier layer, a laminate film of a metal foil and a plastic film, or a vapor-deposited film, or may be a metal foil such as aluminum foil, or a film such as an ethylene-vinyl alcohol copolymer, a polyamide resin, a polyvinylidene chloride resin, or a polyacrylonitrile resin.

[0188] The packaging material may include a sealant film having an auxiliary layer, a first base film laminated onto the auxiliary layer via an adhesive layer, and a second base film having a printed layer laminated onto the first base film via an adhesive layer. The packaging material may also include a sealant film having an auxiliary layer and a first base film laminated onto the auxiliary layer via an adhesive layer, a sealant film having an auxiliary layer, a first base film laminated onto the auxiliary layer via an adhesive layer, and a gas barrier layer provided on the first base film, or a sealant film having an auxiliary layer, a first base film laminated onto the auxiliary layer via an adhesive layer, and two or more functional layers, such as a gas barrier layer or a printed layer, provided on the first base film.

[0189] From the viewpoint of material recycling, the content of plastic material contained in the packaging material of this embodiment (or the laminate of this embodiment) may be 10% by mass or more, or 25% by mass or more, based on the total amount of plastic material in the packaging material (or laminate). When the packaging material of this embodiment is a laminate packaging material, materials other than plastic (for example, adhesives, printing inks, aluminum foil, etc.) may be excluded from the weight calculation.

[0190] Examples of plastic materials contained in recycled materials (so-called recycled plastics) include resins contained in the recycled materials contained in the recycled-material-containing layer according to the present embodiment. Pre-consumer materials among recycled plastics may be calculated by multiplying the weight by 1 / 2.

[0191] The packaging material of this embodiment (or the laminate of this embodiment) can be used for stand-up pouches, three-sided bags, two-sided bags, gusseted bags, pouches with spouts, pouches with beaks, and the like.

[0192] <Packaging Bag> The packaging bag of this embodiment is made from the packaging material of this embodiment described above. The manufacturing style of the packaging bag is not particularly limited, and the packaging bag may be a stand-up pouch, a three-sided bag, a gusseted bag, a pouch with a spout, a pouch with a beak, or the like.

[0193] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0194] <Preparation of Material Recycled Materials> (Recycled Material 1) A film laminated in this order consisting of an LLDPE film (manufactured by Mitsui Chemicals Tocello, product name "TUX FC-S", film thickness 100 μm), an adhesive layer, a PET film (manufactured by Toray Advanced Film, product name "VM-PET 1310", film thickness 12 μm, aluminum vapor deposition), an adhesive layer, and an Ny film (manufactured by Toyobo, product name "Harden Film N1100", film thickness 15 μm) was compressed, cut, and formed into granules to obtain recycled material 1. The adhesive layer was formed by dry lamination using an adhesive mixture of Dick Dry LX-500 (manufactured by DIC Graphics, product name) as the base agent, KW75 (manufactured by DIC Graphics, product name) as the curing agent, and NC401 (manufactured by Toyo Ink, product name) as the solvent.

[0195] (Recycled material 2) A film laminated in this order of an LLDPE film (manufactured by Mitsui Chemicals Tocello, product name "TUX FC-S", film thickness 100 μm), an adhesive layer, an HDPE film (manufactured by Tamapoly, product name "HF31", film thickness 35 μm), an adhesive layer, and an HDPE film (manufactured by Tamapoly, product name "HF31", film thickness 35 μm) was compressed, cut, and formed into granules to obtain recycled material 2. The adhesive layer was formed in the same manner as recycled material 1.

[0196] <Preparation of Chemically Recycled Resin> (CR-PE) Chemically recycled polyethylene (density: 0.94 g / cm 3) was prepared by polymerizing ethylene produced from naphtha obtained by oxygen-free pyrolysis of waste plastic. ３ , MFR: 1.0 g / 10 min.) was obtained.

[0197] (CR-PP) Chemically recycled polypropylene (crystallinity: 48%, MFR: 1.2 g / 10 min) was obtained by polymerizing propylene produced from naphtha obtained by oxygen-free pyrolysis of waste plastics.

[0198] <Preparation of Biomass-Derived Polyethylene Resin> (Biomass LLDPE) Biomass-derived LLDPE "SLL118" (manufactured by Braskem, trade name, density: 0.916 g / cm ３ , MFR: 1.3 g / 10 min, biomass ratio: 87%) was prepared.

[0199] <Preparation of Inorganic Particles> (Inorganic Particles 1) Titanium oxide (titanium oxide PEONY HP WHITE series, model number L-11232-MPT, manufactured by DIC Corporation) was prepared as inorganic particles.

[0200] <Preparation of Sealant Film A> (Example A1) Recycled material 1 was placed in a hopper extruding the recycled material-containing layer, and LLDPE (manufactured by Prime Polymer, product name "EAZ-20") to which 6000 ppm of an anti-blocking agent was added by dry blending was placed in a hopper extruding the sealant layer (manufactured by Prime Polymer, product name "Evolue SP1540"), and a 30 μm thick recycled material-containing layer and a 70 μm thick sealant layer were formed by co-extrusion molding using a single-screw multi-layer extruder, producing a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was minimized to prevent elongational stress from being applied. The molten resin was cooled by an air knife and a cooling roll provided with a matte uneven surface (surface roughness Rz: 6 μm) by sandblasting.

[0201] (Example A2) A sealant film was produced in the same manner as in Example A1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0202] (Example A3) A sealant film was produced in the same manner as in Example A1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0203] (Example A4) A sealant film was produced in the same manner as in Example A1, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0204] (Example A5) A sealant film was produced in the same manner as in Example A1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0205] (Example A6) A sealant film was produced in the same manner as in Example A5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0206] (Example A7) A sealant film was produced in the same manner as in Example A5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0207] (Example A8) A sealant film was produced in the same manner as in Example A5, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0208] (Example A9) A sealant film was produced in the same manner as in Example A2, except that the recycled material 1 and LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") were charged into the hopper for extruding the recycled material-containing layer so as to have a weight ratio of 1:1.

