JP4620996B2 - Easy-open film, lid and container - Google Patents

Description

  The present invention relates to an easily openable film, a lid material using the same, and a container. Specifically, the present invention relates to an easy-open film excellent in low-temperature heat sealability, heat resistance, and peeled surface appearance, and a lid material and a container using the film.

  In the field of containers and packaging for foods, pharmaceuticals, etc., containers equipped with easy-open lids are widely used. Among containers composed of a container body and a lid material, recently, in food containers, there has been an active movement to use a polyester-based resin that hardly absorbs the flavor of food in the container body. Typical examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate and the like. Among these, in particular, PET is being widely used in so-called A-PET containers in a substantially amorphous state, and is widely used in so-called C-PET containers in a partially crystallized and highly heat-resistant state. It's getting on. Moreover, after filling these containers with food or pharmaceuticals, sterilization treatment such as boiling and retort is performed, and from this viewpoint, A-PET containers and C-PET containers are often used. .

On the other hand, in medical containers, engineering plastics such as polycarbonate and polyethersulfone have been used for the containers. As an example, there is a half kit container used for a kit product called a so-called half kit.
This half kit container is generally formed by connecting a solution container containing a solution and a capsule containing a resin needle inside, and integrating them. The capsule is composed of a capsule body and a peelable lid. When mixing the solution and other drugs such as antibiotics using the half kit container provided with the capsule, the capsule lid is first peeled off. Next, a resin needle in the capsule is pierced into a drug container such as a glass vial containing a drug such as an antibiotic and sealed with a rubber stopper. As a result, the solution container and the drug container communicate with each other, and the solution and the drug are mixed. The mixed drug solution is discharged from the solution container through the injection needle.
Among such half kit containers, engineering plastics such as polycarbonate and polyethersulfone are used for the capsule body. There is also a half kit container to which a capsule made of an integrally molded product of a capsule body and a resin needle is connected.
Polycarbonate is used for raw materials such as a method for forming a sheet into a container by vacuum forming or pressure forming, and a method for forming a container or a part constituting a container by an injection molding method. Particularly, the polycarbonate is utilized for its heat resistance. It is being actively used for heat sterilization.

The lid material in these containers generally has a form in which a sealant film, a biaxially stretched polypropylene film, a biaxially stretched polyamide film, a biaxially stretched polyester film, paper, aluminum foil, or the like are bonded together. The sealant film is an easily openable film that can be heat-sealed to a container body made of polyester or polycarbonate, and the sealant film is required to have many functions.
For example, in addition to the low-temperature sealability that can seal the container body at a temperature and pressure that does not deform the container body, it is possible to provide seal strength (usually 5 to 20 N / 15 mm width) that can stably satisfy easy-openability. And its stability is required. Also, heat resistance that does not cause deformation or the like at high temperatures such as boiling and retorting, and that the easy-open film remains unevenly on the peeling surface of the container body or is a so-called film that is stringed There should be no residue and a good appearance (non-film residue) is required.

As an easy-open film, various techniques have been disclosed so far, and some of them have been put into practical use.
For example, Patent Document 1 exemplifies a two-layer film including a support layer (support layer) made of a polyethylene resin and a seal layer made of a composition made of a saturated polyester resin and a specific polyethylene resin. .
Moreover, in patent document 2, the resin composition which consists of specific polyester-type resin, polyethylene, a polypropylene, and those graft modified products is disclosed as a film material which can provide smoothness to a peeling surface.
In Patent Document 3, a layer composed of a mixture of a polar group-containing ethylene copolymer, a polyolefin resin, and an acid-modified polyolefin, and a mixture of a polar group-containing ethylene copolymer and an ethylene / propylene copolymer adjacent to the layer. A two-layer sealant film is also disclosed.
Patent Document 4 discloses a technique of a cohesive failure sealant film having a layer made of a polar group-containing ethylene copolymer and polypropylene or an ethylene / propylene copolymer.
Patent Document 5 discloses a film composed of two layers: a sealing layer made of a polyester-based resin and a layer made of a polar group-containing ethylene-based copolymer adjacent thereto.
JP 59-59444 A JP 60-180833 A Japanese Patent No. 2883025 Japanese Patent No. 2724938 JP 2002-160329 A

