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
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • 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
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
• • 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
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
  • B32B27/22—Layered products comprising a layer of synthetic resin characterised by the use of special additives using plasticisers
• • 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
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
• • 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
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
  • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
• • 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
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
• • 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
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • 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
  • B32B43/00—Operations specially adapted for layered products and not otherwise provided for, e.g. repairing; Apparatus therefor
  • B32B43/006—Delaminating
• • 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
• • 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
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/716—Degradable
  • B32B2307/7166—Water-soluble, water-dispersible
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/72—Density
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/724—Permeability to gases, adsorption
  • B32B2307/7242—Non-permeable
  • B32B2307/7244—Oxygen barrier
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/748—Releasability
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/75—Printability
• • 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
  • B32B2553/00—Packaging equipment or accessories not otherwise provided for
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J11/00—Recovery or working-up of waste materials
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• the present invention relates to a multilayer structure that has excellent oxygen barrier properties and adhesiveness under high humidity, as well as excellent peelability in the separation process, a separation method thereof, and a recycling method.
• a variety of laminated materials with various functions such as mechanical properties, heat resistance, gas barrier properties, and heat sealing properties are used in plastic packaging materials such as food packaging.
• plastic packaging materials such as food packaging.
• examples include polyamides for improving mechanical properties, polyesters for improving heat resistance, ethylene-vinyl alcohol copolymers and polyvinylidene chloride for improving gas barrier properties, and polyethylene and polypropylene for improving heat sealing properties.
• polyolefins such as
• recycling post-consumer recycling
• Non-Patent Document 1 describes that in the mutual separation of general-purpose plastics, separation is improved by adding a wetting-agent to remove the hydrophobicity of the plastic surface when applying the float-sink separation method.
• Patent Document 2 in a packaging film in which at least two base layers made of different materials are laminated, a solvent-soluble intervening layer provided between the base layers is dissolved by solvent immersion. , that each substrate layer can be easily separated.
• polyesters such as polyethylene terephthalate often have a high melting point and are difficult to recycle by mixing with other materials widely used as packaging materials.
• chlorinated resins such as polyvinylidene chloride by mixing them with other materials that are widely used as packaging materials, due to concerns about the impact on processing equipment and quality deterioration of recycled resins.
• Patent Document 2 has insufficient interlaminar adhesion under high humidity or insufficient releasability during stirring in a solution.
• the separation process involving the dissolution of the solvent-soluble layer it is important to separate different materials easily. It is difficult to achieve both interlayer adhesion and releasability in the separation process.
• An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a multilayer structure having excellent oxygen barrier properties, excellent interlaminar adhesion under high humidity, and excellent peelability in the separation process, and its separation. to provide a method. Another object of the present invention is to provide a recycling method for independently melting and molding the separated substances.
• a layer structure (X) and a layer structure (Y) are laminated via a water-soluble layer (A), and the layer structure (X) is at least selected from the group consisting of thermoplastic resins and metals.
• a substrate layer (B) (hereinafter sometimes abbreviated as “substrate layer (B)”) containing one type is provided, and the layer structure (Y) is a polyolefin layer (D) (hereinafter “PO layer (D )”) or a paper layer, and the density difference (XY) between the layer structure (X) and the layer structure (Y) is 0.2 g/cm 3 or more, Oxygen transmission rate (OTR) of at least one of the layer structure (X) and the layer structure (Y) at 20° C.
• OTR Oxygen transmission rate
• the water-soluble layer (A) contains a hydroxyl group-containing resin (a1) and an alkali metal ion (a2), and the alkali in the water-soluble layer (A)
• a method for separating a multilayer structure wherein in the dissolving step, the layer structure (X) is allowed to settle in the water (W), and the layer structure (Y) is suspended; [15]
• a method for recycling a multilayer structure comprising a step of independently melt-molding the layer structure (X) and the layer structure (Y) recovered by the method for separating a multilayer structure of [14]; is resolved by providing
• the multilayer structure of the present invention can provide a multilayer structure that has excellent oxygen barrier properties, excellent interlayer adhesion under high humidity, and excellent peelability in the separation process, and a separation method thereof. Further, it is possible to provide a recycling method in which the substances separated in this way are independently melt-molded.
• “Layered structure” as used herein means a structure that may be a single layer or multiple layers. Moreover, “containing as a main component” means that the content is more than 50% by mass. Also, “water-soluble” means soluble in pure water at 80°C.
• the density difference (XY) between the layer structure (X) and the layer structure (Y) is 0.2 g/cm 3 or more. If the density difference is less than 0.2 g/cm 3 , the releasability tends to be insufficient in the separation step. Although the reason for this is not clear, the difference in ups and downs due to the difference in density between the layer structure (X) and the layer structure (Y) in the separation step and the moderate solubility of the water-soluble layer (A), which will be described later, are combined. This finding was discovered for the first time when the properties and density difference (XY) of the water-soluble layer (A), which will be described later, were in an appropriate range. It is what was done.
• the density difference (XY) is preferably 0.25 g/cm 3 or more, more preferably 0.3 g/cm 3 or more.
• the density difference (XY) may be 2.0 g/cm 3 or less, or 1.0 g/cm 3 or less.
• the density difference (XY) is preferably within the above range from the viewpoint of sedimenting the layer structure (X) and floating and separating the layer structure (Y) in the separation step.
• the lower limit of the OTR of at least one of the layer structure (X) and the layer structure (Y) may be 0.01 cc/(m 2 ⁇ day ⁇ atm), and may be 0.1 cc/(m 2 ⁇ day ⁇ atm) or 0.5 cc/(m 2 ⁇ day ⁇ atm).
• OTR is measured according to JIS K7126-2 (isobaric method; 2006), and specifically, the method described in Examples is employed.
• the base material layer (B) contains at least one selected from the group consisting of thermoplastic resins and metals.
• the substrate layer (B) is preferably a layer containing as a main component at least one selected from the group consisting of thermoplastic resins and metals.
• the content of at least one selected from the group consisting of thermoplastic resins and metals in the substrate layer (B) is preferably 80% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less. More than mass % and below 100 mass % may be more preferable.
• thermoplastic resin examples include polyolefins (polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene and ⁇ -olefin having 4 or more carbon atoms, copolymer of polyolefin and maleic anhydride, ethylene-vinyl ester copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylate copolymer , or modified polyolefin obtained by graft-modifying these with unsaturated carboxylic acid or its derivative), polyamide (nylon 6, nylon 66, nylon 6/66 copolymer, nylon 11, nylon 12, polymetaxylylene adipamide, etc.) , polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, polyvinylidene chloride, polys
• the substrate layer (B) contains a polyester resin as a main component from the viewpoint of excellent balance of heat resistance and mechanical properties and increasing the density of the layer structure (X). Polyester resin is more preferred, and the substrate layer (B) is more preferably polyethylene terephthalate.
