WO2026034308A1 - Corps d'emballage et son procédé de fabrication - Google Patents

Corps d'emballage et son procédé de fabrication

Info

Publication number
WO2026034308A1
WO2026034308A1 PCT/JP2025/026986 JP2025026986W WO2026034308A1 WO 2026034308 A1 WO2026034308 A1 WO 2026034308A1 JP 2025026986 W JP2025026986 W JP 2025026986W WO 2026034308 A1 WO2026034308 A1 WO 2026034308A1
Authority
WO
WIPO (PCT)
Prior art keywords
resin
hydroxyalkanoate
units
resin film
copolymer
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/JP2025/026986
Other languages
English (en)
Japanese (ja)
Inventor
康則 岡田
智文 窪田
裕太 榎本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kaneka Corp
Original Assignee
Kaneka Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kaneka Corp filed Critical Kaneka Corp
Publication of WO2026034308A1 publication Critical patent/WO2026034308A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • B32B27/10—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 paper or cardboard
    • 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
    • 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
    • B65D65/46—Applications of disintegrable, dissolvable or edible 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
    • Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
    • Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics

Definitions

  • the present invention relates to a packaging body including a paper laminate and a resin film, as well as a method for manufacturing such a packaging body.
  • Paper used as packaging material is usually laminated with a resin to impart water resistance, oil resistance, heat sealing properties, etc. It is preferable to use a biodegradable resin as this resin so as not to impair the biodegradability of the paper.
  • poly(3-hydroxyalkanoate) resins are thermoplastic polyesters that are produced and accumulated as energy storage substances within the cells of many microbial species, and are known to be materials that can biodegrade not only in soil but also in seawater.
  • Laminates formed by laminating such poly(3-hydroxyalkanoate) resins onto a paper substrate are extremely promising from an environmental protection perspective.
  • Patent Document 1 discloses such laminates.
  • Patent Document 2 discloses such films.
  • a package exhibiting good rigidity By integrating a paper laminate containing the paper base layer and resin layer described above with a resin film by heat sealing, a package exhibiting good rigidity can be manufactured. By providing an unsealed area in the resin film, a package (e.g., three-sided seal, stand-up pouch, etc.) can be constructed that allows the packaged item to be viewed from the outside through that area.
  • a package e.g., three-sided seal, stand-up pouch, etc.
  • the inventors produced a package including the heat-sealed portion described above using a paper laminate including a paper base layer and a biodegradable resin layer, and a resin film composed of a poly(3-hydroxyalkanoate)-based resin. They found that curling (warping) sometimes occurred in the heat-sealed portion over time after heat sealing. This curling was particularly noticeable when a thick resin film was used.
  • the present invention aims to provide a package that includes a heat-sealed portion between a paper laminate including a paper base layer and a biodegradable resin layer and a resin film including a poly(3-hydroxyalkanoate) resin, whereby curling of the heat-sealed portion is suppressed while maintaining the adhesive strength of the heat-sealed portion, and a method for manufacturing the package.
  • the present invention provides a packaging body including a paper laminate and a resin film
  • the paper laminate includes a paper base layer and an adhesive resin layer containing a biodegradable polyester resin laminated on at least one surface of the paper base layer, the resin film has a sealed region that is heat-sealed to the paper laminate via the adhesive resin layer, and a non-sealed region that is not heat-sealed to the paper laminate; the resin film contains a poly(3-hydroxyalkanoate)-based resin (A),
  • the poly(3-hydroxyalkanoate) resin (A) comprises a copolymer (a-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of the other hydroxyalkanoate units is 1 to 13 mol %, and a copolymer (a-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of the other hydroxyalkanoate units is 24 mol
  • the present invention also relates to a method for producing a package, which comprises at least the following steps: Step (i): A step of forming a raw material containing a poly(3-hydroxyalkanoate)-based resin (A) containing a copolymer (a-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of other hydroxyalkanoate units is 1 to 13 mol%, and a copolymer (a-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, in which the content of other hydroxyalkanoate units is 24 mol% or more, into a resin film.
  • the present invention provides a package including a heat-sealed portion between a paper laminate including a paper base layer and a biodegradable resin layer and a resin film including a poly(3-hydroxyalkanoate) resin, in which curling of the heat-sealed portion is suppressed while maintaining the adhesive strength of the heat-sealed portion, and a method for manufacturing the package.
  • FIG. 1 is a cross-sectional view showing an example of a layered structure constituting a packaging body according to the present disclosure.
  • FIG. 10 is a cross-sectional view showing another example of a laminated structure constituting a packaging body according to the present disclosure.
  • the packaging body according to the present disclosure includes at least a paper laminate including a paper base layer and an adhesive resin layer, and a resin film.
  • the paper substrate layer is not particularly limited as long as it is a commonly used paper containing plant-derived pulp as the main component.
  • the paper substrate can usually be obtained by papermaking a paper stock containing pulp, fillers, various auxiliaries, etc.
  • the type of paper that can be used is not particularly limited, and examples include cup base paper, kraft paper, fine paper, coated paper, tissue paper, glassine paper, and paperboard.
  • the pulp is not particularly limited, and examples include chemical pulps such as bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), unbleached softwood pulp (NUKP), and sulfite pulp; mechanical pulps such as stone-ground pulp and thermomechanical pulp; wood fibers such as deinked pulp and recycled paper pulp; and non-wood fibers obtained from kenaf, bamboo, hemp, etc. These can be used in appropriate combinations.
  • chemical pulps such as bleached hardwood kraft pulp (LBKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), unbleached softwood pulp (NUKP), and sulfite pulp
  • mechanical pulps such as stone-ground pulp and thermomechanical pulp
  • wood fibers such as deinked pulp and recycled paper pulp
  • chemical pulp or mechanical pulp made from wood fibers with chemical pulp being more preferable, for reasons such as the paper being less likely to become contaminated with foreign matter, being less likely to discolor over time when recycled as waste paper raw material, and having a high degree of whiteness that results in a good surface appearance when printed, making it particularly valuable when used as a packaging material.
  • the pulp contain 80% or more of chemical pulp, such as LBKP or NBKP, and it is particularly preferable that the chemical pulp content be 100%.
  • Fillers are not particularly limited, and examples include inorganic fillers such as talc, kaolin, calcined kaolin, clay, heavy calcium carbonate, light calcium carbonate, white carbon, zeolite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, barium sulfate, and calcium sulfate; and organic fillers such as urea-formaldehyde resin, polystyrene resin, phenolic resin, and microhollow particles. Note that fillers are not essential materials and may not be used.
