WO2021215507A1 - Film for heat sealing, and packaging material - Google Patents

Film for heat sealing, and packaging material Download PDF

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Publication number
WO2021215507A1
WO2021215507A1 PCT/JP2021/016331 JP2021016331W WO2021215507A1 WO 2021215507 A1 WO2021215507 A1 WO 2021215507A1 JP 2021016331 W JP2021016331 W JP 2021016331W WO 2021215507 A1 WO2021215507 A1 WO 2021215507A1
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WIPO (PCT)
Prior art keywords
heat
thermoplastic polyester
polyester resin
film
sealing
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PCT/JP2021/016331
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French (fr)
Japanese (ja)
Inventor
伊藤　由実
悟史 河村
優斗 佐藤
伸一郎 船岡
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東洋製罐株式会社
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Publication of WO2021215507A1 publication Critical patent/WO2021215507A1/en

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    • 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
    • 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
    • B65D65/40—Applications of laminates for particular packaging purposes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/66—Polyesters containing oxygen in the form of ether groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
    • 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
    • Y02W30/80—Packaging reuse or recycling, e.g. of multilayer packaging

Definitions

  • the present invention relates to a heat-sealing film for a packaging bag that is molded into a bag shape, a film for a lid material that is melt-bonded to a container body and used, and a packaging material.
  • a laminated film in which a heat-sealing layer is provided on a film base material has been used.
  • these packaging materials are melt-bonded (heat-sealed) by pressure-bonding and heating the heat-sealing layers to each other to form a bag-like or container-like shape with an opening left, and after the contents are put through the opening, the contents are put in.
  • the contents can be sealed by further pressure-bonding and heating the heat-sealing layers of the openings to melt and bond the heat-sealing layers.
  • polyester-based films are widely used from the viewpoints of strength, heat resistance, gas barrier properties, and the like.
  • the heat seal layer a layer made of a polyolefin resin such as polyethylene or polypropylene or a copolymer resin such as ionomer or EMMA is used. It is known that these resins can achieve high adhesion strength by heat sealing.
  • a plastic packaging material is manufactured by combining a plurality of plastic materials according to the required performance and function.
  • the packaging material is preferably composed of a single plastic material, and the product composed of a plurality of plastic materials is separated into the plastic materials constituting the packaging material. Because it is difficult to do, it has to be recycled into low quality plastic products or incinerated.
  • the film base material and the heat-sealing layer use the same type of resin in order to improve recyclability.
  • heat sealing is carried out by superimposing a heat sealing layer of a heat sealing film and a heat sealing layer of another heat sealing film or a film base material surface, and pressure-heating with a heat sealer.
  • the temperature of the heat sealer at this time is lower than the melting point of the material forming the film substrate and higher than the melting point of the material forming the heat seal layer, and the crimping time is as short as 0.1 seconds to several seconds, especially for production.
  • efficiency is important, there is a demand for a heat-sealing film that can obtain strong heat-sealing strength in a short crimping time.
  • the heat-sealing film is also used for retort pouches and the like used for packaging retort foods. Therefore, the heat-sealing film is required to have heat resistance that can withstand retort treatment (120 to 135 ° C.), and the resin forming the heat-sealing layer is required to have a melting point of 150 ° C. or higher. ..
  • PET resin which is generally used as a material for polyester films, has a high glass transition temperature (Tg) of 70 ° C., a melting point (Tm) of 250 ° C., and a large heat of fusion ⁇ H, so that it melts. It is not suitable as a material for forming a heat seal layer because it requires high temperature and long-time heating.
  • PET resin which is widely used as an engineering plastic, has a glass transition temperature (Tg) of 40 ° C. and a melting point (Tm) of 220 ° C., which are lower than those of PET resin.
  • Patent Documents No. 1 discloses a heat-sealed layer made of a copolymer resin having a melting temperature of 125 ° C.
  • Patent Document 2 proposes a laminated polyester film in which a polyester-based film composed of an amorphous polyester copolymer or a low-crystalline polyester copolymer having a crystallization heat ( ⁇ H) of less than 10 J / g is laminated. There is.
  • a film in which a resin layer made of a polyester resin copolymerized with polyoxyalkylene glycol is laminated is also known (see, for example, Patent Documents 3 and 4).
  • this polyester resin is a block copolymer composed of a high melting point crystalline segment and a low melting point amorphous segment, and has a melting point of 180 ° C. or higher.
  • the heat-sealing film laminated on the film substrate can withstand the retort temperature.
  • a resin obtained by copolymerizing PET or PBT with isophthalic acid, adipic acid, sebacic acid, or dimer acid to have a crystal melting heat of 4 cal / g or less has a melting point. Since the temperature is lower than 132 ° C., the packaging bag (pouch) made from the heat-sealing film using this as the heat-sealing layer cannot withstand the retort treatment. If the copolymerization ratio of isophthalic acid, adipic acid, etc. in the resin forming the heat seal layer is lowered in order to improve the heat resistance of the heat seal film, the melting point of the resin will be higher, but the heat of crystal melting will also be higher.
  • the present invention solves the above-mentioned problems, is a heat-sealing film having excellent recyclability and capable of reducing an environmental load, and can obtain strong heat-sealing strength in a short crimping time, and further. It is an object of the present invention to provide a heat-sealing film and a packaging material having heat resistance to withstand high-temperature retort treatment.
  • the heat-sealing film of the present invention is a heat-sealing film provided with a thermoplastic polyester-based resin layer containing a thermoplastic polyester-based resin containing polyoxyalkylene glycol as a diol component on one side or both sides of the base material layer.
  • the thermoplastic polyester resin has a glass transition temperature (Tg) of 50 ° C. or lower and 150 ° C. or higher, which is observed when the thermoplastic polyester resin is melted, rapidly cooled to ⁇ 50 ° C. at 200 ° C./min, and then heated at 10 ° C./min.
  • Tm glass transition temperature
  • the melting point (Tm) is observed, and the heat of fusion ⁇ H is more than 0 J / g and 20 J / g or less.
  • the thermoplastic polyester resin contains terephthalic acid as a main dicarboxylic acid component and ethylene glycol and / or 1,4-tetramethylene glycol as a main diol component. Is preferable. Further, in the heat-sealing film of the present invention, it is preferable that the heat of fusion ⁇ H exceeds 0 J / g and is 10 J / g or less. Further, in the heat-sealing film of the present invention, it is more preferable that the heat of fusion ⁇ H exceeds 0 J / g and is 5 J / g or less.
  • the thermoplastic polyester-based resin contains terephthalic acid as a main dicarboxylic acid component, 1,4-tetramethylene glycol as a main diol component, and the poly.
  • a thermoplastic polyester-based resin containing polytetramethylene glycol as a diol component as the oxyalkylene glycol is preferable.
  • the content of the polytetramethylene glycol component in the thermoplastic polyester resin is 30% by mass or more, or the polytetramethylene glycol component in the thermoplastic polyester resin is It is preferable that the content is 10% by mass or more and the content of the isophthalic acid component is 20 mol% or more.
  • the base material layer is a polyethylene terephthalate film and / or a polybutylene terephthalate film.
  • the base material layer is a non-stretched polybutylene terephthalate film.
  • the packaging material of the present invention is characterized by containing the above-mentioned heat-sealing film.
  • the packaging material of the present invention may be a packaging bag or a lid material for a sealed container.
  • the base material layer is formed of the polyester-based resin by providing the thermoplastic polyester-based resin layer as the heat-sealing layer on one side or both sides of the base material layer.
  • the entire heat-sealing film is composed of polyester-based resin as the main material, it can be easily recycled into high-quality polyester-based materials and polyester-based products, and excellent recyclability can be obtained. As a result, the environmental load can be reduced.
  • thermoplastic polyester resin contains polyoxyalkylene glycol as a diol component and exhibits a specific glass transition temperature (Tg), melting point (Tm) and heat of melting ⁇ H, it takes a short crimping time. A strong heat seal strength can be obtained, and heat resistance that can withstand retort treatment at a high temperature can be obtained. As a result, leakage of contents can be prevented in the packaging material.
  • the heat-sealing film As shown in FIG. 1, the heat-sealing film according to an embodiment of the present invention has a heat-sealing layer (heat) containing a thermoplastic polyester resin containing polyoxyalkylene glycol as a diol component on one side of the base material layer 11. It is a laminated film provided with a plastic polyester resin layer) 12.
  • the heat seal layer 12 contains a thermoplastic glycol as a diol component, and has a glass transition temperature (Tg) observed when the temperature is raised at 10 ° C./min after being rapidly cooled to ⁇ 50 ° C. at 200 ° C./min after melting.
  • Tg glass transition temperature
  • a thermoplastic polyester resin having a melting point (Tm) of 50 ° C. or lower and 150 ° C. or higher and a heat of fusion ⁇ H of more than 0 J / g and 20 J / g or less hereinafter, “specific thermoplastic polyester resin””. Also referred to as).
  • thermoplastic polyester resin Specific thermoplastic polyester resins generally esterify a dicarboxylic acid component such as terephthalic acid, a diol component such as ethylene glycol or 1,4-tetramethylene glycol, and other components used as needed. It is obtained by conducting a polycondensation reaction after a reaction and / or a transesterification reaction.
  • the polyoxyalkylene glycol contained as a diol component in a specific thermoplastic polyester resin is a polyether in which ethylene, propylene, tetramethylene (butylene) and the like are linked by an ether bond, and specifically, polyethylene glycol and polypropylene glycol.
  • polytetramethylene glycol polytetramethylene ether glycol
  • polytetramethylene glycol is preferably contained as a diol component.
  • the polyoxyalkylene glycol preferably has an average molecular weight of 500 to 2,000, and particularly preferably 500 to 1,000. When the average molecular weight of the polyoxyalkylene glycol is less than 500, the melting point of the thermoplastic polyester resin may be lowered and the heat resistance may be lowered. On the other hand, when the average molecular weight of the polyoxyalkylene glycol exceeds 2,000, the melting point of the thermoplastic polyester resin becomes high, and it becomes difficult to obtain sufficient heat seal strength with a short crimping time.
  • the glass transition temperature (Tg) observed when a specific thermoplastic polyester resin is melted, rapidly cooled to -50 ° C at 200 ° C / min, and then heated at 10 ° C / min is 50 ° C or lower and 150 ° C or higher.
  • the melting point (Tm) of the above is observed and the heat of fusion ⁇ H exceeds 0 J / g and is 20 J / g or less, preferably the heat of fusion ⁇ H is 10 J / g or less, more preferably 5 J / g or less. Is.
  • the glass transition temperature (Tg) exceeds 50 ° C. the thermoplastic polyester resin is difficult to soften, and it is difficult to obtain sufficient heat seal strength with a short crimping time.
  • thermoplastic polyester resin If no melting point (Tm) is observed, that is, if the heat of fusion ⁇ H is 0 J / g, or if the melting point (Tm) is less than 150 ° C., heat using this thermoplastic polyester resin as the heat seal layer.
  • the pouch made from the sealing film may not have sufficient heat resistance and may not withstand the retort treatment. Further, when the heat of fusion ⁇ H exceeds 20 J / g, it takes time for the thermoplastic polyester resin to melt, so that it is difficult to obtain sufficient heat seal strength with a short crimping time.
  • the thermoplastic polyester-based resin has the above-mentioned glass transition temperature (Tg) and melting point (Tm) for components other than the polyoxyalkylene glycol component.
  • Tg glass transition temperature
  • Tm melting point
  • heat of fusion ⁇ H are not particularly limited, but those containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol and / or 1,4-tetramethylene glycol as a main diol component are used.
  • the content of the terephthalic acid component is preferably 50 mol% or more, particularly preferably 70 mol% or more, of the total dicarboxylic acid component of the thermoplastic polyester resin.
  • the content of the terephthalic acid component is less than 50 mol%, the melting point (Tm) of the thermoplastic polyester resin decreases, and the pouch obtained by heat-sealing the laminated heat-sealing film withstands the retort treatment. It will not be possible.
  • the content ratio of ethylene glycol and 1,4-tetramethylene glycol is when the total diol component of the thermoplastic polyester resin is 100 mol% and the ratio of polyoxyalkylene glycol is x mol%. , (100-x) is preferably 70% or more of mol%.
  • thermoplastic polyester resin has the above-mentioned glass transition temperature (Tg), melting point (Tm) and heat of fusion ⁇ H. It is a range that satisfies the range of.
  • components other than the above-mentioned polyoxyalkylene glycol, terephthalic acid, ethylene glycol and / or 1,4-tetramethylene glycol for forming a specific thermoplastic polyester resin include isophthalic acid and 2,6-naphthalene.
  • Aromatic dicarboxylic acids such as dicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyetanedicarboxylic acid, diphenyletherdicarboxylic acid, 5-sulfoisophthalic acid, phthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer Dicarboxylic acid components such as aliphatic dicarboxylic acids such as acids, maleic acids and fumaric acids, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acids, diethylene glycols, triethylene glycols, polyethylene glycols, propanediols, butanediols, pentanediols and hexanediols.
  • Aliper glycols such as neopentyl glycol, aromatic glycols such as bisphenol A and bisphenol S, diol components such as alicyclic glycols such as 1,4-cyclohexanedimethanol, and polyfunctional compounds such as trimellitic acid and pentaerythritol. Ingredients are mentioned. These components may be used alone or in combination of two or more, and the melting point, crystallinity, and flexibility of the thermoplastic polyester resin obtained by copolymerizing these components may be used. Can be adjusted. Further, the specific thermoplastic polyester resin may be modified with maleic anhydride or the like in order to improve the adhesiveness with other resins.
  • a polytetramethylene glycol component containing terephthalic acid as a main dicarboxylic acid component and 1,4-tetramethylene glycol as a main diol component as a diol component is contained.
  • the composition is such that the amount is 30% by mass or more, or the content of the polytetramethylene glycol component is 10% by mass or more and the content of the isophthalic acid component is 20 mol% or more.
