Polyester film, laminate, packaging body, food and drink packaging body, cosmetic packaging body, pharmaceutical product / quasi-drug packaging body, and product

Abstract

Provided is a polyester film containing a first polyester resin that includes a first acid unit and a first alcohol unit. The first acid unit includes 90 mol% or more of terephthalic acid units with respect to the total amount of the first acid unit, and the first alcohol unit includes 50 mol% or more of ethylene glycol units, 5-40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1-5 mol% of diethylene glycol units with respect to the total amount of the first alcohol unit. The content of the first polyester resin is 80 mass% or more with respect to the total amount of the polyester film, and the thickness of the polyester film is 25-100 μm.

Description

Polyester films, laminates, packaging, food and beverage packaging, cosmetic packaging, pharmaceutical and quasi-drug packaging, and products Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2023-200241, filed on November 27, 2023, and incorporates all of the contents of that Japanese application by reference.

[0002] The present invention relates to a polyester film, and a laminate, a package, a food and drink package, a cosmetic package, a pharmaceutical and quasi-drug package, and a product, each of which includes the polyester film.

[0003] Sealant films have been used for packaging foods, beverages, cosmetics, pharmaceuticals, quasi-drugs, etc. For example, polyolefin resins such as polyethylene and polypropylene are sometimes used as sealant films. Furthermore, a packaging bag for storing patches has been proposed, which has a heat-sealable layer made of polyacrylonitrile (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2005-328928

[0005] Typically, sealant films are formed into packages by thermocompression bonding together, and then the packaged items are packaged. For this reason, one side of the sealant film (the heat-sealed side) is required to be resistant to adsorption of organic compounds in the packaged items.

[0006] The polyacrylonitrile resin described in Patent Document 1 is expensive and has the problem that good seal strength cannot be obtained even when used in a heat seal layer. Furthermore, polyolefin resins such as polyethylene and polypropylene have excellent seal strength, but tend to adsorb organic compounds, such as medicinal components contained in medicines such as camphor and menthol, and flavoring components contained in foods such as limonene, and when a polyolefin resin is used in a layer that comes into direct contact with a medicine or food, the medicinal efficacy of the medicine is reduced and the aroma and taste of the food are changed.

[0007] Therefore, at present, there is no polyester film available that has low adsorption to organic compounds in the packaged goods and high seal strength.

[0008] An object of the present invention is to provide a polyester film that has low adsorption to organic compounds in the packaged item and high seal strength, as well as a laminate, package, food and beverage package, cosmetic package, pharmaceutical and quasi-drug package, and product that includes the polyester film.

[0009] The means for solving the above problems are as follows. The polyester film of the present invention contains a first polyester resin including first acid units and first alcohol units. The first acid units include 90 mol% or more of terephthalic acid units relative to the total amount of the first acid units. The first alcohol units include 50 mol% or more of ethylene glycol units, 5 mol% to 40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1 mol% to 5 mol% of diethylene glycol units relative to the total amount of the first alcohol units. The content of the first polyester resin is 80 mass% or more relative to the total amount of the polyester film. The polyester film has a thickness of 25 μm to 100 μm.

[0010] In one embodiment of the polyester film of the present invention, in differential scanning calorimetry (DSC) of the polyester film, when measured from 25°C to 300°C at a heating rate of 10°C / min, it is preferable that the enthalpy of fusion (ΔHm) calculated by integrating the endothermic peak at 220°C to 260°C is 10 J / g or less.

[0011] In one embodiment of the polyester film of the present invention, the tear strength of the polyester film determined by a tensile test at 23° C. and 200 mm / min is preferably 2 N / mm to 15 N / mm in both the longitudinal and transverse directions.

[0012] In one embodiment of the polyester film of the present invention, the polyester film is subjected to a tensile test at 23°C and 50 mm / min, and the modulus of elasticity is 1.6 kN / mm in both the longitudinal direction and the transverse direction.２ ~2.2 kN / mm ２ It is preferable that:

[0013] In one embodiment of the polyester film of the present invention, the polyester film preferably has a heat shrinkage rate of 10% or less in both the longitudinal and transverse directions before and after being heat-treated in hot air at 90° C. for 3 minutes.

[0014] In one embodiment of the polyester film of the present invention, when two polyester films 1 and 2 are thermocompression-bonded under conditions of 130°C to 150°C, 0.2 MPa, and 2 seconds, the seal strength between polyester film 1 and polyester film 2 is preferably 15 N / 15 mm to 50 N / 15 mm.

[0015] In one embodiment of the polyester film of the present invention, the polyester film is cut into a 4 cm × 4 cm square test piece, the initial mass of the test piece is measured, the test piece is placed in a beaker, 5 ml of limonene is added, the beaker is covered, and the test piece is stored at 25°C for 7 days. Thereafter, the mass of the test piece is measured, and the difference (B−A) between the initial mass A and the mass B after storage for 7 days is determined to be 0.2 mg / cm ２ It is preferable that:

[0016] In one embodiment of the polyester film of the present invention, the polyester film is preferably an unstretched film.

[0017] In one embodiment of the polyester film of the present invention, the first polyester resin preferably further contains a crosslinking agent unit.

[0018] In one embodiment of the polyester film of the present invention, the first acid units preferably further contain 0.05 mol % to 5 mol % of trimellitic acid units relative to the total amount of the first acid units.

[0019] In one embodiment of the polyester film of the present invention, it is preferable that the polyester film further contains 0.05% by mass to 1% by mass of an antiblocking agent.

[0020] In one aspect of the polyester film of the present invention, the polyester film has a first layer and a second layer, the first layer preferably contains 80% by mass or more of a first polyester resin and less than 20% by mass of a second polyester resin, and the second layer preferably contains 90% by mass or more of the first polyester resin, based on the mass of the first layer. In another aspect of the polyester film of the present invention, the first layer preferably further contains 0.05% to 1% by mass of an antiblocking agent, based on the mass of the first layer.

[0021] In one embodiment of the polyester film of the present invention, the polyester film further comprises a third layer between the first layer and the second layer, the third layer preferably containing 80% by mass or more of the first polyester resin and less than 20% by mass of the second polyester resin, based on the mass of the third layer. In another embodiment of the polyester film of the present invention, the third layer preferably further contains 0.05% by mass to 1% by mass of an antiblocking agent, based on the mass of the third layer.

[0022] The laminate of the present invention has a base film and a sealant layer. The sealant layer contains the polyester film of the present invention.

[0023] The packaging material of the present invention comprises the polyester film of the present invention, and the polyester film is at least partially fused to itself.

[0024] The food and drink package of the present invention comprises the polyester film of the present invention and a food and drink covered with the polyester film.

[0025] The cosmetic packaging of the present invention comprises the polyester film of the present invention and a cosmetic product covered with the polyester film.

[0026] The pharmaceutical / quasi-drug package of the present invention comprises the polyester film of the present invention and a pharmaceutical / quasi-drug covered with the polyester film.

[0027] The product of the present invention includes a packaged item containing an organic compound and the polyester film of the present invention that packages the packaged item, and at least a portion of the polyester film is fused to itself.

[0028] In one embodiment of the product of the present invention, the organic compound is preferably at least one selected from the group consisting of limonene, camphor, menthol, methyl salicylate, tocopherol acetate, isopropylmethylphenol, ketoprofen, ketoprofen sodium, diclofenac sodium, felbinac, loxoprofen sodium, tulobuterol, rivastigmine, clopumazine hydrochloride, haloperidol, risperidone, paliperidone, blonanserin, perospirone hydrochloride hydrate, lurasidone hydrochloride, olanzapine, quetiapine fumarate, asenapine maleate, clozapine, aripiprazole, and brexpiprazole.

[0029] According to the present invention, it is possible to provide a polyester film that has low adsorption properties for organic compounds in the packaged items and high seal strength, as well as laminates, packages, food and beverage packages, cosmetic packages, pharmaceutical and quasi-drug packages, and products that include the polyester film.

[0030] Fig. 1 is a schematic view showing an example of the polyester film of the present invention, Fig. 2 is a schematic view showing another example of the polyester film of the present invention, and Fig. 3 is a schematic view showing another example of the polyester film of the present invention.

[0031] (Polyester Film) The polyester film of the present invention contains a first polyester resin containing a first acid unit and a first alcohol unit, and preferably contains a second polyester resin and an antiblocking agent, and may further contain other components as necessary.

[0032] The polyester film of the present invention contains a first polyester resin including first acid units and first alcohol units, wherein the first acid units contain 90 mol% or more of terephthalic acid units relative to the total amount of the first acid units. The first alcohol units contain 50 mol% or more of ethylene glycol units, 5 mol% to 40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1 mol% to 5 mol% of diethylene glycol units relative to the total amount of the first alcohol units. By satisfying the following requirements (1) and (2), the polyester film can exhibit low adsorption to organic compounds in the packaged goods and have high seal strength.