[0209] Example A10 A sealant film was produced in the same manner as in Example A2, except that a block polypropylene resin (bPP) (manufactured by Japan Polypropylene Corporation, product name "Novatec PP BC6DRF") to which 6,000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") had been added by dry blending was placed in a hopper for extruding the sealant layer.

[0210] Example A11 Only recycled material 1 was placed in a hopper extruding the recycled material-containing layer, LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was placed in a hopper extruding the sealant layer, and LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") was placed in a hopper extruding the auxiliary layer, and a 20 μm-thick auxiliary layer, an 80 μm-thick recycled material-containing layer, and a 20 μm-thick sealant layer were formed in this order by coextrusion molding using a single-screw multilayer extruder to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and narrowing of the flow path before the T-die was avoided as much as possible, making it a mechanism that was less susceptible to elongational stress.The molten resin was cooled using an air knife and a cooling roll that had been sandblasted to create a matte, uneven surface (surface roughness Rz: 6 μm) to produce a sealant film.

[0211] Comparative Example A1 A sealant film was prepared in the same manner as in Example A1, except that no antiblocking agent was added to the sealant layer.

[0212] (Comparative Example A2) A sealant film was produced in the same manner as in Example A1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0213] (Comparative Example A3) A sealant film was produced in the same manner as in Example A1, except that recycled material 2 was placed in a hopper for extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer with a thickness of 80 μm and a sealant layer with a thickness of 20 μm.

[0214] (Comparative Example A4) A sealant film was produced in the same manner as in Example A1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm.

[0215] Comparative Example A5 A sealant film was produced in the same manner as in Example A1, except that the amount of the antiblocking agent added was changed to 600 ppm.

[0216] <Surface Roughness of Sealant Layer> The arithmetic surface roughness Ra of the surface of the sealant layer opposite to the recycled material-containing layer side was measured in accordance with JIS B 0601:2001 standard.

[0217] <Reliability evaluation of sealant> Using a heat sealer (model TP-701-B) manufactured by Tester Sangyo, the heat seal layers of the sealant film were overlapped and sealed at a sealing pressure of 0.2 MPa, a sealing time of 1 second, and a sealing width of 10 mm. The heat sealing temperature was set to a temperature approximately 20°C above the melting point of the heat seal layer material (130°C for LLDPE, 180°C for PP). The heat-sealed portion was then observed under a microscope, and the seal was removed by 1 mm. ２ The area ratio of bubbles present in the observation area was determined. When the area ratio of bubbles was 0% or more but less than 5%, it was marked "◎", when it was 5% or more but less than 10%, it was marked "◯", when it was 10% or more but less than 20%, it was marked "△", and when it was 20% or more, it was marked "X".

[0218] <Convex Portions of Laminate Layer> Using a laser microscope (VK-X200 / VK-X210) manufactured by Keyence Corporation, the maximum height H of the convex portions on the surface of the laminate layer opposite to the recycled material-containing layer (the difference in height between the highest peak and the deepest valley in a predetermined section) and the width W at half the maximum height H of the convex portions were measured, and the ratio [W / H] to the maximum height H was calculated.

[0219] <Film-formability evaluation> The appearance of the film was visually observed from film formation to winding, and the film-formability was evaluated according to the following criteria: "Good": No folds or wrinkles were observed from film formation to winding, and no poor appearance due to folds or wrinkles was observed in the film after winding. "Poor": Folds or wrinkles were observed from film formation to winding, and poor appearance due to folds or wrinkles was observed in the film after winding.

[0220]

[0221]

[0222] As shown in Tables 1 and 2, it was confirmed that the sealant films of Examples A1 to A11 had sufficient reliability during heat sealing and film-forming properties while containing recycled materials. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in sealant films and packaging materials.

[0223] <Preparation of Sealant Film B> (Example B1) Recycled material 1 was charged into a hopper extruding the recycled material-containing layer, and CR-PE to which 6000 ppm of an anti-blocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was charged into a hopper extruding the sealant layer. A 30 μm thick recycled material-containing layer and a 70 μm thick sealant layer were formed by co-extrusion molding using a single-screw multi-layer extruder, and a sealant film was produced. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was minimized, making it difficult for elongation stress to be applied. The molten resin was cooled by an air knife and a cooling roll provided with a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting.

[0224] (Example B2) A sealant film was produced in the same manner as in Example B1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0225] (Example B3) A sealant film was produced in the same manner as in Example B1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0226] (Example B4) A sealant film was produced in the same manner as in Example B1, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0227] (Example B5) A sealant film was produced in the same manner as in Example B1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0228] (Example B6) A sealant film was produced in the same manner as in Example B5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0229] (Example B7) A sealant film was produced in the same manner as in Example B5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0230] (Example B8) A sealant film was produced in the same manner as in Example B5, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0231] Example B9 A sealant film was produced in the same manner as in Example B2, except that the recycled material 1 and CR-PE were charged into the hopper for extruding the recycled material-containing layer so that the weight ratio was 1:1.

[0232] Example B10 A sealant film was produced in the same manner as in Example B2, except that CR-PP to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") had been added by dry blending was placed in a hopper for extruding the sealant layer.

[0233] (Example B11) Only recycled material 1 was added to the hopper extruding the recycled material-containing layer, and CR-PE to which 6000 ppm of an anti-blocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was added to the hopper extruding the sealant layer. CR-PE was added to the hopper extruding the auxiliary layer, and a 20 μm thick auxiliary layer, an 80 μm thick recycled material-containing layer, and a 20 μm thick sealant layer were formed in this order by co-extrusion molding using a single-screw multi-layer extruder. A sealant film was produced. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and narrowing of the flow path before the T-die was minimized to prevent elongational stress from being applied. The molten resin was cooled by a cooling roll provided with an air knife and a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting to produce a sealant film.

[0234] Comparative Example B1 A sealant film was prepared in the same manner as in Example B1, except that no antiblocking agent was added to the sealant layer.