  • auxiliary agents are not particularly limited and include, for example, sizing agents such as rosin, alkyl ketene dimer (AKD), and alkenyl succinic anhydride (ASA), polyacrylamide polymers, polyvinyl alcohol polymers, cationic starch, various modified starches, dry strength agents such as urea-formalin resin and melamine-formalin resin, wet strength agents, retention aids, drainage aids, coagulants, aluminum sulfate, bulking agents, dyes, fluorescent whitening agents, pH adjusters, defoamers, UV inhibitors, anti-fading agents, pitch control agents, and slime control agents. These may be selected and used as needed.
  • sizing agents such as rosin, alkyl ketene dimer (AKD), and alkenyl succinic anhydride (ASA), polyacrylamide polymers, polyvinyl alcohol polymers, cationic starch, various modified starches, dry strength agents such as urea-formalin resin and melamine-
  • the surface of the paper may be treated with various chemicals.
  • chemicals there are no particular limitations on the chemicals used, and examples include oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, polyvinyl alcohol, surface sizing agents, water-resistant agents, water-retention agents, thickeners, lubricants, etc.
  • One type of chemical may be used alone, or two or more types may be used in combination. These chemicals may also be used in combination with pigments.
  • the pigment is not particularly limited, and examples include inorganic pigments such as kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, light calcium carbonate, mica, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicates, colloidal silica, and satin white; and organic pigments such as solid, hollow, and core-shell types. Only one type of pigment may be used, or two or more types may be used in combination.
  • inorganic pigments such as kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, light calcium carbonate, mica, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicates, colloidal silica, and satin white
  • organic pigments such as solid, hollow, and core-shell types. Only one type of pigment may be used, or two or more types may be used in combination.
  • the basis weight of the paper base layer can be selected appropriately depending on the desired quality, the use of the package, etc., but is preferably 30 to 350 g/m 2 , more preferably 40 to 300 g/m 2 , and even more preferably 50 to 200 g/m 2. By setting it within this range, it becomes easy to impart practical mechanical strength to the package.
  • the basis weight of the paper base layer may be less than 150 g/ m2 or may be 100 g/ m2 or less.
  • the adhesive resin layer may be laminated on only one side of the paper base layer or on both sides.
  • the adhesive resin layer is located on the outermost surface of the paper laminate. At least a portion of the surface of the adhesive resin layer is bonded to the resin film described below by heat sealing.
  • the adhesive resin layer may be a coating layer formed by applying a coating liquid to the surface of the paper substrate layer and drying it by heating, or it may be a laminate layer formed by a lamination method. Examples of lamination methods include extrusion lamination, dry lamination, non-solvent lamination, and thermal lamination.
  • the adhesive resin layer is preferably a coating layer, as this provides good adhesion to the paper substrate layer.
  • the adhesive resin layer is a resin layer composed primarily of biodegradable polyester resin. Using biodegradable polyester resin in the adhesive resin layer not only increases the biodegradability of the entire packaging, but also improves the adhesive strength between the adhesive resin layer and the resin film.
  • Biodegradable polyester resins can be any polyester resin generally known to be biodegradable. There are no particular restrictions on the type, but examples include aliphatic polyester resins such as polyhydroxyalkanoate, polycaprolactone, polybutylene succinate adipate, polybutylene succinate, and polylactic acid, as well as aliphatic aromatic polyester resins such as polybutylene adipate terephthalate and polybutylene azelate terephthalate.
  • the proportion of biodegradable polyester resin in the total resin components contained in the adhesive resin layer is preferably 50% by weight or more and 100% by weight or less. It is more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, and particularly preferably 95% by weight or more. It may even be 99% by weight or more.
  • the adhesive resin layer contains a poly(3-hydroxyalkanoate) resin (B) as the biodegradable polyester resin. This can further increase the biodegradability of the entire package and can also improve the adhesive strength when heat-sealed with the resin film, as described below.
  • B poly(3-hydroxyalkanoate) resin
  • the proportion of poly(3-hydroxyalkanoate) resin (B) in the total resin components contained in the adhesive resin layer is preferably 50% by weight or more and 100% by weight or less. It is more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, and particularly preferably 95% by weight or more. It may even be 99% by weight or more.
  • poly(3-hydroxyalkanoate)-based resin refers to a polymer having a 3-hydroxyalkanoate unit. Specifically, it is preferably a polymer containing a unit represented by the following general formula (1): [-CHR-CH 2 -CO-O-] (1)
  • R represents an alkyl group represented by C p H 2p+1
  • p represents an integer of 1 to 15. Examples of R include linear or branched alkyl groups such as methyl, ethyl, propyl, methylpropyl, butyl, isobutyl, t-butyl, pentyl, and hexyl.
  • p is preferably 1 to 10, and more preferably 1 to 8.
  • a poly(3-hydroxyalkanoate) resin produced by a microorganism is particularly preferred.
  • a poly(3-hydroxyalkanoate) resin produced by a microorganism all 3-hydroxyalkanoate units are contained as (R)-3-hydroxyalkanoate units.
  • Poly(3-hydroxyalkanoate) resins preferably contain 3-hydroxyalkanoate units (particularly units represented by general formula (1)) in an amount of 50 mol% or more of all structural units, more preferably 60 mol% or more, and even more preferably 70 mol% or more.
  • Poly(3-hydroxyalkanoate) resins may contain only 3-hydroxyalkanoate units as structural units of the polymer, or may contain one or more types of 3-hydroxyalkanoate units as well as other units (e.g., 4-hydroxyalkanoate units, etc.).
  • the poly(3-hydroxyalkanoate) resin preferably contains a homopolymer having only 3-hydroxybutyrate units and/or a copolymer containing 3-hydroxybutyrate units and other hydroxyalkanoate units.
  • a copolymer containing 3-hydroxybutyrate units and other hydroxyalkanoate units it is preferable to contain a copolymer containing 3-hydroxybutyrate units and other hydroxyalkanoate units.
  • the type of copolymerization in the copolymer is not particularly limited and may be random copolymerization, alternating copolymerization, block copolymerization, graft copolymerization, etc. Copolymers produced by microorganisms are usually random copolymers.
  • the hydroxyalkanoic acid that forms the other hydroxyalkanoate units is not particularly limited, and examples include 4-hydroxybutanoic acid, 3-hydroxypropionic acid, 3-hydroxypentanoic acid, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, and 3-hydroxyoctanoic acid.