[0033] (1) The content of the first polyester resin is 80% by mass or more based on the total mass of the polyester film, and (2) the thickness of the polyester film is 25 μm to 100 μm.

[0034] The polyester film of the present invention contains a first polyester resin including first acid units and first alcohol units, and the first acid units contain 90 mol% or more of terephthalic acid units relative to the total amount of the first acid units. The first alcohol units contain 50 mol% or more of ethylene glycol units, 5 mol% to 40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1 mol% to 5 mol% of diethylene glycol units relative to the total amount of the first alcohol units. In addition to satisfying the requirements (1) and (2) above, the polyester film preferably satisfies at least one of the requirements (3) to (9) below, and more preferably satisfies all of the requirements (1) to (9). This allows the polyester film to have low adsorption to organic compounds in the packaged goods, high seal strength, and excellent hand-tearability and formability.

[0035] Here, hand-tearability refers to the ease with which the film can be cut by hand when opening a package. Shapeability refers to the ease with which the film can be processed in lamination, bag making, drawing, and the like. Furthermore, polyolefin resin films have a problem of poor hand-tearability due to their low elastic modulus. Furthermore, unstretched A-PET films using crystalline PET resins have excellent seal strength and low adsorption to organic compounds, but have a problem of high fusion entropy and poor hand-tearability. Furthermore, biaxially oriented polyethylene terephthalate films have excellent seal strength, low adsorption to organic compounds, and hand-tearability, but have a problem of poor shapeability. The polyester film of the present invention can solve the problems associated with the above-mentioned conventional resin films.

[0036] (3) In differential scanning calorimetry (DSC) of the polyester film, when the temperature is increased from 25°C to 300°C at a heating rate of 10°C / min, the melting enthalpy (ΔHm) calculated by integrating the endothermic peak at 220°C to 260°C is 10 J / g or less. (4) The polyester film is subjected to a tensile test at 23°C and 200 mm / min, and the tear strength is determined to be 2 N / mm to 15 N / mm in both the longitudinal and transverse directions. (5) The polyester film is subjected to a tensile test at 23°C and 50 mm / min, and the modulus of elasticity is determined to be 1.6 kN / mm in both the longitudinal and transverse directions. ２ ~2.2 kN / mm ２ (6) The heat shrinkage rate of the polyester film before and after 3 minutes of heat treatment in hot air at 90°C is 10% or less in both the longitudinal and transverse directions. (7) When two polyester films 1 and 2 are thermocompression bonded under conditions of 130°C to 150°C, 0.2 MPa, and 2 seconds, the seal strength between the polyester film 1 and the polyester film 2 is 15 N / 15 mm to 50 N / 15 mm. (8) The polyester film is cut into a 4 cm x 4 cm square test piece, the initial mass of the test piece is measured, the test piece is placed in a beaker, 5 ml of limonene is added, the beaker is covered, and the beaker is stored at 25°C for 7 days. The mass of the test piece is then measured, and the difference (B - A) between the initial mass A and the mass B after storage for 7 days, which is the limonene adsorption amount, is 0.2 mg / cm.２ (9) The polyester film is an unstretched film.

[0037] Here, the above requirements (1) to (9) will be specifically explained. (1) The content of the first polyester resin is 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 93% by mass or more, even more preferably 96% by mass or more, particularly preferably 98% by mass or more, and even more particularly preferably 100% by mass, based on the total amount of the polyester film. If the content of the first polyester resin is less than 80% by mass, the low adsorption of organic compounds in the packaged goods and / or the tearability of the polyester film may be deteriorated.

[0038] (2) The thickness of the polyester film is 25 μm to 100 μm, preferably 25 μm to 90 μm, more preferably 25 μm to 80 μm, even more preferably 30 μm to 80 μm, even more preferably 30 μm to 70 μm, particularly preferably 30 μm to 60 μm, and even more particularly preferably 30 μm to 50 μm. If the thickness of the polyester film is less than 25 μm, the seal strength may decrease, resulting in a decrease in functionality as a packaging material. If the thickness exceeds 100 μm, the polyester film may become more likely to adsorb organic compounds in the packaged items. The thickness of the polyester film is the average value obtained by measuring the thickness at any five points on the polyester film with a micrometer.

[0039] (3) In differential scanning calorimetry (DSC) of the polyester film of the present invention, when measured from 25°C to 300°C at a heating rate of 10°C / min, the fusion enthalpy (ΔHm) calculated by integrating the endothermic peak at 220°C to 260°C is preferably 10 J / g or less, more preferably 5 J / g or less, even more preferably 2 J / g or less, and particularly preferably 0 J / g (no peak). If the fusion enthalpy (ΔHm) exceeds 10 J / g, the hand-tearability of the unstretched polyester film may be poor.

[0040] (4) In the polyester film of the present invention, the tear strength measured by a tensile test at 23°C and 200 mm / min is preferably 2 N / mm to 15 N / mm in both the longitudinal and transverse directions, more preferably 5 N / mm to 15 N / mm, even more preferably 7 N / mm to 15 N / mm, and particularly preferably 10 N / mm to 15 N / mm. The longitudinal direction is sometimes referred to as the machine direction (MD). The transverse direction is sometimes referred to as the transverse direction (TD). The tear strength can be measured, for example, in accordance with JIS K7128-1 "Testing methods for tear strength of plastic films and sheets - Part 1: Trouser tear method."

[0041] (5) In the polyester film of the present invention, the modulus of elasticity determined by a tensile test at 23°C and 50 mm / min is 1.6 kN / mm in both the longitudinal and transverse directions. ２ ~2.2 kN / mm ２ is preferred, and 1.6 kN / mm ２ ~2.1 kN / mm ２ More preferably, 1.6 kN / mm ２ ~2.0 kN / mm ２ More preferably, 1.7 kN / mm ２ ~2.0 kN / mm ２ Even more preferably, 1.8 kN / mm ２ ~2.0 kN / mm ２ The elastic modulus is particularly preferably 1.6 kN / mm ２ If it is less than 2.2 kN / mm, the hand tearability may be poor. ２ If the modulus exceeds 1 / 2, a large force is required during processing such as drawing, which may result in poor formability. The longitudinal direction is also referred to as the machine direction (MD direction). The width direction is also referred to as the transverse direction (TD direction). The modulus of elasticity can be measured, for example, in accordance with ISO 527-3:2012.

[0042] (6) In the polyester film of the present invention, the heat shrinkage rate before and after heating the polyester film in hot air at 90°C for 3 minutes is preferably 10% or less in both the longitudinal and transverse directions, more preferably 5% or less, even more preferably 3% or less, even more preferably 2% or less, particularly preferably 1% or less, and may even be 0% (no dimensional change). If the heat shrinkage rate exceeds 10%, wrinkles may occur during processing such as lamination, packaging production, and drawing. To measure the heat shrinkage rate, a test piece cut to a predetermined size from the polyester film is placed in a ventilated oven heated to 90°C and allowed to stand for 3 minutes. The lengths of the test piece in the longitudinal (MD) and transverse (TD) directions are measured (AM, AT). After 3 minutes have elapsed, the test piece is removed from the ventilated oven and its lengths in the MD and TD directions are measured (BM, BT). From the measured lengths AM and BM in the MD, the heat shrinkage rate in the MD (%) can be calculated as follows: [(AM-BM) / AM] x 100. On the other hand, from the measured lengths (AT, BT) in the TD, the heat shrinkage rate in the TD (%) can be calculated as follows: [(AT-BT) / AT] x 100.

[0043] (7) In the polyester film of the present invention, when two polyester films 1 and 2 are thermocompression bonded under conditions of 130°C to 150°C, 0.2 MPa, and 2 seconds, the seal strength between polyester film 1 and polyester film 2 is preferably 15 N / 15 mm to 50 N / 15 mm, more preferably 15 N / 15 mm to 45 N / 15 mm, even more preferably 15 N / 15 mm to 40 N / 15 mm, even more preferably 15 N / 15 mm to 35 N / 15 mm, particularly preferably 15 N / 15 mm to 30 N / 15 mm, more particularly preferably 16 N / 15 mm to 30 N / 15 mm, and even more particularly preferably 17 N / 15 mm to 30 N / 15 mm. If the seal strength is less than 15 N / 15 mm, the hermeticity of the package may be reduced. While a higher seal strength is preferable, the current upper limit is 50 N / 15 mm. In conventional techniques, seal strength is often measured at a sealing temperature of 160°C, but in the present invention, seal strength is measured at a low sealing temperature of 130°C to 150°C. Generally, the higher the sealing temperature, the higher the seal strength tends to be. In addition, a lower sealing temperature has the advantage of improving energy efficiency during sealing, reducing environmental impact and costs.

[0044] (8) In the polyester film of the present invention, the polyester film is cut into a 4 cm × 4 cm square test piece, and the initial mass of the test piece is measured. The test piece is placed in a beaker, 5 ml of limonene is added, the beaker is covered, and the test piece is stored at 25°C for 7 days. The mass of the test piece is then measured, and the difference (B - A) between the initial mass A and the mass B after storage for 7 days is determined to be 0.2 mg / cm. ２ Preferably, 0.1 mg / cm or less ２ More preferably, 0.05 mg / cm or less ２ More preferably, 0 mg / cm ２ (without adsorption of limonene).

