Polyester-based laminated film, laminate, packaging bag, and packaging

Abstract

To provide a polyester-based laminate film excellent in heat sealability, aroma retention, thermal resistance, and impact resistance and useful as a material for a packaging bag, and to provide a laminate, a packaging bag, and a package made thereof.SOLUTION: A polyester-based laminate film includes a seal layer containing a polyethylene terephthalate-based resin having a crystal melting peak temperature of 190-270°C of 40.0-80.0 mass%, a thermoplastic copolyester resin having a crystal melting peak temperature of 90-180°C of 10.0-40.0 mass%, and a polyolefin-based resin of 2.0-20.0 mass% and a main layer containing a polyethylene terephthalate-based resin of 90 mass% or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester laminated film, a laminate, a packaging bag, and a packaging body in which contents are filled into a packaging bag. [Background technology]

[0002] Various types of packaging bags are widely used for food, pharmaceuticals, and other products. For sealing these bags, flexible packaging bags are commonly used, consisting of laminates with polyethylene or polypropylene film as the innermost layer, offering excellent heat-sealing and impact-resistant properties. However, because polyethylene and polypropylene adsorb the flavors of some foods and the active ingredients of pharmaceuticals, flexible packaging bags are unsuitable for certain contents, and metal cans or glass bottles continue to be used.

[0003] Polyester resins are known as materials with excellent fragrance retention and non-adsorbent properties. Typical examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN). In particular, biaxially oriented PET films are widely used as a base material for packaging bags. Recently, heat-sealable PET films have been launched that can be used as the innermost layer that comes into direct contact with the contents requiring aroma retention.

[0004] Patent Document 1 discloses a laminated polyester film in which a polyethylene terephthalate polymer in which 6 to 40 mol% of the total dicarboxylic acid components and / or total diol components are copolymer components is laminated with a polyethylene terephthalate polymer in which 0.5 to 5 mol% of the total dicarboxylic acid components and / or total diol components are copolymer components.

[0005] Patent Document 2 discloses a laminated material for paper containers, in which a chain extender consisting of styrene-(meth)acrylate methyl-methacrylate glycidyl is added to PET resin, the material is fed into an extruder, and an extruded PET resin layer is laminated onto a paper layer.

[0006] Patent Document 3 discloses a laminated film in which a polyester-based hot-melt resin having a glass transition temperature of -22°C or higher and 0°C or lower, and a melting point of 100°C or higher and 130°C or lower is laminated onto a biaxially oriented PET film.

[0007] Meanwhile, in line with the United Nations' Sustainable Development Goals (SDGs), the development and adoption of environmentally friendly packaging materials are being promoted in countries around the world. As part of this effort, packaging materials made primarily from a single, easily recyclable material, known as "monomaterials," are attracting attention. In particular, there is a growing movement to use polyester resins, which are relatively easy to recycle, as a single material. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 3-47752 [Patent Document 2] Patent No. 5180272 [Patent Document 3] Japanese Patent Publication No. 2001-279226 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Packaging bags formed using the films or laminates disclosed in Patent Documents 1 to 3 have excellent aroma retention and heat resistance. However, when impact stress such as dropping or collision is applied to the packaging bag, there is a risk of rupture or damage. This is thought to be because PET film has a lower tensile strength and impact resistance compared to polyethylene film and polypropylene film, which are widely used as packaging materials. Therefore, if the contents of the package are liquid, there is a possibility that the liquid leaking due to impact rupture may contaminate the surrounding area of ​​the package.

[0010] This invention has been made in view of the above circumstances, and aims to provide polyester laminated films, laminates, packaging bags, and packaging materials that are excellent in heat sealability, aroma retention, heat resistance, and impact resistance, and are useful as materials for packaging bags. [Means for solving the problem]

[0011] As a result of diligent research, the inventors of the present invention have found that the above problems can be solved by using a polyester-based laminated film, laminate, packaging bag, and packaging body having the following configuration, and have completed the present invention. In other words, the present invention relates to the polyester-based laminated film, laminate, packaging bag, and packaging body shown below. [Item 1] A seal layer containing 40.0 to 80.0% by mass of polyethylene terephthalate resin with a crystal melting peak temperature of 190 to 270°C, 10.0 to 40.0% by mass of thermoplastic copolymer polyester resin with a crystal melting peak temperature of 90 to 180°C, and 2.0 to 20.0% by mass of polyolefin resin, A main layer containing 90% or more by mass of polyethylene terephthalate resin, A polyester laminated film having the following characteristics. [Item 2] The sealing layer is a polyester laminated film according to Item 1, containing a polybutylene terephthalate resin. [Item 3] The polyester laminated film according to item 1 or 2, wherein the crystal melting peak temperature of the thermoplastic copolymer polyester resin is 100 to 135°C. [Item 4] Polyolefin resin is a polyester laminated film according to any one of items 1 to 3, containing a polyethylene resin. [Item 5] A laminate comprising a polyester-based laminated film as described in any one of items 1 to 4. [Item 6] A packaging bag formed by heat-sealing the sealing layers of a polyester laminated film described in any one of items 1 to 4 or a laminate described in item 5. [Item 7] A packaging bag with a spout, comprising the packaging bag described in Item 6 and a spout that allows communication between the internal space of the packaging bag and the outside. [Claim 8] A package obtained by filling contents into the packaging bag according to claim 6 or 7.