[0235] (Comparative Example B2) A sealant film was produced in the same manner as in Example B1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0236] (Comparative Example B3) A sealant film was produced in the same manner as in Example B1, except that recycled material 2 was placed in a hopper for extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer with a thickness of 80 μm and a sealant layer with a thickness of 20 μm.

[0237] (Comparative Example B4) A sealant film was produced in the same manner as in Example B1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm.

[0238] Comparative Example B5 A sealant film was produced in the same manner as in Example B1, except that the amount of the antiblocking agent added was changed to 600 ppm.

[0239] <Evaluation of sealant film> In the same manner as described above, the surface roughness of the sealant layer, reliability at the time of sealing, convex portions of the laminate layer, and film formability were measured, and the environmental impact was evaluated as follows.

[0240] (Environmental Impact) The environmental impact of the sealant film was evaluated using the following criteria. [Evaluation Criteria] ⊚: The content of plastic materials contained in the recycled materials (including chemically recycled resins) in the sealant film was 100% by mass, based on the total amount of plastic materials in the sealant film, and the content of material recycled materials was 50% by mass or more, based on the total amount of plastic materials in the sealant film. ◯: The content of plastic materials contained in the recycled materials (including chemically recycled resins) in the sealant film was 100% by mass, based on the total amount of plastic materials in the sealant film, and the content of material recycled materials was less than 50% by mass. Δ: The content of plastic materials contained in the recycled materials (including chemically recycled resins) in the sealant film was 90% by mass or more and less than 100% by mass, based on the total amount of plastic materials in the sealant film. ×: The content of plastic materials contained in the recycled materials (including chemically recycled resins) in the sealant film was less than 90% by mass, based on the total amount of plastic materials in the sealant film.

[0241]

[0242]

[0243] As shown in Tables 3 and 4, it was confirmed that the sealant films of Examples B1 to B11 had sufficient reliability during heat sealing and film-forming properties while containing recycled materials. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in sealant films and packaging materials.

[0244] <Preparation of Sealant Film C> (Example C1) Recycled material 1 was placed in a hopper extruding the recycled material-containing layer, and biomass LLDPE to which 6000 ppm of an anti-blocking agent (manufactured by Prime Polymer, product name "EAZ-20") had been added by dry blending was placed in a hopper extruding the sealant layer. A 30 μm thick recycled material-containing layer and a 70 μm thick sealant layer were formed by co-extrusion molding using a single-screw multi-layer extruder, producing a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was minimized to prevent elongational stress. The molten resin was cooled using an air knife and a cooling roll provided with a matte uneven surface (surface roughness Rz: 6 μm) by sandblasting.

[0245] (Example C2) A sealant film was produced in the same manner as in Example C1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0246] (Example C3) A sealant film was produced in the same manner as in Example C1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0247] (Example C4) A sealant film was produced in the same manner as in Example C1, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0248] (Example C5) A sealant film was produced in the same manner as in Example C1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0249] (Example C6) A sealant film was produced in the same manner as in Example C5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0250] (Example C7) A sealant film was produced in the same manner as in Example C5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0251] (Example C8) A sealant film was produced in the same manner as in Example C5, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0252] Example C9 A sealant film was produced in the same manner as in Example C2, except that the recycled material 1 and biomass LLDPE were charged into a hopper for extruding the recycled material-containing layer so that the weight ratio was 1:1.

[0253] (Example C10) Only recycled material 1 was charged into the hopper extruding the recycled material-containing layer, and biomass LLDPE with 6000 ppm of anti-blocking agent (manufactured by Prime Polymer, product name "EAZ-20") added by dry blending was charged into the hopper extruding the sealant layer. Biomass LLDPE was charged into the hopper extruding the auxiliary layer, and a 20 μm thick auxiliary layer, an 80 μm thick recycled material-containing layer, and a 20 μm thick sealant layer were formed in this order by co-extrusion molding using a single-screw multi-layer extruder to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and narrowing of the flow path before the T-die was minimized to prevent elongational stress from being applied. The molten resin was cooled by a cooling roll provided with an air knife and a matte uneven surface (surface roughness Rz: 6 μm) by sandblasting to produce a sealant film.

[0254] Comparative Example C1 A sealant film was prepared in the same manner as in Example C1, except that no antiblocking agent was added to the sealant layer.

[0255] (Comparative Example C2) A sealant film was produced in the same manner as in Example C1, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0256] (Comparative Example C3) A sealant film was produced in the same manner as in Example C1, except that recycled material 2 was placed in a hopper for extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer with a thickness of 80 μm and a sealant layer with a thickness of 20 μm.

[0257] (Comparative Example C4) A sealant film was produced in the same manner as in Example C1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm.

[0258] Comparative Example C5 A sealant film was produced in the same manner as in Example C1, except that the amount of the antiblocking agent added was changed to 600 ppm.

[0259] <Evaluation of sealant film> In the same manner as described above, the surface roughness of the sealant layer was measured, the reliability of the sealant was evaluated, the convex portions of the laminate layer were evaluated, and the film formability was evaluated. Furthermore, the biomass degree was evaluated as follows.

[0260] (Biomass Degree) The biomass degree of a sealant film was calculated by measuring the concentration of radioactive carbon (C14) to calculate the content of biomass-derived carbon, and evaluated according to the following criteria. [Evaluation Criteria] ⊚: The content of biomass raw materials in the sealant film is 30% by mass or more, based on the total mass of the sealant film. ○: The content of biomass raw materials in the sealant film is 15% by mass or more and less than 30% by mass, based on the total mass of the sealant film. △: The content of biomass raw materials in the sealant film is 5% by mass or more and less than 15% by mass, based on the total mass of the sealant film. ×: The content of biomass raw materials in the sealant film is less than 5% by mass, based on the total mass of the sealant film.

[0261]

[0262]

[0263] As shown in Tables 5 and 6, the sealant films of Examples C1 to C10 were confirmed to have sufficient reliability during heat sealing and film-forming properties while containing recycled materials. Furthermore, the sealant films of Examples C1 to C10 contained 5% or more by mass of biomass raw materials, which can increase the biomass content of plastic-containing products. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in sealant films and packaging materials.

