JP2023009803A - Polyester-based laminated film, laminate using the same, lid material, container, packaging bag and package - Google Patents

Abstract

To provide a polyester-based laminated film, a laminate, a lid material, a container, a packaging bag, and a package having heat sealability capable of being heat-sealed at a temperature, pressure, etc., at which a container body is not deformed, having a necessary seal strength and easy peelability that can stably exhibit easy opening, and excellent in peeling surface appearance characteristics after opening.SOLUTION: There is provided a polyester-based laminated film, including: 40.0 mass% or more and 70.0 mass% or less of a polyethylene terephthalate resin having a crystal melting peak temperature of 190°C or more and 270°C or less; 5.0 mass% or more and 30.0 mass% or less of a thermoplastic copolyester resin having a crystal melting peak temperature of 90°C or more and 180°C or less; a seal layer containing 20.0 mass% or more and 30.0 mass% or less of a polyolefin resin; and a support layer containing 90.0 mass% or more of a polyethylene terephthalate resin.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a polyester-based laminated film, a laminate, a lid material, a container, a packaging bag, and a package using the same.

2. Description of the Related Art In the field of containers and packaging for foods, pharmaceuticals, and the like, containers and packages provided with easily peelable lid members that facilitate opening of cup- or tray-shaped container bodies are widely used. In particular, for food and pharmaceutical containers, polyethylene terephthalate-based, polybutylene terephthalate-based, and polyethylene terephthalate-based materials, which are relatively easy to recycle and recycle, are used as materials for the container body and lid material. Polyester-based resins such as phthalate-based resins are used. Among these polyester-based resins, A-PET containers composed of substantially amorphous polyethylene terephthalate-based resins are being widely used as polyethylene terephthalate-based containers in particular. Various types of easily peelable films have been developed and commercialized to facilitate the opening of lids for A-PET containers.

In Patent Document 1, a coextruded film comprising a seal layer made of a mixture of a low-crystalline polyester resin and a resin having low compatibility with the polyester resin and a substrate layer made of a polyester-based resin is stretched. A film is described.
Patent Document 2 discloses a polyethylene terephthalate-based polymer in which 6 to 40 mol % of all dicarboxylic acid components and/or all diol components is a copolymer component, and 0.0. A laminated polyester film obtained by laminating a polyethylene terephthalate-based polymer of which 5 to 5 mol % is a copolymer component is disclosed.

JP-A-6-143408 JP-A-3-47752

The easy-peeling film, which can facilitate the opening of containers and packaging bags using films, has heat-sealing properties such as heat-sealing at a temperature and pressure that do not deform the container body, and has the necessary sealing strength and is easy to use. It is required to have an easy peeling property with a peeling strength of usually 4 to 20 N/15 mm width that can stably exhibit peeling. In addition, there is no uniform whitening of the peeling surface after opening, no "film residue" or "stringing" that the lid material remains unevenly on the peeling surface of the container body, and no thermal deformation occurs on the heat-sealed surface. , good appearance characteristics of the peeled surface are required.
However, the film described in Patent Document 1 achieves easy opening by the cohesive peeling method, and fine stringiness of the remaining lid material occurs on the peeling surface of the container, and the lid is directly applied to the mouth. In the case of a container used for a long time, it has a bad texture and has been required to be improved.
In addition, the film described in Patent Document 2 has at least an easy peeling property that can stably exhibit the easy opening property while having the necessary seal strength, and the appearance characteristics of the peeled surface after opening are stringy. It was not excellent like no other.

In view of this situation, the problem to be solved by the present invention is to provide heat sealability that allows heat sealing at a temperature, pressure, etc. that does not deform the container body or the packaging bag, and to facilitate opening while having the necessary seal strength. To provide a polyester-based laminated film, a laminate, a lid material, a container, a packaging bag, and a package, which have easy peelability that can be stably exhibited and excellent peel surface appearance characteristics after opening.

As a result of extensive research, the present inventors found that the above problems can be solved by a polyester-based laminated film, a laminate, a lid material, a container, a packaging bag, and a package having the following configurations, and have completed the present invention. It has reached completion.
That is, the present invention relates to polyester-based laminated films, laminates, lids, containers, packaging bags, and packages shown below.
Item 1: Polyethylene terephthalate resin with a crystal melting peak temperature of 190° C. or higher and 270° C. or lower at 40.0% or higher and 70.0% or lower by mass, and a thermoplastic copolyester with a crystal melting peak temperature of 90° C. or higher and 180° C. or lower a seal layer containing 5.0% by mass or more and 30.0% by mass or less of a resin and 20.0% by mass or more and 30.0% by mass or less of a polyolefin resin;
a support layer containing 90.0% by mass or more of a polyethylene terephthalate-based resin;
A polyester-based laminated film.
Item 2: The polyester-based laminated film according to Item 1, wherein the seal layer further contains a polybutylene terephthalate-based resin.
Item 3: The polyester-based laminated film according to Item 1 or 2, wherein the thermoplastic copolyester resin has a crystalline melting peak temperature of 100°C or higher and 135°C or lower.
Item 4: The polyester-based laminated film according to any one of Items 1 to 3, wherein the polyolefin-based resin contains a polyethylene-based resin.
Item 5: A laminate comprising the polyester-based laminated film according to any one of Items 1 to 4.
Item 6: A lid material constructed using the polyester-based laminated film according to any one of Items 1 to 4 or the laminate according to Item 5.
Item 7: A container comprising the lid material according to Item 6.
Item 8: A packaging bag constructed using the polyester-based laminated film according to any one of Items 1 to 4 or the laminate according to Item 5.
Item 9: A package obtained by filling either the container of Item 7 or the packaging bag of Item 8 with contents.