• the layer structure (Y) contains a paper layer
• the base material layer (B) contains a polyolefin layer and a barrier layer.
• a polyolefin preferred embodiments described in the PO layer (D) described later are preferably used.
• a suitable embodiment described in the later-described barrier layer (E) is preferably used.
• the base layer (B) when containing a thermoplastic resin may contain various additives as long as the effects of the present invention are not impaired.
• additives include heat stabilizers, antioxidants, UV absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, stabilizers, surfactants, desiccants, cross-linking agents, fiber reinforcement agents and the like.
• the content of these additives in the substrate layer (B) is usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less.
• the substrate layer (B) preferably contains metal
• the substrate layer (B) preferably contains metal foil, and may be a layer made of metal foil.
• the metal foil include at least one metal selected from the group consisting of gold, silver, copper, nickel, stainless steel, magnesium alloys and aluminum.
• Aluminum foil is preferred from the viewpoint of economy and gas barrier properties.
• the layer structure (X) has an inorganic deposition layer (I) on the surface of the substrate layer (B) from the viewpoint of making the OTR at 20° C. and 65% RH 20 cc/(m 2 ⁇ day ⁇ atm) or less. It may be preferable to have
• the inorganic vapor deposition layer (I) is a layer formed by vapor deposition and made of an inorganic substance such as a metal or an inorganic oxide.
• the inorganic vapor deposition layer (I) has good gas barrier properties against oxygen and water vapor.
• the average thickness of the inorganic vapor deposition layer (I) is generally less than 500 nm.
• the average thickness is less than 500 nm, the viscosity stability is excellent when the pulverized product of the multilayer structure containing the inorganic vapor deposition layer (I) is melt-molded, and the generation of gels and lumps can be suppressed, which improves recyclability. tend to be better.
• the average thickness of the inorganic deposition layer (I) may be 1 nm or more. From the viewpoint of maintaining a high quality of the layer structure (X) after recycling, it may be preferable that the layer structure (X) does not contain the inorganic deposition layer (I).
• the inorganic vapor deposition layer (I) is preferably either a metal vapor deposition layer or an inorganic oxide vapor deposition layer.
• a metal vapor deposition layer is preferable, and from the viewpoint of the visibility of the contents as a packaging material, the range suitability, and the generation of gels and lumps when melting and molding the pulverized material, it is possible to suppress the formation of inorganic oxides. Vapor-deposited layers are preferred.
• the inorganic oxide deposition layer is an inorganic oxide such as oxides of silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium, preferably alumina (aluminum oxide). Alternatively, a deposited film of silica (oxide of silicon) may be used.
• the average thickness of the inorganic oxide deposition layer is preferably 80 nm or less, more preferably 60 nm or less, and even more preferably 50 nm or less.
• the average thickness of the inorganic oxide deposition layer is preferably 10 nm or more, more preferably 15 nm or more, and even more preferably 20 nm or more.
• the inorganic vapor deposition layer (I) can be formed by a known physical vapor deposition method or chemical vapor deposition method. Specific examples include vacuum deposition, sputtering, ion plating, ion beam mixing, plasma CVD, laser CVD, MO-CVD, thermal CVD, etc. Physical vapor deposition is preferred. is preferred, and it is particularly preferred to use a vacuum deposition method. If necessary, a protective layer (topcoat layer) may be provided on the inorganic deposition layer (I) as long as the effects of the present invention are not hindered.
• the upper limit of the surface temperature during film formation of the inorganic deposition layer (I) is preferably 60°C, more preferably 55°C, and even more preferably 50°C.
• unsaturated carboxylic acids or anhydrides thereof include maleic acid, maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride and the like. is preferably used.
• maleic anhydride graft-modified polyethylene maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft-modified ethylene -
• One or a mixture of two or more selected from the group consisting of vinyl acetate copolymers and the like is preferable.
• the addition amount or graft amount (modification degree) of the ethylenically unsaturated carboxylic acid or its anhydride to the olefinic polymer is 0.01 to 15% by mass, preferably 0.02 to 10% by mass, based on the olefinic polymer. is.
• Adhesiveness may be improved by mixing a rubber/elastomer component such as polyisobutylene or ethylene-propylene rubber with the adhesive resin, or a polyolefin resin different from the base polyolefin resin of the adhesive resin.
• the layer structure (X) may be composed of only the substrate layer (B), or may be composed of only the substrate layer (B) and the inorganic deposited layer (I), or may be composed of the substrate layer (B ) and the adhesive layer (C) alone, or may be composed only of the substrate layer (B), the inorganic deposition layer (I), and the adhesive layer (C).
• the layer structure (X) may have layers other than the substrate layer (B), the inorganic deposition layer (I) and the adhesive layer (C).
• the layer structure (X) includes at least one of the base layers (B). It is preferably provided in the outer layer. From the same point of view, the multilayer structure of the present invention preferably includes the substrate layer (B) as one of the outermost layers.
• the layer structure (X) may consist of a single layer or multiple layers.
• the number of layers is preferably 2 or more and 6 or less from the viewpoint of economically imparting functions such as gas barrier properties and adhesiveness.
• the average thickness of the layer structure (X) is preferably 10 ⁇ m or more and 300 ⁇ m or less, more preferably 25 ⁇ m or more and 150 ⁇ m or less, and may be 75 ⁇ m or more and 150 ⁇ m or less, from the viewpoint of handling property as a packaging material and resource saving.
• the layer structure (Y) comprises a PO layer (D) or a paper layer, and has a density lower than that of the layer structure (X) by 0.2 g/cm 3 or more.
• the layer structure (Y) preferably comprises a PO layer (D).
• the layer structure (Y) preferably has a density of 1.0 g/cm 3 or less. When the density of the layer structure (Y) is 1.0 g/cm 3 or less, the layer structure (Y) can be floated when the solvent (water (W)) used in the recovery step is water. .
• the density of the layer structure (Y) is more preferably 0.98 g/cm 3 or less, still more preferably 0.95 g/cm 3 or less.
• the density of the layer structure (Y) may be 0.8 g/cm 3 or more, 0.85 g/cm 3 or more, or 0.90 g/cm 3 or more.