[0264] <Preparation of sealant film D> (Example D1) Recycled material 1 was charged into a hopper extruding the recycled material-containing layer, and LLDPE (manufactured by Prime Polymer, product name "EAZ-20") to which 6000 ppm of an anti-blocking agent was added by dry blending was charged into a hopper extruding the sealant layer (manufactured by Prime Polymer, product name "Evolue SP1540"), and a 30 μm thick recycled material-containing layer and a 70 μm thick sealant layer were formed by co-extrusion molding using a single-screw multi-layer extruder, to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was minimized, making it difficult for elongational stress to be applied. The molten resin was cooled by an air knife and a cooling roll provided with a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting.

[0265] The surface of the sealant film obtained above opposite to the sealant layer side was irradiated with electron beams using an electron beam irradiation device (line irradiation type low energy electron beam irradiation device EES-L-DP01, manufactured by Hamamatsu Photonics K.K.) under the following conditions: (Irradiation conditions) Voltage: 120 kV, Exposure dose: 100 kGy, Oxygen concentration in the device: 100 ppm or less, Line speed: 25 m / min

[0266] (Example D2) A sealant film was produced in the same manner as in Example D1, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm, and the sealant film was irradiated with electron beams.

[0267] (Example D3) A sealant film was produced in the same manner as in Example D1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm, and the sealant film was irradiated with electron beams.

[0268] (Example D4) A sealant film was produced in the same manner as in Example D1, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm, and the sealant film was irradiated with an electron beam.

[0269] (Example D5) A sealant film was produced in the same manner as in Example D1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm, and then the sealant film was irradiated with an electron beam.

[0270] (Example D6) A sealant film was produced in the same manner as in Example D5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm, and the sealant film was irradiated with electron beams under the same conditions as in Example D1.

[0271] (Example D7) A sealant film was produced in the same manner as in Example D5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm, and the sealant film was irradiated with electron beams under the same conditions as in Example D1.

[0272] (Example D8) A sealant film was produced in the same manner as in Example D5, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm, and the sealant film was irradiated with electron beams under the same conditions as in Example D1.

[0273] (Example D9) A sealant film was produced in the same manner as in Example D2, except that the recycled material 1 and LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") were added to the hopper extruding the recycled material-containing layer in a weight ratio of 1:1, and the sealant film was irradiated with electron beams under the same conditions as in Example D1.

[0274] Example D10 A sealant film was produced in the same manner as in Example D2, except that a block PP (manufactured by Japan Polypropylene Corporation, product name "Novatec PP BC6DRF") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was placed in a hopper for extruding the sealant layer, and the sealant film was irradiated with an electron beam under the same conditions as in Example D1.

[0275] (Example D11) Only recycled material 1 was placed in a hopper extruding the recycled material-containing layer, and LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was placed in a hopper extruding the sealant layer. LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") was placed in a hopper extruding the auxiliary layer, and a 20 μm-thick auxiliary layer, an 80 μm-thick recycled material-containing layer, and a 20 μm-thick sealant layer were formed in this order by coextrusion molding using a single-screw multilayer extruder to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and narrowing of the flow path before the T-die was avoided as much as possible, making it a mechanism that was less susceptible to elongational stress.The molten resin was cooled using an air knife and a cooling roll that had been sandblasted to create a matte, uneven surface (surface roughness Rz: 6 μm) to produce a sealant film.

[0276] The sealant film obtained above was irradiated with electron beams in the same manner as in Example D1.

[0277] Reference Example 1 A commercially available PE sealant film (manufactured by Tamapoly Co., Ltd., product name "MZ434") was prepared.

[0278] Comparative Example D1 A sealant film was prepared in the same manner as in Example D1, except that no antiblocking agent was added to the sealant layer, and was irradiated with electron beams.

[0279] (Comparative Example D2) A sealant film was produced in the same manner as in Example D1, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm, and the sealant film was irradiated with electron beams.

[0280] (Comparative Example D3) A sealant film was produced in the same manner as in Example D1, except that recycled material 2 was placed in a hopper for extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm, and the sealant film was irradiated with an electron beam.

[0281] (Comparative Example D4) A sealant film was produced in the same manner as in Example D1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm, and the sealant film was irradiated with an electron beam.

[0282] Comparative Example D5 A sealant film was prepared in the same manner as in Example D1, except that the amount of the antiblocking agent added was changed to 600 ppm, and the film was irradiated with an electron beam.

[0283] <Evaluation of sealant film> In the same manner as described above, the surface roughness of the sealant layer was measured, the reliability of the sealant was evaluated, the convex portions of the laminate layer were evaluated, and the film formability was evaluated. Furthermore, the puncture strength was evaluated as follows.

[0284] (Puncture Strength) A test piece measuring 50 mm x 50 mm was cut out from the sealant film. Using a Tenshiro AD-7703 (product name, manufactured by A&D Co., Ltd.) and a dedicated semicircular needle with a diameter of 1.0 mm and a tip radius of 0.5 mm, the maximum force (N) until the needle penetrated was measured under conditions of a test speed of 50 mm / min, a load cell of 100 N, and a load range of 10 N (10%), and this was evaluated as the puncture strength. At this time, if the strength was 1 time or more but less than 1.5 times that of a commercially available sealant film (Reference Example 1), it was evaluated as "○", and if it was lower than that of the commercially available sealant film, it was evaluated as "×".

[0285]

[0286]

[0287] As shown in Tables 7 and 8, it was confirmed that the sealant films of Examples D1 to D11 had sufficient reliability during heat sealing, puncture strength, and film formability while containing recycled materials. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in sealant films and packaging materials.