However, in the invention described in Patent Document 1, since the support layer is made of a polyethylene-based resin, the interlayer adhesion strength between the support layer and the seal layer is weak, and therefore, delamination is likely to occur. Therefore, the seal layer is formed on the container body. It was easy to remain unevenly. That is, it was not sufficient in the sense of non-film residue.
In the invention described in Patent Document 2, the low temperature heat sealability is not sufficient. Furthermore, since a special polyester-based resin is used, there is a problem that it is expensive and not economical particularly when a graft-modified product is used.
The invention described in Patent Document 3 is insufficient in terms of stably providing heat seal strength or imparting heat resistance that can withstand temperature conditions such as boiling and retort.
In the invention described in Patent Document 4, a part of the seal layer remains unevenly in the container body, and the non-film residual property is insufficient. Moreover, it was insufficient in terms of expression of necessary heat seal strength and its stability.
The film described in Patent Document 5 not only lacks heat resistance, but also has a weak interlaminar strength between the first and second layers, so delamination often occurs between the first and second layers of the film. However, there has been a drawback that film residue and the like are likely to be generated unevenly in the form of a film piece.

  The present invention has been made in view of such a situation, and provides an easy-open film having good low-temperature heat sealability, heat resistance and non-film residual property, and a lid material and a container using the same. Let it be an issue.

As a result of intensive research on an easily-openable film excellent in low-temperature heat-sealability and heat resistance, having no film residue, non-uniform film residue such as string drawing, and excellent appearance after peeling. The inventors have found that the above-mentioned problems can be solved by using a film having the following constitution, and have completed the present invention.
That is, this invention relates to the easily openable film shown by the following (1)- (6) , a lid | cover material and a container using the same.
(1) and the sealing layer, possess a support layer adjacent to the seal layer, an easily openable film is heat sealed to the container body,
The sealing layer contains 40 to 90% by mass of an ethylene copolymer (A) of ethylene and (meth) acrylic acid alkyl ester or vinyl ester, and 60 to 10% by mass of a polyester resin (B). Consists of
The support layer is made of a support material in which the ethylene copolymer (A) is 40 to 90% by mass in a total of 100% by mass of the ethylene copolymer (A) and the polyolefin resin (C). The
(1) The melting point of the polyester resin (B) is 100 to 135 ° C., which peels off at the interface between the seal layer and the container body. The easy-open film described.
(3) A lid material using the easy-open film described in (1) or (2) .
(4) A container comprising the lid material according to (3) .
(5) A container comprising a container body made of polyester and the lid material according to (3) .
(6) A container comprising a container body made of polycarbonate and the lid material according to (3) .

  ADVANTAGE OF THE INVENTION According to this invention, a low-temperature heat-sealing property, heat resistance, and non-film | membrane remaining property can be provided with an easy-open film, a lid | cover material and a container using the same.

Hereinafter, the present invention will be described in detail. In the following description, “parts” and “%” representing the quantity ratio are based on mass unless otherwise specified.
The easy-open film of the present invention has a seal layer and a support layer adjacent to the seal layer.
The sealing layer comprises an ethylene copolymer (A) of ethylene and a (meth) acrylic acid alkyl ester or vinyl ester (hereinafter sometimes referred to simply as component (A)), and a polyester resin (B) (hereinafter referred to as “component (A)”). , Which may be simply referred to as the component (B)).
Here, the (meth) acrylic acid alkyl ester is a combination of acrylic acid alkyl ester and methacrylic acid alkyl ester.

The component (A) in the sealing material is a copolymer formed by copolymerizing ethylene and a (meth) acrylic acid alkyl ester or vinyl ester.
That is, as the component (A), a copolymer of ethylene and (meth) acrylic acid alkyl ester (ethylene- (meth) acrylic acid alkyl ester copolymer), a copolymer of ethylene and vinyl ester (ethylene- Vinyl ester copolymer).
In the component (A), either an ethylene- (meth) acrylic acid alkyl ester copolymer or an ethylene-vinyl ester copolymer may be used alone, or these may be used in combination.