According to the present invention, it has a heat-sealing property that allows heat-sealing at a temperature, pressure, etc. that does not deform the container body, and has an easy-peeling property that can stably exhibit easy-opening while having the necessary sealing strength. It is possible to provide a polyester-based laminated film, a laminate, a lid material, a container, a packaging bag, and a package having excellent peeling surface appearance properties.

Schematic diagram according to one embodiment of a container provided with a lid made of the polyester-based laminated film of the present invention. FIG. 1 is a schematic view of an embodiment of a container having a lid constructed using the polyester-based laminated film of the present invention, which is opened by peeling off the lid. FIG. 11 is a schematic view of an embodiment when a lid member is peeled off and opened from a container having a lid member constructed using a polyester-based laminated film according to a comparative example in the specification of the present application.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the polyester-based laminated film, laminate, lid material, container, packaging bag, and package according to the present invention will be described in detail.

<Polyester-based laminated film>
(seal layer)
The seal layer in the polyester-based laminated film of the present invention contains 40.0% by mass or more and 70.0% by mass or less of a polyethylene terephthalate resin having a crystal melting peak temperature of 190° C. or more and 270° C. or less, and a crystal melting peak temperature of 90° C. or more. It contains 5.0 to 30.0% by mass of a thermoplastic copolyester resin of 180° C. or less and 20.0 to 30.0% by mass of a polyolefin resin. As the resin contained in the seal layer, a commercially available one may be used, or a synthesized one may be used.

{Polyethylene terephthalate resin}
A polyethylene terephthalate resin having a crystal melting peak temperature of 190 to 270° C. is composed of a polycarboxylic acid component in which 90 mol % or more, preferably 95 mol % or more of the polycarboxylic acid component is a terephthalic acid component, and 90 mol % of the polyol component. It is a resin having a crystalline melting peak temperature of 190 to 270° C. obtained by condensation polymerization with a polyol component containing ethylene glycol at 95 mol % or more, preferably 95 mol % or more. Polyethylene terephthalate-based resins may be used singly or in combination of two or more.
The polycarboxylic acid component may be a free acid, a halide, an alkyl ester having an alkyl group with 1 to 4 carbon atoms, an alkali metal salt, a derivative such as an anhydride.

Polycarboxylic acid components other than the terephthalic acid component include, for example, phthalic acid, isophthalic acid, dibromoisophthalic acid, hydroxyisophthalic acid, sodium sulfoisophthalate, phenylenedioxydicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4, Aromatic dicarboxylic acids such as 4'-diphenyletherdicarboxylic acid, 4,4'-diphenylketonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid and 2,6-naphthalenedicarboxylic acid Acids or derivatives thereof; alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid or derivatives thereof; maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, un aliphatic carboxylic acids such as decadicarboxylic acid and dodecadicarboxylic acid or derivatives thereof; tricarballylic acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetetracarboxylic acid and the like trifunctional or higher carboxylic acids; One or more selected types can be mentioned.

Examples of polyol components other than ethylene glycol components include diethylene glycol, trimethylene glycol, tetramethylene glycol, 1,3-butanediol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentyl glycol, 2 -aliphatic diols such as ethyl-2-butyl-1,3-propanediol, polyethylene glycol, polytetramethylene ether glycol; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, Alicyclic diols such as 1,4-cyclohexanedimethylol and 2,5-norbornanedimethylol; xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis(4'-hydroxyphenyl)propane, 2, aromatic diols such as 2-bis(4'-β-hydroxyethoxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, bis(4-β-hydroxyethoxyphenyl)sulfonic acid; 2,2-bis(4' alkylene oxide adducts of aromatic diol components such as ethylene oxide adducts of 2,2-bis(4'-hydroxyphenyl)propane; propylene oxide adducts of 2,2-bis(4'-hydroxyphenyl)propane; trifunctional or higher polyols such as pentaerythritol and sugar esters; and the like.

Copolymerization components other than the polycarboxylic acid component and the polyol component include, for example, glycolic acid, p-hydroxybenzoic acid, p-β-hydroxyethoxybenzoic acid, gallic acid, and other hydroxycarboxylic acids or alkoxycarboxylic acids; stearyl alcohol; , Heneicosanol, octacosanol, benzyl alcohol, and other monoalcohols; stearic acid, behenic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, and other monocarboxylic acids; good.

The crystalline melting peak temperature of the polyethylene terephthalate-based resin 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 the maximum temperature detected in the second heating process performed at a heating rate of 10 ° C./min when performing differential scanning calorimeter (DSC) measurement in accordance with JIS K 7121. It is the temperature of the strong endothermic peak, or the catalog value in the case of commercial products.