  • Polytetramethylene glycol even when the isophthalic acid component is not contained and the content of the polytetramethylene glycol component is less than 30% by mass, or even when the isophthalic acid component is contained in an amount of 20 mol% or more.
  • the content of the component is less than 10% by mass, and when the content of the polytetramethylene glycol component is 10% by mass or more and less than 30% by mass and the content of the isophthalic acid component is less than 20 mol%.
  • the heat of fusion ⁇ H is a thermoplastic polyester resin exceeding 20 J / g, it takes time for the resin to melt, and it is difficult to obtain sufficient heat seal strength with a short crimping time.
  • the specific thermoplastic polyester resin preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 50,000 to 200,000, which is determined by a size exclusion chromatograph method (SEC), and is 70,000 to 150,000. Is more preferable.
  • Mw polystyrene-equivalent weight average molecular weight
  • Dissolving agents, plastics, antioxidants, reaction catalysts, anticoloring agents, radical banning agents, antistatic agents, terminal sequestering agents, antioxidants, heat stabilizers, mold release agents, flame retardants, antibacterial agents, anti-mold agents Etc. may be added.
  • the heat seal layer (thermoplastic polyester resin layer) 12 may be made of only the above-mentioned specific thermoplastic polyester resin, or may be made of a mixture of the specific thermoplastic polyester resin and other resins. It may be.
  • a thermoplastic polyester resin such as polybutylene terephthalate (PBT) resin is preferable.
  • the other resin may be a mixed resin mixed with hydrophilic silica or the like.
  • the base material layer 11 constituting the heat-sealing film 10 together with the heat-sealing layer 12 has mechanical properties such as tensile strength and piercing strength required for the obtained heat-sealing film 10, heat resistance, chemical resistance, and the like. There is no particular limitation as long as it satisfies. For example, those made of stretched nylon, stretched polyethylene terephthalate, other resins, metals, paper and the like can be mentioned. Further, from the viewpoint of enhancing recyclability, it is preferable to use a polyester film such as a polyethylene terephthalate film or a polybutylene terephthalate film, and more preferably a non-stretched polybutylene terephthalate film.
  • polyester-based films are preferably made of a homopolymer (polyethylene terephthalate, polybutylene terephthalate) from the viewpoint of mechanical properties and heat resistance, and are preferably a dicarboxylic acid such as isophthalic acid or 1,4-cyclohexanedi. It is desirable to minimize the content of copolymerization components such as diols such as methanol and neopentyl glycol, polyfunctional compounds such as trimellitic acid and pentaerythritol.
  • the base material layer 11 is preferably made of a material having a melting point of, for example, 200 ° C. or higher so as not to melt when heat-sealed.
  • the base material layer 11 contains a light stabilizer, an impact resistance improver, a compatibilizer, a lubricant, a plasticizer, an antistatic agent, a reaction catalyst, a color inhibitor, a radical inhibitor, an antistatic agent, a terminal sealant, and an antioxidant. Agents, heat stabilizers, mold release agents, flame retardants, antibacterial agents, antifungal agents and the like may be added.
  • the method for producing the heat-sealing film 10 by laminating the base material layer 11 and the heat-sealing layer 12 is not particularly limited, and a solution prepared by dissolving a specific thermoplastic polyester resin in a solvent is used as the base material layer 11.
  • the coextrusion method which does not require a solvent or an adhesive and does not require a step of bonding films, is particularly preferable from the viewpoint of low environmental load and high production efficiency.
  • a polybutylene terephthalate resin is used as the material for forming the base material layer 11, it is coextruded with a specific thermoplastic polyester resin for forming the heat seal layer 12, and then coextruded.
  • the base material layer 11 is crystallized to form a film having excellent heat resistance and mechanical strength, which is more preferable.
  • the packaging material of the present invention is a packaging material containing the above-mentioned heat-sealing film 10.
  • a packaging bag such as a retort pouch, and a lid material for closing an opening of a container body for forming a sealed container.
  • the heat-sealing film 10 and another heat-sealing film 10' are overlapped so that the heat-sealing layer 12 and the heat-sealing layer 12' face each other, and the outer side (base) is formed.
  • the heat seal layer 12 and the heat seal layer 12' are melt-bonded (heat-sealed) from the material layer 11 and the base material layer 11'side) by heat-pressing the periphery with a heat sealer 13 so as to form a bag.
  • a heat sealer 13 By adhering the periphery of the two heat-sealing films 10 and 10'in this way, a packaging material for sealing the contents can be produced.
  • the heating temperature by the heat sealer 13 is, for example, 160 to 210 ° C.
  • the pressure for crimping is, for example, 0.1 to 1 MPa
  • the crimping time is, for example, 0.1 to 3 seconds.
  • the contents are housed in the container body, and the heat-sealing film 10 is placed on the edge flange of the opening of the container body, and the heat-sealing layer 12 contacts the edge flange.
  • the heat-sealing film 10 is heat-sealed by arranging and heat-pressing the film 10 in a state of being heat-sealed, whereby the contents can be sealed.
  • the container body of such a sealed container is preferably made of a polyester resin such as PET.
  • the heat-sealing film of the present invention is not limited to a structure in which a heat-sealing layer is provided on only one side of the base material layer, and has a structure in which heat-sealing layers are provided on both sides of the base material layer. May be good.
  • the heat-sealing film of the present invention may have an intermediate layer such as an appropriate barrier layer interposed between the heat-sealing layer and the base material layer.
  • the heat-sealing film of the present invention may have a structure in which a heat-sealing layer is provided on one side of the base material layer, and a printing layer, a barrier layer, or the like is provided on the other side.
  • Method for analyzing resin composition of thermoplastic polyester resin method for measuring glass transition temperature (Tg), melting point (Tm), heat of fusion ( ⁇ H), heat-sealing strength of heat-sealing film in the following Examples and Comparative Examples.
  • Tg glass transition temperature
  • Tm melting point
  • ⁇ H heat of fusion
  • heat-sealing strength of heat-sealing film in the following Examples and Comparative Examples.
  • the method for measuring the heat resistance of the packaging material and the method for measuring the heat resistance of the packaging material are as follows.
  • thermoplastic polyester resin ⁇ Resin composition of thermoplastic polyester resin> Thermoplastic polyester resin is dissolved in deuterated trifluoroacetic acid, further diluted with deuterated chloroform (containing 0.1% by mass of trimethylsilane), and nuclear magnetic resonance analyzer (trade name "JNM-ECZ400S", manufactured by JEOL Ltd.). The resin composition was analyzed and calculated by measuring the proton NMR spectrum using.
  • Tg Glass transition temperature
  • Tm melting point
  • Tg glass transition start temperature
  • Heat seal strength of heat seal film Two sheets cut out from the heat-sealing film to a size of 20 mm ⁇ 80 mm were stacked so that the resin layers containing the thermoplastic polyester-based resin faced each other. Then, heat-sealed by heat-sealing with a heat sealer at a sealing width of 10 mm, a sealing temperature of 210 ° C. (one side), and a sealing pressure of 0.3 MPa for 1 second.
  • ⁇ Heat resistance> Two sheets cut out from the heat-sealing film to a size of 140 mm ⁇ 170 mm were stacked so that the resin layers containing the thermoplastic polyester-based resin faced each other. Next, the three sides were heat-sealed with a heat sealer at a sealing width of 5 mm, a sealing temperature of 210 ° C. (one side), and a sealing pressure of 0.3 MPa for 1 second to prepare a packaging bag. After 200 g of water was put through the opening of the packaging bag, the opening was similarly heat-sealed and sealed, and then retort-treated at 127 ° C. for 30 minutes in a retort kettle.
  • Thermoplastic polyester resin [P1] (trade name "Hitrel 2551", manufactured by Toray DuPont Co., Ltd.) is supplied from the hopper of a twin-screw extruder, melted at 270 ° C., extruded into a film by a T-die, and cast roll. A film having a thickness of 40 ⁇ m was produced by cooling and solidifying with. An adhesive (main agent: Takelac A-315, curing agent: Takenate A-50, both manufactured by Mitsui Chemicals, Inc.) was applied to this film, and then adhered to a 34 ⁇ m-thick biaxially stretched polyethylene terephthalate (PET) film.
  • PET biaxially stretched polyethylene terephthalate
  • the film was cured by allowing it to stand at ° C. for 5 days or more to prepare a heat-sealing film.
  • the thermoplastic polyester resin [P1] contains a polytetramethylene glycol component which is a polyoxyalkylene glycol, has a glass transition temperature (Tg) of -3 ° C, a melting point (Tm) of 158 ° C, and a heat of fusion ⁇ H of 0. It was 3 J / g.
  • the resin composition of this thermoplastic polyester resin [P1] is as shown in Table 1.
  • the heat seal strength of this heat seal film was as good as 44.8 (N / 15 mm). Further, the packaging bag produced by using this heat-sealing film did not leak the contents after the retort treatment, and good heat resistance was obtained.
  • Example 2 In Example 1, instead of the thermoplastic polyester resin [P1], the thermoplastic polyester resin [P2] (trade name “Hytrel 4057N", manufactured by Toray DuPont Co., Ltd.) or the thermoplastic polyester resin [P3] ( A heat-sealing film similar to Example 1 except that the product name "Modic GQ430" (manufactured by Mitsubishi Chemical Corporation) was used and the melting temperature when extruded into a film by a T-die was set to 200 ° C. Were prepared respectively. As shown in Table 1, the resin compositions of these thermoplastic polyester resins [P2] and [P3] contain a polytetramethylene glycol component and have a glass transition temperature (Tg) of 50 ° C.
  • Tg glass transition temperature
  • thermoplastic polyester resin [P1] instead of the thermoplastic polyester resin [P1], the thermoplastic polyester resin [P4] (trade name “Hytrel 7247", manufactured by Toray DuPont Co., Ltd.) or the thermoplastic polyester resin [P5] ( A heat-sealing film was produced in the same manner as in Example 1 except that the trade name "Novaduran 5510S” (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was used.
  • the resin compositions of these thermoplastic polyester resins [P4] and [P5] contain a polytetramethylene glycol component and have a glass transition temperature (Tg) of 50 ° C. or lower and 150 ° C.
  • thermoplastic polyester resin [P6] (trade name “600LP”, manufactured by Mitsubishi Chemical Corporation) was used instead of the thermoplastic polyester resin [P2].
  • a film for heat sealing was produced.
  • the resin composition of this thermoplastic polyester resin [P6] was a copolymerized polybutylene terephthalate (PBT) containing 30 mol% of an isophthalic acid component without containing a polytetramethylene glycol component. ..
  • the heat of fusion ⁇ H of this thermoplastic polyester resin [P6] was 30 J / g, which exceeded 20 J / g. Further, the heat seal strength of the heat seal film showed a low value as shown in Table 1, and it was confirmed that a good heat seal strength could not be obtained.
  • thermoplastic polyester resin [P7] (trade name “PETG”, manufactured by Eastman Chemical Company) was used instead of the thermoplastic polyester resin [P1].
  • a film for heat sealing was produced.
  • the resin composition of this thermoplastic polyester resin [P7] is a copolymerized polyethylene terephthalate containing 33 mol% of 1,4-cyclohexanedimethanol (CHDM) without containing a polytetramethylene glycol component. It was (PET).
  • the glass transition temperature (Tg) of this thermoplastic polyester resin [P7] was 70 ° C.
  • the heat seal strength of the heat seal film showed a low value as shown in Table 1, and it was confirmed that a good heat seal strength could not be obtained. Further, it was confirmed that the packaging bag produced by using this heat-sealing film leaked the contents after the retort treatment, and good heat resistance could not be obtained.
  • Example 4 80 parts by mass of a thermoplastic polyester resin [P3] and 20 parts by mass of a mixed resin [B1] obtained by mixing 5% by mass of hydrophilic silica with polybutylene terephthalate (PBT) resin are supplied from the hopper of the twin-screw extruder A. Then, it melted at 245 to 240 ° C. Further, PBT resin [C1] (trade name “1100-211S”, manufactured by Choharu Co., Ltd.) was supplied from the hopper of the twin-screw extruder B and melt-kneaded at 270 to 260 ° C.
  • PBT resin [C1] (trade name “1100-211S”, manufactured by Choharu Co., Ltd.) was supplied from the hopper of the twin-screw extruder B and melt-kneaded at 270 to 260 ° C.
  • the resin extruded from these twin-screw extruders A and B was supplied to a multi-manifold T-die, extruded into a film, and cooled and solidified by a cast roll to produce a heat-sealing film having a thickness of 75 ⁇ m.
  • the heat-sealing film is made of a resin layer (thermoplastic polyester-based resin layer) in which a thermoplastic polyester-based resin [P3] and a mixed resin [B1] in which hydrophilic silica is mixed are blended, and a PBT resin [C1].
  • the thickness ratio of the layer (base material layer) was 1: 2.
  • the heat seal strength of this heat seal film showed a high value as shown in Table 2, and it was confirmed that a good heat seal strength could be obtained. Further, the packaging bag produced by using these heat-sealing films did not leak the contents after the retort treatment, and good heat resistance was obtained.
  • Example 5 80 parts by mass of a thermoplastic polyester resin [P3] and 20 parts by mass of a mixed resin [B1] obtained by mixing 5% by mass of hydrophilic silica with polybutylene terephthalate (PBT) resin are supplied from the hopper of the twin-screw extruder A. Then, it melted at 245 to 240 ° C. Further, a PET resin [C2] (trade name “BK6180”, manufactured by Mitsubishi Chemical Corporation) in which 2 mol% of isophthalic acid was copolymerized was supplied from the hopper of the twin-screw extruder B and melt-kneaded at 270 ° C.
  • a PET resin [C2] (trade name “BK6180”, manufactured by Mitsubishi Chemical Corporation) in which 2 mol% of isophthalic acid was copolymerized was supplied from the hopper of the twin-screw extruder B and melt-kneaded at 270 ° C.
  • the resin extruded from these twin-screw extruders A and B was supplied to a multi-manifold T-die, extruded into a film, and cooled and solidified by a cast roll to produce a heat-sealing film having a thickness of 75 ⁇ m.
  • the heat-sealing film is made of a resin layer (thermoplastic polyester-based resin layer) in which a thermoplastic polyester-based resin [P3] and a mixed resin [B1] in which hydrophilic silica is mixed are blended, and a PET resin [C2].
  • the thickness ratio of the layer (base material layer) was 1: 2.
  • the heat seal strength of this heat seal film showed a high value as shown in Table 2, and it was confirmed that a good heat seal strength could be obtained. Further, in the packaging bag produced by using these heat-sealing films, there was no leakage of the contents after the retort treatment and there was no problem in practicality, but a change in appearance (deformation of the film) was observed.
  • TA is terephthalic acid
  • IA is isophthalic acid
  • EG is ethylene glycol
  • BG is 1,4-tetramethylene glycol
  • CHDM 1,4-cyclohexanedimethanol
  • PTMG indicates polytetramethylene glycol.