The alkyl group of the (meth) acrylic acid alkyl ester is not particularly limited, but generally those having 12 or less carbon atoms are used.
Examples of such (meth) acrylic acid alkyl esters having an alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid. Examples include hexyl, cyclohexyl (meth) acrylate, and octyl (meth) acrylate.
That is, as the component (A) using such (meth) acrylic acid alkyl ester, ethylene- (meth) acrylic acid methyl copolymer, ethylene- (meth) ethyl acrylate copolymer, ethylene- (meta ) Propyl acrylate copolymer, ethylene- (meth) acrylic acid butyl copolymer, ethylene- (meth) acrylic acid hexyl copolymer, ethylene- (meth) acrylic acid cyclohexyl copolymer, ethylene- (meth) acrylic An acid octyl copolymer etc. are mentioned.
Among the (meth) acrylic acid alkyl esters, those having 4 or less carbon atoms are preferably used because of their excellent heat resistance. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate are preferable, and methyl (meth) acrylate is more preferable. When methyl (meth) acrylate is used, methyl acrylate is more preferable.

The vinyl ester is not particularly limited, and examples thereof include vinyl acetate and vinyl butyrate. Vinyl acetate is preferably used.
In the component (A), the above (meth) acrylic acid alkyl ester and vinyl ester can be used singly or in combination of two or more, but not only stabilization of the heat seal strength but also the viewpoint of low odor of the film Therefore, it is preferable to use methyl (meth) acrylate alone, and it is more preferable to use methyl acrylate alone.

  (A) 70 mass%-90 mass% are preferable, and, as for the content rate of ethylene in a component, 80 mass%-85 mass% are more preferable. If it is less than 70% by mass, the heat resistance may be insufficient, or the easy-open film may be easily blocked. If the ethylene content exceeds 90% by mass, when the component (A) is mixed with the polyester resin (B), the mutual dispersion may deteriorate and the heat seal strength may not be stably exhibited.

The melt flow rate (hereinafter referred to as “MFR”) of the component (A) is not particularly limited, but is generally 0.1 g / 10 min to 100 g / 10 min, more preferably 1 g / 10 min to 30 g / 10 min. desirable.
In the present invention, MFR is a value measured under conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K 7210 unless otherwise specified.
Examples of commercially available products that can be used as the component (A) include Jyrex (registered trademark) EVA and Lexpearl (registered trademark) manufactured by Nippon Polyolefin Co., Ltd., and Alift (registered trademark) manufactured by Sumitomo Chemical Co., Ltd. .

The polyester resin (B) in the sealing material is a thermoplastic polyester resin, which is a condensation polymer of a polybasic acid and a polyhydric alcohol.
Examples of the polybasic acid include, but are not limited to, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, succinic acid, adipic acid, 2,6-naphthalenedicarboxylic acid, and the like.
Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1,3-butanediol, 1,4-butanediol, pentaerythritol, neopentyl glycol, 1,6-hexanediol, 1 , 4-cyclohexyldimethanol and the like.
The above polybasic acid and polyhydric alcohol can be used in any combination. That is, any polybasic acid and any polyhydric alcohol may be combined, and two or more polybasic acids or two or more polyhydric alcohols may be used.

The melting point of the component (B) is preferably 100 to 135 ° C. in order to improve the low temperature heat sealability and heat resistance of the easily openable film. In addition, melting | fusing point is the value measured by differential scanning calorimetry (DSC) based on JISK7121.
The MFR of the component (B) is not particularly limited, but is generally 0.1 g / 10 min to 100 g / 10 min, and more preferably 1 g / 10 min to 30 g / 10 min. Examples of commercially available products that can be used for the component (B) include Byron (registered trademark) of Toyobo Co., Ltd.

