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WO2024248080A1 - Matériau d'emballage, sac d'emballage et emballage - Google Patents

Matériau d'emballage, sac d'emballage et emballage Download PDF

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Publication number
WO2024248080A1
WO2024248080A1 PCT/JP2024/019829 JP2024019829W WO2024248080A1 WO 2024248080 A1 WO2024248080 A1 WO 2024248080A1 JP 2024019829 W JP2024019829 W JP 2024019829W WO 2024248080 A1 WO2024248080 A1 WO 2024248080A1
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WO
WIPO (PCT)
Prior art keywords
layer
film
packaging material
mass
resin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/019829
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English (en)
Japanese (ja)
Inventor
充裕 柏
敦史 山崎
卓郎 遠藤
徹 今井
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Toyobo Co Ltd
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Toyobo Co Ltd
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Filing date
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Publication of WO2024248080A1 publication Critical patent/WO2024248080A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/022—Mechanical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
    • B65D65/38—Packaging materials of special type or form
    • B65D65/40—Applications of laminates for particular packaging purposes

Definitions

  • packaging materials As one of the possibilities for making the aforementioned packaging materials more environmentally friendly, active consideration is being given to making packaging materials from the same recyclable material, i.e., mono-materialization.
  • mono-materialization for example, polyester-based or polyolefin-based materials are being developed.
  • polyolefin-based heat seal resins can be used as sealants, which has the advantage of ensuring sufficient heat sealability compared to the polyester-based sealants mentioned above.
  • Polyolefin-based sealants need to have a certain degree of thickness in order to achieve sufficient sealing properties, and they account for a large proportion of the package. This is also a major reason why polyolefin-based mono-material packaging design is being promoted.
  • polyolefin-based sealants have the problem of inferior gas barrier performance compared to packaging with conventional barrier performance.
  • polypropylene film has water vapor barrier properties, these are not sufficient compared to, for example, transparent inorganic vapor-deposited polyester films, which are generally considered to have excellent water vapor barrier properties, and there is also the problem that its oxygen barrier properties are very poor.
  • films are used in which a polymer resin composition, such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride resin, or polyacrylonitrile, which is generally said to have a relatively high oxygen barrier property, is laminated onto a polypropylene film (see, for example, Patent Documents 2 to 4).
  • a polymer resin composition such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride resin, or polyacrylonitrile, which is generally said to have a relatively high oxygen barrier property
  • gas barrier coated films made using the above-mentioned polymer resin composition of polyvinyl alcohol or ethylene-vinyl alcohol copolymer are highly humidity dependent, and therefore exhibit a decrease in gas barrier property under high humidity conditions.
  • polyvinylidene chloride resin and polyacrylonitrile have low humidity dependency, there are problems such as an insufficient barrier value as an absolute value and a high risk of generating harmful substances during disposal or incineration.
  • the polypropylene film used does not have sufficient heat resistance, and there is a problem that the film expands and contracts due to heating during coating, printing, lamination, and sterilization, leading to wrinkles in appearance and reduced performance.
  • Patent Document 5 In regards to improving the gas barrier properties of polypropylene films, attempts have been made to develop stable gas barrier performance that is not humidity dependent by laminating an inorganic thin film (e.g., Patent Document 5). However, there are problems such as the absolute value of the gas barrier performance (particularly the oxygen barrier property) being inferior to conventional polyester vapor deposition films, and being more vulnerable to physical damage than the aforementioned coat-type barrier film. Barrier materials made by vapor deposition of polyolefin sealants have also been investigated (e.g., Patent Document 6), but although water vapor barrier performance is developed, there are problems such as insufficient oxygen barrier property.
  • the heat resistance of the film on the outside and middle layer of the bag is low, so if the heat sealing temperature is too high, wrinkles will occur, resulting in a poor appearance and poor gas barrier properties, and if the heat sealing temperature is too low, sufficient seal strength cannot be obtained.
  • Patent Document 7 it is known that by using a base material with a low thermal shrinkage rate and a melting point 10°C or more higher than that of the sealant, the laminate does not warp due to the heat during bag production, and a packaging bag can be obtained with no dimensional deviation even when the bag is produced at high speed (for example, Patent Document 7).
  • a base material with a low thermal shrinkage rate and a melting point 10°C or more higher than that of the sealant a base material with a low thermal shrinkage rate and a melting point 10°C or more higher than that of the sealant, the laminate does not warp due to the heat during bag production, and a packaging bag can be obtained with no dimensional deviation even when the bag is produced at high speed (for example, Patent Document 7).
  • Patent Document 7 in order to obtain sufficient heat seal strength using a polypropylene-based sealant, it is necessary to increase the heat seal temperature, which causes problems such as increased manufacturing costs and the risk of burns.
  • the polypropylene-based sealant in Patent Document 7 also
  • Patent Documents 1 to 8 it was difficult to achieve both mono-material packaging materials and the various performance properties required of packaging materials, particularly gas barrier properties, sheet sealability, and firmness, and it was not possible to design packaging materials that were both environmentally friendly and convenient.
  • an object of the present invention is to provide a packaging material, a packaging bag, and a packaging body that are made of a resin that has a low environmental impact and that have all three properties of gas barrier property, heat sealability, and firmness.
  • the inventors discovered that by forming a laminated film in which a specific gas barrier layer tailored to the required performance is laminated onto a base film, the gas barrier performance can be greatly improved, and further, by laminating a resin layer with excellent low-temperature heat sealability and stiffness as the heat sealable film to the above-mentioned base film, it is possible to provide an environmentally friendly and highly convenient packaging material, which led to the completion of the present invention.
  • the present invention comprises the following: 1.
  • a packaging material having at least one base film mainly composed of a polyolefin resin and a heat-sealable film, at least one of the base films being a laminated base film having a gas barrier layer, characterized in that when the faces of the heat-sealable films of the packaging material are heat-sealed together at 120°C, 0.1 MPa, for 1 second, the sealing strength is 10 N/15 mm or more, the loop stiffness is 22 mN/25 mm or more, the oxygen transmission rate at 23°C x 65% RH is 50 ml/ m2 ⁇ d ⁇ MPa or less, and the water vapor transmission rate at 40°C x 90% RH is 3.0 g/ m2 ⁇ d or less.
  • the packaging material according to 1. wherein the packaging material has a total thickness of 140 ⁇ m or less.
  • the gas barrier layer is an inorganic thin film layer selected from the group consisting of aluminum, aluminum oxide, silicon oxide, and a composite oxide of silicon oxide and aluminum oxide.
  • the gas barrier layer is a coating layer containing, as a constituent component, a resin selected from the group consisting of polyvinyl alcohol resins, polyester resins, and polyurethane resins.
  • the packaging material according to 4. further comprising an inorganic layered compound. 6.
  • the propylene homopolymer comprises a propylene homopolymer having an MFR of 5 g/10 min or less and a propylene homopolymer having an MFR of more than 5 g/10 min.
  • a packaging bag made of the packaging material according to any one of 1. to 15.
  • a package comprising an item packaged in the packaging material according to any one of 1. to 15.
  • a package comprising an item packaged in the packaging bag according to 16.
  • the present invention makes it possible to provide packaging materials, packaging bags, and packaging bodies that are made of resins that have a low environmental impact and have gas barrier properties, heat sealability, and a firm feel.
  • the packaging material of the present invention is a packaging material having at least one base film whose main component is a polyolefin resin and a heat-sealable film, wherein at least one of the base films is a laminated base film having a gas barrier layer, and is characterized in that when the surfaces of the heat-sealable films of the packaging material are heat-sealed together at 120°C, 0.1 MPa, for 1 second, the seal strength is 10 N/15 mm or more, the loop stiffness value is 22 mN/25 mm or more, the oxygen permeability at 23°C x 65% RH is 50 ml/ m2 ⁇ d ⁇ MPa or less, and the water vapor permeability at 40°C x 90% RH is 3.0 g/ m2 ⁇ d or less.
  • the above-mentioned phrase "mainly a constituent" means that the constituent contains 50% by mass or more.
  • the packaging material of the present invention includes a base film mainly composed of a polyolefin resin.
  • the base film is preferably a base film mainly composed of a polypropylene resin (hereinafter referred to as a polypropylene film), and more preferably a polypropylene stretched film.
  • the polypropylene stretched film used as the base film in the present invention is preferably a biaxially stretched polypropylene film.
  • the biaxially stretched polypropylene film a known biaxially stretched polypropylene film can be used, and the raw material, mixing ratio, etc. are not particularly limited.
  • the polypropylene resin may be, for example, a polypropylene homopolymer (propylene homopolymer), a propylene copolymer (preferably a propylene random copolymer or a propylene block copolymer) containing propylene as the main component and one or more ⁇ -olefins selected from ethylene, butene, pentene, hexene, etc., or a mixture of two or more of these polymers.
  • the propylene homopolymer and the propylene copolymer may each be used alone or in combination of two or more.
  • known additives such as antioxidants, antistatic agents, plasticizers, etc. may be added, for example, petroleum resins, terpene resins, etc. may be added.
  • the polypropylene-based resin constituting the base film is preferably a propylene homopolymer that does not substantially contain comonomers other than propylene (preferably ethylene, propylene, butene), and the amount of comonomer is preferably 0 mol% to 0.5 mol%, more preferably 0 mol% to 0.3 mol%, and even more preferably 0 mol% to 0.1 mol%.
  • the crystallinity is improved, and the rigidity of the film is improved.
  • a small amount of comonomer may be included within a range that does not significantly reduce the crystallinity.
  • a mixture of two or more polypropylene-based resins having different melt flow rates (MFR) may be used as the polypropylene-based resin constituting the surface layer of the base film.
  • MFR melt flow rates
  • each polypropylene-based resin a propylene homopolymer containing no copolymerization component, or a polypropylene resin copolymerized with ethylene and/or an ⁇ -olefin having 4 to 10 carbon atoms at more than 0.5 mol % and not more than 5.0 mol % can be used.
  • the copolymerization component of the copolymerized polypropylene resin is preferably 1.0 to 4.0 mol %, more preferably 1.5 to 3.5 mol %, and even more preferably 2.0 to 3.5 mol %.
  • Examples of the ⁇ -olefin having 4 to 10 carbon atoms include 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene.
  • maleic acid having polarity may be used as another copolymerization component.
  • the propylene copolymer used for the base film is preferably a propylene-ethylene copolymer, a propylene-butene copolymer, or a propylene-ethylene-butene copolymer, and more preferably a propylene-ethylene copolymer.
  • the propylene copolymer may be a block copolymer or a random copolymer.
  • the xylene soluble content of the polypropylene resin that constitutes the base film is preferably 0.1 to 7 mass%, more preferably 0.1 to 6 mass%, and even more preferably 0.1 to 5 mass%. Within the above range, the crystallinity is improved, and the rigidity of the film is improved.
  • the substrate film is preferably composed of a substrate layer and a surface layer, and the substrate layer preferably contains a propylene homopolymer having a mesopentad fraction of 96% or more.
  • the mesopentad fraction of the propylene homopolymer is more preferably 97 to 99.9%, even more preferably 97.5 to 99.9%, and even more preferably 98 to 99.9%.
  • the mesopentad fraction is within the above range, the crystallinity of the polypropylene resin is high, and a base film having a predetermined rigidity and heat resistance can be obtained.
  • the mesopentad fraction is less than 96%, wrinkles may form in part of the packaging material, deteriorating the appearance of the seal.
  • the mesopentad fraction is calculated according to the method described in Zambelli et al., Macromolecules, Vol. 6, p. 925 (1973), and can be measured, for example, by using 13 C-NMR.
  • the 13 C-NMR measurement conditions include, for example, using an AVANCE 500 manufactured by BRUKER, dissolving 200 mg of a sample in a mixed solution of o-dichlorobenzene and deuterated benzene in a ratio of 8:2 at 135°C, and measuring at 110°C.
  • the melt flow rate (MFR) (230°C, 2.16 kgf) of the polypropylene resin is preferably 0.5 g/10 min to 20 g/10 min, more preferably 1.0 g/10 min to 17 g/10 min, even more preferably 2.0 g/10 min to 16 g/10 min, and even more preferably 4.0 g/10 min to 15 g/10 min.
  • MFR melt flow rate
  • the mechanical load is small, making extrusion and stretching easier.
  • stretching is easier, thickness unevenness is reduced, the stretching temperature and heat setting temperature can be easily increased, crystallinity is improved, and the rigidity of the film is improved.
  • the propylene homopolymer preferably includes a propylene homopolymer with an MFR of 5 g/10 min or less and a propylene homopolymer with an MFR of more than 5 g/10 min, more preferably includes a propylene homopolymer with an MFR of 0.5 to 5 g/10 min and a propylene homopolymer with an MFR of more than 5 g/10 min and less than 10 g/10 min, and even more preferably includes a propylene homopolymer with an MFR of 1.0 to 5 g/10 min and a propylene homopolymer with an MFR of more than 5 g/10 min and less than 9 g/10 min.