Abstract

The present invention addresses the problem of providing: a film for heat sealing that has exceptional recycling properties and makes it possible to reduce the load on the environment, the film for heat sealing obtaining high heat seal strength in a short crimping time, and furthermore having heat resistance against a retort process at high temperature; and a packaging material.　This film (10) for heat sealing is such that a thermoplastic polyester resin layer (12) that contains a thermoplastic polyester resin including polyoxyalkylene glycol as a diol component is provided on one or both sides of a substrate layer (11), wherein the film (10) is characterized in that: after the thermoplastic polyester resin is fused and then rapidly cooled to -50°C at a rate of 200°C/min, the glass transition temperature (Tg) of the thermoplastic polyester resin observed upon heating at a rate of 10°C/min is 50°C or less; a melting point (Tm) of 150°C or higher is observed; and the heat of fusion ΔH is greater than 0 J/g and no greater than 20 J/g.

Description

ヒートシール用フィルムおよび包装材料Heat seal film and packaging material
　本発明は、袋状に成形される包装袋用や、容器本体に溶融接着されて使用される蓋材用のヒートシール用フィルム、および、包装材料に関する。 The present invention relates to a heat-sealing film for a packaging bag that is molded into a bag shape, a film for a lid material that is melt-bonded to a container body and used, and a packaging material.
　従来、食品、医薬品等の包装材として、フィルム基材にヒートシール層を設けた積層フィルム（ヒートシール用フィルム）が用いられている。そして、これらの包装材は、ヒートシール層同士を圧着加熱することにより溶融接着（ヒートシール）して開口部を残した袋状あるいは容器状に仕立てられ、開口部から内容物を入れた後、開口部のヒートシール層同士をさらに圧着加熱し、ヒートシール層を溶融、接着させることにより内容物を密封することができる。 Conventionally, as a packaging material for foods, pharmaceuticals, etc., a laminated film (heat-sealing film) in which a heat-sealing layer is provided on a film base material has been used. Then, these packaging materials are melt-bonded (heat-sealed) by pressure-bonding and heating the heat-sealing layers to each other to form a bag-like or container-like shape with an opening left, and after the contents are put through the opening, the contents are put in. The contents can be sealed by further pressure-bonding and heating the heat-sealing layers of the openings to melt and bond the heat-sealing layers.
　このフィルム基材としては、強度や耐熱性、ガスバリア性等の観点から、ポリエステル系フィルムが広く用いられている。一方、ヒートシール層としては、ポリエチレン、ポリプロピレン等のポリオレフィン系樹脂や、アイオノマー、ＥＭＭＡ等のコポリマー樹脂からなる層が用いられている。これらの樹脂は、ヒートシールにより高い密着強度を達成することができることが知られている。 As this film base material, polyester-based films are widely used from the viewpoints of strength, heat resistance, gas barrier properties, and the like. On the other hand, as the heat seal layer, a layer made of a polyolefin resin such as polyethylene or polypropylene or a copolymer resin such as ionomer or EMMA is used. It is known that these resins can achieve high adhesion strength by heat sealing.
　一方、近年、海洋プラスチックゴミ問題に代表されるように、プラスチック廃棄物による環境汚染が社会問題となっている。このため、プラスチック製品のリサイクルが進められている。プラスチック製の包装材料は、求められる性能や機能に合わせて複数のプラスチック素材を複合して製造される。プラスチック製品のリサイクルにおいて高品質の製品に再生するためには、包装材料は単一のプラスチック素材よりなるものであることが好ましく、複数のプラスチック素材からなる製品は、それを構成するプラスチック素材に分離することが難しいため、品質の低いプラスチック製品に再生されるか、あるいは焼却処分されるしかない。 On the other hand, in recent years, environmental pollution caused by plastic waste has become a social problem, as represented by the marine plastic waste problem. For this reason, recycling of plastic products is being promoted. A plastic packaging material is manufactured by combining a plurality of plastic materials according to the required performance and function. In order to recycle a plastic product into a high-quality product, the packaging material is preferably composed of a single plastic material, and the product composed of a plurality of plastic materials is separated into the plastic materials constituting the packaging material. Because it is difficult to do, it has to be recycled into low quality plastic products or incinerated.
　このため、ヒートシール用フィルムにおいても、リサイクル性を高めるため、フィルム基材とヒートシール層とが互いに同じ種類の樹脂を使用することが望まれている。 Therefore, even in the heat-sealing film, it is desired that the film base material and the heat-sealing layer use the same type of resin in order to improve recyclability.
　一般的に、ヒートシールは、ヒートシール用フィルムのヒートシール層と、別のヒートシール用フィルムのヒートシール層あるいはフィルム基材面とを重ね合わせ、ヒートシーラーで圧着加熱することによって実施される。このときのヒートシーラーの温度はフィルム基材を形成する材料の融点未満、ヒートシール層を形成する材料の融点以上の温度であって、圧着時間は０．１秒間～数秒間と短く、特に生産効率が重要視される近年、短い圧着時間で強いヒートシール強度が得られるヒートシール用フィルムが求められている。 Generally, heat sealing is carried out by superimposing a heat sealing layer of a heat sealing film and a heat sealing layer of another heat sealing film or a film base material surface, and pressure-heating with a heat sealer. The temperature of the heat sealer at this time is lower than the melting point of the material forming the film substrate and higher than the melting point of the material forming the heat seal layer, and the crimping time is as short as 0.1 seconds to several seconds, especially for production. In recent years, where efficiency is important, there is a demand for a heat-sealing film that can obtain strong heat-sealing strength in a short crimping time.
　さらに、ヒートシール用フィルムは、レトルト食品のパッケージングに用いられるレトルトパウチ等にも用いられる。このため、ヒートシール用フィルムには、レトルト処理（１２０～１３５℃）に耐えられる耐熱性が必要とされ、ヒートシール層を形成する樹脂は、融点が１５０℃以上のものであることが求められる。 Furthermore, the heat-sealing film is also used for retort pouches and the like used for packaging retort foods. Therefore, the heat-sealing film is required to have heat resistance that can withstand retort treatment (120 to 135 ° C.), and the resin forming the heat-sealing layer is required to have a melting point of 150 ° C. or higher. ..
　ポリエステル系フィルムの材料として一般的に用いられているポリエチレンテレフタレート（ＰＥＴ）樹脂は、ガラス転移温度（Ｔｇ）が７０℃、融点（Ｔｍ）が２５０℃と高く、さらに融解熱ΔＨが大きいため、溶融させるためには高温かつ長時間の加熱が必要とされるので、ヒートシール層を形成する材料としては適していない。また、エンジニアリングプラスチックとして広く用いられているポリブチレンテレフタレート（ＰＢＴ）樹脂は、ガラス転移温度（Ｔｇ）が４０℃、融点（Ｔｍ）が２２０℃とＰＥＴ樹脂よりも低いため、フィルム基材としてＰＥＴフィルムを用いたときのヒートシール層の材料として採用することも不可能ではないが、融解熱ΔＨが大きいため、ヒートシール層として実用化することは難しい。 Polyethylene terephthalate (PET) resin, which is generally used as a material for polyester films, has a high glass transition temperature (Tg) of 70 ° C., a melting point (Tm) of 250 ° C., and a large heat of fusion ΔH, so that it melts. It is not suitable as a material for forming a heat seal layer because it requires high temperature and long-time heating. Further, polybutylene terephthalate (PBT) resin, which is widely used as an engineering plastic, has a glass transition temperature (Tg) of 40 ° C. and a melting point (Tm) of 220 ° C., which are lower than those of PET resin. It is not impossible to use it as a material for the heat-sealing layer when the above-mentioned material is used, but it is difficult to put it into practical use as a heat-sealing layer because the heat of fusion ΔH is large.
　そこで、ＰＥＴやＰＢＴにイソフタル酸、アジピン酸、セバシン酸、ダイマー酸、１，４－シクロヘキサンジメタノール、ネオペンチルグリコール等を共重合したポリエステル系樹脂からなるヒートシール層に用いたヒートシール用フィルムが提案されている（例えば、特許文献１，２参照。）。さらに、これらの中には、ヒートシールした際のヒートシール強度が高くなる条件として、ガラス転移温度（Ｔｇ）、結晶融解熱を特定の範囲に設計することが提案されており、例えば、特許文献１には、溶融温度が１２５℃以上、ガラス転移温度（Ｔｇ）が４０℃以下、結晶融解熱が４ｃａｌ／ｇ以下の共重合樹脂からなるヒートシール層が開示されている。また、特許文献２には、結晶化熱（ΔＨ）が１０Ｊ／ｇ未満の非晶性ポリエステル共重合体または低結晶性ポリエステル共重合体からなるポリエステル系フィルムを積層した積層ポリエステルフィルムが提案されている。 Therefore, a heat-sealing film used for a heat-sealing layer made of a polyester-based resin obtained by copolymerizing PET or PBT with isophthalic acid, adipic acid, sebacic acid, dimer acid, 1,4-cyclohexanedimethanol, neopentyl glycol, etc. It has been proposed (see, for example, Patent Documents 1 and 2). Further, among these, it has been proposed to design the glass transition temperature (Tg) and the heat of crystal melting within a specific range as conditions for increasing the heat seal strength at the time of heat sealing. For example, Patent Documents No. 1 discloses a heat-sealed layer made of a copolymer resin having a melting temperature of 125 ° C. or higher, a glass transition temperature (Tg) of 40 ° C. or lower, and a crystal melting heat of 4 cal / g or lower. Further, Patent Document 2 proposes a laminated polyester film in which a polyester-based film composed of an amorphous polyester copolymer or a low-crystalline polyester copolymer having a crystallization heat (ΔH) of less than 10 J / g is laminated. There is.
　また、共重合成分として、ポリオキシアルキレングリコールを共重合したポリエステル樹脂からなる樹脂層を積層したフィルムも知られている（例えば、特許文献３，４参照。）。このポリエステル樹脂は、特許文献３および特許文献４に開示されているように、高融点結晶性セグメントと低融点非晶性セグメントからなるブロック共重合体であり、融点が１８０℃以上で、これをフィルム基材上に積層したヒートシール用フィルムは、レトルト温度に耐えることができる。 Further, as a copolymerization component, a film in which a resin layer made of a polyester resin copolymerized with polyoxyalkylene glycol is laminated is also known (see, for example, Patent Documents 3 and 4). As disclosed in Patent Documents 3 and 4, this polyester resin is a block copolymer composed of a high melting point crystalline segment and a low melting point amorphous segment, and has a melting point of 180 ° C. or higher. The heat-sealing film laminated on the film substrate can withstand the retort temperature.
特許第２７１４８６６号公報Japanese Patent No. 2714866 特許第３１３７４５０号公報Japanese Patent No. 3137450 特公昭５４－３４９８号公報Special Publication No. 54-3448 特公昭５５－１９２９号公報Special Publication No. 55-1929
　しかしながら、例えば特許文献１に開示されているように、ＰＥＴやＰＢＴにイソフタル酸、アジピン酸、セバシン酸、ダイマー酸を共重合して、結晶融解熱を４ｃａｌ／ｇ以下にした樹脂は、融点が１３２℃未満となるので、これをヒートシール層として用いたヒートシール用フィルムから作製した包装袋（パウチ）はレトルト処理に耐えられない。
　ヒートシール用フィルムの耐熱性を向上させるために、ヒートシール層を形成する樹脂におけるイソフタル酸、アジピン酸等の共重合比率を下げると、樹脂の融点は高くなるものの結晶融解熱も高くなるため、短い圧着時間ではヒートシール層を十分に溶融させることができずに、その結果、高いヒートシール強度を発現することができない、という問題がある。
　また、上述のように共重合成分としてポリオキシアルキレングリコールを共重合したポリエステルを用いたヒートシール層においては、１８０℃以上の融点が得られるので、これをフィルム基材に積層したヒートシール用フィルムはレトルト温度に耐えることができるが、やはり短い圧着時間では強いヒートシール強度が得られない。 However, as disclosed in Patent Document 1, for example, a resin obtained by copolymerizing PET or PBT with isophthalic acid, adipic acid, sebacic acid, or dimer acid to have a crystal melting heat of 4 cal / g or less has a melting point. Since the temperature is lower than 132 ° C., the packaging bag (pouch) made from the heat-sealing film using this as the heat-sealing layer cannot withstand the retort treatment.
If the copolymerization ratio of isophthalic acid, adipic acid, etc. in the resin forming the heat seal layer is lowered in order to improve the heat resistance of the heat seal film, the melting point of the resin will be higher, but the heat of crystal melting will also be higher. There is a problem that the heat seal layer cannot be sufficiently melted with a short crimping time, and as a result, high heat seal strength cannot be exhibited.
Further, as described above, in the heat-sealing layer using polyester copolymerized with polyoxyalkylene glycol as a copolymerization component, a melting point of 180 ° C. or higher can be obtained, and thus a heat-sealing film laminated on a film substrate. Can withstand retort temperatures, but again short crimping times do not provide strong heat seal strength.