The sealing material preferably comprises 40 to 90% by mass of the ethylene copolymer (A) and 60 to 10% by mass of the polyester resin (B). That is, the content ratio of the ethylene copolymer (A) and the polyester resin (B) in the sealing material is preferably 40 to 90/60 to 10. Moreover, 60-80 / 40-20 are more preferable.
When the content ratio of the component (A) exceeds 90, the desired heat seal strength may not be reached. When the content ratio of the component (A) is less than 40, the variation in heat seal strength becomes large, or the interlayer adhesive strength between the seal layer and the support layer becomes weak, and as a result, uneven film residue is likely to occur. Become.
The ratio of the MFR of the component (A) to the MFR of the component (B) is not particularly limited, but the MFR of the component (A) / the MFR of the component (B) is 0.3 to 3 in the sealing material. It is desirable to improve the dispersion of each component and consequently stabilize the heat seal strength.

The support layer is made of a support material containing the ethylene copolymer (A) and a polyolefin resin (C) (hereinafter sometimes simply referred to as component (C)).
Here, the ethylene copolymer (A) in the support material is the same type of copolymer as the ethylene copolymer (A) in the seal material. That is, when the (A) component in the sealing material is an ethylene- (meth) acrylic acid alkyl ester copolymer, the (A) component used for the support material is an ethylene- (meth) acrylic acid alkyl ester copolymer. When the component (A) in the sealing material is an ethylene-vinyl ester copolymer, the component (A) used for the support material is an ethylene-vinyl ester copolymer.
In the support material, the content of the ethylene component in the component (A), the MFR of the component (A), a suitable range such as a commercially available product that can be used for the component (A), or examples thereof are (A) in the seal material. The component (A) in each of the sealing material and the support material is not necessarily the same resin, that is, the type of the compound used as the alkyl methacrylate ester or the type of the compound used as the vinyl ester, the ethylene content. , MFR, etc. need not be the same copolymer. However, it is preferable to use the same copolymer for the seal material and the support material because the interlayer adhesive strength between the seal layer and the support layer is further increased and the film residue is less likely to occur.
In addition, in the support material, in addition to the same type of copolymer as the ethylene copolymer (A) used for the sealing material, an ethylene type that is not the same type as the ethylene copolymer (A) used for the sealing material. If the copolymer (A) is less than 30% by mass relative to the total mass of the component (A), it may be further contained. If it accounts for 30% by mass or more of the component (A), the interlayer adhesion strength between the support layer and the seal layer tends to be weak, and the film tends to remain, such being undesirable.

Examples of the polyolefin resin (C) in the support material include high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene called homo, random, and block.
Of these, linear low-density polyethylene and high-density polyethylene are preferred because of high compatibility with the ethylene-based copolymer (A) and high heat resistance.
The polyolefin resin (C) can be produced by a high pressure method using a peroxide initiator, or by a low / medium pressure method using a Ziegler-Natta catalyst, a metallocene catalyst or the like. The production process can be variously used such as bulk, slurry, gas phase, and solution method, and is not particularly limited.
The MFR of the polyolefin resin (C) is not particularly limited, but generally 0.1 to 100 g / 10 min is used, and 0.1 to 50 g / 10 min is preferable.

  The blending ratio of the (A) component and the (C) component in the support material is not particularly limited, but the blending ratio of the (A) component is 100% by mass in total of the (A) component and the (C) component. It is preferable that it is 40-90 mass%, and 60-80 mass% is more preferable. When it is less than 40% by mass, the interlayer adhesive strength between the seal layer and the support layer is lowered, and delamination may easily occur, and a film residue may be generated. When it exceeds 90 mass%, heat resistance may fall.

The easy-open film of the present invention may be in the form of a two-layer film consisting only of the seal layer and the support layer, or three or more layers in which the seal layer, the support layer, and other layers are laminated. It may be in the form of a multilayer film.
In the easy-open film of the present invention, it is a more preferable embodiment that a polyolefin layer made of a polyolefin resin (C) is provided adjacent to the support layer on the opposite side of the support layer from the seal layer.
By providing such a polyolefin layer, it becomes easy to bond the easy-open film of the present invention to a substrate made of polyester, polyamide, polypropylene or the like. Further, the heat resistance is further improved.
Specific examples of the substrate include uniaxial or biaxially stretched films made of polyester, polyamide, polypropylene, etc., films formed by vapor-depositing aluminum, silica, alumina, etc. on them, paper, aluminum foil, and the like. The substrate may be used alone or in combination of two or more. Since these substrates can be subjected to processing such as coloring and printing, it is possible to provide an easy-open film excellent in design properties, barrier properties, light shielding properties, pinhole resistance, curling resistance, and the like. .
The method of laminating the easy-open film and the substrate is based on the method of previously forming the easy-open film of the present invention and laminating the substrate with the dry lamination method, or sandwich lamination via polyethylene or the like. Examples thereof include, but are not limited to, a method of laminating with a material, or a method of directly laminating a resin constituting the easy-open film of the present invention on a substrate with a multilayer extrusion laminating machine.