• the PO layer (D) is usually a layer containing polyolefin as a main component. Since polyolefin is a resin with excellent recyclability, providing the layer structure (Y) with the PO layer (D) can improve the recyclability after the separation step.
• the polyolefin constituting the PO layer (D) is not particularly limited, and may be linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, vinyl ester resin, ethylene-propylene copolymer, ethylene- ⁇ - Olefin copolymer ( ⁇ -olefin having 4 to 20 carbon atoms), polypropylene, propylene- ⁇ -olefin copolymer ( ⁇ -olefin having 4 to 20 carbon atoms), polybutene, polypentene, etc.
• a polymer etc. are mentioned. Among them, at least one selected from the group consisting of linear low-density polyethylene, low-density polyethylene, and polypropylene is preferable from the viewpoint of melt moldability, separability, and economy.
• the PO layer (D) may contain additives.
• additives include heat stabilizers, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, stabilizers, surfactants, cross-linking agents, fiber reinforcing agents, and the like. . Among them, it may be preferable to include at least one selected from the group consisting of antioxidants, ultraviolet absorbers, and colorants.
• the PO layer (D) is preferably a layer in which the resin constituting the PO layer (D) is composed only of polyolefin. The proportion of polyolefin in the PO layer (D) may be 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more.
• the layer structure (Y) has the PO layer (D) as the outermost layer from the viewpoint of imparting heat-sealing properties to the obtained multilayer structure.
• the multilayer structure of the present invention preferably comprises a PO layer (D) as one of the outermost layers.
• the average thickness of one PO layer (D) is preferably 1 ⁇ m or more and 100 ⁇ m or less, more preferably 5 ⁇ m or more and 50 ⁇ m or less.
• the paper layer By providing the layer structure (Y) with a paper layer, it is possible to reduce the transportation cost of the packaging material by reducing the weight of the multilayer structure.
• the paper layer is not particularly limited, and examples include natural paper, synthetic paper, kraft paper, fine paper, imitation paper, glassine paper, parchment paper, synthetic paper, white paperboard, manila ball, milk carton base paper, cup base paper, ivory paper, Paper such as white silver paper can be used.
• the layer structure (Y) contains at least one selected from the group consisting of PA and EVOH as a main component from the viewpoint of making the OTR at 20° C. and 65% RH 20 cc/(m 2 ⁇ day ⁇ atm) or less. It may be preferred to include a barrier layer (E). Having the barrier layer (E) containing polyamide or EVOH as a main component improves the oxygen barrier properties of the multilayer structure. Moreover, from the viewpoint of recyclability after the separation step, EVOH is more preferable as the main component constituting the barrier layer (E).
• PA examples include polycaproamide (nylon 6), poly- ⁇ -aminoheptanoic acid (nylon 7), poly- ⁇ -aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), polylauryllactam (nylon 12 ), polyethylene diamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyoctamethyleneadipamide (nylon 86), polydecamethyleneadipamide (nylon 106), caprolactam/lauryllactam copolymer (nylon 6/12), caprolactam/ ⁇ -aminononanoic acid copolymer (nylon 6/9), caprolactam/hexamethylenediammonium adipate copolymer (nylon 6/66), lauryllactam/
• PA is preferably nylon 6/66 or nylon 6 because of its excellent economic efficiency, melt moldability and mechanical properties.
• aromatic polyamides polyamides having monomer units having aromatic rings or polyamides modified with modifiers having aromatic rings
• nylon MXD6 is more preferred.
• the barrier layer (E) may contain additives other than PA as long as the effects of the present invention are not impaired.
• additives include resins other than PA, heat stabilizers, antioxidants, UV absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, stabilizers, surfactants, drying agents, cross-linking agents, fiber reinforcing agents, and the like.
• the content of other additives in the barrier layer (E) is usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less.
• the ethylene content of EVOH is 20 mol% or more, preferably 25 mol% or more.
• the flexibility and thermoformability of the resin composition of the layer structure (Y) are improved, and the thermoformability of the obtained multilayer structure is improved.
• the ethylene content is preferably 55 mol % or less, more preferably 50 mol % or less.
• gas barrier properties are improved.
• the degree of saponification of EVOH is preferably 95 mol% or more, more preferably 98 mol% or more, even more preferably 99 mol% or more, from the viewpoint of gas barrier properties and thermal stability.
• the degree of saponification of EVOH may be 100 mol% or less.
• the melt flow rate (MFR) of EVOH under a load of 2160 g at 210°C is preferably 0.1 g/10 min or more and 50 g/10 min or less from the viewpoint of melt moldability and extrusion moldability.
• MFR is more preferably 0.5 g/10 minutes or more, and even more preferably 1 g/10 minutes or more.
• the MFR is more preferably 20 g/10 minutes or less, and even more preferably 10 g/10 minutes or less.
• Examples of the other monomers include alkenes such as propylene, butylene, pentene, and hexene; diacyloxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2- methyl-1-butene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6- Alkenes having an ester group such as acyloxy-1-hexene, 5,6-diacyloxy-1-hexene, 1,3-diacetoxy-2-methylenepropane, or saponified products thereof; acrylic acid, methacrylic acid, crotonic acid, itaconic acid, etc.
• alkenes such as propylene, butylene
• EVOH may be post-modified by methods such as urethanization, acetalization, cyanoethylation, and oxyalkylenation.
• EVOH can be used singly or in combination of two or more.
• the barrier layer (E) may contain additives other than EVOH as long as the effects of the present invention are not impaired.
• additives include antiblocking agents, processing aids, resins other than EVOH, carboxylic acid compounds, phosphoric acid compounds, boron compounds, metal salts, stabilizers, antioxidants, UV absorbers, plasticizers, and electrification. Examples include inhibitors, lubricants, coloring agents, fillers, surfactants, desiccants, cross-linking agents, and reinforcing agents such as various fibers.
• thermoplastic resins such as polyolefin; polyester; polystyrene; polyvinyl chloride; acrylic resin; polyurethane; polycarbonate; and polyvinyl acetate.
• the proportion of PA and EVOH in the resin constituting the barrier layer (E) is preferably 80% by mass or more, more preferably 90% by mass or more, and 95% by mass or more. is more preferable, and 99% by mass or more is particularly preferable.
• the proportion of PA and EVOH in the barrier layer (E) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. 99% by mass or more is particularly preferred.
• the proportion of PA in the resin constituting the barrier layer (E) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. , 99% by mass or more is particularly preferred.