[0045] (9) In the polyester film of the present invention, the polyester film is preferably an unstretched product. An unstretched product refers to a polyester film that has not been stretched during the manufacturing process. The unstretched product can be confirmed by a tensile test conducted at 23°C and 10 mm / min, where the tensile elongation at break is 200% or more in both the longitudinal and transverse directions. An unstretched product (unstretched film) can achieve high seal strength even over a wide temperature range, for example, even at sealing temperatures of 130°C to 150°C. Furthermore, by using an unstretched film, heat shrinkage in the stretching direction can be prevented. As a result, the unstretched film is less likely to wrinkle when heated, improving moldability.

[0046] The compositions of the first polyester resin and the second polyester resin in the polyester film of the present invention, the method for producing the polyester resins, and other components will be described in detail below.

[0047] The compositions of the first and second polyester resins may not necessarily be identical to the compositions of the raw material monomers. In particular, when ethylene glycol is used as the alcohol component, diethylene glycol is included as a by-product. Hereinafter, unless otherwise specified, the notation of mole percent (mol%) concentration indicating the composition refers to the mole percent concentration of the component contained in the produced polyester resin, not the amount of the raw material monomer charged.

[0048] In the present invention, unless otherwise specified, the first and second polyester resins may also include molded articles. The polyester resin is a copolymer of acid units (polycarboxylic acid units) and alcohol units (polyol units, polyhydroxy compound units). In the present invention, a polycarboxylic acid unit refers to a unit consisting of a compound having multiple carboxy groups. Furthermore, a polyol unit or a polyhydroxy compound unit refers to a unit consisting of a compound having multiple hydroxy groups. In this specification and claims, each acid and each alcohol may also include its derivatives. For example, an acid may also include an acid derivative (e.g., an ester). Scraps generated during film production or molding processes can be used as the first and second polyester resins. This allows for efficient resource utilization and reduced manufacturing costs. Scraps may be processed into a convenient form, such as pellets, flakes, or powder. The first and second polyester resins may also contain components derived from recycled polyester resins or biomass.

[0049] <First Polyester Resin> The first polyester resin contains a first acid unit and a first alcohol unit, and is preferably composed mainly of polyethylene terephthalate (PET).

[0050] The first acid units mainly contain terephthalic acid units. The content of the terephthalic acid units is 90 mol% or more, preferably 95 mol% or more, relative to the total amount of the first acid units. The content of the terephthalic acid units can be, for example, 100 mol% relative to the total amount of acid units. If the terephthalic acid units are less than 90 mol%, the low adsorption of organic compounds in the packaged item may be impaired. The content of the terephthalic acid units can be, for example, 98 mol% or less, or 95 mol% or less, relative to the total amount of the first acid units.

[0051] The first acid unit may contain other acid units as long as the essential properties of the first polyester resin are not altered. Examples of other acid units include units formed from isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, succinic acid, dimer acid, 1,4-cyclohexadicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, or derivatives thereof. These may be used alone or in combination of two or more.

[0052] The first alcohol units mainly contain ethylene glycol units. The content of the ethylene glycol units, relative to the total amount of the first alcohol units, can be, for example, 50 mol% or more, 55 mol% or more, 60 mol% or more, 62 mol% or more, 65 mol% or more, 70 mol% or more, or 75 mol% or more. The content of the ethylene glycol units, relative to the total amount of the first alcohol units, can be, for example, 95 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, 70 mol% or less, or 60 mol% or less.

[0053] The first alcohol units further contain 2,2-dimethyl-1,3-propanediol units (hereinafter, sometimes referred to as "neopentyl glycol units"). The content of the neopentyl glycol units is 5 mol% or more, preferably 10 mol% or more, and more preferably 15 mol% or more, relative to the total amount of the first alcohol units. The content of the neopentyl glycol units can be, for example, 20 mol% or more, 25 mol% or more, 30 mol% or more, or 35 mol% or more, relative to the total amount of the first alcohol units. If the content of the neopentyl glycol units is less than 5 mol%, the heat sealing stability will decrease. The content of the neopentyl glycol units is 40 mol% or less, preferably 38 mol% or less, and more preferably 35 mol% or less, relative to the total amount of the first alcohol units. The content of neopentyl glycol units can be, for example, 30 mol% or less, 25 mol% or less, 20 mol% or less, 15 mol% or less, or 10 mol% or less, relative to the total amount of first alcohol units. If the content of neopentyl glycol units exceeds 40 mol%, the adsorption of organic compounds in the packaged items becomes significantly high.

[0054] The total content of the ethylene glycol units and the neopentyl glycol units is preferably 90 mol% or more, more preferably 95 mol% or more, based on the total amount of the first alcohol units. The total content of the ethylene glycol units and the neopentyl glycol units can be 100 mol% based on the total amount of the first alcohol units.

[0055] The first alcohol units contain diethylene glycol units. The content of diethylene glycol units is 0.1 mol% to 5 mol%, preferably 0.5 mol% to 5 mol%, more preferably 1 mol% to 5 mol%, even more preferably 1 mol% to 3 mol%, and particularly preferably 1 mol% to 2 mol%, relative to the total amount of first alcohol units. A diethylene glycol unit content of 0.1 mol% or more means that the first alcohol units necessarily contain diethylene glycol units. If the diethylene glycol unit content exceeds 5 mol%, heat resistance deteriorates, and when the film or a product containing the film is stored in a high-temperature environment such as summer, the films may fuse together, making it impossible to unwind them with a roll or to maintain the shape of the package. Diethylene glycol is a by-product of ethylene glycol during the melt polymerization of the first polyester resin, but diethylene glycol may be added externally as needed.

[0056] The first alcohol unit may contain other alcohol units as long as the essential properties of the first polyester resin are not changed. Examples of other alcohol units include units consisting of 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, or derivatives thereof. These may be used alone or in combination of two or more.

[0057] The first polyester resin may further contain a crosslinking agent unit. Examples of the crosslinking agent unit include a tricarboxylic acid unit or a polyol unit. Examples of the tricarboxylic acid unit include a trimellitic acid unit. By containing the crosslinking agent unit, the melt viscosity of the first polyester resin can be increased. This stabilizes the amount of polyester resin discharged during polyester film formation, making it easier to form a polyester film with a uniform thickness.

[0058] The content of the trimellitic acid units can be, for example, 0.05 mol% or more, 0.1 mol% or more, or 0.15 mol% or more, relative to the total amount of the first acid units. The content of the trimellitic acid units is preferably 5 mol% or less, relative to the total amount of the first acid components. The content of the trimellitic acid units can be, for example, 4 mol% or less, 3.5 mol% or less, 3 mol% or less, 2.5 mol% or less, 2 mol% or less, 1.5 mol% or less, 1 mol% or less, or 0.5 mol% or less, relative to the total amount of the first acid units. If the content of the trimellitic acid units exceeds 5 mol%, the polyester film becomes more prone to breakage.

[0059] The total content of the terephthalic acid units and the trimellitic acid units is preferably 90 mol% or more, more preferably 95 mol% or more, based on the total amount of acid units. The total content of the terephthalic acid units and the trimellitic acid units can be 100 mol% based on the total amount of acid units.

[0060] The polyester films of the first and second embodiments preferably contain a second polyester resin or an antiblocking agent in addition to the first polyester resin.

[0061] <Second Polyester Resin> The second polyester resin contains a second acid unit and a second alcohol unit, and preferably contains polyethylene terephthalate (PET) as a main constituent unit.

[0062] The second acid units mainly contain terephthalic acid units. The content of the terephthalic acid units is preferably 80 mol% or more, more preferably 85 mol% or more, based on the total amount of the second acid units. The content of the terephthalic acid units can be, for example, 90 mol% or more, 95 mol% or less, 90 mol% or less, or 85 mol% or less, based on the total amount of the second acid units.

[0063] The second acid units may further include isophthalic acid units. The content of the isophthalic acid units is preferably 5 mol% or more, more preferably 10 mol% or more, based on the total amount of the second acid units. The content of the isophthalic acid units may be, for example, 15 mol% or more, based on the total amount of the second acid units. The content of the isophthalic acid units may be, for example, 20 mol% or less, 15 mol% or less, or 10 mol% or less, based on the total amount of the second acid components.

[0064] The total content of the terephthalic acid units and the isophthalic acid units is preferably 90 mol% or more, more preferably 95 mol% or more, based on the total amount of the second acid units. The total content of the terephthalic acid units and the isophthalic acid units can be 100 mol% based on the total amount of the second acid units.

[0065] The second acid unit may contain other acid units as long as the essential properties of the second polyester resin are not changed. Examples of other acid units include units formed from orthophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, succinic acid, dimer acid, 1,4-cyclohexadicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, trimellitic acid, and derivatives thereof. These may be used alone or in combination of two or more.