[0288] <Preparation of Sealant Film E> (Example E1) Recycled material 1 was placed in a hopper for extruding the recycled material-containing layer, and inorganic particles 1 were also placed so that the content in the recycled material-containing layer was 10% by mass. LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") had been added by dry blending was placed in the hopper for extruding the sealant layer, and a 30 μm-thick recycled material-containing layer and a 70 μm-thick sealant layer were formed by coextrusion molding using a single-screw multi-layer extruder, thereby producing a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was avoided as much as possible to create a mechanism that was less susceptible to elongational stress. The molten resin was cooled using an air knife and a cooling roll that had been sandblasted to form a matte-like uneven surface (surface roughness Rz: 6 μm).

[0289] (Example E2) A sealant film was produced in the same manner as in Example E1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0290] (Example E3) A sealant film was produced in the same manner as in Example E1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0291] (Example E4) A sealant film was produced in the same manner as in Example E1, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0292] (Example E5) A sealant film was produced in the same manner as in Example E1, except that recycled material 2 was added to the hopper extruding the recycled material-containing layer instead of recycled material 1, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm.

[0293] (Example E6) A sealant film was produced in the same manner as in Example E5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0294] (Example E7) A sealant film was produced in the same manner as in Example E5, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0295] (Example E8) A sealant film was produced in the same manner as in Example E5, except that the molten resin was cooled under a pressure of 1.4 MPa using a nip roll (material: fluororesin) and a cooling roll having a matte texture (surface roughness Rz: 6 μm) formed by sandblasting, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm.

[0296] (Example E9) A sealant film was produced in the same manner as in Example E2, except that the recycled material 1 and LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") were charged into the hopper for extruding the recycled material-containing layer so as to have a weight ratio of 1:1.

[0297] Example E10 A sealant film was produced in the same manner as in Example E2, except that blocked PP (manufactured by Japan Polypropylene Corporation, product name "Novatec PP BC6DRF") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") had been added by dry blending was placed in a hopper for extruding the sealant layer.

[0298] Example E11 Recycled material 1 was placed in a hopper extruding the recycled material-containing layer, and inorganic particles 1 were also placed so that the content in the recycled material-containing layer was 10% by mass. LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") had been added by dry blending was placed in a hopper extruding the sealant layer, and LLDPE (manufactured by Prime Polymer, product name "Evolue SP2040") was placed in a hopper extruding the auxiliary layer. A 20 μm-thick auxiliary layer, an 80 μm-thick recycled material-containing layer, and a 20 μm-thick sealant layer were formed in this order by coextrusion molding using a single-screw multilayer extruder to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and narrowing of the flow path before the T-die was avoided as much as possible, making it a mechanism that was less susceptible to elongational stress.The molten resin was cooled using an air knife and a cooling roll that had been sandblasted to create a matte, uneven surface (surface roughness Rz: 6 μm) to produce a sealant film.

[0299] Example E12 A sealant film was produced in the same manner as in Example E11, except that recycled material 1 was added to a hopper for extruding the recycled material-containing layer, and inorganic particles 1 were further added so that their content in the recycled material-containing layer was 5% by mass, and LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") was added to a hopper for extruding the auxiliary layer, and inorganic particles 1 were further added so that their content in the auxiliary layer was 20% by mass.

[0300] (Example E13) A sealant film was produced in the same manner as in Example E11, except that only recycled material 1 was added to the hopper extruding the recycled material-containing layer, LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") was added to the hopper extruding the auxiliary layer, and inorganic particles 1 were further added so that their content in the auxiliary layer was 40 mass%.

[0301] Example E14 A sealant film was produced in the same manner as in Example E2, except that the amount of inorganic particles 1 added was adjusted so that the content in the recycled material-containing layer was 5% by mass.

[0302] Example E15 A sealant film was produced in the same manner as in Example E2, except that the amount of inorganic particles 1 added was adjusted so that the content in the recycled material-containing layer was 7% by mass.

[0303] Example E16 A sealant film was produced in the same manner as in Example E2, except that the amount of inorganic particles 1 added was adjusted so that the content in the recycled material-containing layer was 20 mass %.

[0304] Example E17 A sealant film was produced in the same manner as in Example E2, except that the amount of inorganic particles 1 added was adjusted so that the content in the recycled material-containing layer was 23 mass %.

[0305] Comparative Example E1 A sealant film was prepared in the same manner as in Example E1, except that no antiblocking agent was added to the sealant layer.

[0306] (Comparative Example E2) A sealant film was produced in the same manner as in Example E1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm.

[0307] (Comparative Example E3) A sealant film was produced in the same manner as in Example E1, except that recycled material 2 was placed in a hopper for extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer with a thickness of 80 μm and a sealant layer with a thickness of 20 μm.

[0308] (Comparative Example E4) A sealant film was produced in the same manner as in Example E1, except that recycled material 2 was added to a hopper for extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm.

[0309] Comparative Example E5 A sealant film was produced in the same manner as in Example E1, except that the amount of the antiblocking agent added was changed to 600 ppm.

[0310] (Comparative Example E6) A sealant film was produced in the same manner as in Example E1, except that the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer with a thickness of 95 μm and a sealant layer with a thickness of 5 μm, and inorganic particles 1 were not added to the hopper used to extrude the recycled material-containing layer.

[0311] <Evaluation of sealant film> In the same manner as described above, the surface roughness of the sealant layer, the reliability at the time of sealing, the convex portions of the laminate layer, and the film formability were measured, and further the appearance (hiding ability) was evaluated as follows.

[0312] (Appearance: Concealment) The concealment of the sealant film obtained in each example was evaluated using a portable transmission densitometer (model number 341C) manufactured by X-RITE Corp. When the measured transmission density was less than 0.20, it was evaluated as "x", when the transmission density was 0.20 or more and less than 0.40, it was evaluated as "Δ", when the transmission density was 0.40 or more and less than 0.50, it was evaluated as "◯", and when the transmission density was 0.50 or more, it was evaluated as "◎".

[0313]

[0314]

[0315]

[0316]

[0317] As shown in Tables 9 to 11, the sealant films of Examples E1 to E17 were confirmed to have sufficient reliability during heat sealing and film-forming properties despite containing recycled materials. Furthermore, the sealant films of Examples E1 to E15 were confirmed to have sufficient hiding power due to the incorporation of inorganic particles. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in sealant films and packaging materials.