  • P3HA-based resins include poly(3-hydroxybutyrate) (abbreviation: PHB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (abbreviation: P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (abbreviation: P3HB3HV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (abbreviation: P3HB4HB), and poly(3-hydroxybutyrate-co Examples include poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (abbreviation: P3HB3HO), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate) (abbreviation: P3HB3HOD), poly(3-hydroxybutyrate-co-3-hydroxydecanoate) (abbreviation: P3HB3HD), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexano
  • P3HB3HH products include Kaneka Biodegradable Polymer Green Planet (registered trademark) from Kaneka Corporation.
  • the poly(3-hydroxyalkanoate) resin (B) contained in the adhesive resin layer preferably contains a poly(3-hydroxybutyrate) copolymer (b-1) containing 3-hydroxybutyrate units and other hydroxyalkanoate units.
  • the content of other hydroxyalkanoate units in the total monomer units in copolymer (b-1) is preferably 6 mol% or more but less than 24 mol%, more preferably 8 mol% or more but less than 20 mol%, and particularly preferably 10 mol% or more but less than 16 mol%.
  • the resin components are easily melted during the heating process of the coating film described below, and the adhesive resin layer is easily homogenized by heating, thereby improving the water resistance and oil resistance of the paper laminate. It also further improves the adhesion strength of the heat-sealed resin film described below.
  • the average content ratio of each monomer unit to all monomer units constituting the poly(3-hydroxyalkanoate) resin can be determined by methods known to those skilled in the art, for example, the method described in paragraph [0047] of WO 2013/147139.
  • the average content ratio refers to the molar ratio of each monomer unit to all monomer units constituting the poly(3-hydroxyalkanoate) resin, and when the resin being measured is a mixture of two or more resins, it refers to the molar ratio of each monomer unit contained in the entire mixture.
  • copolymer (b-1) examples include the copolymers mentioned above, with P3HB3HH, P3HB3HV, and P3HB4HB being preferred, and P3HB3HH being particularly preferred.
  • the weight-average molecular weight of copolymer (b-1) is not particularly limited, but from the viewpoint of achieving both the coatability of the coating liquid and the mechanical properties of the adhesive resin layer, it is preferably 100,000 to 650,000, more preferably 150,000 to 450,000, and even more preferably 200,000 to 350,000.
  • the weight-average molecular weight (hereinafter sometimes referred to as Mw) of a polymer can be determined as the molecular weight in terms of polystyrene by gel permeation chromatography (GPC) (Shodex GPC-101 manufactured by Showa Denko K.K.) using a polystyrene gel column (Shodex K-804 manufactured by Showa Denko K.K.) and chloroform as the mobile phase.
  • GPC gel permeation chromatography
  • the adhesive resin layer preferably further contains poly(3-hydroxyalkanoate) (b-2) as the poly(3-hydroxyalkanoate) resin (B) in addition to the copolymer (b-1). This allows the resin component to melt and then solidify more quickly during the coating film heating process described below, thereby suppressing blocking.
  • Poly(3-hydroxybutyrate) (b-2) refers to a homopolymer composed only of 3-hydroxybutyrate, or a polymer that contains, in addition to 3-hydroxybutyrate units, trace amounts of hydroxyalkanoate units other than 3-hydroxybutyrate units. Specifically, it is preferable that poly(3-hydroxybutyrate) (b-2) contain 3-hydroxybutyrate units in a proportion greater than 99 mol% and less than 100 mol% of all of its constituent monomers.
  • hydroxyalkanoate units other than 3-hydroxybutyrate units that may be contained in poly(3-hydroxybutyrate) (b-2) are not particularly limited as long as they are copolymerizable with 3-hydroxybutyrate units, but examples include 3-hydroxyalkanoate units other than 3-hydroxybutyrate units and hydroxyalkanoate units other than 3-hydroxyalkanoate units (e.g., 4-hydroxyalkanoate units). 3-hydroxyhexanoate units are particularly preferred.
  • the weight-average molecular weight of poly(3-hydroxybutyrate) (b-2) is not particularly limited, but from the viewpoint of achieving both the coatability of the coating liquid and the mechanical properties of the adhesive resin layer, it is preferably 100,000 to 400,000, and more preferably 200,000 to 350,000.
  • the weight-average molecular weight can be measured by the method described above.
  • the content of poly(3-hydroxybutyrate) (b-2) in the adhesive resin layer is preferably 1% by weight or more and 50% by weight or less of the total of copolymer (b-1) and poly(3-hydroxybutyrate) (b-2). From the viewpoint of blocking suppression, this content is more preferably 3% by weight or more, and even more preferably 5% by weight or more. Furthermore, from the viewpoint of improving adhesion strength, it is preferably 30% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less.
  • the average content of other hydroxyalkanoate units in all monomer units contained in the entire poly(3-hydroxyalkanoate) resin (B) contained in the adhesive resin layer is preferably 5 mol% or more and 18 mol% or less, more preferably 7 mol% or more and 15 mol% or less, and particularly preferably 8 mol% or more and 12 mol% or less, from the viewpoint of achieving both meltability in the heating step and productivity of the resin.
  • the weight-average molecular weight of the entire poly(3-hydroxyalkanoate) resin (B) contained in the adhesive resin layer is not particularly limited, but from the viewpoint of achieving both the coatability of the coating liquid and the mechanical properties of the adhesive resin layer, it is preferably 100,000 to 400,000, and more preferably 200,000 to 350,000.
  • the adhesive resin layer may contain one or more of the following, to the extent that it does not impair the effects of the invention: resins other than the poly(3-hydroxyalkanoate) resin (B), adhesives, dispersants or emulsifiers, pH adjusters, inorganic fillers, colorants such as pigments and dyes, odor absorbers such as activated carbon and zeolite, fragrances such as vanillin and dextrin, plasticizers, antioxidants, weather resistance improvers, UV absorbers, crystal nucleating agents, lubricants, release agents, water repellents, antibacterial agents, and sliding improvers.
  • resins other than the poly(3-hydroxyalkanoate) resin (B) adhesives
  • dispersants or emulsifiers such as an emulsifier
  • pH adjusters such as pigments and dyes
  • odor absorbers such as activated carbon and zeolite
  • fragrances such as vanillin and dextrin
  • plasticizers such as antioxidants, weather resistance improver
  • the thickness of the adhesive resin layer is not particularly limited and can be determined appropriately taking into account the performance and productivity desired of the adhesive resin layer, but it may be, for example, 0.5 to 100 ⁇ m, or 1 to 50 ⁇ m. In particular, from the perspective of combining heat-sealing adhesive strength with flexibility as a package, a thickness of 5 to 30 ⁇ m is preferable.