Effects of the Invention

[0012] According to the present invention, there can be provided a polyester-based laminated film which is excellent in heat sealability, aroma retention, heat resistance and impact resistance and is useful as a material for packaging bags, as well as a laminate, a packaging bag and a package using the same.

Brief Description of Drawings

[0013] [Figure 1] A perspective view showing an example in which a spouted packaging bag according to an embodiment of the present invention is filled with contents.

Mode for Carrying Out the Invention

[0014] <Polyester-based Laminated Film> (Seal Layer) The seal layer in the polyester-based laminated film of the present invention contains 40.0 to 80.0 mass% of a polyethylene terephthalate-based resin having a crystal melting peak temperature of 190 to 270°C, 10.0 to 40.0 mass% of a thermoplastic copolymerized polyester resin having a crystal melting peak temperature of 90 to 180°C, and 2.0 to 20.0 mass% of a polyolefin-based resin. As the resin contained in the seal layer, a commercially available product or a synthesized product may be used.

[0015] {Polyethylene Terephthalate-based Resin} The polyethylene terephthalate-based resin having a crystal melting peak temperature of 190 to 270°C is a resin having a crystal melting peak temperature of 190 to 270°C obtained by polycondensation of a polycarboxylic acid component, wherein 90 mol% or more, preferably 95 mol% or more of the polycarboxylic acid component is a terephthalic acid component, and a polyol component, wherein 90 mol% or more, preferably 95 mol% or more of the polyol component is ethylene glycol. The polyethylene terephthalate-based resins may be used alone or in a mixture of two or more thereof. The polycarboxylic acid component may be a derivative of a free acid, a halide, an alkyl ester with 1 to 4 carbon atoms in the alkyl group, an alkali metal salt, or an anhydride.

[0016] Examples of polycarboxylic acid components other than terephthalic acid include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, dibromoisophthalic acid, hydroxyisophthalic acid, sodium sulfisophthalate, phenylenedioxydicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylketonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. One or more substances selected from the group consisting of: acids or their derivatives; alicyclic dicarboxylic acids or their derivatives such as hexahydroterephthalic acid and hexahydroisophthalic acid; aliphatic carboxylic acids or their derivatives such as maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadycarboxylic acid, and dodecadycarboxylic acid; trifunctional or more carboxylic acids such as tricarbaryl acid, trimellitic acid, trimesic acid, pyromellitic acid, and naphthalenetetracarboxylic acid.

[0017] Other polyol components besides ethylene glycol include, for example, aliphatic diols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, 1,3-butanediol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, polyethylene glycol, and polytetramethylene ether glycol; alicyclic diols such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, and 2,5-norbornanedimethylol; xylylene glycol, 4 One or more selected from the group consisting of: aromatic diols such as ,4'-dihydroxybiphenyl, 2,2-bis(4'-hydroxyphenyl)propane, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, and bis(4-β-hydroxyethoxyphenyl)sulfonic acid; alkylene oxide adducts of aromatic diol components such as ethylene oxide adducts of 2,2-bis(4'-hydroxyphenyl)propane and propylene oxide adducts of 2,2-bis(4'-hydroxyphenyl)propane; and trifunctional or more polyols such as trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, and sugar esters.

[0018] Furthermore, one or more copolymer components other than the polycarboxylic acid and polyol components may be used, for example, hydroxycarboxylic acids or alkoxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, and gallic acid; monoalcohols such as stearyl alcohol, heneicosanol, octacosanol, and benzyl alcohol; and monocarboxylic acids such as stearic acid, behenic acid, benzoic acid, t-butylbenzoic acid, and benzoylbenzoic acid.

[0019] The peak crystalline melting temperature of polyethylene terephthalate resins is 190 to 270°C, preferably 200°C or higher, more preferably 240°C or higher, and preferably 265°C or lower. The crystal melting peak temperature is determined in accordance with JIS K 7121, using differential scanning calorimeter (DSC) measurement, and is either the temperature of the maximum intensity endothermic peak detected during the second heating process at a heating rate of 10°C / min, or, in the case of commercially available products, the catalog value.