[0066] The second alcohol units mainly contain ethylene glycol units. The content of ethylene glycol units is preferably 65 mol% or more, and preferably 70 mol% or more, relative to the total amount of second alcohol units. The content of ethylene glycol units can be, for example, 75 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, 95 mol% or more, or 100 mol% relative to the total amount of second alcohol units. If the ethylene glycol units are less than 65 mol%, the low adsorption properties for organic compounds in the packaged item may be impaired. The content of ethylene glycol units can be, for example, 95 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, or 70 mol% or less, relative to the total amount of second alcohol units.

[0067] The second alcohol unit may contain other alcohol units as long as the essential properties of the second polyester resin are not altered. Examples of other alcohol units include units consisting of neopentyl glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, or derivatives thereof. These may be used alone or in combination of two or more.

[0068] <Method for producing polyester resin> The first polyester resin and the second polyester resin can be produced by a known method based on the above-mentioned monomers and additives. For example, an ester prepolymer may be produced by direct esterification using an unsubstituted polycarboxylic acid as a starting material, or an ester prepolymer may be produced by a transesterification reaction using an esterified product such as dimethyl ester as a starting material. From the viewpoint of production efficiency, direct esterification is preferred.

[0069] The addition ratios of the monomers and additives may be the ratios shown in the above description of the first polyester resin and the second polyester resin.

[0070] The direct esterification reaction or transesterification reaction can be carried out, for example, by charging raw materials into a reaction vessel equipped with a heater, a stirrer, and a distillation tube, adding a reaction catalyst, and raising the temperature while stirring under an inert gas atmosphere at atmospheric pressure, and allowing the reaction to proceed while distilling off by-products such as methanol produced by the reaction. The reaction temperature is, for example, preferably 150°C to 270°C, more preferably 160°C to 260°C. The reaction time is, for example, about 3 to 7 hours.

[0071] At least one metal compound can be used as a catalyst for the transesterification reaction. Examples of metal elements include sodium, potassium, calcium, titanium, lithium, magnesium, manganese, zinc, tin, and cobalt. Among these, titanium and manganese compounds are particularly preferred because they have high reactivity and produce a good color tone for the resulting resin. The amount of the transesterification catalyst added is usually preferably 5 ppm to 1,000 ppm, and more preferably 10 ppm to 100 ppm, based on the polyester resin produced.

[0072] To suppress the production of the by-product diethylene glycol, it is preferable to reduce the amount of ethylene glycol in the reaction system. For example, it is preferable to set the molar ratio of the alcohol component amount to the acid component amount (alcohol component / acid component) to 1.3 or less. Furthermore, the production of diethylene glycol can be suppressed by adding, for example, 5 ppm of sodium hydroxide.

[0073] It is also desirable to add a phosphorus compound after the completion of the direct esterification reaction or the transesterification reaction to further promote the esterification reaction. Examples of phosphorus compounds include phosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trimethyl phosphite, triethyl phosphite, and tributyl phosphite. Among these, trimethyl phosphate is particularly preferred. The amount of the phosphorus compound used is preferably 5 ppm to 1,000 ppm, and more preferably 20 ppm to 100 ppm, based on the mass of the polyester resin produced.

[0074] Among the polyol components in the present invention, neopentyl glycol may be added during the direct esterification reaction of the polycarboxylic acid component with ethylene glycol, or may be added after the esterification reaction is completed. It is preferable to first mix the polycarboxylic acid component with ethylene glycol and neopentyl glycol at room temperature to prepare a slurry, and then proceed with the esterification reaction in an esterification reaction tank, since this can prevent neopentyl glycol from scattering. Furthermore, in the present invention, the entire amount of ethylene glycol may be added before the esterification reaction, and it is not necessary to add a portion of it after the esterification reaction.

[0075] Following the transesterification and esterification reactions, a polymerization catalyst can be added to the ester prepolymer, and a polycondensation reaction can be further carried out until the desired molecular weight is achieved. For example, germanium dioxide can be used as the catalyst in the polymerization reaction. The catalyst addition rate can be, for example, 180 ppm to 220 ppm relative to the amount of resin produced. The polycondensation reaction can be carried out, for example, by gradually increasing the temperature and reducing the pressure inside the reaction vessel after adding the polymerization catalyst. The pressure inside the vessel is preferably, for example, ultimately 0.4 kPa or less, and preferably reduced to 0.2 kPa or less. The temperature inside the vessel is preferably, for example, ultimately raised to 250°C to 290°C. The polymerization reaction can be carried out, for example, under reduced pressure until the desired melt viscosity is achieved, with the final vessel pressure being 150 Pa or less. Thereafter, the vessel pressure can be increased to, for example, 0.5 MPa, and the reaction product can be extruded and recovered from the bottom of the vessel. For example, the reaction product can be extruded into water in the form of strands, cooled, and then cut to obtain pelletized polyester resin.

[0076] A catalyst other than germanium dioxide can also be used as the polymerization catalyst. For example, titanium dioxide can be used as the polymerization catalyst. When titanium dioxide is used, the catalyst addition rate can be, for example, 1 ppm to 10 ppm relative to the amount of resin produced.

[0077] <Antiblocking Agent> Antiblocking (slip) agents are blended to improve the slippage between films. As the antiblocking agent, organic or inorganic fine particles can be used, and examples thereof include inorganic particles such as calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, lithium phosphate, magnesium phosphate, calcium phosphate, lithium fluoride, aluminum oxide (alumina), silicon oxide (silica), talc, and kaolin; organic particles such as acrylic resin and guanamine resin, and precipitated particles obtained by granulating catalyst residues. These may be used alone or in combination of two or more. Among these, silica and talc are preferred.

[0078] The content of the antiblocking agent is preferably 0.05% by mass to 1% by mass, more preferably 0.1% by mass to 1% by mass, based on the total amount of the polyester film. If the content of the antiblocking agent is less than 0.05% by mass, sufficient slip properties of the film may not be obtained.

[0079] The resin composition containing the second polyester resin and the antiblocking agent can be used, for example, as a masterbatch for adding the antiblocking agent to a polyester film.

[0080] <Other Components> The polyester film of the present invention can be appropriately blended with various additives, such as antioxidants, heat stabilizers, lubricants, antistatic agents, plasticizers, UV absorbers, and pigments, depending on the application and molding purpose. These additives may be blended in either the polymerization reaction process or the processing / molding process. Examples of antioxidants include hindered phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants, with hindered phenol-based antioxidants being particularly preferred. The amount added is preferably 100 ppm to 5,000 ppm. Furthermore, when molding a melt-extrusion film, metal salts such as magnesium acetate, calcium acetate, and magnesium chloride may be added to stabilize the electrostatic adhesion of the cooling roll.

[0081] <Method for producing polyester film> The method for producing the polyester film of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, a polyester film (unstretched product) can be produced by mixing a first polyester resin, an optional second polyester resin, and other components, feeding the mixture into an extruder equipped with a T-die, melting the mixture, extruding the mixture through the T-die, contacting the mixture with a cooling roll by electrostatic contact or the like, and cooling and solidifying the mixture. In this case, the temperature of the extruder is preferably 250°C to 280°C.

[0082] In addition to the above, the polyester film of the present invention may have characteristics such as a structure that are difficult or impractical to directly identify by its composition. In such cases, the polyester film of the present invention should be identified by its manufacturing method. For example, the composition and properties of the polyester film may vary from the polyester resin before molding depending on the heat-melting conditions during production. In some cases, it is difficult to directly identify the composition and properties of the molded product. In such cases, it is useful to identify the polyester film by the manufacturing method of the polyester film from the polyester resin before molding.

[0083] The polyester film of the present invention may have a single-layer structure consisting of only one layer, or may have a laminate structure consisting of multiple films. In the case of a laminate structure, it preferably has 2 to 5 layers, more preferably 2 or 3 layers. Of the multiple layers, at least one layer must contain the first polyester resin in the polyester film of the first or second embodiment, and it is preferable that all layers contain the first polyester resin.

[0084] The polyester film of the present invention may have a two-layer structure, for example, having a first layer and a second layer. The first layer contains a first polyester resin in an amount of 80% by mass or more and a second polyester resin in an amount less than 20% by mass, based on the mass of the first layer. The content of the first polyester resin is 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 93% by mass or more, even more preferably 96% by mass or more, particularly preferably 98% by mass or more, and may even be 100% by mass. The second layer contains 90% by mass or more of the first polyester resin, based on the mass of the second layer. The content of the first polyester resin is preferably 95% by mass or more and may even be 100% by mass, based on the mass of the second layer. The first layer preferably further contains an antiblocking agent in an amount of 0.05% by mass to 1% by mass, based on the mass of the first layer. The total thickness of the two-layer polyester film is preferably 25 μm to 100 μm, more preferably 25 μm to 90 μm, even more preferably 25 μm to 80 μm, still more preferably 30 μm to 80 μm, particularly preferably 30 μm to 70 μm, more particularly preferably 30 μm to 60 μm, and even more particularly preferably 30 μm to 50 μm.