The intrinsic viscosity of the polyethylene terephthalate-based resin is not particularly limited. For example, 0.50 dl/g or more, preferably 0.60 dl/g or more, more preferably 0.70 dl/g or more, 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 was measured at 25° C. with an Ubbelohde viscometer after dissolving a polyethylene terephthalate resin in a mixed solvent of phenol:tetrachloroethane=1:1.
If the intrinsic viscosity is less than 0.70 dl/g, the melt viscosity tends to decrease in the film-forming process, and, for example, during inflation film-forming, it may be difficult to form tubular bubbles with a stable diameter. , there is a possibility that drawdown and neck-in are likely to occur during cast film formation. When the intrinsic viscosity exceeds 0.90 dl/g, the melt viscosity becomes high, and for example, when forming a film using a multi-layer cast film forming machine equipped with a feed block, the viscosity becomes too high and spreads to the ends in the width direction of the die. There is a possibility that it will not.

The content of the polyethylene terephthalate-based resin in the seal layer is, for example, 40.0% by mass or more, preferably 43.0% by mass or more, more preferably 47.0% by mass or more, for example, 70% by mass or more, relative to the entire seal layer. 0% by mass or less, preferably 65.0% by mass or less, more preferably 60.0% by mass or less. If the amount is less than 40.0% by mass, the peel strength of the seal layer is significantly reduced, and practical sealing may not be ensured. On the other hand, if it exceeds 70% by mass, the peel strength becomes excessively high, which is not preferable.

{Thermoplastic copolyester resin}
The thermoplastic copolyester resin having a crystalline melting peak temperature of 90 to 180°C is a resin having a crystalline melting peak temperature of 90 to 180°C, obtained by condensation polymerization of a polycarboxylic acid component and a polyol component. Thermoplastic copolyester resins can be distinguished from polyethylene terephthalate-based resins and polybutylene terephthalate-based resins in terms of crystal melting peak temperature. The thermoplastic copolyester resin may be used singly or in combination of two or more.
The polycarboxylic acid component used in the polycondensation of the thermoplastic copolyester resin includes one or more selected from the polycarboxylic acid components described in {Polyethylene terephthalate-based resin}. Moreover, the polyol component used for polycondensation of the thermoplastic copolyester resin includes one or more selected from the polyol components described in {Polyethylene terephthalate-based resin}. These polycarboxylic acid component and polyol component are selected so that the crystalline melting peak temperature of the thermoplastic copolyester resin is 90 to 180°C.

The thermoplastic copolyester resin has a crystalline melting peak temperature of 90 to 180°C, preferably 95°C or higher, more preferably 100°C or higher, and preferably 150°C or lower, more preferably 135°C or lower. If the crystalline melting peak temperature is less than 90°C, the impact resistance during heat sealing may deteriorate, and if it exceeds 180°C, the low-temperature heat-sealing property may deteriorate. When the crystalline melting peak temperature of the thermoplastic copolyester resin is 150° C. or less, the heat-sealing property is good, and the process of filling and sealing the contents in the container or packaging bag can be made into a high cycle, and the production efficiency of the package can be improved. can be raised.
Commercially available thermoplastic copolyester resins having a crystalline melting peak temperature of 90 to 180° C. include Vylon (registered trademark) series manufactured by Toyobo Co., Ltd., PETG (registered trademark) series manufactured by Eastman Chemical Co., and the like.
Here, the crystalline melting peak temperature is obtained by the method described in {Polyethylene terephthalate resin}.

The content of the thermoplastic copolyester resin in the sealing layer is, for example, 5.0% by mass or more, preferably 15.0% by mass or more, more preferably 20.0% by mass or more, relative to the entire sealing layer, For example, it is 30.0% by mass or less, preferably 27.0% by mass or less, more preferably 25.0% by mass or less. If it is less than 5.0% by mass, the heat seal strength and peel strength are too low, which is not preferable. On the other hand, if it exceeds 30% by mass, the peel strength becomes excessive, and the film tends to be blocked (mutual adhesion), which may make it difficult to handle as a roll in the processing step.

{Polyolefin resin}
A polyolefin resin is a resin obtained by polymerizing one or more α-olefins having 2 to 20 carbon atoms. For example, it is selected from the group consisting of low-density polyethylene resins, linear low-density polyethylene resins, medium-density polyethylene resins, high-density polyethylene resins, polypropylene resins, copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, and the like. One or more types are mentioned. Polyolefin-based resins may be used singly or in combination of two or more. Among them, polyethylene-based resins, particularly ethylene-α-olefin copolymers, which are copolymers of ethylene and α-olefins having 3 to 20 carbon atoms and are also called linear low-density polyethylene, are preferred. This is because the α-olefin side chains are entangled with each other, so that the elasticity is excellent when an impact is applied.
Examples of α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, and the like. One or more selected from the group, 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 in producing the copolymer of ethylene and the α-olefin having 3 to 20 carbon atoms is not particularly limited. Examples thereof include Ziegler-Natta catalysts and metallocene catalysts. In the present invention, it is preferable to use a metallocene catalyst because linear low-density polyethylene having a narrow molecular weight distribution can be easily obtained and the metallocene catalyst is excellent in impact resistance.

The density of the polyolefin resin is not particularly limited. For example, 0.900 g/cm ³ or 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 is. If the density is less than 0.900 g/cm ³ , the polyester-based laminated film tends to be prone to blocking. If the density exceeds 0.920 g/cm ³ , the transparency of the sealing layer is reduced, the visibility of the contents of the package is reduced, and the rigidity is increased. . Further, in the low-density polyethylene resin, the medium-density polyethylene resin and the high-density polyethylene resin mainly composed of ethylene, 0.900 g/cm ³ or more to less than 0.930 g/cm ³ and 0.930 g/cm ³ or more to 0.930 g/cm 3 or more, respectively. It is less than 942 g/cm ³ and from 0.942 g/cm ³ to 0.968 g/cm ³ , and from 0.90 to less than 0.91 g/cm 3 for polypropylene resin. In the present invention, so-called linear low-density polyethylene is suitable. 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 commercial product.