The thickness of the easy-open film of the present invention is not particularly limited, but those in the range of 10 to 100 μm are suitable for satisfactorily satisfying low-temperature heat sealability, heat seal strength, and the like. A more preferable thickness is 20 to 90 μm, and a more preferable thickness is 25 to 80 μm.
The thickness ratio of the seal layer to the support layer is (the thickness of the seal layer) :( the thickness of the support layer) = 10 to 40:90 to 60 (however, the total thickness of the seal layer and the support layer is 100). And the range of (seal layer thickness) :( support layer thickness) = 20 to 40:80 to 60 is more preferable. Here, when the polyolefin layer is provided in addition to the support layer, the thickness ratio is (seal layer thickness) :( support layer thickness) :( polyolefin layer thickness) = 10-40: 10-30: 30- 80 is preferable, and (thickness of the seal layer) :( thickness of the support layer) :( thickness of the polyolefin layer) = 20 to 40:10 to 30:30 to 70 is more preferable.

The composition comprising each layer such as a sealing material and a supporting material, such as a sealing material and a supporting material, does not contradict the purpose of the present invention, that is, the low-temperature heat-sealing property, heat resistance, and non-film residual property in an easily openable film are impaired. There is no problem even if a resin other than the component (A), the component (B), and the component (C) is contained as long as it is not present.
Specific examples of such a resin include polyolefin resins such as low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, and polybutene, and ethylene-unsaturated monoesters such as ethylene- (meth) acrylic acid copolymers. Carboxylic acid copolymers and metal salts thereof, ethylene-propylene copolymer elastomers, ethylene-1-butene copolymer elastomers, various elastomers such as styrene-butadiene copolymer elastomers and hydrogenated products thereof, or tackifying resins, aliphatic Examples thereof include known adhesive resins used in the field of so-called hot melt adhesives, such as olefin hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, and rosins.

  In the sealing material and support material in the present invention, optional additives such as a lubricant, an antioxidant, an antistatic agent, an antiblocking agent, a colorant, an ultraviolet absorber, and an organic / inorganic filler are blended depending on the purpose. can do.

In the present invention, the sealing material, the support material, and the like constituting each layer are prepared by mixing the components (A), (B), (C), additives, and resins simultaneously or sequentially. Specifically, each component is mixed with a tumbler, Henschel mixer, etc., and then charged into a molding machine. After mixing with a tumbler, Henschel mixer, a single screw extruder, a twin screw extruder, a Banbury mixer, a kneader, etc. The method of melt-mixing is mentioned.
There is no limitation in particular as a method of manufacturing the easily openable film of this invention. The sealing material or the support material is put into a multilayer T-die molding machine or a multilayer inflation molding machine and manufactured by a co-extrusion method, or either the sealing layer or the support layer is previously sealed or supported. Examples include a method in which a film is formed from a material and the other is melt laminated by extrusion lamination on the film.