[0085] The polyester film of the present invention may have a three-layer structure, for example, having a third layer between the first and second layers. The first and second layers are similar to the first and second layers of the two-layer structure described above. The third layer contains the first polyester resin in an amount of 80% by weight or more relative to the weight of the third layer and less than 20% by weight of the second polyester resin relative to the weight of the third layer. The content of the first polyester resin is 80% by weight or more relative to the weight of the third layer, preferably 85% by weight or more, more preferably 90% by weight or more, even more preferably 93% by weight or more, even more preferably 96% by weight or more, particularly preferably 98% by weight or more, and may even be 100% by weight. The third layer preferably further contains 0.05% to 1% by weight of an antiblocking agent relative to the weight of the third layer. The total thickness of the three-layer polyester film is preferably 25 μm to 100 μm, more preferably 25 μm to 90 μm, even more preferably 25 μm to 80 μm, still more preferably 30 μm to 80 μm, particularly preferably 30 μm to 70 μm, more particularly preferably 30 μm to 60 μm, and even more particularly preferably 30 μm to 50 μm.

[0086] The polyester film of the present invention will now be described in detail with reference to the drawings. In each drawing, reference symbols are added to facilitate understanding of the invention and are not intended to limit the invention to the illustrated embodiments. Furthermore, the shapes, dimensions, scales, etc. of the drawings are not intended to limit the invention to the forms shown in the drawings. In each embodiment, the same elements are designated by the same symbols.

[0087] Figure 1 shows an example of a single-layer polyester film of the present invention. The polyester film 1 in Figure 1 comprises a first layer 2. The composition of the first layer 2 may be the same as that of the polyester film of the first or second embodiment. The thickness of the first layer 2 (the thickness of the single-layer polyester film 1) is preferably 25 μm to 100 μm, more preferably 25 μm to 90 μm, even more preferably 25 μm to 80 μm, still more preferably 30 μm to 80 μm, particularly preferably 30 μm to 70 μm, more particularly preferably 30 μm to 60 μm, and even more particularly preferably 30 μm to 50 μm.

[0088] Fig. 2 shows an example of a two-layer polyester film of the present invention. The polyester film 10 in Fig. 2 has a first layer 11 and a second layer 12 laminated on the first layer 11.

[0089] The composition of the first layer 11 can be the same as that of the first polyester resin in the polyester film of the present invention.

[0090] The total thickness of the first layer 11 and the second layer 12 (the thickness of the two-layer polyester film 10) is preferably 25 μm to 100 μm, more preferably 25 μm to 90 μm, even more preferably 25 μm to 80 μm, still more preferably 30 μm to 80 μm, particularly preferably 30 μm to 70 μm, more particularly preferably 30 μm to 60 μm, and even more particularly preferably 30 μm to 50 μm.

[0091] The first layer 11 can be a heat seal layer. The first layer 11 has a thickness of 5 μm or more, preferably 10 μm or more. If the first layer 11 has a thickness of less than 5 μm, sufficient heat seal strength and low adsorption may not be obtained. The first layer 11 can have a thickness of, for example, 20 μm or less, 15 μm or less, or 10 μm or less.

[0092] The composition of the second layer 12 may be the same as that of the second polyester resin in the polyester film of the present invention.

[0093] The second layer 12 has a thickness of 5 μm or more, preferably 10 μm or more. If the second layer 12 has a thickness of less than 5 μm, sufficient heat seal strength and low adsorption may not be obtained. The second layer 12 may have a thickness of, for example, 20 μm or less, 15 μm or less, or 10 μm or less.

[0094] Fig. 3 shows an example of a three-layer polyester film of the present invention. The polyester film 20 in Fig. 3 has a first layer 21, a second layer 22 laminated to the first layer 21, and a third layer 23 laminated to the second layer 22.

[0095] The composition of the first layer 21 can be the same as that of the first polyester resin in the polyester film of the present invention.

[0096] The total thickness of the first layer 21, the second layer 22, and the third layer 23 (the thickness of the three-layer polyester film 20) is preferably 25 μm to 100 μm, more preferably 25 μm to 90 μm, even more preferably 25 μm to 80 μm, still more preferably 30 μm to 80 μm, particularly preferably 30 μm to 70 μm, more particularly preferably 30 μm to 60 μm, and even more particularly preferably 30 μm to 50 μm.

[0097] The first layer 21 can be a heat seal layer. The first layer 21 has a thickness of 5 μm or more, preferably 10 μm or more. If the first layer 21 has a thickness of less than 5 μm, sufficient heat seal strength and low adsorption may not be obtained. The first layer 21 can have a thickness of, for example, 20 μm or less, 15 μm or less, or 10 μm or less.

[0098] The composition of the second layer 22 may be the same as that of the second polyester resin in the polyester film of the present invention.

[0099] The second layer 22 has a thickness of 5 μm or more, preferably 10 μm or more. If the second layer 22 has a thickness of less than 5 μm, sufficient heat seal strength and low adsorption may not be obtained. The second layer 22 may have a thickness of, for example, 20 μm or less, 15 μm or less, or 10 μm or less.

[0100] The composition of the third layer 23 may be the same as that of the first polyester resin in the polyester film of the present invention.

[0101] The third layer 23 has a thickness of 5 μm or more, preferably 10 μm or more. If the third layer 23 has a thickness of less than 5 μm, sufficient heat seal strength and low adsorption may not be obtained. The third layer 23 may have a thickness of, for example, 20 μm or less, 15 μm or less, or 10 μm or less.

[0102] The polyester film of the present invention has low adsorption properties for organic compounds in the packaged items, can achieve high seal strength, and is excellent in hand-tearability and shapeability, and therefore can be used in a wide variety of applications. In particular, it can be suitably used for laminates, packages, food and beverage packages, cosmetic packages, pharmaceutical and quasi-drug packages, and products described below.

[0103] (Laminate) The laminate of the present invention comprises a substrate film, a sealant layer, and optionally other layers, and is suitable for use in packaging applications.

[0104] <Sealant Layer> The polyester film of the present invention is used as the sealant layer. The sealant layer is provided on the outermost surface of the laminate, and can be provided on one or both sides of the base film.

[0105] <Substrate Film> The material, thickness, structure, etc. of the substrate film are not particularly limited and can be appropriately selected depending on the purpose. Examples of the structure include a single-layer structure and a multi-layer structure. Examples of the substrate material include polyester resin, polyolefin resin, polyamide resin, polyurethane resin, fluororesin, polystyrene resin, poly(meth)acrylic resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), vinyl alcohol resin, halogen-containing resin (polyvinyl chloride resin, etc.), polyphenylene ether resin, polycarbonate resin, polyimide resin, polyamideimide resin, polyarylphthalate resin, silicone resin, polysulfone resin, acetal resin, and cellulose resin. The thickness of the substrate is preferably 1 μm to 100 μm, and more preferably 5 μm to 50 μm.

[0106] <Other Layers> Examples of the other layers include a metal layer, an adhesive layer, a primer layer, a resin layer, etc. Examples of the metal layer include an aluminum foil, an aluminum vapor-deposited film, etc.

[0107] (Package) The package of the present invention includes the polyester film of the present invention, and at least a portion of the polyester film is fused to each other. Examples of the package include a package for food and drink, a package for cosmetics, and a package for medicines and quasi-drugs.

[0108] - Food and drink package - The food and drink package of the present invention comprises the polyester film of the present invention and a food or drink covered with the polyester film.

[0109] Depending on the application, only a portion of the food and beverage package may be made of the packaging material (the polyester film of the present invention), or substantially the entire food and beverage package may be made of the packaging material. Examples of the shape of the food and beverage package include a bag, tray, pack, pouch, container, etc. The food and beverage package is used to package various foods and beverages. In the present invention, the food and drink examples include, but are not limited to, beverages such as soft drinks, carbonated drinks, nutritional drinks, fruit drinks, and lactic acid drinks (including concentrated concentrates and powders for adjusting these beverages); frozen desserts such as ice cream, ice sherbet, and shaved ice; noodles such as soba noodles, udon noodles, vermicelli, gyoza wrappers, shumai wrappers, Chinese noodles, and instant noodles; sweets such as candy, chewing gum, candies, chewing gum, chocolate, candy tablets, snacks, biscuits, jelly, jam, cream, and baked goods; processed seafood and livestock foods such as kamaboko, ham, and sausage; dairy products such as processed milk and fermented milk; oils and fats and oil-based foods such as seafood, salad oil, tempura oil, margarine, mayonnaise, shortening, whipped cream, and dressing; condiments such as sauces and dressings; soups, stews, salads, side dishes, and pickles; various other forms of health and nutritional supplements; and energy drinks.

[0110] - Cosmetic Package - The cosmetic package of the present invention comprises the polyester film of the present invention and a cosmetic product covered with the polyester film.