• the proportion of PA in the barrier layer (E) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and 99% by mass or more.
• the proportion of EVOH in the resin constituting the barrier layer (E) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.
• the proportion of EVOH in the barrier layer (E) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and 99% by mass or more. is particularly preferred.
• the average thickness of one barrier layer (E) is preferably 0.5 ⁇ m or more and 10 ⁇ m or less, more preferably 1 ⁇ m or more and 5 ⁇ m or less.
• the layer structure (Y) may comprise an adhesive layer (C) as described above.
• the adhesive layer (C) may be laminated between the PO layer (D) or the paper layer and the barrier layer (E), which will be described later. It may be laminated between other layers and the PO layer (D), paper layer or barrier layer (E), or may be in contact with the water-soluble layer (A).
• the layer structure (Y) includes an adhesive layer (C), and the PO layer (D) or paper layer and other layers (water-soluble layer (A), barrier layer (E)) are bonded through the adhesive layer (C).
• the layer structure (Y) includes an adhesive layer (C), and the PO layer (D) or a layer other than the paper layer and the water-soluble layer (A) are laminated with the adhesive layer (C ) is also a preferred embodiment. If the layer structure (Y) is provided with the adhesive layer (C), the interlayer adhesion under high humidity may be enhanced.
• the layer structure (Y) may consist of a single layer or multiple layers.
• the number of layers is preferably 2 or more and 7 or less from the viewpoint of economically imparting functions such as gas barrier properties, adhesion properties, and heat sealing properties.
• the average thickness of the layer structure (Y) is preferably 10 ⁇ m or more and 500 ⁇ m or less from the viewpoint of handling property as a packaging material and resource saving.
• the water-soluble layer (A) contains a hydroxyl group-containing resin (a1) and alkali metal ions (a2), and the content of the alkali metal ions (a2) in the water-soluble layer (A) is 10 ppm or more and 2000 ppm or less.
• the water-soluble layer (A) has the above structure, it is possible to exhibit good peelability even in the separation step while exhibiting interlayer adhesion under high humidity. Although the reason for this is not clear, it is presumed to be due to the high solubility in water, which allows water to be efficiently drawn in via the alkali metal ions (a2).
• the water-soluble layer (A) has such a property, an unexpected advantageous effect of good peelability is achieved when the density difference (XY) is 0.2 g/cm 3 or more. presumed to be possible.
• the water-soluble layer (A) is usually a layer in which part or all of the constituent main components dissolve in water (W), and part or all of the constituent main components are dissolved in water at 20°C to 95°C ( It may be a layer that dissolves upon contact with W).
• the water-soluble layer (A) contains a hydroxyl-containing resin (a1).
• the water-soluble layer (A) preferably contains the hydroxyl-containing resin (a1) as a main component.
• the hydroxyl group-containing resin (a1) means a resin containing a hydroxyl group.
• the proportion of monomer units having a hydroxyl group in the total monomer units of the hydroxyl-containing resin (a1) is preferably 80 mol% or more, more preferably 85 mol% or more. is more preferable, and may be 90 mol % or more or 95 mol % or more.
• the proportion of monomer units having a hydroxyl group in the total monomer units of the hydroxyl-containing resin (a1) may be 100 mol % or less, or 99 mol % or less.
• hydroxyl group-containing resin (a1) examples include starch-based components such as corn starch and polymer components thereof, cellulose-based polymers such as carboxymethyl cellulose and carboxyethyl cellulose, acrylic acid-based polymers such as sodium polyacrylate, and PVA.
• PVA is preferable from the viewpoint of melt moldability and adhesiveness with the barrier layer (E).
• EVOH means one having an ethylene unit content of 20 mol % or more
• PVA means one having a vinyl alcohol unit and an ethylene unit content of less than 20 mol %.
• the saponification degree of PVA is preferably 70 mol% or more, more preferably 75 mol% or more, and further preferably 85 mol% or more. When the degree of saponification is 70 mol % or more, the water solubility of PVA is excellent, and the peelability in the step of separating the multilayer structure is improved.
• the saponification degree of PVA is preferably 95 mol % or less, more preferably 93 mol % or less, and even more preferably 90 mol % or less. When the degree of saponification is 95 mol% or less, the melt moldability of PVA is excellent.
• the degree of saponification of PVA is measured according to JIS K6726 (1994).
• the total content of vinyl alcohol units and vinyl ester units in all monomer units constituting PVA is preferably 95 mol% or more.
• the total content of vinyl alcohol units and vinyl ester units is more preferably 97 mol % or more, still more preferably 98 mol % or more, and particularly preferably 99 mol % or more.
• Nitriles such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid and salts or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane; and isopropenyl acetate.
• the content of these monomers varies depending on the purpose and application of use, but is preferably 10 mol% or less, more preferably less than 5 mol%, further preferably less than 1 mol%, and less than 0.5 mol%. is particularly preferred, and may be 0 mol %.
• PVA may be used individually by 1 type, and may use 2 or more types.
• the content of alkali metal ions (a2) is more preferably 100 ppm or more, still more preferably 200 ppm or more, and particularly preferably 500 ppm or more.
• the content of alkali metal ions (a2) is more preferably 1500 ppm or less, still more preferably 1200 ppm or less, and particularly preferably 1000 ppm or less.
• Alkali metal ions (a2) are usually derived from salts, but the components constituting the alkali metal ions (a2) are not particularly limited, and fatty acid metal salts and metal salts other than fatty acid metal salts (nitrates, sulfate, etc.) can also be used.
• the fatty acid metal salt may be a higher fatty acid metal salt having 12 or more carbon atoms or a fatty acid metal salt having 11 or less carbon atoms.
• the following aliphatic metal salts are preferred.
• Higher fatty acid metal salts having 12 or more carbon atoms include lauric acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, basic stearic acid, hydroxystearic acid, and basic hydroxystearic acid. , nonadecanic acid, oleic acid, behenic acid, montanic acid, and linoleic acid.
• Examples of fatty acid metal salts having 11 or less carbon atoms include acetates and propionates. From the viewpoint of dispersibility in PVA, etc., any one or more of these may be used as appropriate.
• the water-soluble layer (A) preferably further contains a plasticizer (a3).
• a plasticizer a3
• the melt moldability of the hydroxyl group-containing resin (a1) such as PVA and the solubility in water (W) are improved.
• the molecular weight of the plasticizer (a3) is not particularly limited, it is preferably 10,000 or less, more preferably 2,000 or less, even more preferably 200 or less, and particularly preferably 100 or less from the viewpoint of releasability.