　本発明は、上述の問題点を解決するものであり、リサイクル性に優れて環境負荷を低減させることが可能なヒートシール用フィルムであって、短い圧着時間で強いヒートシール強度が得られ、さらに、高温でのレトルト処理に耐える耐熱性を有するヒートシール用フィルムおよび包装材料を提供することを目的とする。 The present invention solves the above-mentioned problems, is a heat-sealing film having excellent recyclability and capable of reducing an environmental load, and can obtain strong heat-sealing strength in a short crimping time, and further. It is an object of the present invention to provide a heat-sealing film and a packaging material having heat resistance to withstand high-temperature retort treatment.
　本発明のヒートシール用フィルムは、基材層の片側あるいは両側にポリオキシアルキレングリコールをジオール成分として含む熱可塑性ポリエステル系樹脂を含有する熱可塑性ポリエステル系樹脂層が設けられたヒートシール用フィルムであって、
　前記熱可塑性ポリエステル系樹脂は、溶融後、２００℃／分で－５０℃まで急冷後、１０℃／分で昇温した時に観測されるガラス転移温度（Ｔｇ）が５０℃以下、１５０℃以上の融点（Ｔｍ）が観測され、かつ融解熱ΔＨが０Ｊ／ｇを超えて２０Ｊ／ｇ以下であるものであることを特徴とする。 The heat-sealing film of the present invention is a heat-sealing film provided with a thermoplastic polyester-based resin layer containing a thermoplastic polyester-based resin containing polyoxyalkylene glycol as a diol component on one side or both sides of the base material layer. hand,
The thermoplastic polyester resin has a glass transition temperature (Tg) of 50 ° C. or lower and 150 ° C. or higher, which is observed when the thermoplastic polyester resin is melted, rapidly cooled to −50 ° C. at 200 ° C./min, and then heated at 10 ° C./min. The melting point (Tm) is observed, and the heat of fusion ΔH is more than 0 J / g and 20 J / g or less.
　本発明のヒートシール用フィルムにおいては、前記熱可塑性ポリエステル系樹脂が、テレフタル酸を主なジカルボン酸成分として含み、エチレングリコールおよび／または１，４－テトラメチレングリコールを主なジオール成分として含むものであることが好ましい。
　また、本発明のヒートシール用フィルムにおいては、前記融解熱ΔＨが、０Ｊ／ｇを超えて１０Ｊ／ｇ以下であることが好ましい。
　また、本発明のヒートシール用フィルムにおいては、前記融解熱ΔＨが、０Ｊ／ｇを超えて５Ｊ／ｇ以下であることがさらに好ましい。
　また、本発明のヒートシール用フィルムにおいては、前記熱可塑性ポリエステル系樹脂が、テレフタル酸を主なジカルボン酸成分として含み、１，４－テトラメチレングリコールを主なジオール成分として含み、かつ、前記ポリオキシアルキレングリコールとしてポリテトラメチレングリコールをジオール成分として含む熱可塑性ポリエステル系樹脂であることが好ましい。
　また、本発明のヒートシール用フィルムにおいては、前記熱可塑性ポリエステル系樹脂中のポリテトラメチレングリコール成分の含有量が３０質量％以上、あるいは、前記熱可塑性ポリエステル系樹脂中のポリテトラメチレングリコール成分の含有量が１０質量％以上かつイソフタル酸成分の含有量が２０モル％以上であることが好ましい。
　また、本発明のヒートシール用フィルムにおいては、前記基材層が、ポリエチレンテレフタレート系フィルムおよび／またはポリブチレンテレフタレート系フィルムであることが好ましい。
　また、本発明のヒートシール用フィルムにおいては、前記基材層が、無延伸ポリブチレンテレフタレート系フィルムであることが好ましい。 In the heat-sealing film of the present invention, the thermoplastic polyester resin contains terephthalic acid as a main dicarboxylic acid component and ethylene glycol and / or 1,4-tetramethylene glycol as a main diol component. Is preferable.
Further, in the heat-sealing film of the present invention, it is preferable that the heat of fusion ΔH exceeds 0 J / g and is 10 J / g or less.
Further, in the heat-sealing film of the present invention, it is more preferable that the heat of fusion ΔH exceeds 0 J / g and is 5 J / g or less.
Further, in the heat-sealing film of the present invention, the thermoplastic polyester-based resin contains terephthalic acid as a main dicarboxylic acid component, 1,4-tetramethylene glycol as a main diol component, and the poly. A thermoplastic polyester-based resin containing polytetramethylene glycol as a diol component as the oxyalkylene glycol is preferable.
Further, in the heat-sealing film of the present invention, the content of the polytetramethylene glycol component in the thermoplastic polyester resin is 30% by mass or more, or the polytetramethylene glycol component in the thermoplastic polyester resin is It is preferable that the content is 10% by mass or more and the content of the isophthalic acid component is 20 mol% or more.
Further, in the heat-sealing film of the present invention, it is preferable that the base material layer is a polyethylene terephthalate film and / or a polybutylene terephthalate film.
Further, in the heat-sealing film of the present invention, it is preferable that the base material layer is a non-stretched polybutylene terephthalate film.
　本発明の包装材料は、上記のヒートシール用フィルムを含むことを特徴とする。
　本発明の包装材料は、包装袋、または、密封容器の蓋材である構成とすることができる。 The packaging material of the present invention is characterized by containing the above-mentioned heat-sealing film.
The packaging material of the present invention may be a packaging bag or a lid material for a sealed container.
　本発明のヒートシール用フィルムおよび包装材料によれば、基材層の片側あるいは両側に熱可塑性ポリエステル系樹脂層がヒートシール層として設けられていることによって、基材層をポリエステル系樹脂によって形成すればヒートシール用フィルム全体がポリエステル系樹脂を主材料として構成されることとなるので、容易に高品質のポリエステル系材料やポリエステル系製品に再生することができて優れたリサイクル性が得られ、その結果、環境負荷を低減させることができる。しかも、上記の熱可塑性ポリエステル系樹脂が、ポリオキシアルキレングリコールをジオール成分として含み、特定のガラス転移温度（Ｔｇ）、融点（Ｔｍ）および融解熱ΔＨを示すものであることによって、短い圧着時間で強いヒートシール強度が得られるとともに高温でのレトルト処理に耐える耐熱性が得られ、その結果、包装材料において内容物の漏洩の発生を防止することができる。 According to the heat-sealing film and packaging material of the present invention, the base material layer is formed of the polyester-based resin by providing the thermoplastic polyester-based resin layer as the heat-sealing layer on one side or both sides of the base material layer. For example, since the entire heat-sealing film is composed of polyester-based resin as the main material, it can be easily recycled into high-quality polyester-based materials and polyester-based products, and excellent recyclability can be obtained. As a result, the environmental load can be reduced. Moreover, since the above-mentioned thermoplastic polyester resin contains polyoxyalkylene glycol as a diol component and exhibits a specific glass transition temperature (Tg), melting point (Tm) and heat of melting ΔH, it takes a short crimping time. A strong heat seal strength can be obtained, and heat resistance that can withstand retort treatment at a high temperature can be obtained. As a result, leakage of contents can be prevented in the packaging material.
本発明の一実施形態に係る包装材料の製造工程を示す概略断面図である。It is the schematic sectional drawing which shows the manufacturing process of the packaging material which concerns on one Embodiment of this invention.
〔ヒートシール用フィルム〕
　本発明の一実施形態に係るヒートシール用フィルムは、図１に示すように、基材層１１の片側にポリオキシアルキレングリコールをジオール成分として含む熱可塑性ポリエステル系樹脂を含有するヒートシール層（熱可塑性ポリエステル系樹脂層）１２が設けられた積層フィルムである。 [Heat seal film]
As shown in FIG. 1, the heat-sealing film according to an embodiment of the present invention has a heat-sealing layer (heat) containing a thermoplastic polyester resin containing polyoxyalkylene glycol as a diol component on one side of the base material layer 11. It is a laminated film provided with a plastic polyester resin layer) 12.
〔ヒートシール層〕
　ヒートシール層１２は、ポリオキシアルキレングリコールをジオール成分として含み、溶融後、２００℃／分で－５０℃まで急冷後、１０℃／分で昇温した時に観測されるガラス転移温度（Ｔｇ）が５０℃以下、１５０℃以上の融点（Ｔｍ）が観測され、かつ融解熱ΔＨが０Ｊ／ｇを超えて２０Ｊ／ｇ以下である熱可塑性ポリエステル系樹脂（以下、「特定の熱可塑性ポリエステル系樹脂」ともいう。）を含有する。 [Heat seal layer]
The heat seal layer 12 contains a thermoplastic glycol as a diol component, and has a glass transition temperature (Tg) observed when the temperature is raised at 10 ° C./min after being rapidly cooled to −50 ° C. at 200 ° C./min after melting. A thermoplastic polyester resin having a melting point (Tm) of 50 ° C. or lower and 150 ° C. or higher and a heat of fusion ΔH of more than 0 J / g and 20 J / g or less (hereinafter, “specific thermoplastic polyester resin””. Also referred to as).
〔特定の熱可塑性ポリエステル系樹脂〕
　特定の熱可塑性ポリエステル系樹脂は、一般的にテレフタル酸等のジカルボン酸成分と、エチレングリコール、１，４－テトラメチレングリコール等のジオール成分、更に必要に応じて用いられるその他の成分とをエステル化反応および／またはエステル交換反応させた後、重縮合反応することにより得られるものである。
　特定の熱可塑性ポリエステル系樹脂にジオール成分として含まれるポリオキシアルキレングリコールは、エチレン、プロピレン、テトラメチレン（ブチレン）等がエーテル結合でつながったポリエーテルであり、具体的には、ポリエチレングリコール、ポリプロピレングリコール、ポリテトラメチレングリコール（ポリテトラメチレンエーテルグリコール）などが挙げられる。この中でもポリテトラメチレングリコールがジオール成分として含まれていることが好ましい。ポリオキシアルキレングリコールとしては、平均分子量が５００～２，０００のものが好ましく、特に好ましくは５００～１，０００のものである。ポリオキシアルキレングリコールの平均分子量が５００未満である場合は、熱可塑性ポリエステル系樹脂の融点が低くなって耐熱性が低下するおそれがある。一方、ポリオキシアルキレングリコールの平均分子量が２，０００を超える場合は、熱可塑性ポリエステル系樹脂の融点が高くなって短い圧着時間では十分なヒートシール強度が得にくくなる。 [Specific thermoplastic polyester resin]
Specific thermoplastic polyester resins generally esterify a dicarboxylic acid component such as terephthalic acid, a diol component such as ethylene glycol or 1,4-tetramethylene glycol, and other components used as needed. It is obtained by conducting a polycondensation reaction after a reaction and / or a transesterification reaction.
The polyoxyalkylene glycol contained as a diol component in a specific thermoplastic polyester resin is a polyether in which ethylene, propylene, tetramethylene (butylene) and the like are linked by an ether bond, and specifically, polyethylene glycol and polypropylene glycol. , Polytetramethylene glycol (polytetramethylene ether glycol) and the like. Among these, polytetramethylene glycol is preferably contained as a diol component. The polyoxyalkylene glycol preferably has an average molecular weight of 500 to 2,000, and particularly preferably 500 to 1,000. When the average molecular weight of the polyoxyalkylene glycol is less than 500, the melting point of the thermoplastic polyester resin may be lowered and the heat resistance may be lowered. On the other hand, when the average molecular weight of the polyoxyalkylene glycol exceeds 2,000, the melting point of the thermoplastic polyester resin becomes high, and it becomes difficult to obtain sufficient heat seal strength with a short crimping time.
　特定の熱可塑性ポリエステル系樹脂は、溶融後、２００℃／分で－５０℃まで急冷後、１０℃／分で昇温した時に観測されるガラス転移温度（Ｔｇ）が５０℃以下、１５０℃以上の融点（Ｔｍ）が観測され、かつ融解熱ΔＨが０Ｊ／ｇを超えて２０Ｊ／ｇ以下のものであり、好ましくは融解熱ΔＨが、１０Ｊ／ｇ以下、より好ましくは５Ｊ／ｇ以下のものである。ガラス転移温度（Ｔｇ）が５０℃を超える場合は、熱可塑性ポリエステル系樹脂が軟化しにくくなり、短い圧着時間では十分なヒートシール強度を得にくくなる。また、融点（Ｔｍ）が観測されない、すなわち融解熱ΔＨが０Ｊ／ｇである場合、あるいは融点（Ｔｍ）が１５０℃未満である場合は、この熱可塑性ポリエステル系樹脂をヒートシール層として用いたヒートシール用フィルムから作製したパウチが十分な耐熱性が得られずにレトルト処理に耐えられないおそれがある。さらに、融解熱ΔＨが２０Ｊ／ｇを超える場合は、熱可塑性ポリエステル系樹脂が溶融するまでに時間がかかるため、短い圧着時間では十分なヒートシール強度を得にくくなる。 The glass transition temperature (Tg) observed when a specific thermoplastic polyester resin is melted, rapidly cooled to -50 ° C at 200 ° C / min, and then heated at 10 ° C / min is 50 ° C or lower and 150 ° C or higher. The melting point (Tm) of the above is observed and the heat of fusion ΔH exceeds 0 J / g and is 20 J / g or less, preferably the heat of fusion ΔH is 10 J / g or less, more preferably 5 J / g or less. Is. When the glass transition temperature (Tg) exceeds 50 ° C., the thermoplastic polyester resin is difficult to soften, and it is difficult to obtain sufficient heat seal strength with a short crimping time. If no melting point (Tm) is observed, that is, if the heat of fusion ΔH is 0 J / g, or if the melting point (Tm) is less than 150 ° C., heat using this thermoplastic polyester resin as the heat seal layer. The pouch made from the sealing film may not have sufficient heat resistance and may not withstand the retort treatment. Further, when the heat of fusion ΔH exceeds 20 J / g, it takes time for the thermoplastic polyester resin to melt, so that it is difficult to obtain sufficient heat seal strength with a short crimping time.