[0318] <Preparation of sealant film and laminate F> (Example F1) Recycled material 1 was charged into a hopper extruding the recycled material-containing layer, and LLDPE (manufactured by Prime Polymer, product name "EAZ-20") to which 6000 ppm of anti-blocking agent was added by dry blending was charged into a hopper extruding the sealant layer (manufactured by Prime Polymer, product name "Evolue SP1540"), and a 30 μm thick recycled material-containing layer and a 70 μm thick sealant layer were formed by co-extrusion molding using a single-screw multi-layer extruder, and a sealant film was produced. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was minimized, making it difficult to apply elongation stress. The molten resin was cooled by an air knife and a cooling roll provided with a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting.

[0319] Next, a 40 nm thick vapor deposition layer (aluminum vapor deposition layer) made of aluminum was formed on the recycled material-containing layer of the sealant film obtained above using a vacuum deposition device using an electron beam heating method, thereby producing a laminate.

[0320] (Example F2) A sealant film was produced in the same manner as in Example F1, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer with a thickness of 80 μm and a sealant layer with a thickness of 20 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0321] (Example F3) A sealant film was produced in the same manner as in Example F1, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0322] (Example F4) A sealant film was produced in the same manner as in Example F1, except that a nip roll (material: fluororesin) and a cooling roll having a matte uneven surface (surface roughness Rz: 6 μm) formed by sandblasting were used to cool the molten resin under a pressure of 1.4 MPa, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0323] (Example F5) A sealant film was produced in the same manner as in Example F1, except that recycled material 2 was added to a hopper extruding the recycled material-containing layer, and the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0324] (Example F6) A sealant film was produced in the same manner as in Example F5, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm) to form a recycled material-containing layer with a thickness of 90 μm and a sealant layer with a thickness of 10 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0325] (Example F7) A sealant film was produced in the same manner as in Example F5, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer with a thickness of 95 μm and a sealant layer with a thickness of 5 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0326] (Example F8) A sealant film was produced in the same manner as in Example F5, except that a nip roll (material: fluororesin) and a cooling roll having a matte uneven surface (surface roughness Rz: 6 μm) formed by sandblasting were used to cool the molten resin under a pressure of 1.4 MPa, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm), thereby forming a recycled material-containing layer with a thickness of 90 μm and a sealant layer with a thickness of 10 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0327] (Example F9) A sealant film was produced in the same manner as in Example F2, except that the recycled material 1 and LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") were added to the hopper extruding the recycled material-containing layer so as to have a weight ratio of 1:1.

[0328] Next, a transparent vapor deposition layer (aluminum vapor deposition layer) made of aluminum having a thickness of 40 nm was formed on the auxiliary layer of the sealant film obtained above using a vacuum deposition apparatus using an electron beam heating method, thereby producing a laminate.

[0329] Example F10 A sealant film was produced in the same manner as in Example F2, except that blocked PP (manufactured by Japan Polypropylene Corporation, product name "Novatec PP BC6DRF") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was added into a hopper for extruding the sealant layer.

[0330] Next, a transparent vapor deposition layer (aluminum vapor deposition layer) made of aluminum having a thickness of 40 nm was formed on the auxiliary layer of the sealant film obtained above using a vacuum deposition apparatus using an electron beam heating method, thereby producing a laminate.

[0331] Example F11 Only recycled material 1 was placed in a hopper extruding the recycled material-containing layer, LLDPE (manufactured by Prime Polymer, product name "Evolue SP2040") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was placed in a hopper extruding the sealant layer, and LLDPE (manufactured by Prime Polymer, product name "Evolue SP2040") was placed in a hopper extruding the auxiliary layer, and a 20 μm-thick auxiliary layer, an 80 μm-thick recycled material-containing layer, and a 20 μm-thick sealant layer were formed in this order by coextrusion molding using a single-screw multilayer extruder to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and narrowing of the flow path before the T-die was avoided as much as possible to create a mechanism that was less susceptible to elongational stress. The molten resin was cooled using an air knife and a cooling roll that had been sandblasted to provide a matte-like uneven surface (surface roughness Rz: 6 μm).

[0332] Next, a transparent vapor deposition layer (aluminum vapor deposition layer) made of aluminum having a thickness of 40 nm was formed on the auxiliary layer of the sealant film obtained above using a vacuum deposition apparatus using an electron beam heating method, thereby producing a laminate.

[0333] Example F12 A sealant film was produced in the same manner as in Example F11, except that EVOH (manufactured by Kuraray Co., Ltd., product name "EVAL L171B") was charged into the hopper for extruding the auxiliary layer instead of LLDPE.

[0334] Next, a transparent vapor deposition layer (aluminum vapor deposition layer) made of aluminum having a thickness of 40 nm was formed on the auxiliary layer of the sealant film obtained above using a vacuum deposition apparatus using an electron beam heating method, thereby producing a laminate.

[0335] (Comparative Example F1) Except for not adding an antiblocking agent to the sealant layer, a sealant film was produced in the same manner as in Example 1. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1 to produce a laminate.

[0336] (Comparative Example F2) A sealant film was produced in the same manner as in Example F1, except that the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0337] (Comparative Example F3) A sealant film was produced in the same manner as in Example F1, except that recycled material 2 was charged into a hopper for extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0338] (Comparative Example F4) A sealant film was produced in the same manner as in Example F1, except that recycled material 2 was charged into a hopper for extruding the recycled material-containing layer, and the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0339] Comparative Example F5: A sealant film was produced in the same manner as in Example F1, except that the amount of antiblocking agent added was changed to 600 ppm. Next, an aluminum vapor-deposited layer was formed on this sealant film in the same manner as in Example F1, to produce a laminate.

[0340] <Evaluation of Sealant Film> Measurement of the surface roughness of the sealant layer, evaluation of reliability during sealing, evaluation of convex portions of the laminate layer, and evaluation of film formability were carried out in the same manner as described above.