• the content of the plasticizer (a3) is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more.
• the water-soluble layer (A) may contain components other than the hydroxyl group-containing resin (a1), the alkali metal ion (a2), and the plasticizer (a3) as long as the effects of the present invention are not impaired. good.
• Other components include, for example, polyvalent metal ions, carboxylic acids, phosphoric acid compounds, antioxidants, antioxidants, heat stabilizers (melt stabilizers), photoinitiators, deodorants, ultraviolet absorbers, and antistatic agents. , lubricants, colorants, fillers, desiccants, fillers, pigments, dyes, processing aids, flame retardants, antifog agents, and the like.
• the content of other components in the water-soluble layer (A) is usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less.
• the proportion of the hydroxyl group-containing resin (a1) in the water-soluble layer (A) is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more, and 95% by mass. % or more, 97 mass % or more, 98 mass % or more, or 99 mass % or more. Further, the proportion of the hydroxyl group-containing resin (a1) in the total resin constituting the water-soluble layer (A) is preferably 70% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and 99% by mass.
• % or more is particularly preferable, and all the resins constituting the water-soluble layer (A) may substantially consist only of the hydroxyl group-containing resin (a1).
• the ratio of the hydroxyl group-containing resin (a1) and the alkali metal ion (a2) in the water-soluble layer (A) is preferably 70% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and 99% by mass.
• % or more is particularly preferable, and the water-soluble layer (A) may consist essentially of the hydroxyl group-containing resin (a1) and the alkali metal ion (a2).
• the ratio of the hydroxyl group-containing resin (a1) and the alkali metal ion (a2) in the water-soluble layer (A) may be 100% by mass or less, or may be 99% by mass or less. Further, when the water-soluble layer (A) contains the plasticizer (a3), the ratio of the hydroxyl group-containing resin (a1), the alkali metal ion (a2) and the plasticizer (a3) in the water-soluble layer (A) is 70.
• the water-soluble layer (A) is substantially hydroxyl group-containing resin (a1), alkali metal ions It may consist only of (a2) and the plasticizer (a3).
• the ratio of the hydroxyl group-containing resin (a1), the alkali metal ion (a2) and the plasticizer (a3) in the water-soluble layer (A) may be 100% by mass or less.
• a method of blending a hydroxyl group-containing resin (a1), an alkali metal ion (a2), and optionally a plasticizer (a3) and other components, followed by melt kneading and pelletizing a method of pelletizing a hydroxyl group-containing resin ( a1), a method in which alkali metal ions (a2) and, if necessary, a plasticizer (a3) and other components are separately charged at a constant rate while kneading and pelletizing; After introducing a2) in advance, if necessary, the plasticizer (a3) and other components are blended and then melt-kneaded to pelletize. After introduction, these components and, if necessary, the plasticizer (a3) and other components are separately charged into a melt-kneader at a constant rate while kneading and pelletizing.
• any layer may be printed.
• the printing may be applied to any of the layer constituting the layer structure (X), the layer constituting the layer structure (Y), and the water-soluble layer (A). Two or more layers may be printed. If printing is applied, the transparency of the molded article obtained by recycling the multilayer structure of the present invention may be lowered. preferably not. More specifically, when the molded article obtained by recycling the layer structure (X) is required to have high transparency, and the molded article obtained by recycling the layer structure (Y) is not required to have high transparency.
• the printing is applied to the layer constituting the layer structure (Y) or the water-soluble layer (A).
• the layer structure (X) and the layer structure (Y) are laminated via the water-soluble layer (A).
• the layer structure (X) and the layer structure (Y) may each be a single layer, or may be a multi-layer structure consisting of a plurality of layers.
• the water-soluble layer (A) may be directly laminated on the substrate layer (B), or the water-soluble layer (A) may be laminated on the substrate layer (B) via the adhesive layer (C). structure.
• the water-soluble layer (A), the adhesive layer (C), and the base layer (B) may be manufactured in separate steps and laminated in a post-process such as a dry lamination method, or may be laminated by a solution coating method or the like. They may be laminated sequentially, or some or all of them may be produced simultaneously, such as by a coextrusion method.
• the molding temperature during melt molding in the coextrusion molding method or the like is often selected from the range of 150 to 300°C.
• the water-soluble layer (A) is laminated on the base material layer (B) in advance by a solution coating method, and a layer structure ( Y') [PO layer (D)/adhesive resin layer (adhesive layer (C))/barrier layer (E)/adhesive resin layer (adhesive layer (C))/PO layer (D), etc.]
• a method of dry lamination using an adhesive such as the adhesive mentioned in the adhesive layer (C) may also be used.
• the layer structure (Y') means the layer structure (Y) before providing the adhesive layer (C) for dry lamination.
• the number of layers in the multilayer structure is preferably 3 or more and 11 or less.
• the average thickness of the multilayer structure is preferably 20 ⁇ m or more and 500 ⁇ m or less, more preferably 30 ⁇ m or more and 200 ⁇ m or less, and may be 75 ⁇ m or more and 160 ⁇ m or less, from the viewpoint of handling property as a packaging material and resource saving.
• Examples of the layer structure of the multilayer structure of the present invention include the following structure.
• “/” indicates direct lamination
• “//” indicates direct lamination or lamination via an adhesive layer (C).
• “//” is preferably laminated via an adhesive layer (C).
• each layer may have a plurality of layers or may have other layers.
• the multilayer structure of the present invention may have multiple water-soluble layers (A).
• the water-soluble layer (A) dissolves in water, it separates into a plurality of layer structures.
• the layered structure (X) and the layered structure (Y) have the predetermined layers and satisfy the predetermined density conditions.
• a multilayer structure having a portion in which the layer structure (X) and the layer structure (Y) are laminated via the water-soluble layer (A) corresponds to the multilayer structure of the present invention.
• the layer structure (X) is X
• the layer structure (Y) is Y
• the water-soluble layer (A) is A
• the other layer structure is Z
• the present invention having a plurality of water-soluble layers (A)
• the multilayer structure include those having the following layer structure. ⁇ X/A/Y/A ⁇ X/A/Y/A/Z ⁇ Z/A/X/A/Y ⁇ Z/A/X/A/Y/A/Z
• the multilayer structure of the present invention includes an "X/A/Y" laminated structure.
• Other layer structures may satisfy the conditions of the layer structure (X) or the layer structure (Y). That is, a plurality of layer structures (X) and layer structures (Y) may be provided.