  • the adhesive resin layer preferably has melting characteristics such that, in a crystalline melting curve measured by differential scanning calorimetry, it has at least one peak top temperature (Tma) in the range of 90 to 150°C and at least one peak top temperature (Tmb) in the range of 150 to 170°C, with the temperature difference between Tma and Tmb being 10°C or greater. Having such melting characteristics makes it easy to heat seal the adhesive resin layer and the resin film, and good adhesive strength can be achieved in a short time after heating.
  • Tma peak top temperature
  • Tmb peak top temperature
  • the adhesive resin layer has a melting point peak in the relatively high temperature range of 150-170°C, resin crystals with Tmb act as crystal nuclei, accelerating the solidification of the molten resin during heat sealing, making it possible to achieve good adhesive strength in a short time after heat sealing.
  • the temperature difference between Tma and Tmb is 10°C or more, preferably 15°C or more, more preferably 20°C or more, and even more preferably 25°C or more.
  • the temperature difference is 10°C or more, heat sealing becomes easier and good adhesive strength tends to be achieved in a short time after heating.
  • the peak top temperature of a crystalline melting curve in differential scanning calorimetry is defined as follows: 2 to 5 mg of the adhesive resin layer separated from the substrate layer is placed in an aluminum pan, and using a differential scanning calorimetry analyzer, the temperature is raised from 20°C to 190°C at a rate of 10°C/min under a nitrogen stream to melt the adhesive resin layer and obtain a crystalline melting curve.
  • the top temperature of the melting point peak in the range of 90 to 150°C is defined as Tma
  • Tmb the top temperature of the melting point peak in the range of 150 to 170°C
  • the top temperature of the highest peak is defined as Tma
  • Tmb the top temperature of the highest peak
  • the weight per unit area (basis weight) of the poly(3-hydroxyalkanoate) resin (B) in the adhesive resin layer is preferably 3 to 100 g/m 2 , more preferably 5 to 50 g/m 2 , and particularly preferably 10 to 30 g/m 2. Within these ranges, defects such as pinholes can be prevented, strength sufficient for use can be imparted, and functions such as water resistance can be efficiently exhibited.
  • the weight per unit area of the resin (B) in the adhesive resin layer is measured and evaluated by the method described in the examples.
  • the thickness of the entire paper laminate, including the paper base layer and adhesive resin layer is not particularly limited, but is preferably 50 to 500 ⁇ m, and more preferably 60 to 350 ⁇ m.
  • the method for producing a paper laminate containing a paper base layer and an adhesive resin layer is not particularly limited, but a method in which a coating liquid containing a biodegradable polyester resin is applied to one or both sides of the base layer and then heated is preferred.
  • the coating liquid containing the biodegradable polyester resin is preferably an aqueous coating liquid.
  • the manufacturing method may be, for example, a method of manufacturing by mixing and dispersing powdered biodegradable polyester resin in water.
  • a poly(3-hydroxyalkanoate)-based resin (B) as the biodegradable polyester resin
  • microbial cells containing the resin can be crushed in an aqueous dispersion state, followed by centrifugation to obtain a precipitate. This precipitate can then be washed with water, methanol, or the like, and finally an appropriate amount of water can be added to obtain an aqueous coating liquid containing a P3HA-based resin (B) with the desired solids concentration.
  • the solids concentration of the biodegradable polyester resin in the coating liquid is not particularly limited, but from the perspective of achieving a uniform coating, achieving the desired coating thickness, and minimizing the occurrence of coating defects, it is preferably 25 to 65% by weight, more preferably 30 to 55% by weight, and particularly preferably 35 to 50% by weight.
  • the coating liquid does not necessarily need to contain an emulsifier, but it is preferable that it contains one to stabilize the coating liquid.
  • emulsifiers include anionic surfactants such as sodium lauryl sulfate and sodium oleate, cationic surfactants such as lauryltrimethylammonium chloride, nonionic surfactants such as glycerin fatty acid esters and sorbitan fatty acid esters, polyvinyl alcohol and its derivatives, cellulose derivatives such as methyl cellulose and carboxymethyl cellulose, polyvinylpyrrolidone, starch, starch derivatives such as oxidized starch and etherified starch, and water-soluble polymers such as chitin, chitosan, casein, and gum arabic.
  • the amount of emulsifier added is not particularly limited, but is preferably about 1 to 10 parts by weight per 100 parts by weight of the biodegradable polyester resin.
  • the method for applying the coating liquid to the paper substrate layer is not particularly limited, and any known method can be used as appropriate. Specifically, methods that can be used include spraying, scattering, slit coating, air knife coating, roll coating, bar coating, comma coating, blade coating, screen printing, and gravure printing.
  • the coating film After applying the coating liquid to the paper substrate layer, the coating film is heated to form an adhesive resin layer and obtain a paper laminate.
  • This heating process evaporates water and fuses the resin particles contained in the coating liquid together, forming an adhesive resin layer with relatively high uniformity. This makes it possible to form an adhesive resin layer that satisfies the specific melting characteristics described above.
  • the heating temperature in the heating step is not particularly limited, but is preferably 120 to 180°C, more preferably 130 to 170°C, and particularly preferably 140 to 160°C. Heating the coating film at such a temperature makes it easier to form an adhesive resin layer that satisfies the melting characteristics described above.
  • the heating time in the heating step is not particularly limited and can be set as appropriate, but may be, for example, 30 seconds to 10 minutes, with 1 to 5 minutes being preferred.
  • the heating step can be carried out using known heating methods, such as hot air heating, infrared heating, microwave heating, roll heating, and hot plate heating. These can be used alone or in combination of two or more types.
  • the packaging according to the present disclosure includes the above-described paper laminate and a resin film containing a poly(3-hydroxyalkanoate)-based resin (A) as an essential component. Because the resin film is made of a poly(3-hydroxyalkanoate)-based resin, the biodegradability of the entire packaging can be improved.
  • the proportion of poly(3-hydroxyalkanoate) resin (A) in the entire resin film is preferably 50% by weight or more and 100% by weight or less. It is more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, and particularly preferably 95% by weight or more.
  • the poly(3-hydroxyalkanoate) resin (A) contains a copolymer (a-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, with the other hydroxyalkanoate units containing 1 to 13 mol%, and a copolymer (a-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, with the other hydroxyalkanoate units containing 24 mol% or more.
  • highly crystalline P3HA-based resins have excellent processability but poor mechanical strength
  • low-crystalline P3HA-based resins have poor processability but excellent mechanical properties.