[0020] The intrinsic viscosity of polyethylene terephthalate resins is not particularly limited. For example, it is 0.50 dl / g or more, preferably 0.60 dl / g or more, more preferably 0.70 dl / g or more, and for example, 0.95 dl / g or less, preferably 0.92 dl / g or less, more preferably 0.90 dl / g or less. The intrinsic viscosity is measured by dissolving the polyethylene terephthalate resin in a phenol:tetrachloroethane = 1:1 mixed solvent and measuring it with an Ubbelohde viscometer at 25°C. If the intrinsic viscosity is less than 0.70 dl / g, the melt viscosity tends to decrease more strongly during the film-forming process, which may make it difficult to form tubular bubbles with a stable diameter during inflation film formation, and may increase the likelihood of drawdown and neck-in during cast film formation. If the intrinsic viscosity exceeds 0.90 dl / g, the melt viscosity becomes high, which may cause the viscosity to become too high and prevent the film from spreading to the ends in the die width direction when forming a film using a multilayer cast film-forming machine equipped with a feed block.

[0021] The polyethylene terephthalate resin content in the seal layer is, for example, 40.0% by mass or more, preferably 45.0% by mass or more, more preferably 50.0% by mass or more, and for example, 80.0% by mass or less, preferably 75.0% by mass or less, more preferably 70.0% by mass or less, relative to the entire seal layer. If it is less than 40.0% by mass, the heat seal strength of the seal layer will decrease, and practical sealing may not be guaranteed. If it exceeds 80.0% by mass, the content of other components will decrease, and sufficient impact resistance may not be obtained.

[0022] {Thermoplastic copolymer polyester resin} Thermoplastic copolymer polyester resins with a crystal melting peak temperature of 90 to 180°C are resins obtained by condensation polymerization of a polycarboxylic acid component and a polyol component, and have a crystal melting peak temperature of 90 to 180°C. Thermoplastic copolymer polyester resins can be distinguished from polyethylene terephthalate resins and polybutylene terephthalate resins in terms of their crystal melting peak temperature. Thermoplastic copolymer polyester resins may be used alone or as a mixture of two or more types. The polycarboxylic acid component used in the polycondensation of thermoplastic copolymer polyester resins is one or more selected from the polycarboxylic acid components described in {polyethylene terephthalate-based resins}. Similarly, the polyol component used in the polycondensation of thermoplastic copolymer polyester resins is one or more selected from the polyol components described in {polyethylene terephthalate-based resins}. These polycarboxylic acid and polyol components are selected such that the crystal melting peak temperature of the thermoplastic copolymer polyester resin is between 90 and 180°C.

[0023] The crystal melting peak temperature of the thermoplastic copolymer polyester resin is 90 to 180°C, preferably 95°C or higher, more preferably 100°C or higher, preferably 150°C or lower, and more preferably 135°C or lower. If the crystal melting peak temperature is below 90°C, the impact resistance during heat sealing may decrease, and if it exceeds 180°C, the low-temperature heat sealability may deteriorate. Commercially available thermoplastic copolymer polyester resins with a crystal melting peak temperature of 90-180°C include the Byron® series from Toyobo Co., Ltd. and the PETG® series from Eastman Chemical Company. Here, the crystal melting peak temperature is obtained by the method described for {polyethylene terephthalate resin}.

[0024] The content of thermoplastic copolymer polyester resin in the seal layer is, for example, 10.0% by mass or more, preferably 12.0% by mass or more, more preferably 15.0% by mass or more, and for example, 40.0% by mass or less, preferably 35.0% by mass or less, and more preferably 30.0% by mass or less, relative to the entire seal layer. If it is less than 10.0% by mass, the heat seal strength may be low and the impact resistance may be poor. If it exceeds 40.0% by mass, the film may block (adhere) to each other, making it difficult to handle as a roll in the processing step.

[0025] {Polyolefin resin} Polyolefin resins are resins obtained by polymerizing one or more α-olefins having 2 to 20 carbon atoms. Examples include one or more selected from the group consisting of low-density polyethylene resin, linear low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, polypropylene resin, and copolymers of ethylene and α-olefins having 3 to 20 carbon atoms. Polyolefin resins may be used individually or as a mixture of two or more. Among these, polyethylene resins, particularly copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, are preferred. This is because the α-olefin side chains intertwine, resulting in excellent elasticity when impact is applied. Examples of α-olefins having 3 to 20 carbon atoms include one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, etc. Preferably, one or more selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The catalyst used when producing the copolymer of ethylene and α-olefins having 3 to 20 carbon atoms is not particularly limited. Examples include Zigler-Natta catalysts and metallocene catalysts. In the present invention, it is preferable to use a metallocene catalyst because linear low-density polyethylene with a narrow molecular weight distribution can be easily obtained and has excellent impact resistance.