As described above, in the easy-open film of the present invention, an ethylene copolymer (A) and a polyester resin (B) are used in the sealing material, and an ethylene copolymer ( By using A) and the polyolefin resin (C), the low temperature heat sealability is good. Moreover, it has heat resistance which does not deform | transform in sterilization processes, such as a boil and a retort, and can maintain heat seal intensity | strength favorable also on conditions, such as a sterilization process.
In the easy-open film of the present invention, the ethylene copolymer (A) and the polyester resin (B) are used in the sealing material, and the ethylene copolymer (A) in the sealing material is used in the support material. The same kind of ethylene copolymer (A) is used, so that the adhesive strength between the seal layer and the support layer when heat-sealed is high, and the seal layer does not cause cohesive failure. The interface with the container body is easy to peel off. Therefore, it does not cause delamination or cohesive failure when applied to a container and peels off, causing interfacial peeling, so there is no non-uniform film residue and excellent non-film residual property, and a good peel appearance can be achieved. it can.
Here, when the polyester resin (B) having a melting point of 100 to 135 ° C. is used, it is possible to easily achieve both low-temperature heat sealability and heat resistance.
Further, when the content ratio of the ethylene copolymer (A) and the polyester resin (B) in the sealing material is 40 to 90/60 to 10, the heat seal strength is maintained and the variation in the heat seal strength is prevented. be able to.

The lid material of the present invention is configured using the easy-open film of the present invention, and is mainly installed in a container body such as a cup shape or a tray shape to constitute an easily openable container. is there.
When the easy-open film of the present invention is applied to the lid, the easy-open film may be in the form of a two-layer film comprising the seal layer and the support layer, and further through the polyolefin layer. Although the form which provided the base material may be sufficient, generally the latter form which can provide designability, barrier property, light-shielding property, pinhole resistance, curl resistance, etc. easily is used.

  Since the lid | cover material of this invention has the easily openable film of this invention, it will satisfy | fill all of the low-temperature heat-sealing property with respect to a container main body, peeling appearance, and heat resistance.

The container of the present invention includes the lid material of the present invention.
Such a container is, for example, a cup-shaped or tray-shaped container having a cover material of the present invention, an adhesive part such as a flange that can be in close contact with the cover material, and a storage part that stores contents such as food. It can comprise from a main body. In addition, in such a container, the sealing layer side of the easy-open film which comprises a cover material is closely_contact | adhered to the adhesion part of a container main body, and is comprised.
After filling or containing the contents in the container, a lid is placed so as to contact the adhesive part of the container body, and the lid and the container body are heat-sealed using a hot plate, high frequency, ultrasonic waves, etc. Thus, the container of the present invention can be assembled.

Applicable container body resins include polyester, polystyrene, polypropylene, polycarbonate, polyvinyl chloride, and the like. Among these, it is preferable to use polyester or polycarbonate because it is particularly excellent in transparency, low temperature heat sealability, and heat seal strength. Polyester is composed of units derived from terephthalic acid and glycol, A-PET having low crystallinity, PETG in which units derived from 1,4-cyclohexanedimethanol are copolymerized, and C-PET having high crystallinity. Is mentioned. Furthermore, B-PET sheets and containers available from Inabata Sangyo Co., Ltd. can also be used. Furthermore, when the container body made of polyester is provided with a lid material having the easy-open film of the present invention, a film piece-like, string-like film residue is left on the peeling surface of the container body after peeling the lid material. In addition, the release surface has the same excellent appearance as before the heat sealing of the lid. On the other hand, when the lid body having the easy-open film of the present invention is provided on the container body made of polycarbonate, the sealing resin is uniform on the peeling surface of either the container body or the lid material after peeling the lid material. The remaining peeling marks are formed. Such a uniform peeling mark is excellent in appearance and proves that the container body and the lid material are securely sealed before the lid material is peeled off. Thus, it is very important in the medical field that the seal state can be confirmed from the peeling mark. Therefore, the easy-open film, lid material, and container of the present invention are required not only to be used in the fields of foods and the like that require no peeling marks or film residue on the peeling surface, but also to leave uniform peeling marks. It is also preferably used in the medical field.
In addition, the container body can be made of polyethylene, an inner layer made of resin or the like used for the container body described above, and a laminate made of paper, aluminum foil, a barrier resin layer, or the like.

In such a container, the lid and the adhesive part of the container main body are heat-sealed at a low temperature, the contents can be easily sealed and stored, and easily opened and the adhesive part after opening. The appearance of the film, that is, the peeled appearance is excellent. Furthermore, since it is excellent in heat resistance, such a container can be subsequently subjected to sterilization treatment such as boiling and retort.
Here, when a container body made of a polyester resin is used, it is possible to provide a container that hardly adsorbs the flavor of food and that satisfies the low-temperature heat sealability, the peel appearance, and the heat resistance of the lid. When polycarbonate is used as the container body, a container satisfying both heat resistance and transparency can be provided.