  • copolymer (a-2) having a high content of other hydroxyalkanoate units of 24 mol% or more as the P3HA-based resin (A) constituting the resin film crystallization of the P3HA-based resin (A) becomes less likely to proceed after thermal melting during heat sealing, and therefore the resin film does not shrink, and as a result, curling of the heat-sealed portion becomes less likely to proceed.
  • copolymer (a-2) when copolymer (a-2) is not used, it is presumed that crystallization of the P3HA-based resin (A) proceeds after thermal melting during heat sealing, causing the resin film to shrink, and the difference in shrinkage rate between the resin film and the paper base layer causes curling of the heat-sealed portion.
  • the processability of the P3HA resin (A) can be improved. Furthermore, by using the copolymer (a-2), the strength of the resin film and therefore the strength of the package can be increased.
  • copolymer (a-1) and copolymer (a-2) include the copolymers described above in the section on P3HA-based resin (B), with P3HB3HH, P3HB3HV, and P3HB4HB being preferred, and P3HB3HH being particularly preferred.
  • the types of constituent monomers in copolymer (a-1) and copolymer (a-2) may be the same or different.
  • copolymer (a-1) the molar ratio of monomer units (3-hydroxybutyrate units/other hydroxyalkanoate units) is 87/13 to 99/1, preferably 88/12 to 98/2.
  • the weight ratio of (a-1-1) to the total weight of both copolymers: (a-1-2)/[(a-1-1)/(a-1-2)] is preferably 5 to 40% by weight, and more preferably 10 to 20% by weight, from the viewpoint of suppressing curling.
  • the composition ratio of the monomer units, 3-hydroxybutyrate units/other hydroxyalkanoate units is 76/24 to 1/99 in molar ratio, preferably 76/24 to 50/50, more preferably 75/25 to 65/35, and particularly preferably 74/26 to 70/30.
  • the weight-average molecular weight of copolymer (a-1) is not particularly limited, but from the viewpoint of the balance between mechanical properties and productivity, it is preferably 200,000 to 1,000,000, more preferably 250,000 to 700,000, and even more preferably 300,000 to 650,000.
  • the weight-average molecular weight of copolymer (a-2) is not particularly limited, but from the viewpoint of the balance between mechanical properties and productivity, it is preferably 100,000 to 1,500,000, more preferably 150,000 to 1,000,000, and even more preferably 200,000 to 700,000.
  • the blending ratio of copolymer (a-1) and copolymer (a-2) can be set as appropriate, but from the perspective of achieving a good balance between the effects of each copolymer, it is preferable that, of the total of copolymer (a-1) and copolymer (a-2), the proportion of copolymer (a-1) is 40 to 80% by weight and the proportion of copolymer (a-2) is 60 to 20% by weight; it is more preferable that the proportion of copolymer (a-1) is 45 to 75% by weight and the proportion of copolymer (a-2) is 55 to 25% by weight; and it is even more preferable that the proportion of copolymer (a-1) is 50 to 70% by weight and the proportion of copolymer (a-2) is 50 to 30% by weight.
  • P3HA-based resin (A) may further contain other P3HA-based resins that do not meet the definition of these copolymers.
  • the total proportion of copolymer (a-1) and copolymer (a-2) in the entire P3HA-based resin (A) is preferably 70 to 100% by weight, more preferably 80 to 100% by weight, even more preferably 90 to 100% by weight, and particularly preferably 95 to 100% by weight.
  • the average composition ratio of monomer units in the entire P3HA-based resin (A) is preferably a molar ratio of 3-hydroxybutyrate units/other hydroxyalkanoate units (mol %/mol %) of 93/7 to 83/17, more preferably 92/8 to 84/16, and even more preferably 90/10 to 85/15.
  • the ratio of 3-hydroxybutyrate units is 93 mol % or less, sufficient mechanical properties tend to be easily obtained.
  • the ratio of 3-hydroxybutyrate units is 83 mol % or more, the solidification speed of P3HA-based resin (A) tends to be fast, which tends to improve the productivity of resin films.
  • the weight-average molecular weight of the entire P3HA-based resin (A) is not particularly limited, but from the perspective of balancing mechanical properties and productivity, it is preferably 100,000 to 1,500,000, more preferably 150,000 to 1,000,000, and even more preferably 200,000 to 700,000.
  • the method for obtaining a blend of two or more P3HA-based resins is not particularly limited, and may be a method of obtaining a blend by microbial production or a method of obtaining a blend by chemical synthesis.
  • a blend may be obtained by melt-kneading two or more resins using an extruder, kneader, Banbury mixer, roll, etc., or by dissolving two or more resins in a solvent, mixing, and drying them.
  • the resin film may contain one or more resins other than the P3HA-based resin (A), as long as the effects of the invention are achieved.
  • Such other resins are preferably biodegradable, and examples include aliphatic polyester-based resins such as polybutylene succinate, polycaprolactone, and polylactic acid; aliphatic aromatic polyester-based resins such as polybutylene adipate terephthalate, polybutylene sebate terephthalate, and polybutylene azelate terephthalate; and polybutylene succinate adipate-based resins such as copolymers of polybutylene succinate adipate and polybutylene succinate adipate with lactic acid, terephthalic acid, malic acid, or sebacic acid.
  • the amount of these other resins added is preferably 30 parts by weight or less per 100 parts by weight of P3HA-based resin (A). It may also be 20 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less. There is no particular lower limit for the content of the other resins, and it may even be 0 parts by weight.
  • the resin film may contain additives that can be used with the P3HA-based resin (A) to the extent that the effects of the invention are not impaired.
  • additives include colorants such as pigments and dyes, odor absorbers such as activated carbon and zeolite, fragrances such as vanillin and dextrin, fillers, plasticizers, antioxidants, weather resistance improvers, UV absorbers, crystal nucleating agents, lubricants, release agents, water repellents, antibacterial agents, and sliding properties improvers. Only one type of additive may be contained, or two or more types may be contained. The content of these additives can be appropriately determined by those skilled in the art depending on the intended use. The nucleating agent, lubricant, filler, and plasticizer will be described in more detail below.
  • the resin film may contain a crystal nucleating agent.
  • crystal nucleating agents include polyhydric alcohols such as pentaerythritol, galactitol, and mannitol; orotic acid, aspartame, cyanuric acid, glycine, zinc phenylphosphonate, and boron nitride.
  • pentaerythritol is preferred because it has a particularly excellent effect of promoting the crystallization of the P3HA resin (A).