　特定の熱可塑性ポリエステル系樹脂を形成するためのジカルボン酸成分およびジオール成分としては、ポリオキシアルキレングリコール成分以外の成分については、熱可塑性ポリエステル系樹脂が上記のガラス転移温度（Ｔｇ）、融点（Ｔｍ）および融解熱ΔＨの範囲となる成分であれば特に限定されないが、テレフタル酸を主なジカルボン酸成分として含み、エチレングリコールおよび／または１，４－テトラメチレングリコールを主なジオール成分として含むものが好ましい。テレフタル酸成分の含有量は、熱可塑性ポリエステル系樹脂の全ジカルボン酸成分の５０モル％以上であることが好ましく、特に好ましくは７０モル％以上である。テレフタル酸成分の含有量が５０モル％を下回る場合は、熱可塑性ポリエステル系樹脂の融点（Ｔｍ）が低下し、これを積層したヒートシール用フィルムをヒートシールして得られるパウチがレトルト処理に耐えられないものとなる。また、同様の理由で、エチレングリコールおよび１，４－テトラメチレングリコールの含有割合は、熱可塑性ポリエステル系樹脂の全ジオール成分を１００モル％とし、ポリオキシアルキレングリコールの割合をｘモル％としたとき、（１００－ｘ）モル％の７割以上であることが好ましい。さらに、エチレングリコールと１，４－テトラメチレングリコールは共存してもよいが、それらの割合は、得られる熱可塑性ポリエステル系樹脂が上述のガラス転移温度（Ｔｇ）、融点（Ｔｍ）および融解熱ΔＨの範囲を満たす範囲とされる。 As the dicarboxylic acid component and the diol component for forming a specific thermoplastic polyester-based resin, the thermoplastic polyester-based resin has the above-mentioned glass transition temperature (Tg) and melting point (Tm) for components other than the polyoxyalkylene glycol component. ) And heat of fusion ΔH are not particularly limited, but those containing terephthalic acid as a main dicarboxylic acid component and ethylene glycol and / or 1,4-tetramethylene glycol as a main diol component are used. preferable. The content of the terephthalic acid component is preferably 50 mol% or more, particularly preferably 70 mol% or more, of the total dicarboxylic acid component of the thermoplastic polyester resin. When the content of the terephthalic acid component is less than 50 mol%, the melting point (Tm) of the thermoplastic polyester resin decreases, and the pouch obtained by heat-sealing the laminated heat-sealing film withstands the retort treatment. It will not be possible. For the same reason, the content ratio of ethylene glycol and 1,4-tetramethylene glycol is when the total diol component of the thermoplastic polyester resin is 100 mol% and the ratio of polyoxyalkylene glycol is x mol%. , (100-x) is preferably 70% or more of mol%. Further, ethylene glycol and 1,4-tetramethylene glycol may coexist, but their proportions are such that the obtained thermoplastic polyester resin has the above-mentioned glass transition temperature (Tg), melting point (Tm) and heat of fusion ΔH. It is a range that satisfies the range of.
　特定の熱可塑性ポリエステル系樹脂を形成するための上述したポリオキシアルキレングリコール、テレフタル酸、エチレングリコールおよび／または１，４－テトラメチレングリコール以外の成分の例としては、イソフタル酸、２，６－ナフタレンジカルボン酸、ジフェニルジカルボン酸、ジフェニルスルホンジカルボン酸、ジフェノキシエタンジカルボン酸、ジフェニルエーテルジカルボン酸、５－スルホイソフタル酸、フタル酸等の芳香族ジカルボン酸、シュウ酸、コハク酸、アジピン酸、セバシン酸、ダイマー酸、マレイン酸、フマル酸等の脂肪族ジカルボン酸、シクロヘキサンジカルボン酸等の脂環族ジカルボン酸等のジカルボン酸成分、ジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、プロパンジオール、ブタンジオール、ペンタンジオール、ヘキサンジオール、ネオペンチルグリコール等の脂肪族グリコール、ビスフェノールＡ、ビスフェノールＳ等の芳香族グリコール、１，４－シクロヘキサンジメタノール等の脂環族グリコール等のジオール成分、トリメリット酸、ペンタエリスリトール等の多官能化合物成分が挙げられる。これらの成分は、１種単独で使用してもよいし、２種類以上を組み合わせて用いてもよく、これらを共重合することにより、得られる熱可塑性ポリエステル系樹脂の融点や結晶性、柔軟性を調整することができる。
　また、特定の熱可塑性ポリエステル系樹脂は、他の樹脂との接着性を向上させるため、無水マレイン酸等で変性したものであってもよい。 Examples of components other than the above-mentioned polyoxyalkylene glycol, terephthalic acid, ethylene glycol and / or 1,4-tetramethylene glycol for forming a specific thermoplastic polyester resin include isophthalic acid and 2,6-naphthalene. Aromatic dicarboxylic acids such as dicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyetanedicarboxylic acid, diphenyletherdicarboxylic acid, 5-sulfoisophthalic acid, phthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer Dicarboxylic acid components such as aliphatic dicarboxylic acids such as acids, maleic acids and fumaric acids, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acids, diethylene glycols, triethylene glycols, polyethylene glycols, propanediols, butanediols, pentanediols and hexanediols. , Aliper glycols such as neopentyl glycol, aromatic glycols such as bisphenol A and bisphenol S, diol components such as alicyclic glycols such as 1,4-cyclohexanedimethanol, and polyfunctional compounds such as trimellitic acid and pentaerythritol. Ingredients are mentioned. These components may be used alone or in combination of two or more, and the melting point, crystallinity, and flexibility of the thermoplastic polyester resin obtained by copolymerizing these components may be used. Can be adjusted.
Further, the specific thermoplastic polyester resin may be modified with maleic anhydride or the like in order to improve the adhesiveness with other resins.
　特定の熱可塑性ポリエステル系樹脂の好ましい樹脂組成としては、テレフタル酸を主なジカルボン酸成分とするとともに１，４－テトラメチレングリコールを主なジオール成分とし、ジオール成分として含むポリテトラメチレングリコール成分の含有量が３０質量％以上、あるいは、ポリテトラメチレングリコール成分の含有量が１０質量％以上かつイソフタル酸成分の含有量が２０モル％以上である組成である。イソフタル酸成分が含有されておらず、ポリテトラメチレングリコール成分の含有量が３０質量％未満である場合、あるいは、イソフタル酸成分が２０モル％以上含まれている場合であってもポリテトラメチレングリコール成分の含有量が１０質量％未満である場合、さらにポリテトラメチレングリコール成分の含有量が１０質量％以上、３０質量％未満であってイソフタル酸成分の含有量が２０モル％未満である場合は、いずれも、融解熱ΔＨが２０Ｊ／ｇを超える熱可塑性ポリエステル系樹脂となるため、樹脂が溶融するまでに時間を要し、短い圧着時間では十分なヒートシール強度を得にくくなる。 As a preferable resin composition of the specific thermoplastic polyester-based resin, a polytetramethylene glycol component containing terephthalic acid as a main dicarboxylic acid component and 1,4-tetramethylene glycol as a main diol component as a diol component is contained. The composition is such that the amount is 30% by mass or more, or the content of the polytetramethylene glycol component is 10% by mass or more and the content of the isophthalic acid component is 20 mol% or more. Polytetramethylene glycol even when the isophthalic acid component is not contained and the content of the polytetramethylene glycol component is less than 30% by mass, or even when the isophthalic acid component is contained in an amount of 20 mol% or more. When the content of the component is less than 10% by mass, and when the content of the polytetramethylene glycol component is 10% by mass or more and less than 30% by mass and the content of the isophthalic acid component is less than 20 mol%. In each case, since the heat of fusion ΔH is a thermoplastic polyester resin exceeding 20 J / g, it takes time for the resin to melt, and it is difficult to obtain sufficient heat seal strength with a short crimping time.
　特定の熱可塑性ポリエステル系樹脂は、サイズ排除クロマトグラフ法（ＳＥＣ）で求められるポリスチレン換算の重量平均分子量（Ｍｗ）が５０，０００～２００，０００であることが好ましく、７０，０００～１５０，０００であることがより好ましい。 The specific thermoplastic polyester resin preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 50,000 to 200,000, which is determined by a size exclusion chromatograph method (SEC), and is 70,000 to 150,000. Is more preferable.
　特定の熱可塑性ポリエステル系樹脂には、当該特定の熱可塑性ポリエステル系樹脂よりなるフィルムを重ね合わせた際にフィルム同士が固着することを防止するための滑材や他の樹脂、光安定剤、相溶化剤、可塑剤、帯電防止剤、反応触媒、着色防止剤、ラジカル禁止剤、帯電防止剤、末端封鎖剤、酸化防止剤、熱安定剤、離型剤、難燃剤、抗菌剤、抗黴剤等が添加されていてもよい。 A lubricant, other resin, a light stabilizer, and a phase for preventing the films from sticking to each other when the films made of the specific thermoplastic polyester resin are laminated on the specific thermoplastic polyester resin. Dissolving agents, plastics, antioxidants, reaction catalysts, anticoloring agents, radical banning agents, antistatic agents, terminal sequestering agents, antioxidants, heat stabilizers, mold release agents, flame retardants, antibacterial agents, anti-mold agents Etc. may be added.
　ヒートシール層（熱可塑性ポリエステル系樹脂層）１２は、上記の特定の熱可塑性ポリエステル系樹脂のみからなるものであってもよく、特定の熱可塑性ポリエステル系樹脂とその他の樹脂との混合物からなるものであってもよい。その他の樹脂としては、ポリブチレンテレフタレート（ＰＢＴ）樹脂等の熱可塑性ポリエステル系樹脂であることが好ましい。また、このその他の樹脂は、親水性シリカ等が混合された混合樹脂であってもよい。 The heat seal layer (thermoplastic polyester resin layer) 12 may be made of only the above-mentioned specific thermoplastic polyester resin, or may be made of a mixture of the specific thermoplastic polyester resin and other resins. It may be. As the other resin, a thermoplastic polyester resin such as polybutylene terephthalate (PBT) resin is preferable. Further, the other resin may be a mixed resin mixed with hydrophilic silica or the like.
〔基材層〕
　ヒートシール層１２とともにヒートシール用フィルム１０を構成する基材層１１としては、得られるヒートシール用フィルム１０に要求される引張強度や突き刺し強さ等の機械物性、耐熱性、耐薬品性などを満たすものであれば、特に限定されない。例えば、延伸ナイロン、延伸ポリエチレンテレフタレート、その他の樹脂、金属、紙等の材料よりなるものが挙げられる。さらに、リサイクル性を高める観点から、ポリエチレンテレフタレート系フィルム、ポリブチレンテレフタレート系フィルム等のポリエステル系フィルムを用いることが好ましく、より好ましくは無延伸ポリブチレンテレフタレート系フィルムである。さらに、これらのポリエステル系フィルムは、機械物性および耐熱性の観点から、ホモポリマー（ポリエチレンテレフタレート、ポリブチレンテレフタレート）からなるものであることが好ましく、イソフタル酸等のジカルボン酸や１，４－シクロヘキサンジメタノール、ネオペンチルグリコール等のジオール、トリメリット酸、ペンタエリスリトール等の多官能化合物等の共重合成分の含有量は最小限とすることが望ましい。
　また、基材層１１は、ヒートシールしたときに溶融しないよう、例えば２００℃以上の融点を有する材料よりなることが好ましい。 [Base layer]
The base material layer 11 constituting the heat-sealing film 10 together with the heat-sealing layer 12 has mechanical properties such as tensile strength and piercing strength required for the obtained heat-sealing film 10, heat resistance, chemical resistance, and the like. There is no particular limitation as long as it satisfies. For example, those made of stretched nylon, stretched polyethylene terephthalate, other resins, metals, paper and the like can be mentioned. Further, from the viewpoint of enhancing recyclability, it is preferable to use a polyester film such as a polyethylene terephthalate film or a polybutylene terephthalate film, and more preferably a non-stretched polybutylene terephthalate film. Further, these polyester-based films are preferably made of a homopolymer (polyethylene terephthalate, polybutylene terephthalate) from the viewpoint of mechanical properties and heat resistance, and are preferably a dicarboxylic acid such as isophthalic acid or 1,4-cyclohexanedi. It is desirable to minimize the content of copolymerization components such as diols such as methanol and neopentyl glycol, polyfunctional compounds such as trimellitic acid and pentaerythritol.
Further, the base material layer 11 is preferably made of a material having a melting point of, for example, 200 ° C. or higher so as not to melt when heat-sealed.
　基材層１１には、光安定剤、耐衝撃改良剤、相溶化剤、滑剤、可塑剤、帯電防止剤、反応触媒、着色防止剤、ラジカル禁止剤、帯電防止剤、末端封鎖剤、酸化防止剤、熱安定剤、離型剤、難燃剤、抗菌剤、抗黴剤等が添加されていてもよい。 The base material layer 11 contains a light stabilizer, an impact resistance improver, a compatibilizer, a lubricant, a plasticizer, an antistatic agent, a reaction catalyst, a color inhibitor, a radical inhibitor, an antistatic agent, a terminal sealant, and an antioxidant. Agents, heat stabilizers, mold release agents, flame retardants, antibacterial agents, antifungal agents and the like may be added.
　基材層１１とヒートシール層１２とを積層してヒートシール用フィルム１０を製造する方法は、特に限定されず、特定の熱可塑性ポリエステル系樹脂を溶剤に溶解した溶解液を基材層１１の片面あるいは両面の塗布した後に乾燥する方法、特定の熱可塑性ポリエステル系樹脂をフィルム状に成形し、接着剤等を用いて基材層１１と貼り合わせる方法、特定の熱可塑性ポリエステル系樹脂と基材層１１を形成するための樹脂とを別々の押出機に供給、溶融させた後、Ｔダイより共押出して積層する方法等が挙げられる。
　これらの中でも、溶剤や接着剤を必要とせず、フィルムを貼り合わせる工程も不要な共押出しによる方法が、環境負荷が少なく生産効率も高い観点から、特に好ましい。さらに、共押出による方法を用いる場合、基材層１１を形成する材料としてポリブチレンテレフタレート系樹脂を用いると、ヒートシール層１２を形成するための特定の熱可塑性ポリエステル系樹脂と共押出しした後、そのまま冷却、巻き取ることで、基材層１１が結晶化し、耐熱性および機械強度に優れるフィルムとなることから、更に好ましい。 The method for producing the heat-sealing film 10 by laminating the base material layer 11 and the heat-sealing layer 12 is not particularly limited, and a solution prepared by dissolving a specific thermoplastic polyester resin in a solvent is used as the base material layer 11. A method of applying one or both sides and then drying, a method of forming a specific thermoplastic polyester resin into a film and bonding it to the base material layer 11 using an adhesive or the like, a specific thermoplastic polyester resin and a base material Examples thereof include a method in which the resin for forming the layer 11 is supplied to separate extruders, melted, and then co-extruded from a T-die for laminating.