  • Using multiple propylene homopolymers with different MFRs can increase the interfacial adhesive strength with other layers.
  • the polypropylene resin may have a predetermined mass average molecular weight, and the mass average molecular weight of the polypropylene resin is preferably 200,000 to 500,000, more preferably 210,000 to 450,000, and even more preferably 220,000 to 400,000. If the mass average molecular weight is within the above range, the stretching temperature can be increased, and stretching tends to be easier.
  • the polypropylene resin may have a predetermined number average molecular weight, and the number average molecular weight of the polypropylene resin is preferably 30,000 to 100,000, more preferably 40,000 to 90,000, and even more preferably 50,000 to 85,000. If the number average molecular weight is within the above range, the stretching temperature can be increased, and stretching tends to be easier.
  • the molecular weight distribution (mass average molecular weight/number average molecular weight) of the polypropylene resin is preferably 2-10, more preferably 2.5-9, even more preferably 2.7-8, and even more preferably 3-7.
  • the mass average molecular weight, number average molecular weight, and molecular weight distribution of the polypropylene-based resin are calculated by gel permeation chromatography (GPC).
  • the polypropylene resin may have a predetermined DSC melting peak temperature, and the DSC melting peak temperature of the polypropylene resin is, for example, 100 to 175°C, preferably 110 to 170°C, more preferably 120 to 167°C, even more preferably 140 to 165°C, and even more preferably 150 to 164°C.
  • the polypropylene resin has a DSC melting peak temperature in the above range, heat sealing at high temperatures becomes possible.
  • the polypropylene resin may have a predetermined DSC melting peak area, and the DSC melting peak area of the polypropylene resin is, for example, 50 to 120 J/g, preferably 55 to 110 J/g, more preferably 60 to 100 J/g, and even more preferably 70 to 100 J/g.
  • the polypropylene resin has a DSC melting peak area in the above range, a substrate film having a high degree of crystallinity can be obtained. Both the DSC melting peak temperature and the DSC melting peak area are calculated according to the method described in the Examples below.
  • the content of the polyolefin resin constituting the base film is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, even more preferably 95 to 100 mass%, and particularly preferably 100 mass%, based on 100 mass% of the resin composition constituting the base film.
  • the content of the propylene homopolymer (A) having an MFR of 5 g/10 min or less is preferably 15 to 85 mass%, more preferably 20 to 80 mass%, and even more preferably 25 to 75 mass%, based on 100 mass% of the resin composition constituting the base film.
  • the content of the propylene homopolymer (B) having an MFR of more than 5 g/10 min is preferably 15 to 85 mass%, more preferably 20 to 80 mass%, and even more preferably 25 to 75 mass%, based on 100 mass% of the resin composition constituting the base film.
  • any one or each of the plurality of layers may satisfy the above range.
  • the substrate film (preferably a biaxially oriented polypropylene film) used in the present invention may be a single-layer film or a laminated film.
  • a laminated film is preferable, and the type of laminate, the number of layers, the lamination method, etc. are not particularly limited and can be arbitrarily selected from known methods, but it is preferable to improve the lamination strength and the adhesive strength of the coating agent, etc. by controlling the surface roughness and flexibility of the substrate film surface.
  • Examples of the structure of the laminated film include surface layer/substrate layer, surface layer/substrate layer/surface layer, and surface layer/substrate layer/substrate layer/surface layer.
  • An adhesive layer may be provided between the surface layer and the base layer, but it is preferable not to provide an adhesive layer from the standpoint of productivity, etc.
  • the substrate film preferably has a structure of surface layer/substrate layer/surface layer.
  • the surface layer and the base layer preferably contain at least a propylene homopolymer, and more preferably contain a plurality of propylene homopolymers or a propylene homopolymer and a propylene copolymer. It is more preferable that the base layer contains 10 to 50% by mass (preferably 20 to 40% by mass) of a propylene homopolymer having an MFR of 5 g/10 min or less and 50 to 90% by mass (preferably 60 to 80% by mass) of a propylene homopolymer having an MFR of more than 5 g/10 min.
  • the surface layer contains 50 to 90% by mass (preferably 60 to 80% by mass) of a propylene homopolymer having an MFR of 5 g/10 min or less and 10 to 50% by mass (preferably 20 to 40% by mass) of a propylene homopolymer having an MFR of more than 5 g/10 min. It is more preferable that the surface layer contains 40 to 80% by mass (preferably 45 to 75% by mass) of a propylene homopolymer having an MFR of 5 g/10 min or less and 20 to 60% by mass (preferably 25 to 55% by mass) of a propylene copolymer having an MFR of more than 5 g/10 min.
  • the surface layers may be of the same configuration or different configurations, and are preferably of the same configuration.
  • the base film may be a uniaxially stretched film in the longitudinal direction (MD direction) or transverse direction (TD direction), but it is preferable that it is a biaxially stretched film.
  • the rigidity can be improved by stretching at least uniaxially, and by using the above-mentioned preferable raw material, it is possible to obtain a film with high heat resistance and smaller dimensional change when heated, which was not expected with conventional polypropylene films.
  • stretching methods include simultaneous biaxial stretching and sequential biaxial stretching, but sequential biaxial stretching is preferable from the viewpoint of good flatness, dimensional stability, thickness unevenness, etc.
  • polypropylene resin is heated and melted in a single-screw or twin-screw extruder until the resin temperature reaches preferably 200 to 280°C (more preferably 210 to 270°C, and even more preferably 220 to 260°C), formed into a sheet from a T-die, and extruded onto a chill roll at a temperature of preferably 10 to 100°C (more preferably 20 to 80°C, and even more preferably 25 to 60°C) to obtain an unstretched sheet.
  • the film is roll-stretched in the longitudinal direction (MD direction) preferably at 120 to 165°C (more preferably at 120 to 150°C, even more preferably at 120 to 140°C) and preferably 3.0 to 8.0 times (more preferably at 3.5 to 7.0 times, even more preferably at 4.0 to 6.5 times), and subsequently, after preheating with a tenter, it can be stretched in the transverse direction (TD direction) preferably at 150 to 175°C (more preferably at 152 to 170°C, even more preferably at 154 to 165°C, even more preferably at 155 to 164°C, particularly preferably at 156 to 164°C) and preferably 4.0 to 20.0 times (more preferably at 5.0 to 15 times, even more preferably at 6.0 to 14 times, even more preferably at 7.0 to 10 times).
  • heat setting can be performed at a temperature of preferably 165 to 175°C (more preferably 165 to 172°C, even more preferably 165 to 169°C), while allowing relaxation of preferably 1 to 15% (more preferably 2 to 12%, even more preferably 3 to 10%).
  • the substrate film of the present invention is preferably formed by the following method.
  • the stretching temperature in the machine direction is preferably the film melting point (Tm)-20 to -7° C., more preferably Tm-20 to -10° C., and even more preferably Tm-20 to -12° C.
  • Tm film melting point
  • the stretching in the longitudinal direction may be performed in two or more stages using three or more pairs of stretching rolls.
  • the film produced by the above process can be wound into a roll and then annealed offline.
  • particles into the film preferably the surface layer
  • examples of particles to be incorporated into the film include inorganic particles such as silica, kaolinite, talc, calcium carbonate, zeolite, and alumina, and heat-resistant polymer particles such as acrylic, PMMA, nylon, polystyrene, polyester, benzoguanamine-formalin condensate, and silicone.
  • the particles are preferably silica and silicone.
  • the content of particles in the film is preferably small, for example, 1 to 4000 ppm, more preferably 50 to 3500 ppm, based on the total mass of the film (preferably the surface layer).
  • the preferred average particle size of the particles is 1.0 to 3.0 ⁇ m, more preferably 1.0 to 2.7 ⁇ m.
  • the average particle size is measured by taking a photograph with a scanning electron microscope, measuring the Feret diameter in the horizontal direction using an image analyzer device, and expressing the average value.
  • the substrate film may contain antioxidants, ultraviolet absorbers, antistatic agents, dyes, lubricants, nucleating agents, adhesives, antifogging agents, flame retardants, antiblocking agents, inorganic or organic fillers, etc., in order to impart various functions as necessary.
  • polypropylene-based resin used in the present invention other resins can be used to improve the mechanical properties of the base film, the adhesion to the ink layer or adhesive layer laminated on the gas barrier coating layer, reduce the environmental load, etc., without impairing the objectives of the present invention.
  • examples include polyethylene resins, polypropylene resins different from the above, random copolymers that are copolymers of propylene and ethylene and/or ⁇ -olefins with 4 to 10 carbon atoms, and various elastomers.
  • the polyethylene resin that can be used for the base film in the present invention is a resin containing ethylene as a main component.
  • any ethylene homopolymer such as high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene can be used.
  • crystalline or low-crystalline or non-crystalline random or block copolymers with monomers such as ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1,3-methylbutene-1,4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof can also be used.
  • the content of the polyethylene resin is preferably 0 to 25% by mass, more preferably 1 to 25% by mass, even more preferably 5 to 20% by mass, even more preferably 8 to 18% by mass, and particularly preferably 8 to 15% by mass, based on 100% by mass of the total of the polypropylene resin and the polyethylene resin constituting the substrate. If it exceeds 0% by mass, the heat seal strength, blocking resistance, and anti-fogging properties are improved. If it is 25% by mass or less, the rigidity is easily maintained. From the viewpoints of heat resistance, transparency, mechanical properties, and film-forming properties, the melting point of the polyethylene resin is preferably in the range of 100 to 135° C., more preferably 105 to 130° C.
  • the melting point is measured, for example, using a differential scanning calorimeter.
  • the density, measured in accordance with JIS K7112, is preferably 0.90 to 0.94 g/cm 3 , and more preferably 0.91 to 0.94 g/cm 3 .
  • the melt flow rate (MFR) (190°C, 2.16 kgf) of the polyethylene resin is preferably 0.5 g/10 min to 20 g/10 min, more preferably 1 g/10 min to 15 g/10 min, and even more preferably 2 g/10 min to 10 g/10 min, from the viewpoint of stable moldability.
  • the thickness of the base film is set arbitrarily according to each application, but is preferably 2 to 130 ⁇ m, more preferably 3 to 125 ⁇ m, even more preferably 4 to 120 ⁇ m, even more preferably 5 to 100 ⁇ m, and particularly preferably 10 to 50 ⁇ m. If the thickness is thin, the rigidity of the film is also low and the handling property is likely to be poor. On the other hand, if the thickness is thick, not only is there a problem in terms of cost, but also poor flatness is likely to occur due to a curl when the film is wound into a roll and stored.
  • the substrate film includes a surface layer and a substrate layer, the total thickness of the surface layer and the substrate layer may be within the above range.
  • the thickness of the substrate layer is, for example, 2 to 40 ⁇ m, preferably 3 to 35 ⁇ m, more preferably 4 to 30 ⁇ m, and further preferably 5 to 25 ⁇ m.
  • the thickness of the surface layer is, for example, 0.5 to 10 ⁇ m, preferably 0.7 to 7 ⁇ m, and more preferably 0.9 to 5 ⁇ m.
  • the base film of the present invention is preferably transparent from the viewpoint of visibility of the contents, and the haze of the base film is preferably 0.1 to 6%, more preferably 0.5 to 5%, and even more preferably 1 to 4%. Haze tends to deteriorate, for example, when the stretching temperature or heat setting temperature is too high, when the cooling roll (CR) temperature is high and the cooling rate of the stretched raw sheet is slow, or when there is too much low molecular weight, so it can be controlled within the above range by adjusting these.
  • the base film of the present invention may be subjected to corona discharge treatment, glow discharge treatment, flame treatment, surface roughening treatment, and may be subjected to known anchor coat treatment, printing, decoration, etc., so long as the object of the present invention is not impaired.
  • a resin with good adhesiveness such as polyurethane or polyester for the anchor coat, but the anchor coat layer for improving the barrier in the present invention will be described later.
  • the packaging material of the present invention is provided with at least one substrate film having a gas barrier layer, but it is more preferable to use two or more substrate films and bond them together, since this is expected to improve the toughness and gas barrier performance of the packaging material.
  • toughness the use of two polypropylene-based biaxially oriented films, which generally have high puncture strength, makes it possible to design a packaging material that is comparable to a configuration using two different materials, such as polyester film and polyamide film, which are widely used as packaging materials.
  • gas barrier properties the use of two substrate films makes the film located in the middle less susceptible to the effects of the external environment, such as temperature and humidity and external bending, and allows for more stable gas barrier performance. In that sense, when two substrate films are used, it is particularly preferable that the coating layer or inorganic thin film layer having gas barrier properties is laminated on the intermediate film.
  • At least one of the substrate films is a laminated substrate film having a gas barrier layer.
  • an anchor coat (C) or a protective layer (D), which will be described later, can also be laminated in combination.