[0341] <Evaluation of Laminate> The gas barrier properties of the laminate were evaluated as follows.

[0342] (Gas barrier properties) A ​​water vapor transmission rate measuring device manufactured by MOCON (product name: PERMATRAN3 / 34G, measurement conditions: 40°C-90% RH, unit: g / (m ２ The water vapor transmission rate (WVTR) of the laminates obtained in each example and comparative example was evaluated using the water vapor transmission rate (WVTR) of the laminates obtained in each example and comparative example. The measurement method was in accordance with JIS K-7129-2:2019. ２ If it is smaller than 3g / (m ２ ・day) or more 5g / (m ２ ・day) or less is marked as "○", 5g / (m ２ If the value was greater than 1000 days, it was evaluated as "x".

[0343]

[0344]

[0345]

[0346] As shown in Tables 13 and 14, the sealant films and laminates of Examples F1 to F12 were confirmed to have sufficient reliability and film-forming properties during heat sealing while containing recycled materials, as well as excellent gas barrier properties. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in laminates and packaging materials.

[0347] <Preparation of sealant film and laminate G> (Example G1) Recycled material 1 was charged into a hopper extruding the recycled material-containing layer, and LLDPE (manufactured by Prime Polymer, product name "EAZ-20") to which 6000 ppm of anti-blocking agent was added by dry blending was charged into a hopper extruding the sealant layer (manufactured by Prime Polymer, product name "Evolue SP1540"), and a 30 μm thick recycled material-containing layer and a 70 μm thick sealant layer were formed by co-extrusion molding using a single-screw multi-layer extruder, and a sealant film was produced. The screw rotation speed when extruding the recycled material-containing layer was 16 rpm, and narrowing of the flow path before the T-die was minimized, making it difficult for elongational stress to be applied. The molten resin was cooled by an air knife and a cooling roll provided with a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting.

[0348] Next, a solvent-free adhesive TSN-4864A / TSN-4864B3 (manufactured by Toyo-Morton Co., Ltd.) (a mixture of the base agent TSN-4864A and the curing agent TSN-4864B3 in a weight ratio of 1:1) was applied to a silica-deposited PET film (manufactured by TOPPAN HOLDINGS, "GL-RD", PET film thickness 12 μm, silica-deposited). ２ The coated film was then laminated to the recycled material-containing layer of the sealant film to prepare a laminate.

[0349] (Example G2) The extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm), and a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm were formed in the same manner as in Example G1, except that a sealant film was produced. Then, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0350] (Example G3) Extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm), and a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm were formed, except that a sealant film was produced in the same manner as in Example G1. Then, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0351] (Example G4) A sealant film was produced in the same manner as in Example G1, except that a nip roll (material: fluororesin) and a cooling roll having a matte uneven surface (surface roughness Rz: 6 μm) formed by sandblasting were used to cool the molten resin under a pressure of 1.4 MPa, and the extrusion amount of each layer was adjusted to form a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0352] (Example G5) The recycled material 2 was put into the hopper extruding the recycled material-containing layer, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm), so that a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm were formed. A sealant film was produced in the same manner as in Example G1. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0353] (Example G6) Extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm), and a recycled material-containing layer having a thickness of 90 μm and a sealant layer having a thickness of 10 μm were formed in the same manner as in Example G5, except that a sealant film was produced. Then, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0354] (Example G7) Except that the extrusion amount of each layer is adjusted (the screw rotation speed when extruding the recycled material-containing layer is changed to 51 rpm), a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm are formed, a sealant film is produced in the same manner as in Example G5. Then, a laminate is produced in the same manner as in Example G1, except that this sealant film is used.

[0355] (Example G8) Using a nip roll (material: fluororesin) and a cooling roll having a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting, the molten resin was cooled under a pressure of 1.4 MPa, and the extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 48 rpm), so that a recycled material-containing layer with a thickness of 90 μm and a sealant layer with a thickness of 10 μm were formed. A sealant film was produced in the same manner as in Example G5. Then, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0356] Example G9 Recycled material 1 was placed in a hopper extruding the recycled material-containing layer, LLDPE (manufactured by Prime Polymer, product name "Evolue SP1540") to which 6000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was placed in a hopper extruding the sealant layer, and LLDPE (manufactured by Prime Polymer, product name "Evolue SP2040") was placed in a hopper extruding the auxiliary layer, and a 20 μm thick auxiliary layer, an 80 μm thick recycled material-containing layer, and a 20 μm thick sealant layer were formed by coextrusion molding using a single-screw multilayer extruder to produce a sealant film. The screw rotation speed when extruding the recycled material-containing layer was 43 rpm, and the narrowing of the flow path before the T-die was avoided as much as possible, making it a mechanism that is less susceptible to elongational stress, and the molten resin was cooled using an air knife and a cooling roll provided with a matte uneven shape (surface roughness Rz: 6 μm) by sandblasting. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0357] (Example G10) A sealant film was produced in the same manner as in Example G2, except that the recycled material 1 and LLDPE (manufactured by Prime Polymer Co., Ltd., product name "Evolue SP2040") were charged into the hopper extruding the recycled material-containing layer at a weight ratio of 1: 1. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0358] Example G11 A sealant film was produced in the same manner as in Example G2, except that blocked PP (manufactured by Japan Polypropylene Corporation, product name "Novatec PP BC6DRF") to which 6,000 ppm of an antiblocking agent (manufactured by Prime Polymer, product name "EAZ-20") was added by dry blending was placed into a hopper for extruding the sealant layer. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0359] (Example G12) A sealant film was produced in the same manner as in Example G1. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solventless adhesive.

[0360] (Example G13) A sealant film was produced in the same manner as in Example G2. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solvent-free adhesive.

[0361] (Example G14) A sealant film was produced in the same manner as in Example G3. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solventless adhesive.

[0362] (Example G15) A sealant film was produced in the same manner as in Example G4. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solventless adhesive.