Among these, the coextrusion method, which does not require a solvent or an adhesive and does not require a step of bonding films, is particularly preferable from the viewpoint of low environmental load and high production efficiency. Further, when the coextrusion method is used, if a polybutylene terephthalate resin is used as the material for forming the base material layer 11, it is coextruded with a specific thermoplastic polyester resin for forming the heat seal layer 12, and then coextruded. By cooling and winding the film as it is, the base material layer 11 is crystallized to form a film having excellent heat resistance and mechanical strength, which is more preferable.
〔包装材料〕
　本発明の包装材料は、上記のヒートシール用フィルム１０を含む包装材料である。具体的には、レトルトパウチ等の包装袋や、密封容器を形成するための、容器本体の開口部を塞ぐための蓋材などが挙げられる。
　包装袋は、例えば図１に示されるように、ヒートシール用フィルム１０および別のヒートシール用フィルム１０’を、ヒートシール層１２およびヒートシール層１２’同士が対向するよう重ね合わせ、外側（基材層１１および基材層１１’側）から、袋状をなすよう周囲をヒートシーラー１３によって加熱圧着することによって、ヒートシール層１２およびヒートシール層１２’が溶融接着（ヒートシール）される。このように２枚のヒートシール用フィルム１０，１０’の周囲を接着することにより内容物を密封するための包装材料を作製することができる。ヒートシーラー１３による加熱温度は例えば１６０～２１０℃であり、圧着する圧力は例えば０．１～１ＭＰａであり、圧着時間は例えば０．１～３秒間である。
　ヒートシール用フィルム１０を蓋材として用いた密封容器は、容器本体に内容物を収容し、容器本体の開口部の縁フランジ上にヒートシール用フィルム１０をヒートシール層１２がこの縁フランジに接触する状態で配置して加熱圧着することにより、ヒートシール用フィルム１０がヒートシールされ、これにより内容物を密封することができる。このような密封容器の容器本体は、リサイクル性の観点から、例えばＰＥＴ等のポリエステル系樹脂よりなるものであることが好ましい。 [Packaging material]
The packaging material of the present invention is a packaging material containing the above-mentioned heat-sealing film 10. Specific examples thereof include a packaging bag such as a retort pouch, and a lid material for closing an opening of a container body for forming a sealed container.
In the packaging bag, for example, as shown in FIG. 1, the heat-sealing film 10 and another heat-sealing film 10'are overlapped so that the heat-sealing layer 12 and the heat-sealing layer 12' face each other, and the outer side (base) is formed. The heat seal layer 12 and the heat seal layer 12'are melt-bonded (heat-sealed) from the material layer 11 and the base material layer 11'side) by heat-pressing the periphery with a heat sealer 13 so as to form a bag. By adhering the periphery of the two heat-sealing films 10 and 10'in this way, a packaging material for sealing the contents can be produced. The heating temperature by the heat sealer 13 is, for example, 160 to 210 ° C., the pressure for crimping is, for example, 0.1 to 1 MPa, and the crimping time is, for example, 0.1 to 3 seconds.
In a sealed container using the heat-sealing film 10 as a lid material, the contents are housed in the container body, and the heat-sealing film 10 is placed on the edge flange of the opening of the container body, and the heat-sealing layer 12 contacts the edge flange. The heat-sealing film 10 is heat-sealed by arranging and heat-pressing the film 10 in a state of being heat-sealed, whereby the contents can be sealed. From the viewpoint of recyclability, the container body of such a sealed container is preferably made of a polyester resin such as PET.
　以上、本発明の実施形態を詳述したが、本発明は上記実施形態に限定されるものではなく、請求の範囲に記載された本発明を逸脱することなく種々の設計変更を行なうことが可能である。
　例えば、本発明のヒートシール用フィルムは、基材層の片側のみにヒートシール層が設けられた構成に限定されず、基材層の両側にヒートシール層が設けられた構成を有していてもよい。
　また例えば、本発明のヒートシール用フィルムは、ヒートシール層と基材層との間に適宜のバリア層等の中間層が介在されたものであってもよい。
　さらに、本発明のヒートシール用フィルムは、基材層の片側にヒートシール層が設けられ、その反対側には印刷層やバリア層などが設けられた構成を有していてもよい。 Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various design changes can be made without departing from the present invention described in the claims. Is.
For example, the heat-sealing film of the present invention is not limited to a structure in which a heat-sealing layer is provided on only one side of the base material layer, and has a structure in which heat-sealing layers are provided on both sides of the base material layer. May be good.
Further, for example, the heat-sealing film of the present invention may have an intermediate layer such as an appropriate barrier layer interposed between the heat-sealing layer and the base material layer.
Further, the heat-sealing film of the present invention may have a structure in which a heat-sealing layer is provided on one side of the base material layer, and a printing layer, a barrier layer, or the like is provided on the other side.
　以下、本発明の具体的な実施例について説明するが、本発明はこれらに限定されるものではない。
　以下の実施例および比較例における、熱可塑性ポリエステル系樹脂の樹脂組成の分析方法、ガラス転移温度（Ｔｇ）、融点（Ｔｍ）、融解熱（ΔＨ）の測定方法、ヒートシール用フィルムのヒートシール強度の測定方法、包装材料の耐熱性の測定方法は、以下のとおりである。 Specific examples of the present invention will be described below, but the present invention is not limited thereto.
Method for analyzing resin composition of thermoplastic polyester resin, method for measuring glass transition temperature (Tg), melting point (Tm), heat of fusion (ΔH), heat-sealing strength of heat-sealing film in the following Examples and Comparative Examples. The method for measuring the heat resistance of the packaging material and the method for measuring the heat resistance of the packaging material are as follows.
＜熱可塑性ポリエステル系樹脂の樹脂組成＞
　熱可塑性ポリエステル系樹脂を重トリフルオロ酢酸に溶解し、さらに重クロロホルム（トリメチルシラン０．１質量％含有）によって希釈し、核磁気共鳴分析装置（商品名「ＪＮＭ－ＥＣＺ４００Ｓ」、日本電子社製）を用いて、プロトンＮＭＲスペクトルを測定することにより、樹脂組成を分析して算出した。 <Resin composition of thermoplastic polyester resin>
Thermoplastic polyester resin is dissolved in deuterated trifluoroacetic acid, further diluted with deuterated chloroform (containing 0.1% by mass of trimethylsilane), and nuclear magnetic resonance analyzer (trade name "JNM-ECZ400S", manufactured by JEOL Ltd.). The resin composition was analyzed and calculated by measuring the proton NMR spectrum using.
＜熱可塑性ポリエステル系樹脂のガラス転移温度（Ｔｇ）、融点（Ｔｍ）、融解熱ΔＨ＞
　示差走査熱量計（商品名「ＤＳＣ８５００」、パーキンエルマー社製）を用いて、熱可塑性ポリエステル系樹脂の融点を超える温度（２００～２５０℃）で溶融後、２００℃／分で－５０℃まで冷却する。そして、－５０℃から熱可塑性ポリエステル系樹脂の融点を超える温度（２００～２５０）℃まで１０℃／分で昇温したときに観測されるガラス転移の補外開始温度をガラス転移温度（Ｔｇ）とし、融解ピークのピークトップの温度を融点（Ｔｍ）とし、融解ピークとベースラインとによって囲まれた部分の面積から融解熱ΔＨを求めた。 <Glass transition temperature (Tg), melting point (Tm), heat of fusion ΔH of thermoplastic polyester resin>
Using a differential scanning calorimeter (trade name "DSC8500", manufactured by PerkinElmer), melt at a temperature (200 to 250 ° C) that exceeds the melting point of the thermoplastic polyester resin, and then cool to -50 ° C at 200 ° C / min. do. Then, the glass transition start temperature (Tg) is the temperature at which the glass transition is observed when the temperature is raised from −50 ° C. to a temperature (200 to 250) ° C. that exceeds the melting point of the thermoplastic polyester resin at 10 ° C./min. The temperature of the peak top of the melting peak was defined as the melting point (Tm), and the heat of fusion ΔH was obtained from the area of the portion surrounded by the melting peak and the baseline.
＜ヒートシール用フィルムのヒートシール強度＞
　ヒートシール用フィルムから２０ｍｍ×８０ｍｍに切り出した２枚を、熱可塑性ポリエステル系樹脂を含有する樹脂層同士が対向する状態に重ねた。そして、ヒートシーラーによって、シール幅１０ｍｍ、シール温度２１０℃（片面）、シール圧０．３ＭＰａにて１秒間圧着することによりヒートシールした。次いで、ＪＩＳ　Ｚ１７０７（食品包装用プラスチックフィルム通則　７．５　ヒートシール強さ試験）に基づき、ヒートシールしたヒートシール用フィルムから、ヒートシール部（長さ１０ｍｍ）とヒートシールされていない非シール部（長さ７０ｍｍ）からなる、長さ８０ｍｍ、幅１５ｍｍの試験片を切り取った。そして、この試験片を、ヒートシール部を中央にして、１８０°に開き、その両端を引張試験機の両つかみ部に取り付け、速度３００ｍｍ／分でヒートシール部が破断するまで引っ張った際の最大荷重を求めた。 <Heat seal strength of heat seal film>
Two sheets cut out from the heat-sealing film to a size of 20 mm × 80 mm were stacked so that the resin layers containing the thermoplastic polyester-based resin faced each other. Then, heat-sealed by heat-sealing with a heat sealer at a sealing width of 10 mm, a sealing temperature of 210 ° C. (one side), and a sealing pressure of 0.3 MPa for 1 second. Next, based on JIS Z1707 (Plastic film for food packaging general rule 7.5 heat seal strength test), from the heat seal film for heat seal, the heat seal part (length 10 mm) and the non-heat seal part (length 10 mm) and the non-heat seal part (length 10 mm) are not heat-sealed. A test piece having a length of 80 mm and a width of 15 mm, which had a length of 70 mm), was cut out. Then, this test piece is opened at 180 ° with the heat-sealed portion in the center, both ends thereof are attached to both grips of the tensile tester, and the maximum when the test piece is pulled at a speed of 300 mm / min until the heat-sealed portion breaks. The load was calculated.
＜耐熱性＞
　ヒートシール用フィルムから１４０ｍｍ×１７０ｍｍに切り出した２枚を、熱可塑性ポリエステル系樹脂を含有する樹脂層同士が対向する状態に重ねた。次いで、３辺をヒートシーラーによって、シール幅５ｍｍ、シール温度２１０℃（片面）、シール圧０．３ＭＰａにて１秒間圧着することによりヒートシールして包装袋を作製した。この包装袋の開口部より水を２００ｇ入れた後、開口部を同様にヒートシールして密封した後、レトルト釜にて１２７℃で３０分間レトルト処理を行った。この時、ヒートシール部の剥離による内容物（水）の漏洩の有無および外観を、下記の評価基準に従って評価した。
－評価基準－
　〇：内容物の漏洩なし、外観変化なし
　△：内容物の漏洩なし、外観変化あり
　×：内容物の漏洩あり
　－：評価実施できず <Heat resistance>
Two sheets cut out from the heat-sealing film to a size of 140 mm × 170 mm were stacked so that the resin layers containing the thermoplastic polyester-based resin faced each other. Next, the three sides were heat-sealed with a heat sealer at a sealing width of 5 mm, a sealing temperature of 210 ° C. (one side), and a sealing pressure of 0.3 MPa for 1 second to prepare a packaging bag. After 200 g of water was put through the opening of the packaging bag, the opening was similarly heat-sealed and sealed, and then retort-treated at 127 ° C. for 30 minutes in a retort kettle. At this time, the presence or absence of leakage of the contents (water) due to the peeling of the heat seal portion and the appearance were evaluated according to the following evaluation criteria.
-Evaluation criteria-
〇: No leakage of contents, no change in appearance △: No leakage of contents, change in appearance ×: Leakage of contents-: Evaluation cannot be performed
〔実施例１〕
　熱可塑性ポリエステル系樹脂〔Ｐ１〕（商品名「ハイトレル２５５１」、東レ・デュポン株式会社製）を二軸押出機のホッパーから供給し、２７０℃で溶融し、Ｔダイにより膜状に押出してキャストロールで冷却固化することで、厚さ４０μｍのフィルムを製造した。このフィルムに接着剤（主剤：タケラックＡ－３１５、硬化剤：タケネートＡ－５０、いずれも三井化学社製）を塗布後、厚さ３４μｍの二軸延伸ポリエチレンテレフタレート（ＰＥＴ）フィルムに接着し、３７℃で５日間以上静置することにより硬化させ、ヒートシール用フィルムを作製した。熱可塑性ポリエステル系樹脂〔Ｐ１〕は、ポリオキシアルキレングリコールであるポリテトラメチレングリコール成分が含まれ、ガラス転移温度（Ｔｇ）が－３℃、融点（Ｔｍ）が１５８℃、融解熱ΔＨが０．３Ｊ／ｇであった。この熱可塑性ポリエステル系樹脂〔Ｐ１〕の樹脂組成は、表１に記載のとおりであった。このヒートシール用フィルムのヒートシール強度は４４．８（Ｎ／１５ｍｍ）と良好であった。また、このヒートシール用フィルムを用いて作製した包装袋は、レトルト処理後の内容物の漏洩もなく、良好な耐熱性が得られた。 [Example 1]