  • Coating layer (A) In the present invention, it is preferable to provide a coating layer (A) as a gas barrier layer. However, in the present invention, it is necessary to design the coating layer (A) with due consideration given to the fact that the provision of the coating layer (A) increases the number of steps, leading to increased costs, and that the coating layer (A) may impose a burden on the environment, such as making recycling difficult depending on the coating layer thickness.
  • the gas barrier layer is a coating layer containing a resin selected from the group consisting of polyvinyl alcohol resin, polyester resin, and polyurethane resin as a constituent component.
  • a resin selected from the group consisting of polyvinyl alcohol resin, polyester resin, and polyurethane resin as a constituent component.
  • polyvinyl alcohol resin is preferable as the resin used for the coating layer (A).
  • Polyvinyl alcohol resin is a resin whose main constituent component is vinyl alcohol units, and is expected to significantly improve barrier performance due to its high cohesiveness caused by its hydrogen bond structure.
  • the polymerization degree and saponification degree of the polyvinyl alcohol resin are determined based on the desired gas barrier properties and the viscosity of the coating aqueous solution.
  • the high viscosity of the aqueous solution and the tendency to gel make coating difficult and from the viewpoint of coating workability, 100 to 2600 is preferable, 200 to 2000 is more preferable, and 300 to 1500 is even more preferable.
  • the saponification degree if it is less than 90%, sufficient oxygen gas barrier properties cannot be obtained under high humidity conditions, and if it exceeds 99.7%, it is difficult to adjust the aqueous solution and it is prone to gelation, making it unsuitable for industrial production. Therefore, the saponification degree is preferably 90 to 99.7%, and more preferably 93 to 99%.
  • various copolymerized or modified polyvinyl alcohol resins such as polyvinyl alcohol resins copolymerized with ethylene and silanol-modified polyvinyl alcohol resins, can also be used within the range that does not impair processability or productivity.
  • the coating layer (A) of the present invention may further contain an inorganic layered compound.
  • the presence of the inorganic layered compound is expected to provide a labyrinth effect for gases, improving the gas barrier properties.
  • the addition of the inorganic layered compound can suppress the humidity dependency of the gas barrier properties.
  • the material include clay minerals (including synthetic products thereof) such as smectite, kaolin, mica, hydrotalcite, and chlorite.
  • scaly silica and the like can also be used as the inorganic layered compound. These may be used alone or in combination of two or more types. Of these, smectite (including its synthetic products) is particularly preferred because it is highly effective in improving water vapor barrier properties.
  • the inorganic layered compound those containing metal ions, particularly iron ions, having redox properties are preferred.
  • montmorillonite a type of smectite, is preferred from the viewpoints of coating suitability and gas barrier properties.
  • known compounds that have been used in gas barrier agents can be used.
  • the following general formula: (X, Y) 2 ⁇ 3 Z 4 O 10 (OH) 2 ⁇ mH 2 O ⁇ (W ⁇ ) In the formula, X represents Al, Fe(III), or Cr(III). Y represents Mg, Fe(II), Mn(II), Ni, Zn, or Li. Z represents Si or Al.
  • W represents K, Na, or Ca. H 2 O represents interlayer water. m and ⁇ represent positive real numbers.) Among these, those in which W in the formula is Na are preferred from the viewpoint of cleavage in an aqueous medium.
  • the size and shape of the inorganic layered compound are not particularly limited, but the particle size (long diameter) is preferably 1 to 5 ⁇ m, more preferably 1 to 4 ⁇ m, and even more preferably 1 to 3 ⁇ m. If the particle size is larger than 5 ⁇ m, the dispersibility is poor, and as a result, the coatability and coat appearance of the coating layer (A) may deteriorate.
  • the aspect ratio is preferably 50 to 5000, more preferably 100 to 4000, and even more preferably 200 to 3000.
  • the compounding ratio of the resin composition and the inorganic layered compound in the coating layer of the present invention is preferably 75/25 to 35/65 (mass %), more preferably 70/30 to 40/60 (mass %), and even more preferably 65/35 to 45/55 (mass %). If the compounding ratio of the inorganic layered compound is less than 25 mass %, there is a risk of insufficient barrier performance. On the other hand, if it is more than 65 mass %, dispersibility may be poor, which may lead to poor coatability and poor adhesion.
  • crosslinking agents may be blended in the coating layer (A) of the present invention, as long as they do not impair gas barrier properties or productivity.
  • crosslinking agents include silicon-based crosslinking agents, oxazoline compounds, carbodiimide compounds, epoxy compounds, and isocyanate compounds.
  • the silicon-based crosslinking agent is particularly preferred from the viewpoint of improving water-resistant adhesion, since the silicon-based crosslinking agent can be crosslinked with the resin composition having a hydroxyl group or the inorganic thin film layer by blending the silicon-based crosslinking agent.
  • silicon-based crosslinking agents examples include metal alkoxides and silane coupling agents.
  • Metal alkoxides are compounds represented by the general formula M(OR) n (M: metals such as Si and Al, R: alkyl groups such as CH 3 and C 2 H 5 , n is 1 to 4). Specific examples include tetraethoxysilane [Si(OC 2 H 5 ) 4 ] and triisopropoxyaluminum [Al[OCH(CH 3 ) 2 ] 3 ].
  • silane coupling agents include those having an epoxy group such as 3-glycidoxypropyltrimethoxysilane, those having an amino group such as 3-aminopropyltrimethoxysilane, those having a mercapto group such as 3-mercaptopropyltrimethoxysilane, those having an isocyanate group such as 3-isocyanatepropyltriethoxysilane, and tris-(3-trimethoxysilylpropyl)isocyanurate.
  • oxazoline compounds, carbodiimide compounds, epoxy compounds, etc. may be used in combination as crosslinking agents. However, when emphasis is placed on recyclability, the amount of crosslinking agent to be used must be considered.
  • a crosslinking agent When a crosslinking agent is blended, its amount in the composition constituting the coating layer is preferably 0.05 to 4.00 mass%, more preferably 0.10 to 3.50 mass%, and even more preferably 0.15 to 3.00 mass%. By keeping it within the above range, the film hardens and the cohesive strength improves, resulting in a film with excellent water-resistant adhesion. If the amount of crosslinking agent blended exceeds 4.00 mass%, the amount of uncrosslinked portions increases, or the film hardens due to excessive hardening, which may in turn reduce adhesion. On the other hand, if the amount of crosslinking agent blended is less than 0.05 mass%, there is a risk that sufficient cohesive strength will not be obtained.
  • the haze of the film after lamination of the coating layer (A) is preferably 1 to 20%, more preferably 1 to 18%, and even more preferably 1 to 16%, from the viewpoint of visibility of the contents. If the haze is more than 20%, in addition to significantly deteriorating transparency, there is a concern that it may affect the unevenness of the surface, which may lead to poor appearance in the subsequent printing process.
  • the haze can be adjusted by the composition ratio of the coating layer (A), the solvent conditions, the film thickness, etc.
  • the haze is evaluated in accordance with JIS K7136 using a turbidity meter (NDH2000, manufactured by Nippon Denshoku Co., Ltd.).
  • the coating layer (A) is preferably applied in an amount of 0.10 to 0.70 g/m 2 , more preferably 0.15 to 0.65 g/m 2 , even more preferably 0.20 to 0.60 g/m 2 , and even more preferably 0.25 to 0.55 g/m 2. If the coating layer (A) is applied in an amount of more than 0.70 g/m 2 , the gas barrier property is improved, but the cohesive force inside the coating layer is insufficient, and the uniformity of the coating layer is also reduced, so that the coat appearance may be uneven (haze increase, whitening) or defects may occur, and the gas barrier property and adhesive property may not be fully expressed. In terms of processability, the thick film thickness may cause blocking.
  • the coating layer (A) is applied in an amount of less than 0.10 g/m 2 , there is a risk that sufficient gas barrier property and interlayer adhesion may not be obtained.
  • the coating method for the resin composition for the coating layer is not particularly limited as long as it is a method that coats the film surface to form a layer.
  • conventional coating methods such as gravure coating, reverse roll coating, wire bar coating, and die coating can be used.
  • the resin composition for the coating layer pre-dry it at a relatively low temperature to evaporate the solvent, and then dry it at a high temperature, as this will result in a uniform film.
  • the pre-drying temperature is preferably 80 to 110°C, more preferably 85 to 105°C, and even more preferably 90 to 100°C. If the pre-drying temperature is less than 80°C, there is a risk that the coating layer will not be sufficiently dried. Also, if the pre-drying temperature is higher than 110°C, drying will proceed before the coating layer has time to spread, which may result in a poor appearance.
  • the main drying temperature is preferably 110 to 140°C, more preferably 115 to 135°C, and even more preferably 120 to 130°C. If the main drying temperature is less than 110°C, the film formation of the coating layer (A) will not proceed, and the cohesive strength and adhesiveness will decrease, which may result in a negative effect on the barrier properties. If the temperature exceeds 140°C, the film may become too hot, making it brittle and causing large wrinkles due to heat shrinkage.
  • the preferred drying time for preliminary drying is 3.0 to 10.0 seconds, more preferably 3.5 to 9.5 seconds, and even more preferably 4.0 to 9.0 seconds.
  • the preferred drying time for main drying is 3.0 to 10.0 seconds, more preferably 3.5 to 9.5 seconds, and even more preferably 4.0 to 9.0 seconds.
  • care must be taken as the drying conditions vary depending on the heat transfer medium method and the intake and exhaust conditions of the drying furnace.
  • additional heat treatment for 1 to 4 days in as low a temperature range as possible, specifically in the temperature range of 40 to 60°C is also more effective in accelerating the formation of the coating layer (A).
  • the inorganic thin film layer (B) is preferably a thin film made of a metal or an inorganic oxide.
  • inorganic materials such as metals such as aluminum, silicon oxide (silica), aluminum oxide (alumina), and mixtures of silicon oxide and aluminum oxide are preferred. Among these, oxides are preferred.
  • the gas barrier layer is preferably an inorganic thin film layer made of any one of aluminum, aluminum oxide, silicon oxide, and a composite oxide of silicon oxide and aluminum oxide.
  • the inorganic thin film layer is made of any one of composite oxides of aluminum.
  • a composite oxide of silicon oxide and aluminum oxide is preferred from the viewpoint of achieving both flexibility and density of the thin film layer.
  • the mixture ratio of silicon oxide and aluminum oxide is 1/2 to 1/2 of the metal content.
  • the mass ratio (Al/(Al+Si) ⁇ 100) of Al is preferably in the range of 20 to 70 mass%, more preferably in the range of 25 to 65 mass%, and still more preferably in the range of 30 to 60 mass%. If the Al ratio is less than 20% by mass, the water vapor barrier property may be reduced.
  • silicon oxide here refers to various silicon oxides such as SiO and SiO2 , or mixtures thereof
  • aluminum oxide are various aluminum oxides such as AlO and Al2O3 , or mixtures thereof.
  • the thickness of the inorganic thin film layer (B) is usually 1 to 100 nm, preferably 5 to 50 nm. If the thickness of the inorganic thin film layer (B) is less than 1 nm, it may be difficult to obtain satisfactory gas barrier properties, while if the thickness is excessively greater than 100 nm, the corresponding improvement in gas barrier properties cannot be obtained, and it is rather disadvantageous in terms of flex resistance and production costs.
  • the thickness of the aluminum layer is, for example, 10 to 100 nm, preferably 15 to 90 nm, more preferably 20 to 80 nm, and further preferably 25 to 70 nm.
  • the thickness of the silicon oxide layer is, for example, 10 to 80 nm, preferably 15 to 70 nm, and more preferably 20 to 60 nm.
  • the thickness of the silicon oxide and aluminum oxide layers is, for example, 5 to 60 nm, preferably 7 to 50 nm, and more preferably 10 to 40 nm.
  • the method for forming the inorganic thin film layer (B) is not particularly limited, and may be any known deposition method, such as physical deposition methods (PVD methods) such as vacuum deposition, sputtering, and ion plating, or chemical deposition (CVD).
  • PVD methods physical deposition methods
  • CVD chemical deposition
  • a typical method for forming the inorganic thin film layer (B) will be described below using a silicon oxide/aluminum oxide thin film as an example.
  • a mixture of SiO 2 and Al 2 O 3 , or a mixture of SiO 2 and Al is preferably used as the deposition raw material.
  • Particles are usually used as these deposition raw materials, and in this case, it is desirable that the size of each particle is such that the pressure during deposition does not change, and the preferred particle diameter is 1 to 5 mm.
  • heating methods such as resistance heating, high-frequency induction heating, electron beam heating, and laser heating can be used. It is also possible to introduce oxygen, nitrogen, hydrogen, argon, carbon dioxide, water vapor, etc. as a reactive gas, or to adopt reactive deposition using means such as ozone addition and ion assist.
  • the film formation conditions can be changed as desired, such as by applying a bias to the deposition target (a substrate film to be subjected to deposition), heating or cooling the deposition target, etc.