  • One or more crystal nucleating agents may be used, and the usage ratio can be appropriately adjusted depending on the purpose.
  • nucleating agent when used, its amount is not particularly limited, but is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, and even more preferably 0.7 to 1.5 parts by weight, per 100 parts by weight of P3HA-based resin (A).
  • the resin film may contain a lubricant.
  • lubricants include behenamide, oleamide, erucamide, stearamide, palmitamide, N-stearylbehenamide, N-stearylerucamide, ethylenebisstearamide, ethylenebisoleamide, ethylenebiserucamide, ethylenebislauricamide, ethylenebiscapricamide, p-phenylenebisstearamide, and polycondensates of ethylenediamine, stearic acid, and sebacic acid.
  • behenamide or erucamide is preferred because of its particularly excellent lubricating effect on the P3HA-based resin (A).
  • One or more lubricants may be used, and the ratio of use can be appropriately adjusted depending on the purpose.
  • a lubricant When a lubricant is used, its amount is not particularly limited, but is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and even more preferably 0.1 to 1.5 parts by weight, per 100 parts by weight of P3HA-based resin (A).
  • the resin film may contain a filler. By including a filler, the film can have higher strength.
  • the filler may be either an inorganic filler or an organic filler, or both may be used in combination.
  • the inorganic filler is not particularly limited, but examples thereof include silicates, carbonates, sulfates, phosphates, oxides, hydroxides, nitrides, and carbon black. Only one type of inorganic filler may be used, or two or more types may be used in combination.
  • the filler When the filler is used, its content is not particularly limited, but is preferably 1 to 100 parts by weight per 100 parts by weight of P3HA-based resin (A), more preferably 3 to 80 parts by weight, even more preferably 5 to 70 parts by weight, and even more preferably 10 to 60 parts by weight.
  • the resin film may be substantially free of filler. "Substantially free of filler” means that the amount of filler blended is less than 1 part by weight per 100 parts by weight of P3HA-based resin (A). It may also be less than 0.1 part by weight.
  • the resin film may contain a plasticizer.
  • plasticizers include glycerin ester compounds, citrate ester compounds, sebacic acid ester compounds, adipate ester compounds, polyether ester compounds, benzoic acid ester compounds, phthalic acid ester compounds, isosorbide ester compounds, polycaprolactone compounds, and dibasic acid ester compounds.
  • glycerin ester compounds, citrate ester compounds, sebacic acid ester compounds, and dibasic acid ester compounds are preferred because of their particularly excellent plasticizing effect on the P3HA resin (A).
  • glycerin ester compounds include glycerin diacetomonolaurate.
  • citrate ester compounds include acetyl tributyl citrate.
  • sebacic acid ester compounds include dibutyl sebacate.
  • dibasic acid ester compounds include benzyl methyl diethylene glycol adipate.
  • plasticizer may be used, or two or more types may be used, and the ratio of use can be adjusted appropriately depending on the purpose.
  • a plasticizer When a plasticizer is used, its amount is not particularly limited, but is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, and even more preferably 3 to 10 parts by weight, per 100 parts by weight of P3HA-based resin (A). However, the resin film may be substantially free of plasticizer. "Substantially free of plasticizer” means that the amount of plasticizer blended is less than 1 part by weight per 100 parts by weight of P3HA-based resin (A). It may also be less than 0.1 part by weight.
  • the thickness of the resin film can be selected appropriately depending on the desired quality and the use of the package, but a thicker film is preferable in order to provide sufficient strength to the resin film. A specific thickness of 50 to 400 ⁇ m is preferable. This will provide the film with strength suitable for use as a package, and if the package is a standing pouch, for example, it will be able to stand upright.
  • the thicker the resin film the more likely it is that curling will occur at the heat-sealed portion as described above.
  • curling can be suppressed even when the resin film is 50 ⁇ m or thicker. It is preferably 70 ⁇ m or thicker.
  • the upper limit may be 300 ⁇ m or less, 200 ⁇ m or less, 150 ⁇ m or less, 100 ⁇ m or less, 90 ⁇ m or less, or 80 ⁇ m or less.
  • the ratio of the thickness of the paper laminate to the thickness of the resin film is preferably 0.45 to 3.5, and more preferably 0.8 to 3.0, as this helps to prevent the packaging from curling.
  • the method for producing the resin film is not particularly limited, as long as it can be used to form a film from a raw material containing P3HA-based resin (A).
  • Extrusion molding makes it easy to produce a resin film with a uniform thickness.
  • a single-screw extruder, twin-screw extruder, or the like can be used as appropriate.
  • the conditions for melting the film raw material may be any conditions that melt the P3HA-based resin (A), and the temperature of the molten film raw material may be, for example, approximately 140 to 210°C.
  • the molten film raw material is then extruded onto a casting roll to form a film.
  • the molten film raw material comes into contact with the casting roll and moves along the surface of the casting roll, where it cools and solidifies, forming a resin film.
  • a stretched film obtained by stretching a molded resin film in the MD direction and/or TD direction may also be used.
  • the resin film may be a resin film composed of an independent single layer, or may have other layers laminated on one or both sides of the resin film.
  • Such other layers may include other resin layers, inorganic layers, metal layers, metal oxide layers, printed layers, etc.
  • the packaging according to the present disclosure includes at least the paper laminate and the resin film, and a portion of the surface of the resin film is heat-sealed to the paper laminate via an adhesive resin layer.
  • the heat-sealed portion is hereinafter also referred to as the "sealed area.”
  • the paper laminate and the resin film are connected and integrated by this sealed area.
  • the resin film also includes an unsealed area that is not heat-sealed to the paper laminate.
  • the resin film is not laminated with the paper laminate and exists as a single layer.
  • the paper laminate may also include a non-sealed area that is not heat-sealed to the resin film.
  • the heat sealing refers to the adhesion of the resin film and adhesive resin layer by thermal fusion of at least a portion of the resin component contained in the resin film with at least a portion of the resin component contained in the adhesive resin layer.
  • This type of heat sealing can be achieved by overlapping the resin film and the paper laminate so that a portion of the surface of the resin film contacts the adhesive resin layer, applying heat and/or pressure to thermally melt the resin component, and then cooling and solidifying it.
  • heat sealing In addition to the general heat sealing method, other methods that can be used for heat sealing include impulse sealing, ultrasonic sealing, high-frequency sealing, hot air sealing, and frame sealing.
  • the heat sealing temperature when heat sealing is performed varies depending on the type of heat sealing method, the types of components contained in the resin film and adhesive resin layer, and the thickness of the resin film and adhesive resin layer.