[0026] The density of the polyolefin resin is not particularly limited. For example, 0.900 g / cm³. 3or more, preferably 0.913 g / cm 3 or more, for example 0.968 g / cm 3 or less, preferably 0.920 g / cm 3 or less, more preferably 0.917 g / cm 3 or less. When the density is 0.900 g / cm 3 If it is less than this, the polyester-based laminated film tends to be prone to blocking. If the density exceeds 0.920 g / cm 3 If it exceeds, the transparency of the seal layer decreases, so the visibility of the contents of the package tends to decrease. Furthermore, for low-density polyethylene resin, medium-density polyethylene resin, and high-density polyethylene resin mainly composed of ethylene, the respective densities are 0.900 g / cm 3 or more to 0.930 g / cm 3 less than, 0.930 g / cm 3 or more to 0.942 g / cm 3 less than and 0.942 g / cm 3 or more to 0.968 g / cm 3 or less, and for polypropylene resin, it is 0.90 to 0.91 g / cm 3 . The density is a value measured according to the density gradient tube method in JIS K 7112, or a catalog value in the case of a commercially available product.

[0027] The melt flow rate (MFR) of the polyolefin resin is not particularly limited. For example, it is 0.5 g / 10 min or more, preferably 1.0 g / 10 min or more, and 20.0 g / 10 min or less, preferably 15.0 g / 10 min or less. If the MFR is less than 1.5 g / 10 min or more than 20.0 g / 10 min, the polyolefin-based resin may not mix uniformly during melt-kneading when forming the seal layer.

[0028] The polyolefin resin content in the seal layer is, for example, 2.0% by mass or more, preferably 3.0% by mass or more, more preferably 5.0% by mass or more, and for example, 20.0% by mass or less, preferably 18.0% by mass or less, more preferably 16.0% by mass or less, relative to the entire seal layer. If it is less than 2.0% by mass, the seal layer may become brittle and may not have sufficient impact resistance. If it exceeds 20.0% by mass, the heat seal strength will decrease, and the heat seal portion may easily become brittle and fracture under impact stress, making it prone to bag rupture and potentially reducing aroma retention.

[0029] {Polybutylene terephthalate resin} The sealing layer in the polyester laminated film of the present invention may further contain a polybutylene terephthalate resin. Polybutylene terephthalate resins are resins obtained by condensation polymerization of a polycarboxylic acid component in which 90 mol% or more, preferably 95 mol% or more, of the polycarboxylic acid component is terephthalic acid, and a polyol component in which 90 mol% or more, preferably 95 mol% or more, of the polyol component is tetramethylene glycol (1,4-butanediol). The polycarboxylic acid component may be a derivative of a free acid, halide, alkyl ester with 1 to 4 carbon atoms in the alkyl group, alkali metal salt, anhydride, etc. Examples of polycarboxylic acid and polyol components other than terephthalic acid and tetramethylene glycol (1,4-butanediol) components used in the condensation polymerization of polybutylene terephthalate resins include the polycarboxylic acid and polyol components described in {Polyethylene terephthalate resins}. When polybutylene terephthalate resin is included in the seal layer, the pinhole resistance and weather resistance of the seal layer are improved. Furthermore, because it has lower hydrolysis resistance than polyethylene terephthalate resin, pre-drying and other treatments in the film formation process of the seal layer are made easier.

[0030] The peak melting temperature of polybutylene terephthalate resins is not particularly limited, and is, for example, 215 to 230°C. The intrinsic viscosity of polybutylene terephthalate resins is not particularly limited, and is, for example, 0.85 to 1.20 dl / g. If the intrinsic viscosity is less than 0.85 dl / g or greater than 1.20 dl / g, the difference in melt viscosity between the polybutylene terephthalate resin and the polybutylene terephthalate resin may become unsuitable during high-temperature melt kneading in the film-forming process of the seal layer, which may reduce the uniformity of the kneading of the two. Here, the crystal melting peak temperature and intrinsic viscosity are obtained by the method described for {polyethylene terephthalate resin}.

[0031] The content of polybutylene terephthalate resin in the seal layer is, for example, 0% by mass or more, preferably 7.0% by mass or less, for example, 15.0% by mass or less, preferably 12.0% by mass or less, and more preferably 10.0% by mass or less, relative to the entire seal layer. When the polybutylene terephthalate resin content is in the range of 0 to 15.0% by mass, the balance between pinhole resistance, low-temperature heat sealability, and impact resistance of the seal layer is excellent. If it exceeds 15.0% by mass, the heat seal strength decreases, and practical sealing may not be guaranteed.

[0032] {Other components} The sealing layer may contain various additives, to the extent that they do not impair the effects of the present invention. Examples of additives include antistatic agents, antioxidants, lubricants, antiblocking agents (inorganic particles such as silica, organic resin particles such as silicone resin and (meth)acrylic resin, etc.), antifogging agents, colorants (organic pigments, inorganic pigments, etc.), ultraviolet absorbers, dispersants, and fillers (talc, calcium carbonate, etc.).