  • Such deposition materials, reactive gases, bias, heating/cooling of the deposition target, etc. can be changed in the same manner even when a sputtering method or a CVD method is adopted.
  • an anchor coat layer may be laminated between the substrate film and the gas barrier layer (preferably the inorganic thin film layer) as an auxiliary layer for achieving sufficient gas barrier properties and adhesion when the gas barrier layer is laminated.
  • the gas barrier layer preferably the inorganic thin film layer
  • the anchor coat layer it is possible to suppress the exposure of oligomers and antiblocking materials from the polypropylene resin.
  • other layers are laminated on the anchor coat layer (C)
  • the inorganic thin film layer not only adhesion but also the effect of smoothing the surface to promote the formation of the inorganic layer and improve the gas barrier properties can be expected.
  • the gas barrier performance of the film when the gas barrier layer is laminated can be greatly improved.
  • the anchor coat layer (C) prevents the intrusion of hot water into the substrate, and as a result, the whitening of the film after boiling or retorting can also be reduced.
  • the oxygen transmission rate in a 23°C x 65% RH environment is 1 to 10,000 ml/ m2 d MPa in order to exhibit good gas barrier properties after lamination of the gas barrier layer, and more preferably 2 to 9,000 ml/ m2 d MPa, and even more preferably 3 to 8,000 ml/ m2 d MPa. If the oxygen transmission rate exceeds 10,000 ml/ m2 d MPa, sufficient barrier performance cannot be obtained even after lamination of the gas barrier layer, making it difficult to meet the needs of applications requiring high gas barrier properties.
  • the adhesion amount of the anchor coat layer (C) is preferably 0.10 to 0.60 g/m 2. This allows the anchor coat layer (C) to be uniformly controlled during coating, resulting in a film with fewer coating unevenness and defects. Furthermore, the anchor coat layer (C) contributes to suppressing oligomer exposure, stabilizing the haze after wet heat treatment.
  • the adhesion amount of the anchor coat layer (C) is more preferably 0.15 to 0.50 g/m 2 , more preferably 0.20 to 0.45 g/m 2 , and even more preferably 0.35 to 0.40 g/m 2.
  • the adhesion amount of the anchor coat layer (C) exceeds 0.60 g/m 2 , the gas barrier property is improved, but the cohesive force inside the anchor coat layer becomes insufficient and the uniformity of the anchor coat layer is also reduced, resulting in unevenness and defects in the coat appearance.
  • a thick film thickness may cause blocking or increase manufacturing costs.
  • the recyclability of the film may be adversely affected, and the environmental load may be increased due to the increased amount of raw materials, solvents, etc.
  • the thickness of the anchor coat layer (C) is less than 0.10 g/ m2 , there is a risk that sufficient gas barrier properties and interlayer adhesion may not be obtained.
  • the resin composition used in the anchor coat layer (C) of the present invention may be a resin such as a urethane-based, polyester-based, acrylic-based, titanium-based, isocyanate-based, imine-based, or polybutadiene-based resin to which a curing agent such as an epoxy-based, isocyanate-based, or melamine-based curing agent has been added. It may further contain a crosslinking agent such as a silicon-based crosslinking agent, an oxazoline compound, a carbodiimide compound, or an epoxy compound.
  • a crosslinking agent such as a silicon-based crosslinking agent, an oxazoline compound, a carbodiimide compound, or an epoxy compound.
  • urethane resins are preferred because, in addition to the barrier performance due to the high cohesiveness of the urethane bond itself, the polar group interacts with the inorganic thin film layer, and the presence of amorphous parts gives flexibility, so that damage can be suppressed even when a bending load is applied.
  • Polyester resins are also preferred because they can be expected to have the same effect.
  • it is particularly preferred to contain polyurethane containing polyester resins and isocyanate curing agents as constituents, and it is more preferred to add a silicon-based crosslinking agent from the viewpoint of improving adhesion.
  • the urethane resin used in the anchor coat layer (C) of the present invention is preferably a urethane resin containing an aromatic or aromatic aliphatic diisocyanate component as the main constituent component from the viewpoint of gas barrier properties. Among them, it is particularly preferable to contain a metaxylylene diisocyanate component.
  • the proportion of aromatic or araliphatic diisocyanate in the urethane resin used in the anchor coat layer (C) is preferably in the range of 50 mol % or more (50 to 100 mol %) in 100 mol % of the polyisocyanate component.
  • the total proportion of aromatic or araliphatic diisocyanate is more preferably 60 to 100 mol %, even more preferably 70 to 100 mol %, and even more preferably 80 to 100 mol %. If the total proportion of aromatic or araliphatic diisocyanate is less than 50 mol %, good gas barrier properties may not be obtained.
  • the urethane resin used in the anchor coat layer (C) of the present invention may be blended with various crosslinking agents for the purpose of improving the cohesive strength of the film and improving the wet heat resistance adhesion.
  • crosslinking agents include silicon-based crosslinking agents, oxazoline compounds, carbodiimide compounds, epoxy compounds, etc.
  • silicon-based crosslinking agents are particularly preferred from the viewpoint that blending a silicon-based crosslinking agent can improve the water-resistant adhesion, particularly with the inorganic thin film layer.
  • Other crosslinking agents such as oxazoline compounds, carbodiimide compounds, and epoxy compounds may also be used in combination.
  • alkoxy silanes having an amino group (amino C2-4 alkyl tri C1-4 alkoxy silanes such as 2-aminoethyl trimethoxy silane, 3-aminopropyl trimethoxy silane, 3-aminopropyl triethoxy silane and other amino di C2-4 alkyl di C1-4 alkoxy silanes such as 3-aminopropyl methyl dimethoxy silane, 3-aminopropyl methyl diethoxy silane, 2-[N-(2-aminoeth) ethyl trimethoxy silane, 2-(3,4-epoxycyclohexyl) ethyl triethoxy silane, 3-(3,4-epoxycyclohexyl) propyl trimethoxy silane and other (epoxy cycloalkyl) C2-4 alkyl tri C1-4 alkoxy silanes], alkoxy silanes having an amino group (amino C2-4 alkyl tri C1-4 alkoxy silanes
  • silane coupling agents can be used alone or in combination of two or more.
  • silane coupling agents having an amino group are preferred, (2-amino C2-4 alkyl) amino C2-4 alkyl tri C1-4 alkoxy silane is more preferred, and 3-[N-(2-aminoethyl) amino] propyl trimethoxy silane is even more preferred.
  • the silicon-based crosslinking agent is preferably added in an amount of 0.05 to 4.00% by mass to the composition that constitutes the coating layer, more preferably 0.10 to 3.50% by mass, and even more preferably 0.15 to 3.00% by mass.
  • the addition of a silicon-based crosslinking agent promotes hardening of the film and improves cohesive strength, resulting in a film with excellent water-resistant adhesion, and is also expected to have the effect of preventing the exposure of oligomers. If the amount added exceeds 4.00% by mass, the film will harden and improve cohesive strength, but some unreacted areas will be generated, and there is a risk of reduced adhesion between layers. On the other hand, if the amount added is less than 0.05% by mass, there is a risk that sufficient cohesive strength will not be obtained.
  • the polyester resin used in the anchor coat layer (C) of the present invention is produced by polycondensation of a polyvalent carboxylic acid component and a polyhydric alcohol component.
  • the molecular weight of the polyester resin is preferably 1,000 to 50,000, and more preferably 1,500 to 30,000.
  • the functional group at the polyester end and it may be an alcohol end, a carboxylic acid end, or both.
  • an isocyanate-based curing agent it is necessary to use a polyester polyol that is mainly alcohol-terminated.
  • the Tg of the polyester resin used in the anchor coat layer (C) of the present invention is preferably 10°C or higher. If the temperature is lower than this, the resin will become sticky after the coating operation and will be prone to blocking, making the winding operation after coating difficult. If the Tg is less than 10°C, it will be difficult to prevent blocking even under conditions where the pressure near the winding core is high, even with the addition of an anti-blocking agent.
  • the Tg is more preferably 15 to 70°C, and even more preferably 20 to 60°C.
  • the polyester resin used in the anchor coat layer (C) of the present invention is a polycondensate of a polyvalent carboxylic acid component and a polyhydric alcohol component.
  • the polyvalent carboxylic acid component of the polyester resin used in the present invention contains at least one of ortho-oriented aromatic dicarboxylic acids or their anhydrides.
  • aromatic polycarboxylic acids or anhydrides thereof in which a carboxylic acid is substituted at the ortho position include orthophthalic acid or anhydride, naphthalene 2,3-dicarboxylic acid or anhydride, naphthalene 1,2-dicarboxylic acid or anhydride, anthraquinone 2,3-dicarboxylic acid or anhydride, and 2,3-anthracene carboxylic acid or anhydride. These compounds may have a substituent at any carbon atom of the aromatic ring.
  • substituents examples include a chloro group, a bromo group, a methyl group, an ethyl group, an i-propyl group, a hydroxyl group, a methoxy group, an ethoxy group, a phenoxy group, a methylthio group, a phenylthio group, a cyano group, a nitro group, an amino group, a phthalimide group, a carboxyl group, a carbamoyl group, an N-ethylcarbamoyl group, a phenyl group, or a naphthyl group.
  • polyester polyols having a content of 70 to 100 mol% relative to 100 mol% of the total polycarboxylic acid components are particularly preferred because they have a high effect of improving barrier properties and excellent solvent solubility, which is essential for a coating material.
  • examples of aliphatic polycarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid;
  • examples of unsaturated bond-containing polycarboxylic acids include maleic anhydride, maleic acid, and fumaric acid;
  • examples of alicyclic polycarboxylic acids include 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid;
  • examples of aromatic polycarboxylic acids include terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic
  • polybasic acids can be used alone or in mixtures of two or more kinds.
  • succinic acid, 1,3-cyclopentanedicarboxylic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalic acid, and diphenic acid are preferred from the viewpoints of organic solvent solubility and gas barrier properties.
  • the polyhydric alcohol component of the polyester used in the anchor coat layer (C) of the present invention is not particularly limited as long as it is possible to synthesize a polyester that exhibits gas barrier compensation performance, but it is preferable that the polyhydric alcohol component contains at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, and 1,3-bishydroxyethylbenzene.
  • ethylene glycol it is most preferable to use ethylene glycol as the main component, since it is presumed that the fewer the number of carbon atoms between oxygen atoms, the less flexible the molecular chain is and the less oxygen permeable it is.
  • diols include 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol, and trihydric or higher alcohols include glycerol, trimethylolpropane, trimethylolethane, tris(2-hydroxyethyl)isocyanurate, 1,2,4-butanetriol, pentaerythritol, and dipentaerythritol.
  • polyesters using glycerol and tris(2-hydroxyethyl)isocyanurate in combination among trihydric alcohols are particularly preferred because they have a moderately high crosslinking density due to their branched structure, have good solubility in organic solvents, and have excellent barrier function.
  • Catalysts used in the reaction to obtain the polyester of the present invention include acid catalysts such as tin-based catalysts such as monobutyltin oxide and dibutyltin oxide, titanium-based catalysts such as tetra-isopropyl-titanate and tetra-butyl-titanate, and zirconia-based catalysts such as tetra-butyl-zirconate. It is preferable to use the above titanium-based catalysts such as tetra-isopropyl-titanate and tetra-butyl-titanate, which have high activity in ester reactions, in combination with the above zirconia catalyst.
  • acid catalysts such as tin-based catalysts such as monobutyltin oxide and dibutyltin oxide
  • titanium-based catalysts such as tetra-isopropyl-titanate and tetra-butyl-titanate
  • the amount of the catalyst is preferably 1 to 1000 ppm, more preferably 10 to 100 ppm, based on the total mass of the reaction raw materials used. If the amount is less than 1 ppm, it is difficult to obtain the catalytic effect, and if it exceeds 1000 ppm, a problem of inhibiting the urethane reaction may occur when an isocyanate curing agent is used.
  • the coating layer becomes a crosslinked system, which has the advantage of improving heat resistance, abrasion resistance, and rigidity.
  • the liquid cannot be reused after mixing with the curing agent, and a curing (aging) process is necessary after coating.
  • Advantages include, for example, that as a simple overcoat varnish, there is no risk of thickening of the coating liquid, coating production is easy to manage, the coating liquid can be diluted and reused, and in addition, a curing process (so-called aging process) is not required.
  • the end of the polyester used can be polyol, polycarboxylic acid, or a mixture of these two without any problems.
  • the resin of the coating layer is linear, problems such as insufficient heat resistance and abrasion resistance may occur.
  • the coating layer becomes a crosslinked system, which has the advantage of improving heat resistance, abrasion resistance, and rigidity.
  • the liquid cannot be reused after the hardener is mixed in, and a hardening (aging) process is necessary after coating.