[0111] Depending on the intended use, the cosmetic package may be partially or entirely made of the packaging material (the polyester film of the present invention). Examples of the cosmetic package include a bag, tray, pack, and container. The cosmetic package is used to package various cosmetics. In the present invention, the cosmetics are not particularly limited, but examples thereof include perfume, cream, emulsion, skin lotion, lotion, face mask, foundation, lip balm, lipstick, hair tonic, hair lotion, shampoo, rinse, and conditioner.

[0112] -Drug / quasi-drug package- The drug / quasi-drug package of the present invention comprises the polyester film of the present invention and a drug / quasi-drug covered with the polyester film.

[0113] Depending on the intended use, the pharmaceutical / quasi-drug package may be partially or entirely composed of the packaging material (the polyester film of the present invention). Examples of the pharmaceutical / quasi-drug package include blister packs, bags, trays, packs, and containers. The pharmaceutical / quasi-drug package is used to package various pharmaceuticals and quasi-drugs. In the present invention, pharmaceuticals and quasi-drugs refer to pharmaceuticals and quasi-drugs defined in Article 2, Paragraphs 1 and 2 of the Pharmaceutical and Medical Device Act. These pharmaceuticals and quasi-drugs may be in oral dosage forms such as liquids, suspensions, tablets, capsules, and powders, or parenteral dosage forms such as ointments, patches, poultices, dentifrices, mouthwashes, mouth fresheners, gels, ointments, gargle tablets, sprays, and aerosols.

[0114] (Product) The product of the present invention comprises a packaged item containing an organic compound and the polyester film of the present invention that packages the packaged item, and at least a portion of the polyester film is fused to itself.

[0115] The product of the present invention comprises a packaged item (contents) containing an organic compound and at least one polyester film selected from the polyester film of the first embodiment and the polyester film of the second embodiment, which packages the packaged item. In the product of the present invention, at least portions of the polyester films are fused, particularly heat-fused, to each other. The product of the present invention comprises a packaged item (contents) containing an organic compound and a package that packages the packaged item. It is preferable that the packaged item is completely surrounded (sealed) by the polyester film. According to the product of the present invention, adsorption of organic compounds to the polyester film can be suppressed, thereby maintaining the quality of the packaged item.

[0116] The organic compound may be at least one selected from the group consisting of limonene, camphor, menthol, methyl salicylate, tocopherol acetate, isopropylmethylphenol, ketoprofen, ketoprofen sodium, diclofenac sodium, felbinac, loxoprofen sodium, tulobuterol, rivastigmine, clopumazine hydrochloride, haloperidol, risperidone, paliperidone, blonanserin, perospirone hydrochloride hydrate, lurasidone hydrochloride, olanzapine, quetiapine fumarate, asenapine maleate, clozapine, aripiprazole, and brexpiprazole.

[0117] Limonene can be used, for example, as a citrus fragrance, etc. Examples of packaged items containing limonene as an organic compound include hair care cosmetics and skin care cosmetics.

[0118] Camphor can be used, for example, as a blood circulation improver, anti-inflammatory agent, analgesic, etc. Examples of packaged items containing camphor as an organic compound include pharmaceuticals and quasi-drugs such as patches.

[0119] Menthol can be used, for example, as a fragrance, a flavoring agent, a deodorant, etc. Examples of packaged items containing menthol as an organic compound include pharmaceuticals such as patches, quasi-drugs, dentifrices, cosmetics, beverages, and foods such as confectionery.

[0120] Methyl salicylate can be used, for example, as an analgesic, an anti-inflammatory agent, etc. Examples of packaged items containing methyl salicylate as an organic compound include pharmaceuticals and quasi-drugs such as patches.

[0121] Tocopherol acetate can be used, for example, as a therapeutic agent for vitamin E deficiency, a blood circulation promoter, etc. Examples of packaged items containing tocopherol acetate as an organic compound include pharmaceuticals and quasi-drugs such as patches.

[0122] Isopropylmethylphenol can be used, for example, as a disinfectant, etc. Examples of packaged items containing isopropylmethylphenol as an organic compound include external skin preparations such as ointments, cosmetics, etc.

[0123] Ketoprofen, ketoprofen sodium, and loxoprofen sodium can be used, for example, as an anti-inflammatory agent, analgesic, antipyretic, etc. Packaged items containing ketoprofen, ketoprofen sodium, or loxoprofen sodium as an organic compound include, for example, pharmaceuticals and quasi-drugs such as patches.

[0124] Diclofenac sodium and felbinac can be used, for example, as an anti-inflammatory agent, an analgesic, etc. Packaged items containing diclofenac sodium or felbinac as an organic compound include, for example, pharmaceuticals and quasi-drugs such as patches.

[0125] Tulobuterol can be used, for example, as a bronchodilator, etc. Examples of packaged items containing tulobuterol as an organic compound include pharmaceuticals and quasi-drugs such as patches.

[0126] Rivastigmine can be used, for example, as a therapeutic agent for Alzheimer's disease, etc. Examples of packaged items containing rivastigmine as an organic compound include pharmaceuticals and quasi-drugs such as patches.

[0127] Clopumazine hydrochloride and haloperidol can be used, for example, as antipsychotic drugs, etc. Packaged items containing clopmazine hydrochloride or haloperidol as an organic compound include, for example, pharmaceuticals such as antipsychotic drugs.

[0128] Risperidone, paliperidone, blonanserin, perospirone hydrochloride hydrate, and lurasidone hydrochloride can be used, for example, as an SDA (serotonin dopamine antagonist), etc. Packaged items containing risperidone, paliperidone, blonanserin, perospirone hydrochloride hydrate, or lurasidone hydrochloride as an organic compound include, for example, pharmaceuticals such as antipsychotic drugs.

[0129] Olanzapine, quetiapine fumarate, asenapine maleate, and clozapine can be used, for example, as MARTA (multi-receptor acting antipsychotics), etc. Packaged items containing olanzapine, quetiapine fumarate, or clozapine as an organic compound include, for example, pharmaceuticals such as antipsychotic drugs.

[0130] Aripiprazole and brexpiprazole can be used, for example, as DPA / DSS (dopamine partial agonists), etc. Packaged items containing aripiprazole or brexpiprazole as an organic compound include, for example, pharmaceuticals such as antipsychotic drugs.

[0131] Examples of the present invention will be described below, but the present invention is not limited to these examples in any way.

[0132] (Synthesis Example 1 of Polyester Resin 1) 99.8 mol % of terephthalic acid, 0.2 mol % of trimellitic anhydride, 70 mol % of ethylene glycol, and 30 mol % of neopentyl glycol were charged into a stainless steel (registered trademark) autoclave equipped with a stirrer and a distillation column, and esterification was carried out under conditions of 250°C and 250 kPa. Thereafter, triethyl phosphate and germanium dioxide were charged, and a polycondensation reaction was carried out at 275°C and a reduced pressure of 100 Pa until a predetermined viscosity was reached. The mixture was extruded into cooling water and pelletized using a strand cutter. In this manner, polyester resin 1 (hereinafter sometimes referred to as "resin 1") was synthesized. The intrinsic viscosity (IV) of the obtained resin 1 was 0.83 dl / g.

[0133] <Intrinsic Viscosity> 0.5000±0.0005 g of polyester resin was dissolved in a mixed solvent of phenol:tetrachloroethane = 60:40 (mass ratio), and the intrinsic viscosity (IV) of the polyester resin at 20°C was measured using an automatic viscometer (AVL-6C, manufactured by Sun Electronics Industries Co., Ltd.).

[0134] (Synthesis Examples 2 to 7 of Polyester Resins 2 to 7) Polyester Resins 2 to 7 (hereinafter sometimes referred to as "Resins 2 to 7") were synthesized in the same manner as in Synthesis Example 1 of Resin 1, except that in Synthesis Example 1 of Polyester Resin 1, the types and amounts of monomers in the charged composition were changed to those shown in Table 1. Polyester Resin 8 (Resin 8) is a commercially available product.

[0135] Next, the resin composition of each of the obtained polyester resins was measured by NMR as follows: The results of the resin composition are shown in Table 1 together with the molar composition of the charged monomers.

[0136] <Composition of Polyester Resin> Using an FT-NMR apparatus (DPX400 model, manufactured by Bruker Biospin), a polyester resin was dissolved in deuterated chloroform, and tetramethylsilane was mixed as a standard. The proton NMR spectrum was measured, and the type and content of each unit were calculated from the obtained NMR spectrum.

[0137]

[0138] The following abbreviations are used in Table 1: TPA: terephthalic acid IPA: isophthalic acid TMA: trimellitic acid EG: ethylene glycol NPG: neopentyl glycol (2,2-dimethyl-1,3-propanediol) CHDM: 1,4-cyclohexanedimethanol DEG: diethylene glycol

[0139] (Test Examples 1 to 29) Using polyester resins 1 to 8 shown in Table 1 (resin 8 is a commercially available product) and commercially available L-LDPE (linear low-density polyethylene), polyester films shown in Tables 2-1 to 2-5 were produced as follows.