  • the heat sealing temperature is usually 220°C or lower, preferably 210°C or lower, and more preferably 200°C or lower. If it is within this range, melting of the resin near the sealed area can be avoided and good adhesive strength can be ensured.
  • the lower limit of the heat sealing temperature is usually 120°C or higher, preferably 140°C or higher. If it is within this range, adequate adhesion at the sealed area can be ensured.
  • the heat sealing pressure used when performing heat sealing also varies depending on the conditions of the heat sealing method, etc.
  • it is usually 0.1 MPa or higher, preferably 0.3 MPa or higher. If it is within this range, appropriate adhesion at the sealed area can be ensured.
  • the upper limit of the heat sealing pressure is usually 1.0 MPa or lower, preferably 0.75 MPa or lower. If it is within this range, thinning of the sealed area can be avoided and good adhesion strength can be ensured.
  • the packaging body according to the present disclosure has at least a heat-sealed region between the P3HA-based resin (A)-containing resin film and the adhesive resin layer, but may also have other heat-sealed regions.
  • heat-sealed regions include heat-sealed regions between adhesive resin layers, heat-sealed regions between resin films, and heat-sealed regions between the adhesive resin layer and the paper base layer.
  • heat sealing is preferably performed by superimposing the P3HA-based resin (A)-containing resin film, adhesive resin layer, and paper base layer in this order, and then heating from the paper base layer side. In this case, heating is not performed from the resin film side.
  • This method is suitable for suppressing deformation of the resin film due to excessive heat and suppressing warping at the heat-sealed portion. It also prevents the resin film from fusing to the seal bar, enabling the stable production of packaging according to the present disclosure.
  • packaging include shopping bags, bags, packaging materials for food, beverages, and confectionery, blister packaging materials for storing miscellaneous goods, cups, trays, cartons, etc.
  • packaging materials it is particularly suitable for use as packaging materials that are configured so that the packaged items can be seen through the resin film in the non-sealed area.
  • packaging materials for example, a space is formed surrounded by the resin film in the non-sealed area and the paper laminate or the resin film in the sealed area, and the packaged items are stored in this space. The packaged items can be seen from outside the packaging material through the transparent resin film.
  • each package includes three-sided sealed bags, four-sided sealed bags, standing pouches, pillow packaging bags, gusset bags, envelope-type bags, square-bottom bags, etc.
  • the specific structure of each package is not particularly limited and can be selected appropriately by the manufacturer.
  • the package according to the present disclosure may contain an item to be packaged inside, or may be in a state before the item to be packaged is contained inside.
  • the packaging body 10 includes a paper laminate 11 and a resin film 12.
  • the paper laminate 11 includes a paper base layer 11a and an adhesive resin layer 11b, with the adhesive resin layer 11b formed on the surface of the paper base layer 11a.
  • a portion of the resin film 12 is in contact with the adhesive resin layer 11b, and in this sealed region 21, the resin film is heat-sealed to the surface of the adhesive resin layer 11b.
  • the resin film 12 also has a region 22 that is not in contact with the adhesive resin layer 11b, which corresponds to a non-sealed region.
  • this laminate structure is formed into a bag with the resin film 12 on the inside, and the resin films are heat-sealed as appropriate to form a space surrounded by the resin film 22, within which the packaged item can be placed (not shown). In this case, too, the packaged item can be seen through the resin film 13 in the non-sealed area 22.
  • the position of the non-sealed area in the formed bag is not particularly limited. Furthermore, a single bag may include multiple non-sealed areas. Specific examples of packages of this type include stand-up pouches and pillow packaging bags.
  • the layered structure shown in Figure 1 or Figure 2 is merely one embodiment, and the layered structure of the packaging body according to the present disclosure is not limited to that shown in Figure 1 or Figure 2.
  • a packaging body comprising a paper laminate and a resin film
  • the paper laminate includes a paper base layer and an adhesive resin layer containing a biodegradable polyester resin laminated on at least one surface of the paper base layer, the resin film has a sealed region that is heat-sealed to the paper laminate via the adhesive resin layer, and a non-sealed region that is not heat-sealed to the paper laminate; the resin film contains a poly(3-hydroxyalkanoate)-based resin (A),
  • the packaged body includes the poly(3-hydroxyalkanoate) resin (A) comprising a copolymer (a-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 1 to 13 mol %, and a copolymer (a-2) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 24 mol % or more.
  • Tma peak top temperature
  • Tmb peak top temperature
  • the biodegradable polyester resin comprises a poly(3-hydroxyalkanoate)-based resin (B), and the resin (B) comprises a copolymer (b-1) of 3-hydroxybutyrate units and other hydroxyalkanoate units, the content of which is 10 to 16 mol%.
  • the heat sealing in step (iii) is performed by heating from the paper base layer side in a state where the resin film, the adhesive resin layer, and the paper base layer are superimposed in this order.
  • Pentaerythritol (Mitsubishi Chemical Corporation: Neuraizer P)
  • partially saponified polyvinyl alcohol manufactured by Kuraray Co., Ltd., Kuraray Poval: 5-88
  • a dispersant was added to 3 parts by weight, and stirred with water, P3HB3HH, PHB, and an aqueous coating liquid containing a total solids concentration of 40 wt% of the dispersant was obtained.
  • An aqueous coating solution containing the P3HB3HH-6 was applied to one side of an A4-sized bleached kraft paper having a basis weight of 50 g/ m2 in the longitudinal direction of the A4 size paper using a bar coater to a dry weight of 10 g/ m2 (thickness of 8 to 10 ⁇ m), and then heated for 2 minutes in a hot air drying oven set at 180°C to form an adhesive resin layer, thereby obtaining coated paper.
  • the dry weight of the adhesive resin layer was calculated by cutting the coated paper into 100 mm square pieces, measuring the weight, subtracting the weight of the base paper from the weight value, and multiplying the result by 100.
  • aqueous coating solution containing the P3HB3HH-6 was applied to a 50 ⁇ m thick PET film using a bar coater to a dry weight of 10 g/m 2 , and then heated for 2 minutes in a hot air drying oven set at 180 ° C. to form a resin layer.
  • 2 to 5 mg of the resin layer peeled from the PET film was loaded into an aluminum pan, and using a differential scanning calorimeter, the resin layer was melted by heating from 20 ° C. to 190 ° C. at a rate of 10 ° C./min under a nitrogen stream to obtain a crystalline melting curve.
  • Tma was 115 ° C.
  • Tmb was 162 ° C.