  • the polyisocyanate compound used in the present invention reacts at least partially to form a urethane structure, which makes the resin component highly polar, and the polymer chains are aggregated to further strengthen the gas barrier function.
  • the resin of the coating material is a straight-chain resin
  • crosslinking with a trivalent or higher polyisocyanate can impart heat resistance and abrasion resistance.
  • the polyisocyanate compound used in the present invention may be any of diisocyanates, trivalent or higher polyisocyanates, low molecular weight compounds, and high molecular weight compounds, but it is preferable to contain an aromatic ring or an aliphatic ring in a part of the skeleton from the viewpoint of improving the gas barrier function.
  • examples of isocyanates having an aromatic ring include toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate; examples of isocyanates having an aliphatic ring include hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, isophorone diisocyanate, norbornine diisocyanate, or trimers of these isocyanate compounds; and compounds containing terminal isocyanate groups obtained by reacting an excess amount of these isocyanate compounds with low molecular weight active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, and triethanolamine, or high molecular weight active hydrogen compounds such as various polyester polyols, polyether polyols, and polyamides.
  • the polyisocyanate compound may be an adduct, an allophanate, a biuret, or the like. Among them, it is preferable to use a trimethylolpropane adduct of metaxylylene diisocyanate as the polyisocyanate compound.
  • the method for forming the anchor coat layer (C) is not particularly limited, and any conventionally known method such as a coating method can be used.
  • preferred methods include an offline coating method and an in-line coating method.
  • the conditions for drying and heat treatment during coating will vary depending on the coating thickness and the conditions of the equipment, but it is preferable to send the film to a stretching process in the perpendicular direction immediately after coating and dry it in the preheating zone or stretching zone of the stretching process. In such cases, it is usually preferable to set the temperature at about 50 to 250°C.
  • the coating method for the resin composition for the anchor coat layer (C) is not particularly limited as long as it is a method that coats the film surface to form a layer.
  • conventional coating methods such as gravure coating, reverse roll coating, wire bar coating, and die coating can be used.
  • the resin composition for the anchor coat layer When forming the anchor coat layer (C), it is preferable to apply the resin composition for the anchor coat layer and then heat and dry it.
  • the drying temperature is preferably 100 to 145°C, more preferably 110 to 140°C, and even more preferably 110 to 130°C. If the drying temperature is less than 100°C, the anchor coat layer may not be sufficiently dried. On the other hand, if the drying temperature exceeds 145°C, the film may be too hot, making it brittle or shrinking, resulting in poor processability.
  • a protective layer may be laminated on the gas barrier layer, or a protective layer (D) may be laminated on the inorganic thin film layer that is a gas barrier layer.
  • the inorganic thin film layer made of a metal or metal oxide layer is not a completely dense film, and minute defects are scattered therein.
  • the amount of the protective layer (D) attached is preferably 0.10 to 0.40 g/m 2 , more preferably 0.13 to 0.37 g/m 2 , even more preferably 0.16 to 0.34 g/m 2 , and even more preferably 0.19 to 0.31 g/m 2.
  • This allows the protective layer to be uniformly controlled during coating, resulting in a film with fewer coating unevenness and defects.
  • the cohesive force of the protective layer (D) itself is improved, and the adhesion between the inorganic thin film layer and the protective layer is also strengthened.
  • the amount of the protective layer (D) attached exceeds 0.40 g/m 2 , the gas barrier property is improved, but the cohesive force inside the protective layer becomes insufficient and the uniformity of the protective layer is also reduced, so that unevenness or defects may occur in the coat appearance, and gas barrier property and adhesive property may not be fully expressed.
  • the amount of the protective layer (D) attached is less than 0.10 g/m 2 , there is a risk that sufficient gas barrier property and interlayer adhesion may not be obtained.
  • the resin composition used in the protective layer (D) of the present invention may be a polyvinyl alcohol-based, urethane-based, polyester-based, acrylic-based, titanium-based, isocyanate-based, imine-based, polybutadiene-based resin, etc., and may contain a curing agent such as an epoxy-based, isocyanate-based, melamine-based, silanol-based, etc. Furthermore, it may contain a crosslinking agent such as a silicon-based crosslinking agent, an oxazoline compound, a carbodiimide compound, an epoxy compound, etc.
  • the protective layer is preferably made of a composition containing a polyvinyl alcohol resin and a silicon-based crosslinking agent, examples of which include the same polyvinyl alcohol resin and silicon-based crosslinking agent as those described above.
  • the method of coating the resin composition for the protective layer is not particularly limited as long as it is a method that coats the film surface to form a layer.
  • conventional coating methods such as gravure coating, reverse roll coating, wire bar coating, and die coating can be used.
  • the protective layer (D) it is preferable to apply the resin composition for the protective layer and then heat and dry it.
  • the drying temperature is preferably 100 to 160°C, more preferably 110 to 150°C, and even more preferably 120 to 140°C. If the drying temperature is less than 100°C, the protective layer may not be sufficiently dried, or the film formation of the protective layer may not progress, resulting in a decrease in cohesive strength and water-resistant adhesion, and as a result, the barrier properties and hand-tearability may be reduced. On the other hand, if the drying temperature exceeds 160°C, the film may become too hot, making it brittle and reducing puncture strength, or shrinking and reducing processability.
  • the packaging material may contain other films other than the base film mainly composed of a polyolefin resin, within a range that satisfies the monomaterial ratio described below.
  • the other films used in the present invention are, for example, films obtained by melt-extruding plastics and, as necessary, stretching, cooling, and heat setting in the longitudinal and/or transverse directions.
  • plastics examples include polyamides such as nylon 4.6, nylon 6, nylon 6.6, and nylon 12, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate, as well as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, wholly aromatic polyamides, polyamideimides, polyimides, polyetherimides, polysulfones, polystyrene, and polylactic acid.
  • polyamides such as nylon 4.6, nylon 6, nylon 6.6, and nylon 12
  • polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate
  • polyvinyl chloride polyvinylidene chloride
  • polyvinyl alcohol polyvinyl alcohol
  • ethylene vinyl alcohol ethylene vinyl alcohol
  • the other films in the present invention can be of any thickness depending on the desired purpose, such as mechanical strength and transparency. There are no particular limitations on the thickness of the other films, but it is usually recommended that the thickness be 5 to 250 ⁇ m, and when used as a packaging material, it is desirable that the thickness be 10 to 60 ⁇ m. However, it is necessary to take into consideration the mono-material ratio of the packaging material, which will be described later.
  • the other film in the present invention may be a laminated film of one or more types of plastic films.
  • the type of laminate, the number of layers, the lamination method, etc. are not particularly limited, and can be arbitrarily selected from known methods depending on the purpose.
  • the heat sealable film of the present invention includes at least a laminate layer and a heat seal layer.
  • the laminate layer and the heat seal layer will be described in detail below.
  • the heat seal layer in the present invention is preferably made of a resin composition containing as a main component a mixture of a polypropylene resin and a polyethylene resin.
  • the "main component” means that the mixture of polypropylene-based resin and polyethylene-based resin accounts for 90 mass% or more in the resin composition, but it is more preferable that it is 95 mass% or more, even more preferable that it is 97 mass% or more, even more preferable that it is 99 mass% or more, and particularly preferable that it is 100 mass%.
  • the polypropylene resin in the heat seal layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, propylene copolymers (propylene random copolymers, block copolymers) of propylene and ⁇ -olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1.
  • main component means that the proportion of propylene in the polypropylene resin is 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.
  • the polypropylene-based resin constituting the heat seal layer is preferably a propylene copolymer, more preferably a propylene-ethylene copolymer, a propylene-butene copolymer, or a propylene-ethylene-butene copolymer, even more preferably a propylene-ethylene-butene copolymer, and even more preferably a propylene-ethylene-butene random copolymer.
  • the melt flow rate of the polypropylene resin constituting the heat seal layer is preferably 0.1 g/10 min to 9 g/10 min, more preferably 0.5 g/10 min to 8 g/10 min, and even more preferably 1 g/10 min to 7 g/10 min.
  • the melting point of the polypropylene resin constituting the heat seal layer is preferably 120 to 150°C, more preferably 125 to 150°C, and even more preferably 130 to 140°C.
  • the polypropylene resin constituting the heat seal layer may have a predetermined flexural modulus, and the flexural modulus of the polypropylene resin is preferably 300 to 1500 MPa, more preferably 400 to 1200 MPa, and even more preferably 500 to 900 MPa from the viewpoint of loop stiffness.
  • the flexural modulus is measured, for example, based on JIS K7171.
  • the polypropylene resin constituting the heat seal layer preferably contains 80 to 100% by mass of a propylene copolymer, more preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and particularly preferably 100% by mass.
  • the content of the polypropylene resin constituting the heat seal layer is preferably 30 to 90% by mass, more preferably 35 to 85% by mass, and even more preferably 35 to 80% by mass, based on 100% by mass of the resin composition constituting the heat seal layer.
  • the polyethylene resin in the heat seal layer preferably contains a linear low density polyethylene resin (straight-chain low density polyethylene resin) as a main component.
  • a linear low density polyethylene resin straight-chain low density polyethylene resin
  • at least one ethylene homopolymer selected from the group consisting of high pressure low density polyethylene, medium density polyethylene and high density polyethylene can be used.
  • random or block copolymers mainly made of ethylene and copolymerized with other monomers such as ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof can be used.
  • ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof
  • ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1
  • vinyl acetate vinyl
  • the melt flow rate (190° C., 2.16 kgf) of the polyethylene resin constituting the heat seal layer is, for example, 0.1 to 9 g/10 min, preferably 0.5 to 8 g/10 min, and more preferably 1 to 7 g/10 min.
  • the melting point of the polyethylene resin constituting the heat seal layer is, for example, 100 to 140°C, preferably 105 to 135°C, and more preferably 110 to 130°C.
  • the polyethylene resin constituting the heat seal layer may have a predetermined flexural modulus, and the flexural modulus of the linear low-density polyethylene resin is preferably 200 MPa or less, more preferably 10 to 190 MPa, even more preferably 20 to 180 MPa, even more preferably 30 to 170 MPa, and particularly preferably 40 to 160 MPa.
  • the flexural modulus of the linear low-density polyethylene resin is within the above range, the seal strength can be increased.
  • the polyethylene resin constituting the heat seal layer preferably contains 90% or more by mass of straight-chain linear polyethylene resin, more preferably 95% or more by mass, even more preferably 97% or more by mass, even more preferably 99% or more by mass, and particularly preferably 100% by mass.
  • the content of the polyethylene resin constituting the heat seal layer is preferably 10 to 70% by mass, more preferably 15 to 65% by mass, and even more preferably 20 to 65% by mass, based on 100% by mass of the resin composition constituting the heat seal layer.
  • the heat sealable film has a heat seal layer containing a linear low density polyethylene resin and a propylene copolymer.
  • the heat seal layer preferably contains 1 to 90% by mass of polypropylene resin, more preferably 5 to 90% by mass of polypropylene resin, relative to 100% by mass of the mixture of polypropylene resin and polyethylene resin.
  • polypropylene resin is 1% by mass or more, the rigidity is excellent.
  • polyethylene resin is preferably contained at 10 to 99% by mass, more preferably 20 to 90% by mass. When the polyethylene resin is 10% by mass or more, the low-temperature sealability is excellent.
  • the difference in melting point between the polypropylene-based resin and the polyethylene-based resin constituting the heat seal layer is preferably 15 to 25° C., more preferably 16 to 25° C., even more preferably 17 to 25° C., even more preferably 18 to 25° C., and particularly preferably 19 to 25° C.
  • the difference in melting point between the polypropylene-based resin and the polyethylene-based resin is 15° C. or more, the low-temperature sealability is improved, the mixability of the polypropylene-based resin and the polyethylene-based resin is good, and the variation in heat seal strength is reduced.
  • the arithmetic average melting point of the polypropylene resin and polyethylene resin constituting the heat seal layer is preferably 100 to 130° C., more preferably 112 to 130° C., even more preferably 115 to 130° C., even more preferably 116 to 130° C., and particularly preferably 121 to 130° C.
  • the arithmetic average melting point of the polypropylene resin and polyethylene resin is 100° C. or higher, the boiling suitability as a packaging material is improved, when it is 116° C. or higher, the semi-retort suitability is improved, and when it is 121° C. or higher, the high retort suitability is improved.
  • the resin composition in the heat seal layer may contain, as an antiblocking agent, inorganic particles such as synthetic silica, diatomaceous earth, talc, and mica, and organic particles such as silicone particles, acrylic particles, nylon particles, and polyethylene particles (preferably ultra-high molecular weight polyethylene particles).
  • the antiblocking agent is preferably synthetic silica or ultra-high molecular weight polyethylene.
  • the average particle size of the particles used in the present invention is preferably from 2 to 20 ⁇ m, more preferably from 3 to 15 ⁇ m, and even more preferably from 5 to 10 ⁇ m.