• the multilayer structure of the invention preferably has only one water-soluble layer (A).
• the multilayer structure of the present invention preferably has an "X/A/Y" laminated structure.
• the oxygen permeation rate of the multilayer structure of the present invention may be adjusted according to the application, but is not particularly limited, but the oxygen permeation rate at a temperature of 20° C. and a relative humidity of 65% is preferably 10 cc/(m 2 ⁇ day ⁇ atm) or less. , 1 cc/(m 2 ⁇ day ⁇ atm) or less is more preferable, and 0.1 cc/(m 2 ⁇ day ⁇ atm) or less is more preferable.
• a multi-layered structure having an oxygen permeability within this range can suppress putrefaction and deterioration of the content and maintain the quality of the content over a long period of time.
• Oxygen permeability is measured according to JIS K7126-2 (isobaric method; 2006), and specifically, the method described in Examples is employed.
• each layer of the multilayer structure of the present invention may contain the various additives, modifiers, fillers, other resins, etc. described above in order to improve moldability and various physical properties, as long as the effects of the present invention are not impaired. can also be added with
• the method for separating the multilayer structure of the present invention comprises contacting the multilayer structure of the present invention with water (W) at 20° C. to 95° C. to dissolve part or all of the water-soluble layer (A).
• the layer structure (X) is allowed to settle in the water (W), and the layer structure (Y) is suspended.
• “partially or entirely dissolved” means that the layer structure (X) and the layer structure (Y) are dissolved to the extent that they can be peeled off, but the water-soluble layer (A) is 75% by mass. It is preferably dissolved at least 90% by mass, more preferably at least 90% by mass, and even more preferably completely dissolved.
• the method for separating a multilayer structure of the present invention is expected to have the effect of removing adhering contaminants by raising the temperature of the water, but the separation efficiency may decrease due to water convection and the like. .
• the size of the multilayer structure dropped into water (W) is also not particularly limited, but in the case of the multilayer structure, it is preferably smaller than 10 cm square in order to promote delamination.
• separation can be efficiently achieved by vigorously stirring the multilayer structure of the present invention immediately after dropping it to promote delamination and then allowing it to stand still.
• the method for recycling a multilayer structure of the present invention comprises a step of independently melt-molding the layer structure (X) and the layer structure (Y) recovered by the method for separating a multilayer structure of the present invention.
• the separation method of the present invention include.
• the extent to which the layer structure (X) and the layer structure (Y) were separated can be evaluated by the separation ratio, and specifically by the method described in Examples.
• the separation rate in the separation method of the present invention is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, and particularly preferably 95% or more.
• the water (W) may be an aqueous solution containing a chloride salt such as sodium chloride or potassium chloride as a solute, or water (pure water) containing no solute.
• the pH range of water (W) is not particularly limited, but the equipment and processes required for dissolution and removal are greatly simplified, so the pH of water (W) is preferably in the range of 5 to 9, and 6 to It may be in the range of 8 or in the range of 6.5 to 7.5.
• the water-soluble layer (A) included in the multilayer structure of the present invention has excellent solubility even in a pH range close to neutrality, eg pH 5 to 9, and can be easily removed by dissolution.
• Water (W) is preferably pure water from the viewpoint of economic efficiency and handling in the process of collecting the separated film.
• the film (layer structure) from which the water-soluble layer (A) has been removed floats or sinks in water (W) is determined by the relative specific gravities of the film and water (W).
• W water
• a chloride salt such as sodium chloride, potassium chloride, or calcium chloride to increase the specific gravity of water (W)
• the concentration of the chloride salt or the like necessary for developing the necessary specific gravity of water (W) is 40% by mass or less.
• the specific gravity of water (W) is preferably positioned between the specific gravity of the layer structure (X) and the specific gravity of the layer structure (Y) from the viewpoint of improving the releasability in the separation step.
• the layer structure after part of the water-soluble layer (A) is dissolved and removed by positioning the specific gravity of water (W) between the specific gravity of the layer structure (X) and the specific gravity of the layer structure (Y)
• the peelability is affected by the difference in ups and downs due to the difference in specific gravity (density difference) between the layer structure (X) and the layer structure (Y). The effect tends to be more pronounced, and the handling in the post-separation recovery process is improved.
• a preferred embodiment of the present invention is a packaging material comprising the multilayer structure of the present invention.
• the packaging material is processed into a tube shape, a bag shape, etc., and is useful as various packaging materials such as foods, beverages, pharmaceuticals, cosmetics, industrial chemicals, agricultural chemicals, detergents, etc., but it can be used for a wide range of applications. are possible and are not limited to these uses.
• Example 1 (1) Preparation of EVOH resin composition pellets EVOH-38 (ethylene content 38 mol%, degree of saponification 99.6 mol%, MFR (190°C, 2.16 kg load) 1.69 g/10 min, density 1.2 g /cm 3 , oxygen permeability (at 20° C., 65% RH) 0.71 cc ⁇ 20 ⁇ m/(m 2 ⁇ day ⁇ atm), sodium acetate is 250 ppm in terms of sodium ions, phosphoric acid is 90 ppm in terms of phosphate ions. , containing 180 ppm of orthoboric acid as a boron compound in terms of boron element) were melt-kneaded to obtain EVOH resin composition pellets.
• a vinyl acetate polymer obtained by polymerizing vinyl acetate by a conventional method is saponified by a conventional method to obtain a viscosity average polymerization degree of 800, a saponification degree of 88 mol%, and a total monomer PVA having a total content of vinyl alcohol units and vinyl acetate units of 99.9 mol % relative to the units was obtained.
• sodium acetate aqueous solution was added so that the content of sodium ions (alkali metal ions (a2)) was 800 ppm.
• a PET film with an average thickness of 100 ⁇ m (“Toyobo Ester (trademark) E5101” manufactured by Toyobo Co., Ltd., density 1.38 g/cm 3 ) was prepared.
• An anchor coating agent was applied onto the substrate layer (B) using a bar coater so that the average thickness after drying was 80 nm.
• a two-component adhesive (“Takelac (trademark) A-626” manufactured by Mitsui Chemicals, Inc. and "Takenate (trademark) A-50” manufactured by Mitsui Chemicals, Inc.) was used. The coated film was dried at 80° C.
• the density of the layer structure (X) was 1.38 g/cm 3 when measured using an automatic dry densitometer ("Acubic 1330" manufactured by Shimadzu Corporation).
• the PVA coating liquid obtained in the above (3) was applied onto the adhesive layer (C) using a bar coater so that the average thickness after drying was 4 ⁇ m.