[0033] (main layer) The main layer of the polyester laminated film of the present invention contains 90% by mass or more of polyethylene terephthalate resin. Examples of polyethylene terephthalate resins used in the main layer include those described in {Polyethylene Terephthalate Resin}. The polyethylene terephthalate resin contained in the main layer and the polyethylene terephthalate resin contained in the heat-seal layer may be the same or different. In the present invention, from the viewpoint of reducing manufacturing costs and recyclability, it is preferable that the polyethylene terephthalate resins contained in the main layer and the heat-seal layer are the same. The main layer may contain less than 10% by mass of various resins and additives, as long as it does not impair the effects of the present invention. The resin is not particularly limited as long as it is a resin other than polyethylene terephthalate resin containing 90% by mass or more. Examples include one or more selected from the group consisting of polyolefin resins, copolymerized polyester resins, polybutylene terephthalate resins, etc. The additives are not particularly limited, and examples include one or more of the various additives described in the <seal layer> section.

[0034] (Composition of polyester laminated film) The layer structure of the polyester-based laminated film of the present invention is not particularly limited. For example, (1-1) to (1-4): (1-1) Sealing layer / Main layer (1-2) Seal layer / Main layer / Main layer (second) (1-3) Seal layer / Intermediate layer / Main layer (1-4) Seal layer / Main layer / Intermediate layer / Main layer (second) This can result in a layered structure such as the following. The main layer (second) can be a heat-resistant resin layer (for example, a polyethylene naphthalate resin layer). In this case, when a packaging bag is formed using the polyester laminated film as is, the outer layer of the bag can be a heat-resistant resin layer, thus widening the range of selectable heat-seal temperatures during packaging bag manufacturing. Furthermore, the seal layer / main layer configuration is preferable because it is easy to control the desired thickness as described later, and it reduces the number of steps in the manufacturing method described later. The intermediate layer can be one or more layers selected from the group consisting of a printed layer, an adhesive layer, a primer layer, a vapor-deposited layer, etc.

[0035] The thickness of the polyester laminated film of the present invention is not particularly limited. The thickness of the polyester laminated film is, for example, 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more, and for example, 200 μm or less, preferably 100 μm or less, more preferably 70 μm or less, and even more preferably 60 μm or less. When the thickness is in the range of 5 μm to 200 μm, a film with a good balance of flexibility and rigidity can be made, it has practical heat sealability and can provide sufficient impact resistance to the formed packaging.

[0036] In the polyester laminated film of the present invention, the ratio of the thickness of the seal layer to the thickness of the main layer, when the total thickness of the polyester laminated film is taken as 100%, is not particularly limited. The thickness of the seal layer is, for example, 5% or more, preferably 10% or more, more preferably 15% or more, even more preferably 20% or more, preferably 50% or less, and even more preferably 40% or less. The thickness of the main layer is, for example, 40% or more, preferably 50% or more, more preferably 60% or more, and for example, 95% or less, preferably 90% or less, even more preferably 85% or less, and even more preferably 80% or less. A larger ratio of the main layer thickness allows for the stable formation of an impact-resistant film and also improves handling properties such as subsequent winding.

[0037] <Laminate> The laminate of the present invention includes a polyester-based laminated film. For example, a base layer may be provided on the surface of the main layer of the polyester-based laminated film where a seal layer is not formed. The base layer may include one or more layers made of, for example, unoriented, uniaxially oriented, or biaxially oriented films of polyester resin, polyamide resin, polyolefin resin, etc.; gas barrier films obtained by vapor-depositing aluminum, silica, alumina, etc. onto these films; paper; metals such as aluminum foil; etc. The base layer may also have two or more base layers that are identical or different to each other, as needed. These base layers can be processed by coloring, printing, etc., and packaging bags with excellent design, gas barrier properties, light shielding properties, pinhole resistance, curl resistance, etc. can be provided. In particular, from the viewpoint of monomaterialization, a polyester-based resin film is preferred for the base layer. An intermediate layer may be provided between the polyester laminated film and the substrate layer, or between multiple substrate layers. Here, the intermediate layer can be one or more layers selected from the group consisting of a printing layer, an adhesive layer, a primer layer, a vapor deposition layer, etc.

[0038] The layer configuration of the laminate of the present invention is not particularly limited. For example, (2-1) to (2-5): (2-1) Polyester laminated film / substrate layer (2-2) Polyester laminated film / intermediate layer / base layer (2-3) Polyester laminated film / Intermediate layer / Intermediate layer / Base layer (2-4) Polyester laminated film / base layer / intermediate layer / base layer (2-5) Polyester laminated film / base layer / base layer This can result in a layered structure such as the following.