The melt flow rate (MFR) of the polyolefin resin is not particularly limited. For example, it is 0.5 g/10 minutes or more, preferably 1.0 g/10 minutes or more, and 20.0 g/10 minutes or less, preferably 15.0 g/10 minutes or less. If the MFR is less than 1.5 g/10 minutes or more than 20.0 g/10 minutes, the polyolefin resin may not be uniformly mixed during melt-kneading for forming the sealing layer.

The content of the polyolefin resin in the seal layer is, for example, 20.0% by mass or more, preferably 22.0% by mass or more, more preferably 24.0% by mass or more, relative to the entire seal layer. It is 0% by mass or less, preferably 28.0% by mass or less, more preferably 26.0% by mass or less. If it is less than 20.0% by mass, the peeling state of the sealing layer becomes brittle when the lid material or packaging bag is peeled off from the package, and the polyester-based laminated film breaks or partially peels off during peeling or opening. There may be leftovers. On the other hand, if it exceeds 30.0% by mass, not only is it not possible to obtain a practically sufficient seal strength, but there is also a risk that peeling or stringiness may occur at the time of opening.

{Polybutylene terephthalate resin}
The sealing layer in the polyester-based laminated film of the present invention may further contain a polybutylene terephthalate-based resin.
The polybutylene terephthalate resin comprises a polycarboxylic acid component in which 90 mol% or more, preferably 95 mol% or more of the polycarboxylic acid component is a terephthalic acid component, and 90 mol% or more, preferably 95 mol% of the polyol component. The above is a resin obtained by polycondensation with a polyol component, which is tetramethylene glycol (also known as 1,4-butanediol). The polycarboxylic acid component may be a free acid, a halide, an alkyl ester having an alkyl group with 1 to 4 carbon atoms, an alkali metal salt, a derivative such as an anhydride.
As the polycarboxylic acid component and the polyol component other than the terephthalic acid component and the tetramethylene glycol component, which are used for condensation polymerization of the polybutylene terephthalate-based resin, the polycarboxylic acid component and the polyol component described in {Polyethylene terephthalate-based resin} are used. mentioned.
When the seal layer contains a polybutylene terephthalate-based resin, the pinhole resistance and weather resistance of the seal layer are improved. Moreover, since the hydrolyzability is lower than that of the polyethylene terephthalate-based resin, pre-drying and other treatments in the process of forming the seal layer are facilitated.

The crystal melting peak temperature of the polybutylene terephthalate-based resin is not particularly limited, and is, for example, 215 to 230°C.
The intrinsic viscosity of the polybutylene terephthalate-based resin 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 more than 1.20 dl/g, the difference in melt viscosity from that of the polyethylene terephthalate-based resin becomes inappropriate during high-temperature melt-kneading in the film-forming process of the seal layer, and the two are kneaded. Uniformity may decrease.
Here, the crystalline melting peak temperature and intrinsic viscosity are obtained by the method described in {Polyethylene terephthalate-based resin}.

The content of the polybutylene terephthalate-based resin in the sealing layer is, for example, 0% by mass or more, preferably 3.0% by mass or more, and for example, 10.0% by mass or less, preferably 7.0% by mass, relative to the entire sealing layer. % by mass or less. When the content of the polybutylene terephthalate-based resin is in the range of 0 to 10.0% by mass, the pinhole resistance, low-temperature heat sealability, and peel strength of the sealing layer are well balanced. If it exceeds 10.0% by mass, the peel strength is remarkably lowered, and practical sealing cannot be guaranteed, which is not preferable.

{Other components}
The seal layer may contain various additives as long as the effects of the present invention are not impaired. Additives include, for example, antistatic agents, antioxidants, lubricants, antiblocking agents (silica, zeolite, talc and other inorganic particles, silicone resin and (meth)acrylic resin and other organic resin particles, etc.), and antifog agents. , colorants (organic pigments, inorganic pigments, etc.), ultraviolet absorbers, dispersants, and fillers (talc, calcium carbonate, etc.).

(support layer)
The support layer in the polyester-based laminated film of the present invention contains 90% by mass or more of polyethylene terephthalate-based resin. Examples of the polyethylene terephthalate-based resin used for the support layer include those described in {Polyethylene terephthalate-based resin}. The polyethylene terephthalate-based resin contained in the support layer and the polyethylene terephthalate-based resin contained in the heat seal layer may be the same or different. In the present invention, it is preferable that the polyethylene terephthalate-based resin contained in the support layer and the heat-seal layer is the same from the viewpoint of reduction of manufacturing cost and recyclability.
The support layer may contain less than 10% by mass of various resins and additives as long as the effects of the present invention are not impaired.
The resin is not particularly limited as long as it is a resin other than a polyethylene terephthalate-based resin containing 90% by mass or more. species or more.
The additive is not particularly limited, and includes, for example, one or more of the various additives described in <Seal layer>.