• the coated film was dried at 100° C. for 3 minutes to form a water-soluble layer (A) on the adhesive layer (C) of the layer structure (X).
• the PO layer (D) is made of low-density polyethylene (LDPE; "Novatec (trademark) LJ400” manufactured by Japan Polyethylene Co., Ltd., density 0). .92 g/cm 3
• the barrier layer (E) is made of the EVOH resin composition obtained in (1) above
• the adhesive layer (C) is made of maleic anhydride-modified polyethylene (manufactured by Mitsui Chemicals, Inc.
• Hydrophilic treatment was applied to one surface of the layer structure (Y') prepared in (5) above using the following apparatus.
• the table speed scale and the output setting of the high-frequency power source were adjusted so that the hydrophilic treatment strength was 130 W ⁇ min/m 2 .
• a dry lamination adhesive is applied to the surface of the layer structure (Y′) that has been subjected to hydrophilic treatment, and the composition is layer structure (X)/water-soluble layer (A)/adhesive layer (C)/layer structure ( Y′) (PET layer/anchor coat layer/PVA resin composition layer/dry laminate layer/LDPE layer (surface-treated)/maleic anhydride-modified polyethylene layer/EVOH resin composition layer/maleic anhydride-modified polyethylene layer/LDPE
• the layer structure (X) and the layer structure (Y′) were laminated by dry lamination so as to form a layer) and dried at 80° C. for 3 minutes to obtain a multilayer structure (laminate film).
• a two-liquid type adhesive (“Takelac A-520” manufactured by Mitsui Chemicals, Inc. and “Takenate A-50” manufactured by Mitsui Chemicals, Inc.) was used.
• the adhesive was applied in an amount of 4.0 g/m 2 , and after lamination, curing was performed at 40° C. for 3 days to obtain a laminate film.
• "adhesive layer (C) / layer structure (Y')" dry laminate layer / LDPE layer (surface-treated) / maleic anhydride-modified polyethylene layer / EVOH resin composition layer /
• the maleic anhydride-modified polyethylene layer/LDPE layer) portion corresponds to the layer structure (Y).
• the obtained multilayer structure has a layer structure of "layer structure (X)/water-soluble layer (A)/layer structure (Y)". Since the adhesive layer (C) provided for dry lamination is much thinner than the layer structure (Y'), the density of the layer structure (Y) is similar to that of the layer structure (Y'). It was 0.95 g/cm 3 . Also in other Examples 2 to 17 and Comparative Examples 1 to 5 described later, the density of the layer structure (Y) is the same as that of the layer structure (Y') before providing the adhesive layer (C) for dry lamination. was equal to the density.
• Table 1 shows the results.
• OTR Oxygen barrier property evaluation
• the layer structure (X), the layer structure (Y′) and the multilayer structure obtained in (4), (5) and (7) above are subjected to a temperature of 20° C. and a relative humidity of 65% for 24 hours. After conditioning, the oxygen transmission rate (cc/ (m 2 ⁇ day ⁇ atm)) was measured. It was confirmed that the OTR of the layer structure (Y) was equal to the OTR of the layer structure (Y') before providing the adhesive layer (C) for dry lamination. Also in other Examples 2 to 17 and Comparative Examples 1 to 5, which will be described later, the OTR of the layer structure (Y) was equal to the OTR of the layer structure (Y').
• the oxygen barrier property of the multilayer structure was evaluated according to the following criteria. Table 1 shows the results.
• D Oxygen transmission rate of 15 cc/(m 2 ⁇ day ⁇ atm) or more
• Example 2 As the hydroxyl group-containing resin (a1), PVA having a viscosity average degree of polymerization of 600, a degree of saponification of 80 mol%, and a total content of vinyl alcohol units and vinyl acetate units of 99.9 mol% with respect to all monomer units; A blend of PVA having an average degree of polymerization of 800, a degree of saponification of 74 mol%, and a total content of vinyl alcohol units and vinyl acetate units of 99.9 mol% with respect to all monomer units at a mass ratio of 70/30.
• PVA resin in the same manner as in Example 1, except that an aqueous sodium acetate solution was added without adding a plasticizer (glycerin) so that the content of sodium ions (alkali metal ions (a2)) was 400 ppm.
• a composition pellet was produced, and a layer structure (X) and the like and a multilayer structure were produced and evaluated. Table 1 shows the results.
• Examples 3-5 PVA resin composition pellets were produced in the same manner as in Example 1, except that the plasticizer shown in Table 1 was added instead of glycerin, and the layer structure (X) and the like and the multilayer structure were produced and evaluated. bottom.
• the PEG used in Example 3 was Dow's "CARBOWAX" 1000 (molecular weight: 1000). Table 1 shows the results.
• Examples 6-9 A PVA resin composition was prepared in the same manner as in Example 1, except that the amount of sodium acetate solution added was changed so that the content of sodium ions (alkali metal ions (a2)) was as shown in Tables 1 and 2. A pellet was produced, and a layer structure (X) and the like and a multilayer structure were produced and evaluated. Tables 1 and 2 show the results.
• Example 10 As the hydroxyl group-containing resin (a1), PVA having a viscosity average degree of polymerization of 350, a degree of saponification of 88 mol%, and a total content of vinyl alcohol units and vinyl acetate units relative to all monomer units of 99.9 mol% was used. Except for this, PVA resin composition pellets were produced in the same manner as in Example 1, and a layer structure (X) and the like and a multilayer structure were produced and evaluated. Table 2 shows the results.
• Example 12 As the hydroxyl group-containing resin (a1), the amount of ethylene modification is 8 mol%, the viscosity average degree of polymerization is 350, the degree of saponification is 98 mol%, and the total content of vinyl alcohol units and vinyl acetate units is 92 mol% with respect to all monomer units.
• PVA resin composition pellets were prepared in the same manner as in Example 1 except that the ethylene-modified PVA was used and glycerin was not added, and the layer structure (X) and the like and the multilayer structure were prepared and evaluated. Table 2 shows the results.
• Example 13 Nylon MXD6 (“S6007” manufactured by Mitsubishi Gas Chemical Co., Ltd., density 1.2 g/cm 3 ) was used as the barrier layer (E), and the coextrusion temperature was changed as follows to obtain the average thickness of the barrier layer (E).
• a layer structure (X) and the like and a multilayer structure were produced and evaluated in the same manner as in Example 1, except that the thickness was changed to 10 ⁇ m. Table 3 shows the results.