Thermoplastic polyester resin [P1] (trade name "Hitrel 2551", manufactured by Toray DuPont Co., Ltd.) is supplied from the hopper of a twin-screw extruder, melted at 270 ° C., extruded into a film by a T-die, and cast roll. A film having a thickness of 40 μm was produced by cooling and solidifying with. An adhesive (main agent: Takelac A-315, curing agent: Takenate A-50, both manufactured by Mitsui Chemicals, Inc.) was applied to this film, and then adhered to a 34 μm-thick biaxially stretched polyethylene terephthalate (PET) film. The film was cured by allowing it to stand at ° C. for 5 days or more to prepare a heat-sealing film. The thermoplastic polyester resin [P1] contains a polytetramethylene glycol component which is a polyoxyalkylene glycol, has a glass transition temperature (Tg) of -3 ° C, a melting point (Tm) of 158 ° C, and a heat of fusion ΔH of 0. It was 3 J / g. The resin composition of this thermoplastic polyester resin [P1] is as shown in Table 1. The heat seal strength of this heat seal film was as good as 44.8 (N / 15 mm). Further, the packaging bag produced by using this heat-sealing film did not leak the contents after the retort treatment, and good heat resistance was obtained.
〔実施例２，３〕
　実施例１において、熱可塑性ポリエステル系樹脂〔Ｐ１〕の代わりに熱可塑性ポリエステル系樹脂〔Ｐ２〕（商品名「ハイトレル４０５７Ｎ」、東レ・デュポン株式会社製）、または熱可塑性ポリエステル系樹脂〔Ｐ３〕（商品名「モディックＧＱ４３０」、三菱化学株式会社製）を用い、いずれも、Ｔダイにより膜状に押出す際の溶融温度を２００℃としたこと以外は実施例１と同様にしてヒートシール用フィルムをそれぞれ作製した。これらの熱可塑性ポリエステル系樹脂〔Ｐ２〕，〔Ｐ３〕の樹脂組成は、表１に記載のとおり、ポリテトラメチレングリコール成分が含まれ、ガラス転移温度（Ｔｇ）が５０℃以下、１５０℃以上の融点（Ｔｍ）が観測され、融解熱ΔＨが２０Ｊ／ｇ以下であった。また、これらのヒートシール用フィルムのヒートシール強度は表１に示すようにいずれも高い値を示し、良好なヒートシール強度が得られることが確認された。さらに、これらのヒートシール用フィルムを用いて作製した包装袋は、いずれも、レトルト処理後の内容物の漏洩もなく、良好な耐熱性が得られた。 [Examples 2 and 3]
In Example 1, instead of the thermoplastic polyester resin [P1], the thermoplastic polyester resin [P2] (trade name "Hytrel 4057N", manufactured by Toray DuPont Co., Ltd.) or the thermoplastic polyester resin [P3] ( A heat-sealing film similar to Example 1 except that the product name "Modic GQ430" (manufactured by Mitsubishi Chemical Corporation) was used and the melting temperature when extruded into a film by a T-die was set to 200 ° C. Were prepared respectively. As shown in Table 1, the resin compositions of these thermoplastic polyester resins [P2] and [P3] contain a polytetramethylene glycol component and have a glass transition temperature (Tg) of 50 ° C. or lower and 150 ° C. or higher. The melting point (Tm) was observed, and the heat of fusion ΔH was 20 J / g or less. Further, as shown in Table 1, the heat-sealing strengths of these heat-sealing films all showed high values, and it was confirmed that good heat-sealing strength could be obtained. Further, all of the packaging bags produced by using these heat-sealing films did not leak the contents after the retort treatment, and good heat resistance was obtained.
〔比較例１，２〕
　実施例１において、熱可塑性ポリエステル系樹脂〔Ｐ１〕の代わりに熱可塑性ポリエステル系樹脂〔Ｐ４〕（商品名「ハイトレル７２４７」、東レ・デュポン株式会社製）、または熱可塑性ポリエステル系樹脂〔Ｐ５〕（商品名「ノバデュラン５５１０Ｓ」、三菱エンジニアリングプラスチックス株式会社製）を用いたこと以外は実施例１と同様にしてヒートシール用フィルムをそれぞれ作製した。これらの熱可塑性ポリエステル系樹脂〔Ｐ４〕，〔Ｐ５〕の樹脂組成は、表１に記載のとおり、ポリテトラメチレングリコール成分が含まれ、ガラス転移温度（Ｔｇ）が５０℃以下であって１５０℃以上の融点（Ｔｍ）が観測されたが、融解熱ΔＨが２０Ｊ／ｇを超えていた。また、これらのヒートシール用フィルムのヒートシール強度は表１に示すようにいずれも極めて低い値を示し、良好なヒートシール強度は得られないことが確認された。 [Comparative Examples 1 and 2]
In Example 1, instead of the thermoplastic polyester resin [P1], the thermoplastic polyester resin [P4] (trade name "Hytrel 7247", manufactured by Toray DuPont Co., Ltd.) or the thermoplastic polyester resin [P5] ( A heat-sealing film was produced in the same manner as in Example 1 except that the trade name "Novaduran 5510S" (manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was used. As shown in Table 1, the resin compositions of these thermoplastic polyester resins [P4] and [P5] contain a polytetramethylene glycol component and have a glass transition temperature (Tg) of 50 ° C. or lower and 150 ° C. The above melting point (Tm) was observed, but the heat of fusion ΔH exceeded 20 J / g. Further, as shown in Table 1, the heat-sealing strengths of these heat-sealing films all showed extremely low values, and it was confirmed that good heat-sealing strength could not be obtained.
〔比較例３〕
　実施例２において、熱可塑性ポリエステル系樹脂〔Ｐ２〕の代わりに熱可塑性ポリエステル系樹脂〔Ｐ６〕（商品名「６００ＬＰ」、三菱化学株式会社製）を用いたこと以外は実施例２と同様にしてヒートシール用フィルムを作製した。この熱可塑性ポリエステル系樹脂〔Ｐ６〕の樹脂組成は、表１に記載のとおり、ポリテトラメチレングリコール成分を含まず、イソフタル酸成分を３０モル％含有する共重合ポリブチレンテレフタレート（ＰＢＴ）であった。この熱可塑性ポリエステル系樹脂〔Ｐ６〕の融解熱ΔＨは３０Ｊ／ｇであって２０Ｊ／ｇを超えていた。また、ヒートシール用フィルムのヒートシール強度は表１に示すように低い値を示し、良好なヒートシール強度は得られないことが確認された。 [Comparative Example 3]
In the second embodiment, the same as in the second embodiment except that the thermoplastic polyester resin [P6] (trade name “600LP”, manufactured by Mitsubishi Chemical Corporation) was used instead of the thermoplastic polyester resin [P2]. A film for heat sealing was produced. As shown in Table 1, the resin composition of this thermoplastic polyester resin [P6] was a copolymerized polybutylene terephthalate (PBT) containing 30 mol% of an isophthalic acid component without containing a polytetramethylene glycol component. .. The heat of fusion ΔH of this thermoplastic polyester resin [P6] was 30 J / g, which exceeded 20 J / g. Further, the heat seal strength of the heat seal film showed a low value as shown in Table 1, and it was confirmed that a good heat seal strength could not be obtained.
〔比較例４〕
　実施例１において、熱可塑性ポリエステル系樹脂〔Ｐ１〕の代わりに熱可塑性ポリエステル系樹脂〔Ｐ７〕（商品名「ＰＥＴＧ」、イーストマンケミカル社製）を用いたこと以外は実施例１と同様にしてヒートシール用フィルムを作製した。この熱可塑性ポリエステル系樹脂〔Ｐ７〕の樹脂組成は、表１に記載のとおり、ポリテトラメチレングリコール成分を含まず、１，４－シクロヘキサンジメタノール（ＣＨＤＭ）を３３モル％含有する共重合ポリエチレンテレフタレート（ＰＥＴ）であった。この熱可塑性ポリエステル系樹脂〔Ｐ７〕のガラス転移温度（Ｔｇ）は７０℃であって５０℃を超えており、融点（Ｔｍ）は観測されず、融解熱ΔＨは０Ｊ／ｇであった。また、ヒートシール用フィルムのヒートシール強度は表１に示すように低い値を示し、良好なヒートシール強度は得られないことが確認された。さらに、このヒートシール用フィルムを用いて作製した包装袋は、レトルト処理後の内容物の漏洩が発生し、良好な耐熱性が得られないことが確認された。 [Comparative Example 4]
In the first embodiment, the same as in the first embodiment except that the thermoplastic polyester resin [P7] (trade name “PETG”, manufactured by Eastman Chemical Company) was used instead of the thermoplastic polyester resin [P1]. A film for heat sealing was produced. As shown in Table 1, the resin composition of this thermoplastic polyester resin [P7] is a copolymerized polyethylene terephthalate containing 33 mol% of 1,4-cyclohexanedimethanol (CHDM) without containing a polytetramethylene glycol component. It was (PET). The glass transition temperature (Tg) of this thermoplastic polyester resin [P7] was 70 ° C. and exceeded 50 ° C., no melting point (Tm) was observed, and the heat of fusion ΔH was 0 J / g. Further, the heat seal strength of the heat seal film showed a low value as shown in Table 1, and it was confirmed that a good heat seal strength could not be obtained. Further, it was confirmed that the packaging bag produced by using this heat-sealing film leaked the contents after the retort treatment, and good heat resistance could not be obtained.
〔実施例４〕
　熱可塑性ポリエステル系樹脂〔Ｐ３〕８０質量部と、ポリブチレンテレフタレート（ＰＢＴ）樹脂に親水性シリカを５質量％混合した混合樹脂〔Ｂ１〕２０質量部とを、二軸押出機Ａのホッパーから供給し、２４５～２４０℃で溶融した。さらにＰＢＴ樹脂〔Ｃ１〕（商品名「１１００－２１１Ｓ」、長春社製）を二軸押出機Ｂのホッパーから供給し、２７０～２６０℃で溶融混練した。これらの二軸押出機Ａ、Ｂから押出された樹脂をマルチマニフォールドＴダイに供給し、膜状に押出してキャストロールで冷却固化することにより、厚さ７５μｍのヒートシール用フィルムを製造した。このヒートシール用フィルムの、熱可塑性ポリエステル系樹脂〔Ｐ３〕及び親水性シリカが混合された混合樹脂〔Ｂ１〕がブレンドされた樹脂層（熱可塑性ポリエステル系樹脂層）と、ＰＢＴ樹脂〔Ｃ１〕による層（基材層）の厚さ比率は１：２であった。このヒートシール用フィルムのヒートシール強度は表２に示すように高い値を示し、良好なヒートシール強度が得られることが確認された。さらに、これらのヒートシール用フィルムを用いて作製した包装袋は、レトルト処理後の内容物の漏洩もなく、良好な耐熱性が得られた。 [Example 4]
80 parts by mass of a thermoplastic polyester resin [P3] and 20 parts by mass of a mixed resin [B1] obtained by mixing 5% by mass of hydrophilic silica with polybutylene terephthalate (PBT) resin are supplied from the hopper of the twin-screw extruder A. Then, it melted at 245 to 240 ° C. Further, PBT resin [C1] (trade name “1100-211S”, manufactured by Choharu Co., Ltd.) was supplied from the hopper of the twin-screw extruder B and melt-kneaded at 270 to 260 ° C. The resin extruded from these twin-screw extruders A and B was supplied to a multi-manifold T-die, extruded into a film, and cooled and solidified by a cast roll to produce a heat-sealing film having a thickness of 75 μm. The heat-sealing film is made of a resin layer (thermoplastic polyester-based resin layer) in which a thermoplastic polyester-based resin [P3] and a mixed resin [B1] in which hydrophilic silica is mixed are blended, and a PBT resin [C1]. The thickness ratio of the layer (base material layer) was 1: 2. The heat seal strength of this heat seal film showed a high value as shown in Table 2, and it was confirmed that a good heat seal strength could be obtained. Further, the packaging bag produced by using these heat-sealing films did not leak the contents after the retort treatment, and good heat resistance was obtained.
〔実施例５〕
　熱可塑性ポリエステル系樹脂〔Ｐ３〕８０質量部と、ポリブチレンテレフタレート（ＰＢＴ）樹脂に親水性シリカを５質量％混合した混合樹脂〔Ｂ１〕２０質量部とを、二軸押出機Ａのホッパーから供給し、２４５～２４０℃で溶融した。さらにイソフタル酸を２モル％共重合したＰＥＴ樹脂〔Ｃ２〕（商品名「ＢＫ６１８０」、三菱ケミカル株式会社製）を二軸押出機Ｂのホッパーから供給し、２７０℃で溶融混練した。これらの二軸押出機Ａ、Ｂから押出された樹脂をマルチマニフォールドＴダイに供給し、膜状に押出してキャストロールで冷却固化することにより、厚さ７５μｍのヒートシール用フィルムを製造した。このヒートシール用フィルムの、熱可塑性ポリエステル系樹脂〔Ｐ３〕及び親水性シリカが混合された混合樹脂〔Ｂ１〕がブレンドされた樹脂層（熱可塑性ポリエステル系樹脂層）と、ＰＥＴ樹脂〔Ｃ２〕による層（基材層）の厚さ比率は１：２であった。このヒートシール用フィルムのヒートシール強度は表２に示すように高い値を示し、良好なヒートシール強度が得られることが確認された。さらに、これらのヒートシール用フィルムを用いて作製した包装袋は、レトルト処理後の内容物の漏洩はなく実用性に問題はないが、外観に変化（フィルムの変形）が観察された。 [Example 5]
80 parts by mass of a thermoplastic polyester resin [P3] and 20 parts by mass of a mixed resin [B1] obtained by mixing 5% by mass of hydrophilic silica with polybutylene terephthalate (PBT) resin are supplied from the hopper of the twin-screw extruder A. Then, it melted at 245 to 240 ° C. Further, a PET resin [C2] (trade name “BK6180”, manufactured by Mitsubishi Chemical Corporation) in which 2 mol% of isophthalic acid was copolymerized was supplied from the hopper of the twin-screw extruder B and melt-kneaded at 270 ° C. The resin extruded from these twin-screw extruders A and B was supplied to a multi-manifold T-die, extruded into a film, and cooled and solidified by a cast roll to produce a heat-sealing film having a thickness of 75 μm. The heat-sealing film is made of a resin layer (thermoplastic polyester-based resin layer) in which a thermoplastic polyester-based resin [P3] and a mixed resin [B1] in which hydrophilic silica is mixed are blended, and a PET resin [C2]. The thickness ratio of the layer (base material layer) was 1: 2. The heat seal strength of this heat seal film showed a high value as shown in Table 2, and it was confirmed that a good heat seal strength could be obtained. Further, in the packaging bag produced by using these heat-sealing films, there was no leakage of the contents after the retort treatment and there was no problem in practicality, but a change in appearance (deformation of the film) was observed.
　下記表１において、「ＴＡ」はテレフタル酸、「ＩＡ」はイソフタル酸、「ＥＧ」はエチレングリコール、「ＢＧ」は１，４－テトラメチレングリコール、「ＣＨＤＭ」は１，４－シクロヘキサンジメタノール、「ＰＴＭＧ」はポリテトラメチレングリコールを示す。 In Table 1 below, "TA" is terephthalic acid, "IA" is isophthalic acid, "EG" is ethylene glycol, "BG" is 1,4-tetramethylene glycol, and "CHDM" is 1,4-cyclohexanedimethanol. "PTMG" indicates polytetramethylene glycol.