[0140] [Film Production] Using a T-die method, polyester films of Test Examples 1 to 27 shown in Tables 2-1 to 2-5 were produced by coextrusion at a molding temperature of 280° C. The films of Test Examples 28 and 29 were commercially available products.

[0141] In Test Examples 1 to 17 and 21 to 27, the resulting melt was fed into a T-die, formed into a sheet, extruded from a nozzle, and cooled and solidified on a cast roll to obtain polyester films (unstretched) with the thicknesses shown in Tables 2-1 to 2-5. The tensile elongation of the resulting polyester films was 200% or more. In Test Example 18, a polyester film prepared in the same manner as in Test Example 5 was uniaxially stretched at a ratio of 3.5 times in the machine direction (MD) at a temperature of 90°C to obtain a polyester film with a thickness of 30 μm. In Test Example 19, a polyester film prepared in the same manner as in Test Example 13 was uniaxially stretched at a ratio of 3.5 times in the MD at a temperature of 90°C to obtain a polyester film with a thickness of 30 μm. In Test Example 20, a polyester film prepared in the same manner as in Test Example 13 was biaxially stretched three times in the machine direction at a temperature of 80°C and three times in the transverse direction (TD) at a temperature of 95°C, and then heat-set at a temperature of 180°C to obtain a polyester film having a thickness of 30 μm.

[0142] The properties of the obtained polyester films of each test example were evaluated as follows. The results are shown in Tables 2-1 to 2-5. The content of the first polyester resin in the polyester film in Tables 2-1 to 2-5 refers to the content of the first polyester resin defined in claim 1, and specifically refers to the content of polyester resin 1, polyester resin 2, or polyester resin 3 in Table 1 that corresponds to the first polyester resin.

[0143] <Seal Strength> Two polyester films 1 and 2 were prepared from each polyester film of each test example, and the first layers of the two polyester films 1 and 2 were overlapped with each other. Using a heat sealer (TP-701-B HEAT SEAL TESTER manufactured by Tester Sangyo Co., Ltd.), the laminates were heat-sealed at temperatures of 130°C, 140°C, and 150°C for 2 seconds at a pressure of 0.2 MPa. The resulting laminates were then cut into 15 mm wide rectangular test pieces, and the crimped portions of the test pieces were pulled at a pulling rate of 100 mm / min using a tensile tester (TECHNO GRAPH TG-5kN manufactured by Minebea Co., Ltd.), to measure the seal strength and evaluate it according to the following criteria. [Evaluation Criteria] A: Seal strength of 15 N / 15 mm or more B: Seal strength of less than 15 N / 15 mm

[0144] <Adsorption Test> The polyester film of each test example was cut into a 4 cm x 4 cm square, and the initial mass A of each test piece was measured. The test piece was placed in the bottom of a beaker with the seal layer (first layer) facing up, and 5 ml of limonene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added thereto. The beaker was then covered with aluminum foil and stored at 25°C for 7 days. After storage for 7 days, the test piece was removed, and the limonene adhering to the surface of the test piece was wiped off and removed. The mass of the test piece was then measured, and the amount of limonene adsorbed was calculated from the difference (B - A) between the initial mass A and the mass B after storage for 7 days. The limonene adsorption was evaluated according to the following criteria. [Evaluation Criteria] A: The amount of limonene adsorbed was 0.2 mg / cm ２ B: Limonene adsorption amount is 0.2 mg / cm ２ super

[0145] <Melting Enthalpy (ΔHm)> A 10 mg test piece was cut out from the polyester film of each test example and measured using a differential scanning calorimeter (DSC2500, manufactured by TA Instruments Japan Co., Ltd.) from 25°C to 300°C at a heating rate of 10°C / min. The endothermic peak from 220°C to 260°C was integrated to determine the melting enthalpy (ΔHm).

[0146] <Tear Strength> Measurement was performed based on the trouser tear method of JIS K7128-1 (1998). A test specimen was cut from the polyester film of each test example into a strip measuring 150 mm long and 50 mm short. A 75 mm long slit was made in the center of the short side parallel to the long side. Tensile tests were performed in the machine direction (MD) and the transverse direction (TD) at a speed of 200 mm / min using a tensile tester (Minebea Co., Ltd., TECHNO GRAPH TG-5kN) at 23°C. The tear strength was calculated by dividing the average tear load at 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, and 70 mm from the start of tearing of the test specimen by the thickness of the test specimen.

[0147] <Elastic Modulus> The polyester film of each Test Example was cut into a strip shape with a long side of 100 mm and a short side of 10 mm. Tensile tests were performed on test pieces in the machine direction (MD) and the transverse direction (TD) at a rate of 50 mm / min using a tensile tester (manufactured by Minebea Co., Ltd., TECHNO GRAPH TG-5kN) in an environment of 23°C, to measure the elastic modulus in the machine direction (MD) and the transverse direction (TD), and the average value was calculated.

[0148] <Heat Shrinkage Rate> A test specimen cut into a square shape with sides of 200 mm from the polyester film of each test example was placed in a fan oven heated to 90°C and allowed to stand for 3 minutes. The lengths of the test specimen in the longitudinal (MD) direction and the transverse (TD) direction were measured (A) before leaving it standing. After 3 minutes had elapsed, the test specimen was removed from the fan oven and the lengths of the test specimen in the longitudinal (MD) direction and the transverse (TD) direction were measured (B). From the measured lengths A and B, the heat shrinkage rate (%) = [(A - B) / A] x 100 was calculated.

[0149]

[0150]

[0151] *1: Measurement is not possible because the material is torn at an angle.

[0152]

[0153] *Resin 8: Commercially available product (polyester resin) *L-LDPE: Commercially available product (linear low-density polyethylene)

[0154] In Test Examples 1 to 29 in Tables 2-1 to 2-5, the adsorption properties were evaluated using limonene as a representative organic compound. However, the same level of adsorption results was also obtained when camphor, menthol, methyl salicylate, tocopherol acetate, isopropylmethylphenol, ketoprofen, ketoprofen sodium, diclofenac sodium, felbinac, loxoprofen sodium, tulobuterol, rivastigmine, clopumazine hydrochloride, haloperidol, risperidone, paliperidone, blonanserin, perospirone hydrochloride hydrate, lurasidone hydrochloride, olanzapine, quetiapine fumarate, asenapine maleate, clozapine, aripiprazole, or brexpiprazole was used instead of limonene.

[0155] The results in Tables 2-1 to 2-5 indicate that Test Examples 1 to 12, 18, 22 to 23, and 25 to 26 satisfied all of the following requirements (A) to (C), thereby enabling the production of polyester films that exhibit low adsorption to organic compounds in packaged materials and high seal strength, as well as packages and products using the polyester films. (A) The polyester film contains a first polyester resin including first acid units and first alcohol units, wherein the first acid units contain 90 mol% or more of terephthalic acid units relative to the total amount of the first acid units, and the first alcohol units contain 50 mol% or more of ethylene glycol units, 5 mol% to 40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1 mol% to 5 mol% of diethylene glycol units relative to the total amount of the first alcohol units. (B) The content of the first polyester resin is 80 mass% or more relative to the total amount of the polyester film. (C) The thickness of the polyester film is 25 μm to 100 μm.

[0156] Furthermore, it is also desirable for the polyester film of the present invention to have low adsorption to organic compounds in the packaged goods, high seal strength, and excellent hand-tearability and shapeability. Therefore, it is preferable that the polyester film satisfy all of the above requirements (A) to (C) and also satisfy at least one of the following requirements (D) to (J), and it is particularly preferable that the polyester film satisfy all of the requirements (A) to (J). (D) In ​​differential scanning calorimetry (DSC) of the polyester film, the melting enthalpy (ΔHm) calculated by integrating the endothermic peak between 220°C and 260°C when measured from 25°C to 300°C at a heating rate of 10°C / min is 10 J / g or less. (E) The tear strength of the polyester film measured by subjecting it to a tensile test at 23°C and 200 mm / min is 2 N / mm to 15 N / mm in both the longitudinal and transverse directions. (F) The elastic modulus of the polyester film was determined by performing a tensile test at 23°C and 50 mm / min. in both the longitudinal and transverse directions of the film was 1.6 kN / mm. ２ ~2.2 kN / mm ２(G) The heat shrinkage rate of the polyester film before and after 3 minutes of heat treatment in hot air at 90°C is 10% or less in both the longitudinal and transverse directions. (H) When two polyester films 1 and 2 are thermocompression bonded under conditions of 130°C to 150°C, 0.2 MPa, and 2 seconds, the seal strength between polyester film 1 and polyester film 2 is 15 N / 15 mm to 50 N / 15 mm. (I) The polyester film is cut into a 4 cm x 4 cm square test piece, the initial mass of the test piece is measured, the test piece is placed in a beaker, 5 ml of limonene is added, the beaker is covered, and the test piece is stored at 25°C for 7 days. The mass of the test piece is then measured, and the difference (B - A) between the initial mass A and the mass B after storage for 7 days, that is, the limonene adsorption amount, is 0.2 mg / cm. ２ (J) The polyester film is unstretched.