[0039] <Method for manufacturing polyester-based laminated films and laminates> The method for manufacturing polyester-based laminated films and laminates is not particularly limited. The preparation of the resins or resin compositions constituting each layer of polyester laminated films and laminates is carried out by mixing the constituent components simultaneously or sequentially. For example, methods include mixing each constituent component in a tumbler, Henschel mixer, etc., and then directly feeding them into a film-making machine, or mixing them in a tumbler, Henschel mixer, etc., and then melt-kneading them using a single-screw extruder, twin-screw extruder, Banbury mixer, kneader, etc. Examples of methods for manufacturing polyester laminated films include a co-extrusion method in which each resin component constituting the seal layer and the main layer is fed into a multi-layer T-die molding machine or a multi-layer inflation molding machine; a melt-extrude lamination method in which the resin components constituting the seal layer are melt-extruded onto at least one surface of the main layer; and a dry lamination method in which the seal layer and the main layer are formed separately. Among these, the co-extrusion method using a multi-layer T-die or multi-layer inflation molding machine is preferred because it requires fewer steps, is simple, and provides sufficiently high interlayer adhesion strength. Examples of methods for manufacturing the laminate include laminating a base layer onto a polyester laminated film using a dry lamination method, laminating a base layer by sandwich lamination via molten polyethylene or the like, laminating a polyester laminated film onto a base layer by multilayer extrusion lamination, and co-extruding all layers constituting the laminate. Among these, dry lamination is particularly preferable for achieving a high monomaterial ratio (in this invention, the total mass %) of polyethylene terephthalate resin and thermoplastic copolymer polyester resin contained in the laminate, as these base layers can be laminated via a thin adhesive.

[0040] <Packaging bags and packaging bodies> The packaging bag of the present invention is formed by heat-sealing the sealing layers of a polyester laminated film or a laminate of polyester laminated films. The form of the packaging bag is not particularly limited and includes three-sided bags, gusseted bags, self-standing bags with a bottom, and bags with a flap. Another example is a packaging bag with a so-called "envelope-type" construction, in which a laminate is created by layering polyester laminated films on both sides of a base material, forming it into a tube, and then heat-sealing the overlapping front and back surfaces. This form does not have the rigid protrusions of the heat-sealed parts of typical packaging materials, reducing the risk of injury to hands during use, and also reduces the surface area of ​​packaging material used, thereby lowering the environmental impact. Furthermore, the polyester laminated film of the present invention, by having a sealing layer containing a thermoplastic copolymer polyester resin and a polyolefin resin, makes it possible to improve the impact resistance of the packaging bag when it is formed.

[0041] The spouted packaging bag of the present invention can be formed by heat-sealing the sealing layers of a polyester laminated film or a laminate of polyester laminated films to form a bag with an open top, and then providing a spout at the opening at the top and heat-sealing it. The spouted packaging bag of the present invention has a spout at the upper end seal portion that communicates with the inside of the bag, and a spout cap is provided at the top of the spout that screws onto the spout to close the spout opening. This allows the contents contained in the packaging bag to be poured or drunk via the spout as needed.

[0042] The material of the spout is not particularly limited. Among these, using a polyester resin is advantageous from the viewpoint of reducing manufacturing costs and recyclability. Furthermore, it is preferable to use a spout formed from a resin composition similar to the composition that constitutes the seal layer of the present invention, as this can strengthen the seal strength with the laminated film or laminate. The spout can be manufactured, for example, by injection molding.

[0043] Figure 1 shows one embodiment of the spouted packaging bag of the present invention. In Figure 1, a packaging bag 20 is formed using a polyester laminated film and / or a laminate 10 according to the present invention, comprising an upper seal portion 11, a side seal portion 12, a bottom seal portion (not shown), a horizontal surface 13, and a lateral gusset portion 14. A spout 21 is heat-sealed and integrated into the upper seal portion 11, and a spout cap 22 is screwed onto the tip of the spout 21, forming a spouted packaging bag 30. By removing the spout cap 22, the contents can be poured out from the spout 22 from inside the spouted packaging bag 30, or the contents can be consumed from the spout 22.

[0044] The packaging of the present invention is formed by filling a packaging bag with contents and heat-sealing the opening of the packaging bag. Alternatively, the packaging of the present invention can be formed by placing a spout on the opening of the packaging bag and heat-sealing it, filling the contents through the spout, and sealing the spout with a cap or the like.