(Structure of polyester-based 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) Seal layer/support layer (1-2) Seal layer/support layer/other layers (1-3) Seal layer/intermediate layer/support layer (1-4) Seal layer/support layer/intermediate layer / Other layers and the like can be used.
Other layers can be heat-resistant resin layers (eg, polyethylene naphthalate resin layers), and can be formed by means of coextrusion film formation or the like. In this case, when a container or packaging bag is formed using the polyester laminated film as it is, the layer in contact with the heat-sealing device becomes a heat-resistant resin layer. can be wide. The structure of the seal layer/support layer is preferable because it is easy to control the thickness to be preferable as described later, and the number of man-hours in the manufacturing method described later can be reduced.
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 deposition layer, and the like.

The thickness of the polyester-based laminated film of the present invention is not particularly limited.
The thickness of the polyester-based laminated film is, for example, 5 µm or more, preferably 10 µm or more, more preferably 20 µm or more, still more preferably 30 µm or more, for example 200 µm or less, preferably 100 µm or less, more preferably 70 µm or less, and still more preferably 60 μm or less. When the thickness is in the range of 5 μm or more and 200 μm or less, the film can be made with a good balance of flexibility and rigidity, has a practical heat-sealing property, and can easily peel off the lid material and the packaging bag from the package. It can be excellent in easy peelability.

In the polyester-based laminated film of the present invention, the thickness ratio of the seal layer and the support layer is not particularly limited when the total thickness of the polyester-based laminated film is taken as 100%. The thickness of the sealing layer is, for example, 5% or more, preferably 10% or more, more preferably 15% or more, still more preferably 20% or more, and for example 50% or less, preferably 40% or less. Further, the thickness of the support layer is, for example, 40% or more, preferably 50% or more, more preferably 60% or more, and is, for example, 95% or less, preferably 90% or less, more preferably 85% or less, further preferably 80% or less.
If the sealing layer is as thin as less than 5%, for example, the sealing layer may not be discharged uniformly during film formation. There is a possibility that the strength becomes too strong and it becomes difficult to peel off easily.
When the seal layer is thicker than 40%, for example, when it is used as a lid material, after the peeling between the seal layer and the support layer at the seal edge that should occur when peeling starts, the seal layer on the inner wall side of the container body. Delamination between the sealing layer and the support layer continues without breaking at the edge, and a part of the sealing layer remains like a thin skin, which may make it impossible to take out the contents. This is a state in which the sealing layer 1 remains on the container body 3 side instead of the state shown in FIG.
Incidentally, when the ratio of the thickness of the support layer is large, the polyester-based laminated film can be stably formed, and the handling property such as subsequent winding is also good.

<Laminate>
The laminate of the present invention contains a polyester-based laminated film. For example, a support layer of a polyester-based laminated film having a substrate layer provided on the surface on which the seal layer is not formed can be used. The substrate layer is, for example, a non-stretched, uniaxially stretched or biaxially stretched film such as a polyester resin, a polyamide resin, or a polyolefin resin; a gas barrier film obtained by vapor-depositing aluminum, silica, alumina, or the like on these films; paper. a metal such as an aluminum foil; and the like. Moreover, the substrate layer may have two or more substrate layers that are the same or different from each other, if necessary. Processing such as coloring and printing can be applied to these base material layers, and packaging bags having excellent design, gas barrier properties, light shielding properties, pinhole resistance, curl resistance and the like can be provided. In particular, from the viewpoint of monomaterialization, which will be described later, the base material layer is preferably a polyester-based resin film.
An intermediate layer may be provided between the polyester-based laminated film and the substrate layer or between a plurality of substrate layers. Here, 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 deposition layer, and the like.

The layer structure of the laminate of the present invention is not particularly limited. For example, (2-1) to (2-4):
(2-1) Polyester laminated film/base layer (2-2) Polyester laminated film/intermediate layer/base layer (2-3) Polyester laminated film/intermediate layer/intermediate layer/base layer (2 -4) It can have a layer structure such as polyester-based laminated film/base layer/intermediate layer/base layer.

<Method for producing polyester-based laminated film and laminate>
The method for producing the polyester-based laminated film and laminate is not particularly limited.
The resin or resin composition constituting each layer of the polyester-based laminated film and laminate is prepared by mixing the constituent components simultaneously or sequentially. For example, each component is mixed with a tumbler, Henschel mixer, etc., and then directly charged into a film forming machine. a method of melt-kneading using

As a method for producing a polyester-based laminated film, for example, each resin component constituting the seal layer and the support layer is put into a multi-layer T-die molding machine or a multi-layer inflation molding machine and co-extruded. a melt extrusion lamination method in which a resin component or the like constituting a seal layer is laminated by melt extrusion on at least one surface of the layer; Among them, the co-extrusion method using a multi-layer T-die or a multi-layer inflation molding machine is preferable because the number of man-hours is small, it is simple, and the adhesive strength between the layers can be sufficiently increased.

Examples of the method for producing a laminate include a method of laminating a base layer on a polyester laminated film by a dry lamination method, a method of laminating a base layer by sandwich lamination via molten polyethylene or the like, and a method of laminating a polyester laminated film. , a method of laminating by multilayer extrusion lamination on a substrate layer, a method of coextrusion of all layers constituting a laminate, and the like. Among them, the dry lamination method can laminate these base layers and the like via a thin adhesive, so that a high monomaterial ratio (composition ratio of materials of the same type; in the present invention, polyethylene terephthalate contained in the laminate) mass % of the total of the base resin and the thermoplastic copolyester resin).