  • Example 1 70 parts by weight of P3HB3HH-3 as copolymer (a-1), 30 parts by weight of P3HB3HH-5 as copolymer (a-2), and 100 parts by weight of copolymer (a-1) and copolymer (a-2) in total were dry-blended with 1 part by weight of pentaerythritol and 0.5 parts by weight of behenic acid amide (the resin components were mixed in a non-molten state), and then melt-kneaded and extruded in a twin-screw extruder into strands. The extrusion was passed through a water bath heated to 40°C to crystallize and solidify, and then cut with a pelletizer to produce P3HA-based resin pellets.
  • the obtained pellets were extruded using a single-screw extruder ("20C200” Labo Plastomill” manufactured by Toyo Seiki Seisaku-sho) equipped with a T-die having a width of 150 mm and a lip opening width of 0.25 mm, with the cylinder temperature set to 140 to 160°C and the die temperature set to 170°C, and the extruded pellets were taken up on a cooling roll controlled to 40°C. Both ends of the film were trimmed and the film was taken up to produce a P3HA-based resin film having a width of 100 mm and a thickness of 80 ⁇ m.
  • the resulting resin film and the coated paper were cut into 25 mm wide and 100 mm long pieces (100 mm in the film unwinding direction for the resin film, and 100 mm in the direction of coating with the bar coater for the coated paper).
  • the resin film and the coated paper were stacked so that their adhesive resin layers were in contact with each other, and placed in a heat sealer (TP-701-B, manufactured by Tester Sangyo Co., Ltd.) equipped with a heating plate above the pressure-bonding section and a natural rubber plate below, in the following order: heating plate, paper base layer, adhesive resin layer, resin film, and natural rubber plate.
  • TP-701-B manufactured by Tester Sangyo Co., Ltd.
  • the heat-bonding was performed under the following conditions: heating plate temperature setting: 150°C, surface pressure: 0.4 MPa, sealing time: 0.5 seconds, to obtain a package including a heat-sealed area.
  • the size of the heat-sealed area was 20 mm (width of the heating plate) ⁇ 25 mm (width of the test piece).
  • Examples 2 to 7, Comparative Examples 1 and 2 A package including a heat seal region was obtained in the same manner as in Example 1, except that the type of copolymer (a-1) and the blending ratio (parts by weight) of copolymer (a-1) and (a-2) were changed as shown in Table 1 or 2.
  • Examples 8 to 21 The type of copolymer (a-1) and the blending ratio (parts by weight) of copolymers (a-1) and (a-2) were the same as in Example 4, and packages including a heat-sealed region were obtained in the same manner as in Example 1, except that the thickness of the resin film, the basis weight of the paper, the dry weight and thickness of the adhesive resin layer, and the set temperature of the heating plate during heat-sealing were changed as shown in Table 1 or 2.
  • Tables 1 and 2 show that the packages of each Example had good adhesion strength between the paper base layer and the resin film and suppressed curling at the heat-sealed portion.
  • the packages of each Comparative Example did not use copolymer (a-2) in the resin film, and although the adhesion strength between the paper base layer and the resin film was good, significant curling occurred at the heat-sealed portion.

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

Abstract

L'invention concerne un corps d'emballage qui comprend un stratifié de papier et un film de résine. Le stratifié de papier comporte une couche de matériau de base en papier et une couche de résine adhésive stratifiée. Le film de résine comporte : une région d'étanchéité qui est thermoscellée au stratifié de papier par l'intermédiaire de la couche de résine adhésive; et une région de non-étanchéité qui n'est pas thermoscellée au stratifié de papier. Le film de résine contient une résine à base de poly (3-hydroxyalcanoate) (A). La résine (A) comprend : (a-1) un copolymère d'une unité 3-hydroxybutyrate et d'une autre unité hydroxyalcanoate, le rapport de teneur de l'autre unité hydroxyalcanoate étant de 1 à 13 % en moles ; et (a-2) un copolymère d'une unité 3-hydroxybutyrate et d'une autre unité hydroxyalcanoate, le rapport de teneur de l'autre unité hydroxyalcanoate étant supérieur ou égal à 24 % en moles.
PCT/JP2025/026986 2024-08-06 2025-07-30 Corps d'emballage et son procédé de fabrication Pending WO2026034308A1 (fr)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3096070U (ja) * 2003-02-24 2003-08-29 株式会社メイテンス 包装おにぎりとその包装材
WO2015146195A1 (fr) * 2014-03-28 2015-10-01 株式会社カネカ Microorganisme ayant de multiples gènes codant pour la pha synthase et procédé de production de pha utilisant ce dernier
JP2017159664A (ja) * 2017-05-17 2017-09-14 大日本印刷株式会社 容器用のブランク板及び筒状カートンの製造方法
JP2022182524A (ja) * 2021-05-28 2022-12-08 株式会社カネカ 積層体の製造方法、及び、積層体
WO2023085375A1 (fr) * 2021-11-12 2023-05-19 株式会社カネカ Corps multicouche et son utilisation
JP7285387B1 (ja) * 2023-03-07 2023-06-01 日本製紙株式会社 ヒートシール紙
WO2023153277A1 (fr) * 2022-02-08 2023-08-17 株式会社カネカ Corps stratifié biodégradable, son procédé de production et corps moulé
JP2023154875A (ja) * 2022-04-08 2023-10-20 アツギ株式会社 ストッキング類の包装用袋及びその製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3096070U (ja) * 2003-02-24 2003-08-29 株式会社メイテンス 包装おにぎりとその包装材
WO2015146195A1 (fr) * 2014-03-28 2015-10-01 株式会社カネカ Microorganisme ayant de multiples gènes codant pour la pha synthase et procédé de production de pha utilisant ce dernier
JP2017159664A (ja) * 2017-05-17 2017-09-14 大日本印刷株式会社 容器用のブランク板及び筒状カートンの製造方法
JP2022182524A (ja) * 2021-05-28 2022-12-08 株式会社カネカ 積層体の製造方法、及び、積層体
WO2023085375A1 (fr) * 2021-11-12 2023-05-19 株式会社カネカ Corps multicouche et son utilisation
WO2023153277A1 (fr) * 2022-02-08 2023-08-17 株式会社カネカ Corps stratifié biodégradable, son procédé de production et corps moulé
JP2023154875A (ja) * 2022-04-08 2023-10-20 アツギ株式会社 ストッキング類の包装用袋及びその製造方法
JP7285387B1 (ja) * 2023-03-07 2023-06-01 日本製紙株式会社 ヒートシール紙

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