[0045] <Application> The polyester laminated film, laminate, packaging bag, and packaging body of the present invention are suitable for applications requiring airtightness and aroma retention, such as packaging films, packaging bags, and packaging bodies for foods such as tea, coffee, seasonings, spices, fragrances, ham, smoked foods, and tofu; chemical products such as insect repellents, fragrances, bath additives, perfumes, and lotions; and pharmaceuticals such as intravenous fluids and blood products. Furthermore, the polyester laminated film of the present invention can also be suitably used as a sealant film. In particular, it is less likely to tear or break even when subjected to unexpected impact stress during packaging, transportation, storage, and use of the contents, making it especially suitable when the enclosed contents are liquid. Furthermore, in the laminate comprising the polyester laminated film and the base layer of the present invention, when a transparent base layer is used, the contents are easily visible. In addition, the base layer can be printed, colored, vapor-deposited, etc., to provide aesthetic appeal, barrier properties, light-shielding properties, pinhole resistance, curl resistance, etc., making it suitable for a wide range of applications. In particular, when a polyester film is used as the base layer, it is possible to provide a packaging bag and packaging body that has practical heat-sealability and aroma retention properties, as well as high single-material properties and is recyclable. [Examples]

[0046] Examples and comparative examples of the present invention are shown below, but the present invention is not limited to these.

[0047] <Resin / Resin Film> • Polyethylene terephthalate resin (PET): "CR8816" (manufactured by China Resources Corporation, intrinsic viscosity = 0.810 dl / g, crystal melting peak temperature = 247°C) • Polybutylene terephthalate resin (PBT): "500FP" (manufactured by Polyplastics, intrinsic viscosity = 0.875 dl / g, crystal melting peak temperature = 225°C) • Thermoplastic copolymer polyester resin (coPET): "Byron® GM913" (manufactured by Toyobo Co., Ltd., crystal melting peak temperature = 126°C) • Ethylene-α-olefin copolymer (LLD): Ethylene-hexene copolymer, "Evolu® SP1510" (manufactured by Prime Polymer, density = 0.915 g / cm³) 3 (MFR = 1.0g / 10 mins) • Biaxially oriented polyethylene terephthalate film (OPET): "Toyobo Ester® Film E5100" (manufactured by Toyobo Co., Ltd., 12μm thickness)

[0048] <Fabrication of polyester laminated films> Various resins were mixed in a Henschel mixer according to the compositions shown in Table 1 to prepare the seal layer forming component and the main layer forming component. These were placed in the hopper of a two-layer T-die molding machine and film-formed at a die temperature of 285°C to obtain a polyester laminated film (seal layer 10 μm, main layer 30 μm, total thickness 40 μm) having the seal layer and main layer configurations shown in Table 1. A 12 μm thick biaxially oriented polyethylene terephthalate film (OPET) was dry-laminated as a base layer to the surface of the main layer opposite the seal layer of the film to form a laminate, which was used as a sample for packaging material production. Furthermore, even when the sealing layer was prepared using only PET and LLD, film cracking occurred during film formation, making it impossible to create a laminated film.

[0049] [Table 1]

[0050] <Fabrication of laminates and packaging bags> In each laminated film obtained in Examples 1-7 and Comparative Examples 1-5, a biaxially oriented polyethylene terephthalate film (OPET) ("Toyobo Ester® Film E5100", manufactured by Toyobo Co., Ltd., 12 μm thick) was dry-laminated as a base layer to the surface of the main layer that did not have a sealing layer to obtain a laminate. The monomaterial ratio of the obtained laminates was 97.9% (Examples 3, 4, 7) to 99.3% (Examples 5, 6). The resulting laminate was cut to 100 x 300 mm. This was then folded in half to 100 x 150 mm with the sealing layer facing inward, and the two long sides (the sides that make up 150 mm) were heat-sealed at a pressure of 0.2 MPa, a sealing time of 3 seconds, a temperature of 170°C, and a heat seal width of 5 mm to obtain a packaging bag with an opening.

[0051] <Evaluation of the impact resistance of packaging> 100 mL of distilled water was injected into the resulting packaging bag, and the opening was heat-sealed at a pressure of 0.2 MPa, a sealing time of 3 seconds, a temperature of 170°C, and a heat-seal width of 5 mm to obtain a package with a surface (horizontal plane) of 100 × 150 mm. The obtained packages were dropped so that the horizontal surface of the package touched the ground, according to the drop height (distance between the package and the surface of impact) shown in Table 2. If no rupture or damage occurred, the same package was dropped from a higher height, and this process was repeated. The evaluation of the samples was terminated when rupture or damage occurred. The results of the bag rupture were as follows: A: Do not tear the bag B: Part of the heat-sealed area peeled off and the bag ruptured. C: The bag ruptured due to a break at the seal. The results are shown in Table 2.