  • the particle content in the resin composition in the heat seal layer is preferably 0.1 to 2 mass % relative to the heat seal layer of the film, more preferably 0.3 to 1.5 mass %, and even more preferably 0.4 to 1.0 mass %. If the amount of particles added is less than 0.1 mass %, it becomes difficult to achieve a surface roughness Ra of 0.1 ⁇ m or more on at least one surface layer, making it difficult to obtain anti-blocking properties and slip properties. Furthermore, if the amount of particles added is more than 2 mass %, the number of surface protrusions increases, resulting in poor appearance and poor abrasion resistance.
  • the resin composition in the heat seal layer preferably contains 0.01 to 2.0% by mass of an organic lubricant (preferably a fatty acid amide), more preferably 0.05 to 1.5% by mass, and particularly preferably 0.1 to 1.0% by mass. If the amount of the organic lubricant is less than 0.01% by mass, blocking between the films is strong, and the handling properties of the film are not satisfactory. If the amount of the organic lubricant is 2.0% by mass or more, the seal strength is reduced.
  • organic lubricant preferably a fatty acid amide
  • fatty acid amides include erucic acid amide, ethylene bis oleic acid amide, behenic acid amide, etc., and these may be used in combination.
  • the antiblocking agent and organic lubricant have sufficient suitability for bag-making as long as they are contained in the outermost layer side of the packaging material, i.e., the heat seal layer side, it is preferable from the viewpoint of cost to contain them only in the heat seal layer.
  • the ratio of the melt flow rates of the raw resins mixed in the seal layer is preferably 0.5 to 2.0, more preferably 0.8 to 1.8, and even more preferably 1.0 to 1.6. If the melt flow rate ratio is within this range, it is less likely to cause appearance defects such as layer misalignment, spots, and unevenness.
  • the heat-sealable film preferably includes an intermediate layer and a laminate layer in addition to the heat-seal layer, and the heat-sealable layer, intermediate layer and laminate layer are laminated in this order.
  • the intermediate layer and the laminate layer preferably contain a propylene copolymer.
  • the laminate layer in the present invention is preferably made of a resin composition mainly composed of a polypropylene resin.
  • the term "main component" means that the proportion of the polypropylene resin in the resin composition is 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, even more preferably 99% by mass or more, and particularly preferably 100% by mass.
  • the laminate layer is made of a resin composition mainly composed of a polypropylene resin, so that the rigidity required to ensure a firm feel can be obtained. The loop stiffness evaluation as an index of firm feel will be described later.
  • the polypropylene resin in the laminate layer is a resin containing propylene as the main component, and examples thereof include propylene homopolymers, propylene copolymers (preferably propylene random copolymers and block copolymers) of propylene and ⁇ -olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1.
  • main component means that the proportion of propylene in the polypropylene resin is 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.
  • a film with excellent rigidity can be obtained.
  • the polypropylene-based resin constituting the laminate layer is preferably a propylene copolymer, more preferably a propylene-ethylene copolymer, a propylene-butene copolymer, or a propylene-ethylene-butene copolymer, even more preferably a propylene-ethylene-butene copolymer, even more preferably a propylene-ethylene-butene random copolymer, and particularly preferably a propylene-ethylene-butene random copolymer.
  • the melt flow rate (230°C, 2.16 kgf) of the polypropylene resin constituting the laminate layer is preferably 0.1 g/10 min to 9 g/10 min, more preferably 0.5 g/10 min to 8 g/10 min, and even more preferably 1 g/10 min to 7 g/10 min.
  • the melting point (JIS K7121) of the polypropylene resin constituting the laminate layer is preferably 120 to 160°C, more preferably 125 to 155°C, and even more preferably 130 to 150°C.
  • the polypropylene-based resin constituting the laminate layer may have a predetermined flexural modulus. From the viewpoint of loop stiffness, the flexural modulus of the polypropylene-based resin is preferably 400 to 1500 MPa, more preferably 500 to 1300 MPa, and even more preferably 600 to 1100 MPa.
  • the polypropylene resin constituting the laminate layer preferably contains 80 to 100% by mass of a propylene copolymer, more preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and particularly preferably 100% by mass.
  • the content of the polypropylene resin constituting the laminate layer is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, even more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, particularly preferably 90 to 100% by mass, and most preferably 100% by mass, based on 100% by mass of the resin composition constituting the laminate layer.
  • the resin composition of the laminate layer may contain, for example, at least one ethylene homopolymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene.
  • random or block copolymers obtained by copolymerizing ethylene as the main component with other monomers such as ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof can be used. These may be crystalline, low-crystalline, or non-crystalline.
  • the melt flow rate (190°C, 2.16 kgf) of the polyethylene resin constituting the laminate layer is preferably 0.1 g/10 min to 9 g/10 min, more preferably 0.5 g/10 min to 8 g/10 min, and even more preferably 1 g/10 min to 7 g/10 min.
  • the melting point (JIS K7121) of the polyethylene resin constituting the laminate layer is preferably 100 to 140°C, more preferably 105 to 135°C, and even more preferably 110 to 130°C.
  • the melting point of a polyethylene resin may show two or more melting endothermic peaks, and the peak with the largest amount of melting endothermic heat is defined as the main peak.
  • the resin composition in the laminate layer may contain, as an antiblocking agent, inorganic particles such as synthetic silica, diatomaceous earth, talc, mica, etc., and organic particles such as silicone particles, acrylic particles, nylon particles, polyethylene particles, etc.
  • the average particle size of the particles used in the present invention is preferably 2 to 20 ⁇ m, more preferably 3 to 15 ⁇ m, and even more preferably 5 to 10 ⁇ m.
  • the particle content in the resin composition in the laminate layer is preferably 0.1 to 2 mass% relative to the film seal layer, more preferably 0.3 to 1.5 mass%, and even more preferably 0.4 to 1.0 mass%. If the amount of particles added is less than 0.1 mass%, it becomes difficult to achieve a surface roughness Ra of 0.1 ⁇ m or more on at least one surface layer, making it difficult to obtain anti-blocking properties and slip properties. Furthermore, if the amount of particles added is more than 2 mass%, the number of surface protrusions increases, resulting in poor appearance and poor abrasion resistance.
  • the resin composition in the laminate layer preferably contains 0.01 to 2.0% by mass of an organic lubricant (preferably a fatty acid amide), more preferably 0.05 to 1.5% by mass, and particularly preferably 0.1 to 1.0% by mass. If the amount of the organic lubricant is less than 0.01% by mass, blocking between the films is strong, and the handling properties of the film are not satisfactory. If the amount of the organic lubricant is 2.0% by mass or more, the seal strength is reduced.
  • an organic lubricant preferably a fatty acid amide
  • the fatty acid amide include erucic acid amide, ethylene bis oleic acid amide, and behenic acid amide, and these may be used in combination.
  • the ratio of the melt flow rates of the raw resins mixed in the laminate layer is preferably 0.5 to 2.0, more preferably 0.8 to 1.8, and even more preferably 1.0 to 1.6. If the melt flow rate ratio is within this range, it is less likely to cause appearance defects such as layer misalignment, spots, and unevenness.
  • the heat-sealable film of the present invention may include an intermediate layer between the laminate layer and the seal layer.
  • the intermediate layer in the present invention is preferably made of a resin composition mainly composed of a polypropylene resin.
  • the term "main component" means that the proportion of the polypropylene resin in the resin composition is 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.
  • the polypropylene-based resin in the intermediate layer is a resin containing propylene as a main component, and examples thereof include propylene homopolymers, propylene copolymers (preferably propylene random copolymers and block copolymers) of propylene and ⁇ -olefins such as ethylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, octene-1, etc.
  • the polypropylene-based resin constituting the laminate layer is more preferably a propylene-ethylene copolymer, a propylene-butene copolymer, or a propylene-ethylene-butene copolymer, even more preferably a propylene-ethylene-butene copolymer, and even more preferably a propylene-ethylene-butene random copolymer.
  • main component means that the proportion of propylene in the polypropylene resin is 90% by mass or more, preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.
  • the melt flow rate (230°C, 2.16 kgf) of the polypropylene resin constituting the intermediate layer is preferably 0.1 g/10 min to 9 g/10 min, more preferably 0.5 g/10 min to 8 g/10 min, and even more preferably 1 g/10 min to 7 g/10 min.
  • the melting point of the polypropylene resin constituting the intermediate layer is preferably 120 to 160°C, more preferably 125 to 150°C, and even more preferably 130 to 140°C.
  • the polypropylene resin constituting the intermediate layer may have a predetermined flexural modulus, and the flexural modulus of the polypropylene resin is preferably 300 to 1200 MPa, more preferably 400 to 1100 MPa, and even more preferably 500 to 1000 MPa.
  • the polypropylene resin constituting the intermediate layer preferably contains 80 to 100% by mass of a propylene copolymer, more preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and particularly preferably 100% by mass.
  • the content of the polypropylene resin constituting the intermediate layer is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, even more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, particularly preferably 90 to 100% by mass, and most preferably 100% by mass, based on 100% by mass of the resin composition constituting the intermediate layer.
  • the resin composition for the intermediate layer may be, for example, at least one ethylene homopolymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene.
  • random or block copolymers mainly made of ethylene and copolymerized with other monomers such as ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid esters, or mixtures thereof can be used.
  • ⁇ -olefins such as propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, and octene-1, vinyl acetate, (meth)acrylic acid, and (meth)acrylic acid
  • the melt flow rate (190°C, 2.16 kgf) of the polyethylene resin constituting the intermediate layer is preferably 0.1 g/10 min to 9 g/10 min, more preferably 0.5 g/10 min to 8 g/10 min, and even more preferably 1 g/10 min to 7 g/10 min.
  • the melting point of the polyethylene resin constituting the intermediate layer is preferably from 100 to 140°C, more preferably from 105 to 135°C, and even more preferably from 110 to 130°C.
  • the resin composition in the intermediate layer may contain an antiblocking agent used in the sealing layer or laminate layer.
  • the resin composition in the intermediate layer may contain an organic lubricant used in the seal layer or laminate layer.
  • the ratio of the melt flow rates of the raw resins mixed in the sealing layer is preferably 0.5 to 2.0, more preferably 0.8 to 1.8, and even more preferably 1.0 to 1.6. If the melt flow rate ratio is within this range, it is less likely to cause appearance defects such as layer misalignment, spots, and unevenness.
  • the layer structure of the heat sealable film of the present invention may be laminate layer/heat seal layer, laminate layer/intermediate layer/heat seal layer, or laminate layer/intermediate layer 1/intermediate layer 2/heat seal layer. It is preferable to provide an intermediate layer between the laminate layer and the heat seal layer because peeling between the laminate layer and the seal layer is unlikely to occur and recycled raw materials can be easily used, and the raw material composition of the intermediate layer is preferably intermediate between the laminate layer and the heat seal layer in order to make peeling between the laminate layer and the heat seal layer unlikely to occur.
  • the thickness of the heat sealable film is, for example, 5 to 100 ⁇ m, preferably 10 to 80 ⁇ m, and more preferably 20 to 60 ⁇ m.
  • the thickness of the laminate layer and the heat seal layer is, for example, 1 to 30 ⁇ m, preferably 2 to 15 ⁇ m, and more preferably 3 to 10 ⁇ m.
  • the thickness of the intermediate layer is, for example, 5 to 50 ⁇ m, preferably 7 to 40 ⁇ m, and more preferably 9 to 30 ⁇ m.
  • the ratio of the melt flow rates of the raw resins of adjacent layers is preferably 0.5 to 2.0. When the melt flow rate ratio is within this range, poor appearance such as layer misalignment, blemishes, and unevenness is unlikely to occur.
  • the main peak of the melting point of the heat-sealable film of the present invention is preferably 121° C. or higher, more preferably 130° C. or higher, even more preferably 140° C. or higher, even more preferably 150° C. or higher, and particularly preferably 160° C. or higher. When the main peak of the melting point of the heat-sealable film is 121° C. or higher, the high retort suitability is further improved.
  • the method for producing the heat-sealable film of the present invention will be described in detail below, but the present invention is not limited thereto.
  • the resin compositions for the laminate layer and the heat seal layer may be prepared by blending the above-mentioned resin raw materials and, if necessary, various additives in a mixer such as a Henschel mixer, a Banbury mixer, or a tumbler mixer, and then pelletizing the mixture using a single-screw or twin-screw extruder to form a film.
  • a mixer such as a Henschel mixer, a Banbury mixer, or a tumbler mixer
  • the components may be blended together and fed to a film forming machine.
  • the mixed resin composition is melted under conditions of a resin temperature of, for example, 110 to 300° C., melt-extruded into a sheet from, for example, a T-shaped die, cast onto a cooling roll, and cooled and solidified to obtain an unstretched sheet.
  • a specific method for this is preferably casting onto a cooling roll.
  • a multi-layering device such as a multi-layer feed block, a static mixer, a multi-manifold die, etc., can be used.