[0363] (Example G16) A sealant film was produced in the same manner as in Example G5. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solventless adhesive.

[0364] (Example G17) A sealant film was produced in the same manner as in Example G6. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solventless adhesive.

[0365] (Example G18) A sealant film was produced in the same manner as in Example G7. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solventless adhesive.

[0366] (Example G19) A sealant film was produced in the same manner as in Example G8. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solvent-free adhesive.

[0367] (Example G20) A sealant film was produced in the same manner as in Example G9. Next, using this sealant film, a laminate was produced in the same manner as in Example G1, except that a solvent-based adhesive containing an organic solvent, "Takelac A626 (manufactured by Mitsui Chemicals, Inc.)" and "Takenate A-50 (manufactured by Mitsui Chemicals, Inc.)," ​​mixed at a weight ratio of 8:1, was used instead of the solvent-free adhesive.

[0368] (Comparative Example G1) A sealant film was produced in the same manner as in Example G1, except that no antiblocking agent was added to the sealant layer. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0369] (Comparative Example G2) The extrusion amount of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 51 rpm) to form a recycled material-containing layer having a thickness of 95 μm and a sealant layer having a thickness of 5 μm, except that the sealant film was produced in the same manner as in Example G1. Next, a laminate was produced in the same manner as in Example G1, except that the sealant film was used.

[0370] (Comparative Example G3) A sealant film was produced in the same manner as in Example G1, except that recycled material 2 was charged into the hopper extruding the recycled material-containing layer, no antiblocking agent was added to the sealant layer, and the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 43 rpm) to form a recycled material-containing layer having a thickness of 80 μm and a sealant layer having a thickness of 20 μm. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0371] (Comparative Example G4) A sealant film was produced in the same manner as in Example G1, except that recycled material 2 was added to the hopper extruding the recycled material-containing layer, and the extrusion rate of each layer was adjusted (the screw rotation speed when extruding the recycled material-containing layer was changed to 52 rpm) to form a recycled material-containing layer having a thickness of 98 μm and a sealant layer having a thickness of 2 μm. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0372] Comparative Example G5 A sealant film was produced in the same manner as in Example G1, except that the amount of antiblocking agent added was changed to 600 ppm. Next, a laminate was produced in the same manner as in Example G1, except that this sealant film was used.

[0373] <Evaluation of Sealant Film> Measurement of the surface roughness of the sealant layer, evaluation of reliability during sealing, evaluation of convex portions of the laminate layer, and evaluation of film formability were carried out in the same manner as described above.

[0374] <Evaluation of Appearance of Laminate (Packaging Material)> The laminates (packaging materials) produced in each of the Examples and Comparative Examples were evaluated for appearance (bubbles) as follows.

[0375] (Appearance: bubbles) Each laminate obtained in each Example and Comparative Example was cut into a square of 100 mm square and evaluated based on the following criteria: [Evaluation criteria] ⊚: No bubbles with a diameter of 0.1 mm or more are present. ◯: Bubbles with a diameter of 0.1 mm or more but less than 0.5 mm are present. Δ: Bubbles with a diameter of 0.5 mm or more but less than 1 mm are present. ×: Bubbles with a diameter of 1 mm or more are present.

[0376]

[0377]

[0378]

[0379]

[0380] As shown in Tables 16 to 19, the sealant films and laminates of Examples G1 to G20 were confirmed to have sufficient reliability and film-forming properties during heat sealing while containing recycled materials, and also to have excellent appearance. Therefore, according to the present invention, material recycling of recycled materials containing two or more resins can be realized in laminates and packaging materials.

[0381] 1a, 1b... sealant film, 2... recycled material-containing layer, 3... sealant layer, 4... auxiliary layer, 5... adhesive layer, 6... base film, 7... printed layer, 10a, 10b, 10c, 10d... laminate, 12... gas barrier layer, 50... aggregate, 100, 101, 102... packaging material.

Claims

1. A sealant film comprising a recycled material-containing layer containing recycled material containing two or more types of resin, and a sealant layer laminated on one main surface of the recycled material-containing layer, wherein the arithmetic surface roughness of the surface of the sealant layer opposite to the recycled material-containing layer is 0.5 μm or more and 5 μm or less.

2. The sealant film according to claim 1, wherein at least one of the recycled material-containing layer and the sealant layer contains a chemically recycled resin.

3. The sealant film according to claim 1, wherein the sealant film contains a polyethylene resin derived from biomass.

4. The sealant film according to claim 1, wherein the sealant film has been subjected to an electron beam irradiation treatment.

5. The sealant film according to claim 1, wherein the sealant film contains inorganic particles.

6. The sealant film according to claim 1, wherein the thickness of the sealant layer is from 5 μm to 70 μm.

7. A sealant film as described in claim 1, wherein the maximum height H of the protrusions on the surface of the sealant layer is 0.5 μm or more and 10 μm or less, and the ratio [W / H] of the width W at half the maximum height H to the maximum height H of the protrusions having the maximum height H is 20 or less.

8. The sealant film according to claim 1, wherein the resin having the largest content among the two or more types of resin contained in the recycled material is a polyethylene-based resin or a polypropylene-based resin.

9. The sealant film according to claim 1, further comprising an auxiliary layer laminated on the other main surface of the recycled material-containing layer.

10. The sealant film according to claim 9, wherein the auxiliary layer contains the same type of virgin resin as the resin having the highest content in the recycled material-containing layer.

11. A laminate comprising the sealant film according to any one of claims 1 to 10, and a gas barrier layer provided on the surface of the sealant film opposite to the sealant layer side.

12. A laminate comprising, in this order, the sealant film according to any one of claims 1 to 10, an adhesive layer, and a base film.

13. A packaging material comprising the sealant film according to any one of claims 1 to 10.

14. The packaging material according to claim 13, wherein the content of plastic material contained in the recycled material is 10 mass% or more based on the total amount of plastic material in the packaging material.

15. A packaging bag made from the packaging material according to claim 13.

16. A packaging bag made from the packaging material according to claim 14.

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