• Example 14 As the EVOH resin composition, EVOH-48 (ethylene content 48 mol%, degree of saponification 99.6 mol%, MFR (190°C, 2.16 kg load) 6.40 g/10 min, density 1.1 g/cm 3 , Oxygen permeability (at 20°C, 65% RH) 3.5 cc/20 ⁇ m/(m 2 /day/atm), sodium acetate converted to 200 ppm in terms of sodium ions, phosphoric acid converted to phosphate ions in terms of 120 ppm, boron compounds EVOH resin composition pellets were produced in the same manner as in Example 1 except that orthoboric acid was used in terms of 150 ppm in terms of boron element, and a layer structure (X) and the like and a multilayer structure were produced and evaluated. . Table 3 shows the results.
• Example 15 The same procedure as in Example 1 was performed except that high-density polyethylene (HDPE; "Novatec (trademark) HD HY331” manufactured by Nippon Polyethylene Co., Ltd., density 0.95 g/cm 3 ) was used as the PO layer (D) instead of LDPE.
• HDPE high-density polyethylene
• D the PO layer
• a layer structure, etc. and a multilayer structure were produced and evaluated by the method. Table 3 shows the results.
• Example 16 The layer structure (X) and the like and the multilayer structure were prepared in the same manner as in Example 1, except that the layer structure (X) was not provided with an anchor coat layer and the PET film was used as the layer structure (X). was manufactured and evaluated. Table 3 shows the results.
• Example 17 instead of the PET film (base layer (B)), a known Using a transparent vapor-deposited PET film (a laminate of a substrate layer (B) and an inorganic vapor deposition layer (I)) provided with an alumina vapor deposition layer having an average thickness of 50 nm by a vacuum vapor deposition method, an anchor coating agent was applied onto the alumina vapor deposition layer.
• a layer structure (X) and the like and a multilayer structure were produced and evaluated in the same manner as in Example 1, except that they were coated. Table 3 shows the results.
• Example 18 Using a coextrusion multilayer cast film forming apparatus, the water-soluble layer (A) is made of the PVA resin composition pellets obtained in Example 1, and the base layer (B) is polyethylene terephthalate (PET; Bell Polyester Products Co., Ltd.).
• the adhesive layer (C1) is made of maleic anhydride-modified ethylene acrylate copolymer (Bynel 21E533 made by Dow Chemical Co.), and the PO layer (D) is made of low density polyethylene (LDPE; Japan Polyethylene Co., Ltd.
• the barrier layer (E) is made of the EVOH resin composition obtained in Example 1
• the adhesive layer (C2) is made of maleic anhydride-modified polyethylene (Mitsui Chemicals Co., Ltd.
• the results are shown in Table 3.
• Comparative example 1 The layer structure (X) and the like and the multilayer structure were prepared in the same manner as in Example 1, except that the water-soluble layer (A) and the anchor coat layer (adhesive layer (C)) of the layer structure (X) were not provided.
• (PET layer/dry laminate layer/LDPE layer (surface-treated)/maleic anhydride-modified polyethylene layer/EVOH resin composition layer/maleic anhydride-modified polyethylene layer/LDPE layer) were prepared or produced and evaluated. Table 4 shows the results.
• Comparative Example 2 Comparative Example 3 PVA resin composition pellets were prepared in the same manner as in Example 1, except that the amount of sodium acetate solution added was changed so that the content of sodium ions (alkali metal ions (a2)) was as shown in Table 4.
• alkali metal ions (a2)) was as shown in Table 4.
• a layer structure (X) and the like and a multilayer structure were produced and evaluated. Table 4 shows the results.
• Comparative example 4 Polyamide 6/66 ("Ultramid C40L” manufactured by BASF Corporation, density 1.1 g/cm 3 ) was used as the barrier layer (E), and the coextrusion temperature was changed as follows, and the average thickness of the barrier layer (E) was A layer structure (X) and the like and a multilayer structure were produced and evaluated in the same manner as in Example 1, except that the thickness was changed to 25 ⁇ m. Table 4 shows the results.
• Comparative example 5 A layer structure (X) and the like and a multilayer A structure was fabricated and evaluated. Table 4 shows the results.
• Example 19 A multilayer structure in the same manner as in Example 1 except that the surface of the water-soluble layer (A) of the "laminate in which the water-soluble layer (A) is laminated on the layer structure (X)" is printed with ink. made the body.
• the obtained multilayer structure was cut into 100 squares of 1 cm square to obtain test pieces. After the obtained test piece was stirred in water at a temperature of 80°C for 60 minutes, it was allowed to stand still for 5 minutes, and 100 sheets of the precipitated film were collected. The remaining two sheets were multi-layered structures in which the layered structure (X) and the layered structure (Y) were sedimented without being separated.
• Example 20 After printing with ink on the surface of the PET film (base layer (B)), the surface of the printed base layer (B) was coated with a bar coater so that the average thickness after drying was 80 nm.
• a multilayer structure was produced in the same manner as in Example 1, except that the layer structure (X) having the adhesive layer (C) was produced by applying an anchor coating agent.
• the obtained multilayer structure was cut into 100 squares of 1 cm square to obtain test pieces. The obtained test piece was stirred in water at a temperature of 80° C. for 60 minutes and then allowed to stand for 5 minutes. When 100 sheets of the precipitated film were collected, the layer structure (X) and the layer structure (Y) were separated. 98 sheets of the film were peeled off, and 2 sheets of the multilayer structure did not separate the layer structure (X) and the layer structure (Y), but the number of transparent films from which the printed ink was peeled off was 0. Met.
• Example 19 From the results of Examples 19 and 20, as in Example 19, by printing on the surface of the water-soluble layer (A) of the layer structure (X), a transparent substrate can be obtained by stirring and washing in water. A material layer (B) can be obtained, and recycling becomes easy.
• the transparent substrate layer (B) cannot be recovered, and PET cannot be used for applications that require transparency. can be difficult to recycle for such applications.
• Polyethylene terephthalate and other polyesters have a high melting point, making it difficult to recycle by mixing them with other materials that are widely used as packaging materials. can also be recycled.
• the multilayer structure of the present invention exhibits sufficient oxygen barrier properties and interlayer adhesion under normal conditions of use as a packaging material, while exhibiting excellent peelability in the separation process after use as a packaging material.
• the body (X) and the layer structure (Y) can be separated and recovered. As a result, the recyclability of the packaging material can be improved without deteriorating the performance and quality of the packaging material, thereby contributing to the realization of a recycling-oriented society.

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• 2022
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