[0157] Test Examples 1 to 12, 22 to 23, and 25 to 26 met all of the requirements (A) to (J) above, and were therefore found to have low adsorption to organic compounds in the packaged items, high seal strength, and excellent low adsorption and hand tearability.

[0158] Test Example 13 did not satisfy the requirements (A), (D), and (E) above, and as a result, the melting enthalpy (ΔHm) was high, resulting in poor hand-tearability.

[0159] Test Examples 14, 15, and 17 did not satisfy the requirements (A), (D), and (E) above, and the polyester films did not contain 2,2-dimethyl-1,3-propanediol units, resulting in a high melting enthalpy (ΔHm), and therefore poor hand-tearability.

[0160] Test Example 16 did not satisfy the requirements (A) and (I) above, and because the content of 2,2-dimethyl-1,3-propanediol units was high, the amount of limonene adsorbed was large, resulting in poor low adsorption properties for organic compounds in the packaged items.

[0161] Test Example 18 did not satisfy the requirements (D), (E), (F), (G) and (J) above, and was stretched in the MD direction, resulting in poor formability due to the high elastic modulus, tear strength and thermal shrinkage rate in the MD direction.

[0162] Test Example 19 did not satisfy the requirements (A), (D), (E), (F), (G), and (J) above, and was stretched in the MD direction, resulting in poor shapability due to high MD modulus, tear strength, and heat shrinkage. In addition, the melting enthalpy (ΔHm) was high, resulting in poor hand-tearability.

[0163] Test Example 20 did not satisfy the requirements (A), (D), (F), and (J) above, and was stretched in both the MD and TD directions, resulting in a high elastic modulus and poor shaping ability. Also, the melting enthalpy (ΔHm) was high, resulting in poor hand-tearability.

[0164] Test Example 21 did not satisfy the requirements (C) and (H) above, and the thickness of the polyester film was thin, resulting in poor seal strength.

[0165] Test Example 24 did not satisfy the requirements (C) and (I) above, and because the polyester film was thick, the amount of limonene adsorbed was large, resulting in poor low adsorption of organic compounds in the packaged items.

[0166] Test Example 27 did not satisfy the requirements (A) and (I) above, and since the content of the first polyester resin was low, the amount of limonene adsorbed was large, resulting in poor low adsorption properties for organic compounds in the packaged items.

[0167] Test Example 28 did not satisfy the requirements (A), (G), and (I) above, resulting in a high thermal shrinkage rate and poor shapability. In addition, because the polyester film did not contain 2,2-dimethyl-1,3-propanediol units but contained 1,4-cyclohexanedimethanol units, the amount of limonene adsorbed increased, resulting in poor low adsorption of organic compounds in the packaged items.

[0168] Test Example 29 did not satisfy the above requirements (A), (D), (E), (F), (H), and (I). It used commercially available linear low-density polyethylene (L-LDPE), and the results showed poor shapability and hand-tearability. In addition, the amount of limonene adsorbed was large, resulting in poor low adsorption of organic compounds in the packaged items.

[0169] The polyester film of the present invention has low adsorption properties for organic compounds in the packaged items, high seal strength, and preferably excellent hand-tearability and shapeability, and is therefore widely used for laminates and various types of packaging, and is particularly suitable for use in packaging for food and beverages, cosmetics, and pharmaceuticals and quasi-drugs.

[0170] REFERENCE SIGNS LIST 1 Polyester film 2 First layer 10 Polyester film 11 First layer 12 Second layer 20 Polyester film 21 First layer 22 Second layer 23 Third layer

Claims

1. A polyester film containing a first polyester resin comprising a first acid unit and a first alcohol unit, and an antiblocking agent, The first acid unit contains 90 mol% or more of terephthalic acid units relative to the total amount of the first acid unit. The first alcohol unit comprises, with respect to the total amount of the first alcohol unit, 50 mol% or more of ethylene glycol units, 5 mol% to 40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1 mol% to 5 mol% of diethylene glycol units. The content of the first polyester resin is 80% by mass or more relative to the total amount of the polyester film. The content of the antiblocking agent is 0.05% by mass to 1% by mass. A polyester film characterized in that the thickness of the polyester film is 25 μm to 100 μm.

2. The polyester film according to claim 1, wherein, in differential scanning calorimetry (DSC) of the polyester film, the enthalpy of fusion (ΔHm) calculated by integrating the endothermic peaks between 220°C and 260°C when measured from 25°C to 300°C at a heating rate of 10°C / min is 10 J / g or less.

3. The polyester film was subjected to a tensile test at 23°C and 200 mm / min, and the resulting tear strength was determined to be between 2 N / mm and 15 N / mm in both the longitudinal and width directions. The aforementioned polyester film was subjected to a tensile test at 23°C and 50 mm / min, and the resulting modulus of elasticity was determined to be 1.6 kN / mm² to 2.2 kN / mm² in both the longitudinal and width directions. The polyester film according to claim 1.

4. The first alcohol unit comprises, with respect to the total amount of the first alcohol unit, 50 mol% or more of ethylene glycol units, 15 mol% to 40 mol% of 2,2-dimethyl-1,3-propanediol units, and 0.1 mol% to 5 mol% of diethylene glycol units. The polyester film according to claim 1, wherein the total content of the ethylene glycol units and the 2,2-dimethyl-1,3-propanediol units is 95 mol% or more relative to the total amount of the first alcohol units.

5. The polyester film according to claim 1, wherein the heat shrinkage rate before and after heating the polyester film in hot air at 90°C for 3 minutes is 10% or less in both the longitudinal and width directions.

6. The polyester film according to claim 1, wherein when two polyester films 1 and 2 are heat-pressed together under the conditions of 130°C to 150°C, 0.2 MPa, and 2 seconds, the seal strength between polyester film 1 and polyester film 2 is 15 N / 15 mm to 50 N / 15 mm.

7. The initial mass of a test piece cut from the polyester film into a 4 cm x 4 cm square was measured. The test piece was placed in a beaker, 5 ml of limonene was added, the beaker was covered, and it was stored at 25°C for 7 days. After that, the mass of the test piece was measured, and the difference between the initial mass A and the mass B after 7 days of storage (B - A) was determined to be the amount of limonene adsorbed, which is 0.2 mg / cm³. ２ The polyester film according to claim 1, which is as follows:

8. The polyester film according to claim 1, wherein the polyester film is an unstretched material.

9. The polyester film according to claim 1, wherein the first polyester resin further comprises crosslinking agent units.

10. The polyester film according to claim 1, wherein the first acid units further comprise 0.05 mol% to 5 mol% of trimellitic acid units relative to the total amount of the first acid units.

11. It has a first layer and a second layer, The first layer contains 80% by mass or more of the first polyester resin relative to the mass of the first layer, and less than 20% by mass of the second polyester resin relative to the mass of the first layer. The polyester film according to claim 1, wherein the second layer contains 90% by mass or more of the first polyester resin relative to the mass of the second layer.

12. A third layer is further provided between the first layer and the second layer. The third layer comprises the first polyester resin in an amount of 80% by mass or more relative to the mass of the third layer, and the second polyester resin in an amount of less than 20% by mass relative to the mass of the third layer. A polyester film according to claim 11, comprising the same material.

13. The polyester film according to claim 12, wherein the third layer further contains 0.05% to 1% by mass of an antiblocking agent relative to the mass of the third layer.

14. A laminate having a base film and a sealant layer, A laminate comprising the sealant layer containing the polyester film described in any one of claims 1 to 13.

15. Having a polyester film according to any one of claims 1 to 13, A packaging in which at least a portion of the aforementioned polyester film is fused together.

16. A food and beverage packaging, cosmetic packaging, or pharmaceutical / quasi-drug packaging characterized by comprising a polyester film according to any one of claims 1 to 13, and food and beverages, cosmetics, or pharmaceuticals / quasi-drugs covered with the polyester film.

17. Packaged materials containing organic compounds, A polyester film according to any one of claims 1 to 13 for packaging the aforementioned packaged item, A product in which at least a portion of the aforementioned polyester film is fused together.

18. The product according to claim 17, wherein the organic compound is at least one selected from the group consisting of limonene, camphor, menthol, methyl salicylate, tocopherol acetate, isopropylmethylphenol, ketoprofen, ketoprofen sodium, diclofenac sodium, felbinac, loxoprofen sodium, tulobuterol, rivastigmine, chlorpromazine hydrochloride, haloperidol, risperidone, paliperidone, blonanserin, perospirone hydrochloride hydrate, lurasidone hydrochloride, olanzapine, quetiapine fumarate, asenapine maleate, clozapine, aripiprazole, and brexpiprazole.