  • there is a method in which resins discharged from different flow paths using two or more extruders are laminated into multiple layers using a multi-layer feed block or a multi-manifold die.
  • Examples of the method include a method in which a melt-kneaded laminated resin composition sheet is melt-extruded and then formed into a film by a T-die method or an inflation method, and the T-die method is particularly preferred because it allows the melting temperature of the resin to be increased.
  • the cooling roll temperature is preferably 10 to 70°C. If it is less than the above, not only may the crystallization suppression effect become saturated, but also problems such as condensation may occur, which is not preferable. If it exceeds the above, crystallization proceeds and transparency deteriorates, which is not preferable. Furthermore, when the temperature of the cooling roll is in the above range, it is preferable to lower the humidity of the environment near the cooling roll to prevent condensation. During casting, the surface of the chill roll rises in temperature because the hot resin comes into contact with it.
  • the thickness of the unstretched sheet is preferably in the range of 3 to 130 ⁇ m.
  • the thickness of the film is preferably in the range of 5 to 125 ⁇ m, more preferably 10 to 120 ⁇ m.
  • the film thickness is 3 ⁇ m or more, the rigidity required to ensure firmness can be obtained.
  • the film thickness is 130 ⁇ m or less, the film is not too firm and is easy to process, and a suitable package can be easily produced.
  • the substrate film and the heat-sealable film can be laminated by a dry lamination method using an adhesive.
  • the adhesive layer used in the present invention can be a general-purpose adhesive for lamination.
  • (solvent-free), aqueous, or hot-melt adhesives containing poly(ester)urethane, polyester, polyamide, epoxy, poly(meth)acrylic, polyethyleneimine, ethylene-(meth)acrylic acid, polyvinyl acetate, (modified) polyolefin, polybutadiene, wax, casein, or the like as the main component can be used.
  • urethane or polyester adhesives are preferred in consideration of heat resistance and flexibility that can follow the dimensional changes of each substrate.
  • the adhesive layer can be laminated by, for example, direct gravure coating, reverse gravure coating, kiss coating, die coating, roll coating, dip coating, knife coating, spray coating, fountain coating, or other methods.
  • the coating amount after drying is preferably 1 to 8 g/m 2 , more preferably 2 to 7 g/m 2 , and even more preferably 3 to 6 g/m 2. If the coating amount is less than 1 g/m 2 , it becomes difficult to bond the entire surface, and the adhesive strength decreases.
  • the thickness of the adhesive layer is, for example, 0.1 to 10 ⁇ m, preferably 0.5 to 7 ⁇ m, and more preferably 1 to 5 ⁇ m.
  • At least one printed layer may be laminated between the base film layer and the heat-sealable film or on the outer side thereof.
  • the printing ink for forming the printing layer water-based and solvent-based resin-containing printing inks can be preferably used.
  • resins used in the printing ink include acrylic resins, urethane resins, polyester resins, vinyl chloride resins, vinyl acetate copolymer resins, and mixtures thereof.
  • the printing ink may contain known additives such as antistatic agents, light blocking agents, ultraviolet absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, defoamers, crosslinking agents, anti-blocking agents, and antioxidants.
  • known printing methods such as offset printing, gravure printing, and screen printing can be used.
  • known drying methods such as hot air drying, hot roll drying, and infrared drying can be used.
  • one of the suitable configurations is to laminate the printed layer to a white base film or a heat sealable film to enhance the concealing property, or to laminate the printed layer to an ultraviolet ray cut film to block light.
  • the packaging material of the present invention is a coating layer/surface layer/substrate layer/surface layer/adhesive layer/laminate layer/intermediate layer/heat seal layer, inorganic thin film layer/surface layer/substrate layer/surface layer/adhesive layer/laminate layer/intermediate layer/heat seal layer, inorganic thin film layer/anchor coat layer/surface layer/substrate layer/surface layer/adhesive layer/laminate layer/intermediate layer/heat seal layer, protective layer/inorganic thin film layer/surface layer/substrate layer/surface layer/adhesive layer/laminate layer/intermediate layer/heat seal layer, protective layer/inorganic thin film layer/anchor coat layer/surface layer/substrate layer/surface layer/adhesive layer/laminate layer/intermediate layer/heat seal layer, coating layer/surface layer/substrate layer/surface layer/adhesive layer/laminate layer/
  • the packaging material of the present invention must have a seal strength of 10 N/15 mm or more in the MD or TD direction when heat sealed at 120°C, 0.1 MPa, for 1 second.
  • the heat seal strength is preferably 10 N/15 mm to 40 N/15 mm, more preferably 12 N/15 mm to 35 N/15 mm, even more preferably 14 N/15 mm to 30 N/15 mm, and particularly preferably 15 N/15 mm to 30 N/15 mm.
  • a seal strength of 15 N/15 mm or more is required. Details of the method for measuring the heat seal strength will be shown in the examples below, but it can be measured, for example, based on JIS Z1707.
  • the heat sealing temperature is preferably from 60 to 180°C, more preferably from 70 to 170°C, and even more preferably from 80 to 160°C.
  • the heat sealing temperature is preferably set at a lower limit of 20°C or more lower than the lowest melting point of the polyethylene-based resin and/or polypropylene-based resin in the seal layer of the heat-sealable film, and at an upper limit of 10°C or more higher than the highest melting point of the polyethylene-based resin and/or polypropylene-based resin in the laminate layer.
  • the packaging material of the present invention has an excellent appearance after heat sealing. Specifically, it is preferable that the sealed portion does not wrinkle and the bag does not distort. In order to maintain the appearance after sealing, it is possible to set the difference in melting point between the polyethylene resin and the polypropylene resin in the sealing layer of the heat sealable film within the above-mentioned specified range.
  • the packaging material of the present invention must have a loop stiffness value of 22 mN/25 mm or more.
  • Loop stiffness refers to the resilience of a loop formed by cutting a film into a strip of a specified size, and is measured when the loop is crushed by a specified amount in the radial direction, and is an index of the film's rigidity. By setting the loop stiffness value within the above range, for example, the necessary firmness during bag manufacturing can be ensured.
  • the loop stiffness value is preferably 23 mN/25 mm to 800 mN/25 mm, more preferably 25 mN/25 mm to 750 mN/25 mm, and even more preferably 27 mN/25 mm to 700 mN/25 mm.
  • loop stiffness value is less than 22 mN/25 mm, there is a risk that sufficient firmness will not be obtained during bag manufacturing, resulting in a poor finish. If the loop stiffness value is more than 800 mN/25 mm, there is a risk that the firmness will be too strong and bag manufacturing will be difficult.
  • the details of the method for measuring the loop stiffness are shown in the Examples below, but for example, it may be measured using a loop stiffness tester.
  • the loop stiffness value can be achieved by adjusting the type and thickness of the polypropylene-based resin and polyethylene-based resin in the laminate layer and seal layer that constitute the heat-sealable film. However, care must be taken because increasing the thickness is undesirable from the viewpoint of reducing the volume and leads to increased costs.
  • the value of (loop stiffness value) ⁇ (total thickness) is preferably 0.10 to 8.00, more preferably 0.15 to 7.50, even more preferably 0.20 to 7.00, even more preferably 0.50 to 3.0, and particularly preferably 0.53 to 2.0.
  • the packaging material of the present invention preferably has an oxygen transmission rate of 60 ml/ m2 ⁇ d ⁇ MPa or less under conditions of 23°C ⁇ 65% RH in terms of exhibiting good gas barrier properties. Furthermore, by providing a barrier layer on each film, the oxygen transmission rate can be preferably 0.5 to 50 ml/ m2 ⁇ d ⁇ MPa, more preferably 1.0 to 40 ml/ m2 ⁇ d ⁇ MPa, and even more preferably 1.5 to 35 ml/ m2 ⁇ d ⁇ MPa. If the oxygen transmission rate exceeds 60 ml/ m2 ⁇ d ⁇ MPa, it becomes difficult to meet applications requiring high gas barrier properties.
  • the oxygen transmission rate is less than 0.5 ml/ m2 ⁇ d ⁇ MPa, although the barrier performance is excellent, the residual solvent is less likely to permeate to the outside of the bag, and there is a risk of a relatively large amount of migration to the contents, which is not preferable.
  • the oxygen transmission rate is measured, for example, based on JIS K7126B.
  • the packaging material of the present invention preferably has a water vapor permeability of 3.0 g/ m2 ⁇ d or less under conditions of 40°C x 90% RH in terms of exhibiting good gas barrier properties. Furthermore, by providing a barrier layer on each film, the water vapor permeability can be preferably 0.1 to 2.5 g/ m2 ⁇ d, more preferably 0.2 to 2.0 g/ m2 ⁇ d. If the water vapor permeability exceeds 3.0 g/ m2 ⁇ d, it becomes difficult to meet applications requiring high gas barrier properties.
  • the water vapor permeability is less than 0.1 g/ m2 , although the barrier performance is excellent, the residual solvent is less likely to permeate to the outside of the bag, and there is a risk of a relatively large amount of migration to the contents, which is not preferable.
  • the water vapor permeability is measured, for example, based on JIS K7129B.
  • the mono-material ratio is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more.
  • a polypropylene-based resin as the polyolefin-based resin that constitutes the base film, but if a polypropylene-based resin is also used for the heat-sealable film, a configuration that is even easier to recycle can be obtained. If all the polyolefin-based materials used are polypropylene-based resins, a configuration that is even easier to recycle can be obtained.
  • the total thickness of the packaging material is, for example, 140 ⁇ m or less, preferably 20 to 140 ⁇ m, more preferably 25 to 135 ⁇ m, and even more preferably 30 to 130 ⁇ m.
  • the total thickness of the packaging material is, for example, 140 ⁇ m or less, preferably 20 to 140 ⁇ m, more preferably 25 to 135 ⁇ m, and even more preferably 30 to 130 ⁇ m.
  • the total thickness is less than 20 ⁇ m, the bag will not have enough firmness and will not stand on its own.
  • the total thickness exceeds 140 ⁇ m, the heat sealing temperature must be increased to exhibit sufficient heat sealing strength, and there is a risk of poor appearance such as wrinkles and distortion. In addition, this leads to increased costs for the package, which is economically undesirable.
  • the packaging material of the present invention has excellent gas barrier properties, heat sealability, firmness, and visibility as described above, and therefore can be used as various types of packaging.
  • the packaging material of the present invention is preferably used for microwave heating.
  • the packaging material of the present invention remains unchanged on the film surface and does not develop wrinkles even when heated in a microwave oven.
  • the shape of the package using the packaging material of the present invention is not particularly limited and can take various shapes.
  • Examples of packaging shapes include three-sided and four-sided pouches, standing pouches, spout pouches, etc.
  • the present invention also encompasses packages in which the packaged item is packaged in a packaging material.
  • the contents filled into a packaging bag using the packaging material of the present invention are not particularly limited, and the contents may be liquid, powder, or gel.
  • the contents may also be food or non-food.
  • the film thickness composition was measured using a fluorescent X-ray analyzer ("Supermini 200" manufactured by Rigaku Corporation) based on a calibration curve prepared in advance.
  • the excitation X-ray tube conditions were 50 kV and 4.0 mA.
  • each laminate film obtained at the stage where a predetermined coating layer (A), anchor coat layer (C), and protective layer (D) were laminated on a substrate film was used as a sample, and a test piece of 100 mm x 100 mm was cut out from this sample, and the coating layer was wiped off with either water, ethanol, or acetone, and the amount of adhesion was calculated from the change in mass of the film before and after wiping.
  • Preparation of packaging materials (8) Preparation of Packaging Material for Evaluation When there was one base film, a polyurethane adhesive (TM569/cat10L manufactured by Toyo-Morton Co., Ltd.) was applied to the gas barrier layer side of the base film described in the Examples and Comparative Examples so that the thickness after drying treatment at 80°C would be 3 ⁇ m, and then various heat-sealable films described below were dry-laminated on a metal roll heated to 60°C, and aging was performed at 40°C for 2 days (48 hours) to obtain a packaging material that was a laminate for evaluation.
  • a polyurethane adhesive TM569/cat10L manufactured by Toyo-Morton Co., Ltd.
  • a polyurethane adhesive (TM569/cat10L manufactured by Toyo Morton Co., Ltd.) was applied to the substrate film described in the Examples and Comparative Examples so that the thickness after drying at 80° C. was 3 ⁇ m, and then another substrate film was dry-laminated on a metal roll heated to 60° C. to form a take-up roll.
  • the same adhesive was applied to this roll so that the thickness after drying at 80° C. was 3 ⁇ m, and then a heat-sealable film described later was dry-laminated on a metal roll heated to 60° C., and aging was performed at 40° C. for 2 days (48 hours) to obtain a packaging material for evaluation.
  • OTR oxygen transmission rate
  • the peel strength was measured in the MD direction at a tensile speed of 200 mm/min using a universal tensile tester "DSS-100" (manufactured by Shimadzu Corporation).