<Lid material, container and package>
The lid material of the present invention is constructed using a polyester-based laminated film or a laminate obtained by laminating polyester-based laminated films. Further, the container of the present invention is composed of, for example, the lid material of the present invention, a container body having a welded portion such as a flange having a shape capable of being in close contact with the lid material, and an accommodating portion for accommodating contents such as food. . The shape of the container body is not particularly limited. For example, it can have any shape such as a cup shape or a tray shape. Further, the position of the welded portion provided on the container is not particularly limited. For example, it can be provided on the top surface of the container body.
The lid member and the container body are heat-sealed in a state where the seal layer side of the lid member and the welded portion of the container body are in contact with each other after the contents are stored in the storage portion. In addition, a part of the lid material protrudes from the welded part of the container body or an unsealed part is provided as a starting part for peeling when unsealing, thereby providing a gripping part called a "tab" that is not heat-sealed. It is practically preferable to keep

The material forming the container body is not particularly limited. For example, 1 selected from the group consisting of polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyolefin resins such as polypropylene, polystyrene resins, ABS resins, composites of these resins, and the like. More than one species can be used. Among these, polyester-based resins are preferred, and polyethylene terephthalate-based resins are particularly preferred. When applying the polyester-based laminated film or laminate of the present invention to a lid material, from the viewpoint of recyclability, it is preferable to use a container body made of the same material, polyester-based resin, particularly polyethylene terephthalate-based resin.

In one aspect of the package of the present invention, after the content is filled or stored in the storage portion of the container body, the opening of the container body is closed by placing a lid material so that the sealing layer is in contact with the adhesive portion of the container body. It can be formed by heat-sealing and sealing the cover, the lid member and the container body using a hot plate, high-frequency dielectric heating, ultrasonic heating, or the like.
An example of such a container is shown in FIG. In FIG. 1, the polyester-based laminated film composed of the seal layer 1 and the support layer 2 is used as it is as a lid material, and shows a state in which it is sealed with the container body 3 . A tab 4 is provided for gripping the cover material with fingers when opening the package.
When the package of the present invention is opened by removing the lid material from the container, separation occurs at the interface between the seal layer of the lid material and the support layer, and the seal layer is formed on the welded peeling surface of the container body after the lid material is peeled off. shows a state of so-called "interlayer delamination" in which the layer is whitened and remains uniformly, and the delamination surface is preferably whitened. Such uniform peeling proves that the container body and the lid material were reliably sealed before the lid material was peeled off, and also proves that the container has been unsealed. The tamper-proof property that allows confirmation of the sealed state from the trace of peeling is very useful in the fields of food packaging and medical packaging.
As shown in FIG. 2, when the container is to be unsealed, the seal layer 1 and the support layer 2 are separated from each other. Since the sealing layer 2 is sealed with the container main body 3, it remains on the container main body 3 side. Moreover, since the seal layer 2 is broken at the edge of the seal, the package can be properly unsealed. The interfacial peeled surface indicated by A formed in this manner is free from stringiness and has a good texture. On the other hand, in the case of the lid material shown in FIG. 3, which is both a conventional example and a comparative example, stringiness or the like may occur on the agglomerated peeling surface indicated by B, and when the contents are eaten directly from the container, the mouthfeel is not good. be in a bad state.

Moreover, the polyester-based laminated film of the present invention can be used not only as a cover material, but also as an inner wall of a container body and a welded portion of a container body. In this case, the sealing surface of the lid member may be, on the contrary, a general polyethylene terephthalate resin film or the polyester-based laminated film of the present invention. A common polyethylene terephthalate resin film has only one separation layer in the thickness direction at the sealed location, and there is no room for movement between layers, so the appearance tends to be more favorable.

<Packaging bag and package>
The packaging bag of the present invention is formed by heat-sealing the seal layers of a polyester laminated film or a laminate obtained by laminating polyester laminated films, and the heat-sealed seal portion on the side of the seal layer can be easily peeled off. be able to.
The form of the packaging bag is not particularly limited, and examples include a three-sided bag, a folded bag, a gusseted bag, a self-supporting bag with a bottom, and a bag with a spout or mouth plug. In the case of bags without spouts or mouth plugs, such as three-sided bags, it is practically preferable to provide a non-heat-sealed gripping portion called a "tab" at the peeling start portion when the bag is opened.
In addition, a packaging bag obtained by making a laminate by placing polyester laminated films on the front and back of a base material and laminating them on the front and back of a base material, forming it into a cylindrical shape and heat sealing the overlapping front and back, and the end of the polyester laminated film. A so-called "envelope-like" packaging bag, such as a packaging bag obtained by stacking and heat-sealing the front and back surfaces, may also be used. This form does not form a rigid protrusion like the heat-sealed portion of the package of the folding bag, and not only does it reduce the risk of hurting the hand during use, but it also reduces the area used for the packaging bag material and reduces the environmental load. .
In addition, in the polyester-based laminated film of the present invention, the seal layer contains a thermoplastic copolymer polyester resin and a polyolefin resin, so that when a packaging bag is formed, the easy-openability and impact resistance of the packaging bag are improved. can be improved.
Another aspect of the package of the present invention is formed by filling a packaging bag with contents and heat-sealing the opening of the packaging bag. Alternatively, a spout may be placed in the opening of the packaging bag, heat-sealed, and the content may be filled through the spout to form a package.