[0052] <Evaluation of aroma retention of packaging> 10 g of d-limonene was poured into a 300 mL glass bottle with a lid. A metal mesh, with its ends bent to create U-shaped legs, was placed on top of the limonene so as not to come into direct contact with it. The polyester laminated films obtained in Examples 1-7 and Comparative Examples 1-5 were cut to 100 × 250 mm, rolled into cylinders, and placed vertically on top of the mesh, and the bottle was sealed with the lid. This was left standing in a constant temperature and humidity chamber at 50°C × 20% RH, and the weight of the polyester laminated film was measured at regular intervals. The weight increase (%) calculated by the following formula: Weight increase (%) = (Weight at time of measurement - Initial weight) × 100 / Initial weight This was defined as d-limonene adsorbed onto the film. A smaller weight increase indicates superior practical fragrance retention. The results are shown in Table 2.

[0053] [Table 2]

[0054] As is clear from Table 2, the polyester laminated film of the present invention showed a significant improvement in impact resistance as a polyester packaging material. In addition, as is clear from the comparison with polyethylene film and the like listed in Comparative Example 5, it also exhibited excellent aroma retention.

[0055] <Preparation of packaging bags with spouts> (Packaging bag A with spout) A transparent vapor-deposited polyethylene terephthalate resin film ("Barrierox" (registered trademark) 1011HGCW, manufactured by Toray Industries, Inc., 12 μm thick) was prepared as the base layer. A laminate was obtained by dry laminating the side of a polyester laminated film (total thickness 30 μm) prepared with the composition of Example 1 that does not have a sealing layer to the base material layer. From the resulting laminate, two sheets X were cut into 80mm x 135mm rectangles, and two sheets Y were cut into 54mm x 135mm rectangles. The sealing layers of sheet X were aligned, and sheet Y, folded in half with the sealing layer facing outwards to a size of 27 mm x 135 mm, was inserted in pairs between them. The three edges were then heat-sealed at a pressure of 0.2 MPa, a sealing time of 3 seconds, a temperature of 170°C, and a heat-seal width of 5 mm to obtain a gusset bag. A polyester spout, molded from the resin composition of the sealing layer composition of Example 1, was placed at the opening on one edge of the bag, and then heat-sealed to produce a spouted packaging bag A.

[0056] (Packaging bag with spout B) A polyethylene terephthalate resin film ("Espet" (registered trademark) E5102, manufactured by Toyobo Co., Ltd., 12 μm thick) was prepared as base layer 1, and aluminum foil (8021 material, manufactured by UACJ Foil Co., Ltd., 7 μm thick) was prepared as base layer 2. A light-shielding laminate was obtained by dry laminating a polyester laminate film (total thickness 40 μm) prepared with the composition of Example 1 onto the side without a sealing layer, in the order of base layer 2 and then base layer 1. Using the obtained light-shielding laminate, spouted packaging bag B was fabricated in the same manner as spouted packaging bag A.

[0057] <Evaluation of impact resistance of spouted packaging> 180 mL of distilled water was injected into each of the spouted packaging bags A, and the spouts were sealed with caps to obtain packaging body A having a surface (horizontal plane) of 80 × 135 mm. Packaging body B was obtained in the same manner as packaging body A, using spouted packaging bag B. For the obtained packages A and B, they were dropped from 70 cm with the horizontal surface touching the ground. If no rupture or damage occurred, the same packages were dropped repeatedly up to 100 cm. The evaluation of the samples was terminated when rupture or damage occurred. Both spout-equipped packaging bags A and B did not rupture even when dropped from a height of 100 cm. [Explanation of Symbols]

[0058] 10 Polyester-based laminated film / lamination 11 Upper end sealing portion 12 Side seal section 13 Horizontal plane 14 Side gusset section 20 Packaging bag 21 Spout 22 Spout cap 30 spouted packaging bags

Claims

1. A seal layer containing 40.0 to 80.0% by mass of polyethylene terephthalate resin with a crystal melting peak temperature of 240°C to 270°C, 10.0 to 40.0% by mass of thermoplastic copolymer polyester resin with a crystal melting peak temperature of 90°C to 180°C, 2.0 to 20.0% by mass of polyolefin resin, and polybutylene terephthalate resin, A main layer containing 90% or more by mass of polyethylene terephthalate resin, A polyester laminated film having the following characteristics.

2. The polyester laminated film according to claim 1, wherein the crystal melting peak temperature of the thermoplastic copolymer polyester resin is 100°C to 135°C.

3. The polyester laminated film according to claim 1 or 2, wherein the polyolefin resin contains a polyethylene resin.

4. A laminate comprising the polyester-based laminated film according to claim 1 or 2.

5. A packaging bag formed by heat-sealing the sealing layers together using the laminate described in claim 4.

6. A packaging bag with a spout, comprising the packaging bag according to claim 5 and a spout that allows communication between the internal space of the packaging bag and the outside.

7. A package in which contents are filled into a packaging bag as described in claim 5.

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