  • the heat seal strength was expressed as the strength per 15 mm (N/15 mm). A total of three measurements were performed, and the average value was taken as the heat seal strength.
  • the appearance of the seal was evaluated (finished) on a relative basis, with ⁇ being a seal without wrinkles, ⁇ being a seal with some wrinkles, and ⁇ being a seal with wrinkles over the entire surface.
  • loop Stiffness of Packaging Material The loop stiffness of the packaging material prepared in (8) above was measured. The material was cut into strips of film with widths of 25 mm and 110 mm, and the longitudinal direction of the strips was aligned with the direction of the object being measured. The strips were set in a loop stiffness tester manufactured by Toyo Seiki Seisakusho Co., Ltd., and the repulsive force was measured. The measurement frequency was 50 Hz. The repulsive force value (mN/25 mm) obtained by the measurement was taken as the loop stiffness value.
  • the base layer (A) was extruded with a 45 mm extruder, the surface layer (B) with a 25 mm extruder, and the second surface layer (B) (surface layer (C)) with a 20 mm extruder.
  • the raw material resins were melted at 250 ° C. and co-extruded from a T-die into a sheet shape, and the surface layer (B) was cooled and solidified so that it contacted a cooling roll at 40 ° C., and then stretched 4.5 times in the longitudinal direction (MD) at 125 ° C.
  • both ends of the film in the width direction (TD) were clamped with clips, preheated at 167 ° C., stretched 8.2 times in the width direction (TD) at 163 ° C., and heat-set at 169 ° C. while relaxing 6.7% in the width direction (TD).
  • the film formation conditions at this time were film formation conditions a.
  • a biaxially oriented polypropylene film having a structure of surface layer (B)/base layer (A)/second surface layer (B) (surface layer (C)) was obtained.
  • the surface of the surface layer (B) of the biaxially oriented polypropylene film was subjected to a corona treatment using a corona treatment machine manufactured by Softal Corona & Plasma GmbH under the condition of an applied current value of 0.75 A, and then wound up with a winder.
  • the thickness of the obtained film was 20 ⁇ m (thickness of the surface layer (B)/base layer (A)/second surface layer (B) was 1.0 ⁇ m/18.0 ⁇ m/1.0 ⁇ m). Details of this configuration are shown in Table 4.
  • the film was formed under the conditions of b in Table 3, and other conditions were the same as those for OPP1 to obtain a biaxially oriented polypropylene film of 20 ⁇ m. The details of this configuration are shown in Table 4.
  • the surface of the surface layer (C) of the biaxially oriented polypropylene film was subjected to corona treatment using a corona treatment machine manufactured by Softal Corona & Plasma GmbH at an applied current value of 0.75 A, and other conditions were the same as those of OPP1, to obtain a 20 ⁇ m biaxially oriented polypropylene film. Details of this configuration are shown in Table 4.
  • Coating layer (A) The coating liquid for forming the coating layer (A) used in the examples and comparative examples will be described in detail below.
  • Polyvinyl alcohol resin (a) 10 parts by mass of a fully saponified polyvinyl alcohol resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name: G Polymer OKS8049Q (saponification degree 99.0% or more, average polymerization degree 450)) was added to 90 parts by mass of purified water, and the mixture was heated to 80° C. with stirring, and then stirred for about 1 hour. The mixture was then cooled to room temperature, thereby obtaining a nearly transparent polyvinyl alcohol solution (PVA solution) with a solid content of 10%.
  • PVA solution polyvinyl alcohol solution
  • Inorganic layered compound dispersion (b) 5 parts by mass of montmorillonite (trade name: Kunipia F, manufactured by Kunimine Industries Co., Ltd.), which is an inorganic layered compound, was added to 95 parts by mass of purified water while stirring, and thoroughly dispersed with a homogenizer set at 1500 rpm. After that, the mixture was kept at 23° C. for 1 day to obtain an inorganic layered compound dispersion liquid with a solid content of 5%.
  • montmorillonite trade name: Kunipia F, manufactured by Kunimine Industries Co., Ltd.
  • Coating solution 1 used for coating layer 1 The materials were mixed in the following ratio to prepare a coating liquid (resin composition for coating layer).
  • Coating solution 2 used for coating layer 2 The materials were mixed in the following ratio to prepare a coating liquid (resin composition for coating layer). Ion-exchanged water 15.00% by mass Isopropyl alcohol 15.00% by mass Polyvinyl alcohol resin (a) 70.00% by mass
  • the coating solution prepared above was applied onto the corona-treated surface of the substrate film by gravure roll coating, pre-dried at 90°C for 4 seconds, and then dried at 120°C for 4 seconds to obtain a coating layer.
  • the coating layer had an adhesion weight of 0.30 g/ m2 .
  • a post-heat treatment was performed at 40°C for 2 days (48 hours). In this manner, a laminate film having either coating layer 1 or 2 was produced.
  • inorganic thin film layer (B) The method for producing the inorganic thin film layer (B) used in each of the Examples and Comparative Examples will be described below.
  • Formation of inorganic thin film layer 2 Silicon oxide was deposited on the substrate film or the anchor coat layer to form the inorganic thin film layer 2 (deposition 2). Using a small vacuum deposition apparatus (VWR-400/ERH, manufactured by ULVAC KIKO Co., Ltd.), the pressure was reduced to 10 ⁇ 3 Pa or less, and silicon oxide was then placed in a Nilaco deposition source B-110 from below the substrate and evaporated by heating to form a silicon oxide film with a thickness of 30 nm on the substrate film.
  • VWR-400/ERH manufactured by ULVAC KIKO Co., Ltd.
  • inorganic thin film layer 3 Metallic aluminum was deposited on the base film or the anchor coat layer to form inorganic thin film layer 3 (deposition 3). Using a small vacuum deposition apparatus (VWR-400/ERH, manufactured by ULVAC KIKO Co., Ltd.), the pressure was reduced to 10 ⁇ 3 Pa or less, and aluminum foil with a purity of 99.9% was placed on a Nilaco deposition source CF-305W from below the substrate. Metallic aluminum was heated and evaporated to form a metallic aluminum film with a thickness of 30 nm on the base film.
  • VWR-400/ERH manufactured by ULVAC KIKO Co., Ltd.
  • Anchor Coat Layer (C) The method for producing the anchor coat layer (C) used in each of the Examples and Comparative Examples will be described below.
  • polyester resin (a) As the polyester component, a polyester polyol (DF-COAT GEC-004C manufactured by DIC Corporation: solid content 30%) was used.
  • Polyisocyanate Crosslinking Agent (b) As the polyisocyanate component, a trimethylolpropane adduct of metaxylylene diisocyanate ("Takenate D-110N" manufactured by Mitsui Chemicals, Inc.: solid content 75%) was used.
  • silane coupling agent (c) N-2-(aminoethyl)-3-aminopropyltrimethoxysilane ("KBM-603" manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
  • urethane resin (d) As the urethane resin, a polyester urethane resin dispersion (HYDRAN (registered trademark) AP-201, manufactured by DIC Corporation; solid content 23%) was used.
  • HYDRAN registered trademark
  • Coating solution 2 for anchor coat layer 2 The following coating materials were mixed to prepare Coating Liquid 2. Water 43.91% by mass Isopropanol 30.00% by mass Urethane resin (d) 26.09% by mass
  • Coating solution 1 or 2 was applied to the corona-treated surface of the substrate film by gravure roll coating, pre-dried at 95°C for 4 seconds, and then dried at 115°C for 4 seconds to obtain an anchor coat layer.
  • the adhesion amount of the anchor coat layer at this time was 0.40 g/ m2 .
  • a post-heat treatment at 40°C for 4 days (96 hours) was performed to obtain the desired laminate film.
  • the above-mentioned coating solution 1 was applied onto the inorganic thin film layer of the substrate film by a gravure roll coating method, and dried for 10 seconds in a dry oven at 120°C to obtain a protective layer 1.
  • the amount of the protective layer attached at this time was 0.30 g/ m2 .
  • a post-heat treatment was performed at 40°C for 2 days (48 hours). In this manner, a laminate film provided with a protective layer was produced.
  • Table 5 shows the details of the polypropylene-based resin raw materials and the polyethylene-based resin raw materials used in the preparation of the heat-sealable films CPP-1 to 5, as well as the raw material blending ratios.
  • Erucamide master batch Erucamide was mixed with Noblen (registered trademark) FL6745A manufactured by Sumitomo Chemical Co., Ltd. to prepare a master batch containing 5% by mass of erucamide.
  • Behenic acid amide master batch Behenic acid amide was mixed with Noblen (registered trademark) FL6745A manufactured by Sumitomo Chemical Co., Ltd. to prepare a master batch containing 2 mass % of behenic acid amide.
  • the laminate layer was made of FL8115A, the intermediate layer was made of FL6745A, and the seal layer was made of the resin and additives shown in Table 5.
  • the master batches were melted at 240°C in each of three extruders, filtered through a sintered filter with a filtration accuracy of 60 ⁇ m, and then co-extruded from a T-die into a sheet.
  • the laminate layer, intermediate layer, and seal layer were melt-extruded so that the thickness ratio was 25:50:25 vol.%, cooled and solidified with a cooling roll at 30°C, and then wound up into a roll at a speed of 20 m/min to obtain a heat-sealable film with a total thickness of 30 ⁇ m (laminate layer thickness 7.5 ⁇ m, intermediate layer thickness 15 ⁇ m, seal layer thickness 7.5 ⁇ m) and a wet tension of the laminate layer of 45 mN/m.
  • the content ratio of polypropylene-based resin and polyethylene-based resin in each layer is based on the total of polypropylene-based resin and polyethylene-based resin.
  • packaging materials were produced that had a coating layer, an anchor coat layer, an inorganic thin film layer, or a protective layer on each film, and further had a heat-sealable film.
  • each film was used and bonded by dry lamination using the adhesive described above to produce a packaging material with the configuration shown in Table 6A.
  • various evaluations were carried out on the resulting packaging material. The results are shown in Table 6B.
  • a laminate film is formed by laminating a predetermined gas barrier layer tailored to the required performance on a base film, thereby greatly improving the gas barrier performance, and further, by laminating a resin layer excellent in low-temperature heat sealability as a heat sealable film to the above-mentioned base film, it is possible to provide an environmentally friendly and highly convenient packaging material. Moreover, since the packaging material of the present invention can be easily produced with fewer processing steps, it is excellent in both economy and production stability, and it is possible to provide a gas barrier package with uniform characteristics.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)
  • Wrappers (AREA)

Abstract

La présente invention aborde le problème de la fourniture d'un matériau d'emballage et similaire qui sont composés d'une résine ayant une faible charge environnementale et qui possèdent toutes les trois performances de propriétés de barrière aux gaz, d'étanchéité à la chaleur et de sensation de rigidité.　La présente invention concerne un matériau d'emballage ayant un ou plusieurs films de substrat ayant chacun une résine à base de polyoléfine en tant que composant constitutif principal et un film thermoscellable. Au moins l'un des films de substrat est un film de substrat stratifié ayant une couche barrière aux gaz. Le matériau d'emballage est caractérisé en ce que, lorsque les surfaces du film thermoscellable du matériau d'emballage sont thermoscellées à 120°C avec 0,1 MPa pendant 1 seconde, la résistance d'étanchéité est de 10 N/15 mm ou plus, la valeur de rigidité de boucle est de 22 mN/25 mm ou plus, la perméabilité à l'oxygène à 23°C × 65 % RH est de 50 ml/m2·d·MPa ou moins et la perméabilité à la vapeur d'eau à 40°C × 90 % RH est de 3,0 g/m2·d ou moins.
PCT/JP2024/019829 2023-05-31 2024-05-30 Matériau d'emballage, sac d'emballage et emballage Pending WO2024248080A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021199637A1 (fr) * 2020-03-31 2021-10-07 大日本印刷株式会社 Stratifié, sachet, et matériau de couvercle
WO2022030361A1 (fr) * 2020-08-06 2022-02-10 東洋紡株式会社 Film stratifié et matériau d'emballage
JP2023013959A (ja) * 2021-07-16 2023-01-26 東洋紡株式会社 二軸配向積層ポリプロピレンフィルム
WO2023074754A1 (fr) * 2021-10-26 2023-05-04 大日本印刷株式会社 Film d'étanchéité

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021199637A1 (fr) * 2020-03-31 2021-10-07 大日本印刷株式会社 Stratifié, sachet, et matériau de couvercle
WO2022030361A1 (fr) * 2020-08-06 2022-02-10 東洋紡株式会社 Film stratifié et matériau d'emballage
JP2023013959A (ja) * 2021-07-16 2023-01-26 東洋紡株式会社 二軸配向積層ポリプロピレンフィルム
WO2023074754A1 (fr) * 2021-10-26 2023-05-04 大日本印刷株式会社 Film d'étanchéité

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