<Application>
The polyester-based laminated film, laminate, lid material, container, packaging bag, and package of the present invention have excellent peelability or easy-openability, as well as excellent sealability and aroma-retaining properties. For this reason, applications that require easy-opening, sealing, and aroma-retaining properties, such as tea, coffee, seasonings, spices, flavors, ham, smoked products, tofu, pudding, jelly, yogurt, ice cream, sweets, etc. Food products; chemical products such as insect repellents, fragrances, bath agents, perfumes, and lotions; packaging films, lids, containers, packaging bags, and packages containing pharmaceuticals such as medicines, infusions, blood products, etc. It is suitable as a body. Moreover, the polyester-based laminated film of the present invention can also be suitably used as a sealant film.
In particular, since the surface of the release surface is smooth while having easy releasability, the appearance of the release surface is good, and the finger and tongue feel good. Furthermore, the heat-sealing temperature for sealing the contents can be set in a low temperature range comparable to that of polyethylene materials used for ordinary packaging films.
Moreover, in the laminate containing the polyester-based laminated film of the present invention and a substrate layer, when a transparent substrate layer is used, the contents can be easily visually recognized. In addition, the substrate layer can be printed, colored, vapor-deposited, etc. to impart design properties, barrier properties, light-shielding properties, pinhole resistance, curl resistance, etc., so that it can be suitably used in various applications. can be done. In particular, when a polyester-based film is used as the base material layer, the lid has practical easy peelability, easy openability, heat sealability, and aroma retention properties, and also has high single material properties and can be recycled by recycling. Materials, containers, packaging bags and packages can be provided.

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

<Resin/resin film>
・Polyethylene terephthalate resin (PET):
"CR8816" (manufactured by Huayuan Co., Ltd., intrinsic viscosity = 0.810 dl / g, crystalline melting peak temperature = 247 ° C.)
- Thermoplastic copolyester resin (coPET):
"Vylon (registered trademark) GM913" (manufactured by Toyobo Co., Ltd., crystal melting peak temperature = 126 ° C.)
- Polybutylene terephthalate resin (PBT):
"500FP" (manufactured by Polyplastics, intrinsic viscosity = 0.875 dl/g, crystalline melting peak temperature = 225°C)
・Polyolefin resin:
Ethylene-hexene copolymer, which is an ethylene-α-olefin copolymer (LLD), "Evolue (registered trademark) SP1510" (manufactured by Prime Polymer Co., Ltd., density = 0.915 g/cm ³ , MFR = 1.0 g/10 min. )
- Biaxially oriented polyethylene terephthalate film (OPET):
“Toyobo Ester (registered trademark) film E5100” (manufactured by Toyobo Co., Ltd., thickness 12 μm)

[Examples 1 to 4, Comparative Examples 1 to 6]
<Preparation of polyester laminate film and laminate>
As Examples 1 to 4 and Comparative Examples 1 to 5, various resins having the compositions shown in Table 1 were mixed in a Henschel mixer to prepare seal layer forming components and support layer forming components. These were put into the hopper of a two-layer T-die molding machine and film-formed at a die temperature of 285° C. to obtain a polyester-based laminated film having a seal layer and a support layer having the constitution shown in Table 1. The thickness of the seal layer was 15 μm, the thickness of the support layer was 45 μm, and the total thickness was 60 μm. The opposite side of the film to the seal layer, that is, the surface of the support layer, was subjected to corona treatment, and a 12 μm-thick biaxially oriented polyethylene terephthalate film (manufactured by Toyobo Co., Ltd.: T4102) was prepared as a base layer, and a urethane adhesive was applied thereto. (RU-40 manufactured by ROCK PAINT Co., Ltd.) was applied so that the average solid content was 3.1 g/m ² , dried, and then dry-laminated by nipping at a pressure of 3.5 kgf/cm ² . ° C. for 3 days to form a laminate, which was used as a sample for producing a lid member and a package.
As Comparative Example 6, a sealing layer was prepared with only 70% by mass of PET and 30% by mass of LLD.

<Evaluation of polyester-based laminated film as lid material>
Each of the polyester laminated films of Examples 1 to 4 and Comparative Examples 1 to 5 was cut to a width of 20 mm. Each polyester laminated film cut and an A-PET sheet (thickness 300 μm, "Teijin Tetoron Sheet" manufactured by Teijin) cut to a width of 20 mm assumed as the container body are cut, and the sealing layer of the polyester laminated film is A- It was superimposed so as to be in contact with the PET sheet.
At a sealing pressure of 0.2 MPa, a sealing time of 1 second, and a sealing temperature of 160° C., 180° C. or 200° C., heat sealing is performed by heating one side of the polyester laminated film from the support layer side with a hot plate to form a lid material. A sample for evaluation was obtained.
The obtained sample for evaluation as the lid material was evaluated for peel strength and peel surface appearance by the following methods. Table 2 shows the results.

(Peel strength)
Both ends of the heat-sealed 20 mm wide sample were cut to obtain a 15 mm wide test piece for peel strength measurement. This test piece was allowed to stand for 24 hours or more in an environment of a temperature of 23° C. and a relative humidity of 50% to condition it. After conditioning, using a tensile tester according to JIS Z 0238, 90° peeling was performed at a peeling speed of 300 mm/min, and the peel strength per 15 mm width was measured.