 
Figure JPOXMLDOC01-appb-T000001
 
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
１０、１０’・・・　ヒートシール用フィルム
１１、１１’・・・　基材層
１２、１２’・・・　ヒートシール層（熱可塑性ポリエステル系樹脂層）
１３　　　　・・・　ヒートシーラー
 
  10, 10'... Heat sealing film 11, 11'... Base material layer 12, 12'... Heat sealing layer (thermoplastic polyester resin layer)
13 ・ ・ ・ Heat sealer

Claims (10)

  1. 　基材層の片側あるいは両側にポリオキシアルキレングリコールをジオール成分として含む熱可塑性ポリエステル系樹脂を含有する熱可塑性ポリエステル系樹脂層が設けられたヒートシール用フィルムであって、
    　前記熱可塑性ポリエステル系樹脂は、溶融後、２００℃／分で－５０℃まで急冷後、１０℃／分で昇温した時に観測されるガラス転移温度（Ｔｇ）が５０℃以下、１５０℃以上の融点（Ｔｍ）が観測され、かつ融解熱ΔＨが０Ｊ／ｇを超えて２０Ｊ／ｇ以下であるものであることを特徴とするヒートシール用フィルム。     A heat-sealing film provided with a thermoplastic polyester-based resin layer containing a thermoplastic polyester-based resin containing polyoxyalkylene glycol as a diol component on one side or both sides of the base material layer.
    The thermoplastic polyester resin has a glass transition temperature (Tg) of 50 ° C. or lower and 150 ° C. or higher, which is observed when the thermoplastic polyester resin is melted, rapidly cooled to −50 ° C. at 200 ° C./min, and then heated at 10 ° C./min. A heat-sealing film characterized in that a melting point (Tm) is observed and the heat of fusion ΔH exceeds 0 J / g and is 20 J / g or less.
  2. 　前記熱可塑性ポリエステル系樹脂が、テレフタル酸を主なジカルボン酸成分として含み、エチレングリコールおよび／または１，４－テトラメチレングリコールを主なジオール成分として含むものであることを特徴とする請求項１に記載のヒートシール用フィルム。 The first aspect of claim 1, wherein the thermoplastic polyester resin contains terephthalic acid as a main dicarboxylic acid component and ethylene glycol and / or 1,4-tetramethylene glycol as a main diol component. Film for heat sealing.
  3. 　前記融解熱ΔＨが、０Ｊ／ｇを超えて１０Ｊ／ｇ以下であることを特徴とする請求項１または請求項２に記載のヒートシール用フィルム。 The heat-sealing film according to claim 1 or 2, wherein the heat of fusion ΔH exceeds 0 J / g and is 10 J / g or less.
  4. 　前記融解熱ΔＨが、０Ｊ／ｇを超えて５Ｊ／ｇ以下であることを特徴とする請求項３に記載のヒートシール用フィルム。 The heat-sealing film according to claim 3, wherein the heat of fusion ΔH exceeds 0 J / g and is 5 J / g or less.
  5. 　前記熱可塑性ポリエステル系樹脂が、テレフタル酸を主なジカルボン酸成分として含み、１，４－テトラメチレングリコールを主なジオール成分として含み、かつ、前記ポリオキシアルキレングリコールとしてポリテトラメチレングリコールをジオール成分として含む熱可塑性ポリエステル系樹脂であることを特徴とする請求項１乃至請求項４のいずれかに記載のヒートシール用フィルム。 The thermoplastic polyester resin contains terephthalic acid as a main dicarboxylic acid component, 1,4-tetramethylene glycol as a main diol component, and polytetramethylene glycol as the polyoxyalkylene glycol as a diol component. The heat-sealing film according to any one of claims 1 to 4, which is a thermoplastic polyester-based resin containing the same.
  6. 　前記熱可塑性ポリエステル系樹脂中のポリテトラメチレングリコール成分の含有量が３０質量％以上、あるいは、前記熱可塑性ポリエステル系樹脂中のポリテトラメチレングリコール成分の含有量が１０質量％以上かつイソフタル酸成分の含有量が２０モル％以上であることを特徴とする請求項５に記載のヒートシール用フィルム。 The content of the polytetramethylene glycol component in the thermoplastic polyester resin is 30% by mass or more, or the content of the polytetramethylene glycol component in the thermoplastic polyester resin is 10% by mass or more and the isophthalic acid component. The heat-sealing film according to claim 5, wherein the content is 20 mol% or more.
  7. 　前記基材層が、ポリエチレンテレフタレート系フィルムおよび／またはポリブチレンテレフタレート系フィルムであることを特徴とする請求項１乃至請求項６のいずれかに記載のヒートシール用フィルム。 The heat-sealing film according to any one of claims 1 to 6, wherein the base material layer is a polyethylene terephthalate film and / or a polybutylene terephthalate film.
  8. 　前記基材層が、無延伸ポリブチレンテレフタレート系フィルムであることを特徴とする請求項１乃至請求項７のいずれかに記載のヒートシール用フィルム。 The heat-sealing film according to any one of claims 1 to 7, wherein the base material layer is a non-stretched polybutylene terephthalate film.
  9. 　請求項１乃至請求項８のいずれかに記載のヒートシール用フィルムを含むことを特徴とする包装材料。 A packaging material comprising the heat-sealing film according to any one of claims 1 to 8.
  10. 　包装袋、または、密封容器の蓋材であることを特徴とする請求項９に記載の包装材料。
     
          The packaging material according to claim 9, wherein the packaging material is a packaging bag or a lid material for a sealed container.
PCT/JP2021/016331 2020-04-22 2021-04-22 Film for heat sealing, and packaging material WO2021215507A1 (en)

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Citations (5)

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JPS51131582A (en) * 1975-05-12 1976-11-16 Toray Ind Inc Laminated polyester film
JPS5242545A (en) * 1975-10-02 1977-04-02 Toray Ind Inc Polyester film
JPH03120044A (en) * 1989-10-03 1991-05-22 Daicel Chem Ind Ltd Laminated film
JP2008538093A (en) * 2005-01-17 2008-10-09 デュポン テイジン フィルムズ ユー．エス．リミテッド パートナーシップ Self-venting composite polymer film
WO2018153795A1 (en) * 2017-02-24 2018-08-30 Packconnect B.V. Container covered with a film

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JPS51131582A (en) * 1975-05-12 1976-11-16 Toray Ind Inc Laminated polyester film
JPS5242545A (en) * 1975-10-02 1977-04-02 Toray Ind Inc Polyester film
JPH03120044A (en) * 1989-10-03 1991-05-22 Daicel Chem Ind Ltd Laminated film
JP2008538093A (en) * 2005-01-17 2008-10-09 デュポン テイジン フィルムズ ユー．エス．リミテッド パートナーシップ Self-venting composite polymer film
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