(Appearance of peeled surface)
The peeled surface of the test piece used for measuring the peel strength was visually observed and evaluated according to the following two grades. The state of stringiness is roughly the state of detachment shown in FIG.
◯: Whitening of the peeled surface is uniform, and there is no stringiness, film residue, or thermal deformation of the A-PET film or support layer.
x: One or more of uneven whitening of the peeled surface, stringiness, film residue, and thermal deformation of the sample occurred.

<Evaluation of polyester-based laminated film as a packaging bag>
Two pieces each of the polyester laminated films of Examples 1 to 4 and Comparative Examples 1 to 5 were prepared by cutting them into a width of 20 mm. The cut polyester-based laminated films were superimposed so that the seal layers were in contact with each other.
At a sealing pressure of 0.2 MPa, a sealing time of 1 second, and a sealing temperature of 140° C., 160° C. or 180° C., heat sealing was performed on one side by heating with a hot plate to obtain samples for evaluation as packaging bags.
The evaluation samples obtained as packaging bags were evaluated for peel strength and peel surface appearance by the following methods. Table 3 shows the results.

(Peel strength)
For the evaluation sample as each packaging bag, both ends of the heat-sealed 20 mm wide sample were cut to obtain a 15 mm wide test piece for peel strength measurement. This test piece was allowed to stand for 24 hours or more in an environment of a temperature of 23° C. and a relative humidity of 50% to condition it. After conditioning, using a tensile tester according to JIS Z 0238, 90° peeling was performed at a peeling speed of 300 mm/min, and the peel strength per 15 mm width was measured.

(Appearance of peeled surface)
The peeled surface of the test piece used for measuring the peel strength was visually observed and evaluated according to the following two grades.
◯: Whitening of the peeled surface is uniform, and there is no stringiness, film residue, or thermal deformation of the A-PET film or support layer.
x: One or more of uneven whitening of the peeled surface, stringiness, film residue, and thermal deformation of the sample occurred.

As is clear from Tables 2 and 3, the polyester-based laminated films of the present invention according to Examples 1 to 4 are heat-sealed at 160 to 200 ° C. in the case of lids, and 140 in the case of packaging bags. By heat-sealing at ~180°C, it is possible to achieve practically sufficient peeling strength (4-20N/15mm) while maintaining easy peelability over a wide range of suitable heat-sealing temperatures. Furthermore, the supporting layer and the A-PET sheet containing 90.0% by mass or more of polyethylene terephthalate resin were not deformed. Moreover, it was easily peelable, and there was no threading or film residue between the support layer and the sealing layer of the polyester-based laminated film, and the appearance was good.

When the polyester-based laminated films according to Comparative Examples 1 to 5 were used as cover materials, problems occurred in the appearance of the peeled surface at temperatures other than 160° C. in Comparative Example 3 and 160° C. in Comparative Example 4 in Table 2. The reason why there was no problem in the appearance was that the seal was not sufficient in the first place, and as a result, the interface between the polyester-based laminated film and the A-PET was peeled off. Furthermore, in Comparative Examples 1 and 2 in Table 2 (the content of the ethylene-α-olefin copolymer in the seal layer was 10% by mass or less), the peel strength increased significantly, causing a problem with easy peelability in practical use. Threads were scattered on the surface. In addition, in Comparative Example 4, the required sealing strength was not obtained, but the strength was not such that easy peeling could be stably exhibited.

When the polyester-based laminated films according to Comparative Examples 1 to 5 were used as packaging bags, problems occurred in the appearance of the peeled surface at temperatures other than 140° C. in Comparative Example 2 in Table 3. Furthermore, in Comparative Example 4 in Table 3, stringiness was occasionally observed on the peeled surface.
As described above, the polyester-based laminated film of the present invention, and the laminate, lid material, container, packaging bag, and package using the same have excellent easy-openability. In addition, when polyester-based resin is applied to the base layer and intermediate layer that make up the laminate, it can be recycled as a "mono-material" in accordance with the SDGs (Sustainable Development Goals) set by the United Nations. The packaging material can be made of a highly suitable single material as a main component.

1 sealing layer 2 support layer 3 container body 4 tab A interfacial peeling surface B aggregation peeling surface

Claims (9)

40.0% by mass or more and 70.0% by mass or less of a polyethylene terephthalate resin having a crystal melting peak temperature of 190°C or more and 270°C or less, and 5 thermoplastic copolyester resins having a crystal melting peak temperature of 90°C or more and 180°C or less. a sealing layer containing 0% by mass or more and 30.0% by mass or less and a polyolefin resin of 20.0% by mass or more and 30.0% by mass or less;
a support layer containing 90.0% by mass or more of a polyethylene terephthalate-based resin;
A polyester-based laminated film. The polyester-based laminated film according to claim 1, wherein the seal layer further contains a polybutylene terephthalate-based resin. The polyester-based laminated film according to claim 1 or 2, wherein the thermoplastic copolyester resin has a crystalline melting peak temperature of 100°C or higher and 135°C or lower. The polyester-based laminated film according to any one of claims 1 to 3, wherein the polyolefin-based resin contains a polyethylene-based resin. A laminate comprising the polyester-based laminated film according to any one of claims 1 to 4. A cover material constructed using the polyester-based laminated film according to any one of claims 1 to 4 or the laminate according to claim 5. A container comprising the lid material according to claim 6 . A packaging bag constructed using the polyester-based laminated film according to any one of claims 1 to 4 or the laminate according to claim 5. A package obtained by filling either the container according to claim 7 or the packaging bag according to claim 8 with contents.

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