Examples of the present invention are shown below, but the present invention is not limited to these examples.
<Resin>
Below, MFR was measured on condition of temperature 190 degreeC and load 21.18N based on JISK7120.
[Ethylene copolymer (A)]
E1: MFR 6 g / 10 min, ethylene-methyl acrylate copolymer having a methyl acrylate content of 20% by mass (“Lex Pearl RB” 4200, manufactured by Nippon Polyolefin Co., Ltd.)
E2: MFR 7 g / 10 min, ethylene-methyl methacrylate copolymer having a methyl methacrylate content of 15% by mass (“Aclift” WH302, manufactured by Sumitomo Chemical Co., Ltd.)
E3: MFR 2 g / 10 min, ethylene-vinyl acetate copolymer having a vinyl acetate content of 15% by mass (“Jyrex EVA” VE430A manufactured by Nippon Polyolefin Co., Ltd.)
[Polyester resin (B)]
ES1: MFR 13 g / 10 minutes, melting point 126 ° C. polyester resin (manufactured by Toyobo Co., Ltd., “Byron” GM-913)
ES2: MFR 10 g / 10 min, polyester resin having a melting point of 112 ° C. (manufactured by Toyobo Co., Ltd., “Byron” GM-990)
[Polyolefin resin (C)]
PO1: MFR 3.5 g / 10 min, density 0.955 g / cm ³ high-density polyethylene (manufactured by Nippon Polyolefin Co., Ltd., “Jyrex HD”)
PO2: Linear low-density polyethylene (MFR 10 g / 10 min, density 0.922 g / cm ³ , manufactured by Nippon Polyolefin Co., Ltd., “Harmolex LL”)
PO3: Linear low-density polyethylene (MFR 3.5 g / 10 min, density 0.905 g / cm ³ , manufactured by Nippon Polyolefin Co., Ltd., “Harmolex LL NC524A”)
PO4: linear low density polyethylene (MFR 3.5 g / 10 min, density 0.921 g / cm ³ , manufactured by Nippon Polyolefin Co., Ltd., “Harmolex LL NC574R”)

<Preparation of easy-open film>
Various resins were mixed in the composition shown in Table 1 using a Henschel mixer to prepare a seal material forming a seal layer, a support material forming a support layer, and optionally a polyolefin resin forming a polyolefin layer. These were put into a three-layer T-die molding machine and molded at a temperature of 210 ° C. to obtain an easy-open film having a seal layer and a support layer having the structure shown in Table 1. The side opposite to the seal layer of the easy-open film, that is, the surface of the support layer or the polyolefin layer is subjected to corona treatment, and a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm is dry laminated as a base material to form a laminate. Samples of
In Table 1, “%” indicates “% by mass”.

<Evaluation of easy-open film>
The lid material obtained above was cut into a width of 20 mm. An A-PET sheet (thickness 300 μm, manufactured by Teijin Ltd., “Teijin Tetron Sheet”) or polycarbonate sheet (thickness 2 mm, manufactured by Asahi Glass Co., Ltd.), “Lexane Sheet”, which is obtained by cutting the lid material into an adherend of 20 mm width. Carbograss ") was used so that the seal layer of the easy-open film was in contact.
Heat sealing was performed by one-side heating from the lid side with a hot plate at a pressure of 0.2 MPa, a sealing time of 3 seconds, temperatures of 130 ° C., 150 ° C. and 170 ° C.
[Heat resistant heat seal strength]
The heat seal strength (heat resistant heat seal strength) of the easy-open film placed under high heat conditions was evaluated.
Both ends of the heat-sealed sample were cut to obtain a heat seal strength measurement sample having a width of 15 mm. In the case of a sample using an A-PET sheet, this sample was immersed in 85 ° C. hot water for 30 minutes, and in the case of a sample using a polycarbonate sheet, heat treatment was performed at 121 ° C. for 30 minutes with a hot water sterilizer. The sample after the heat treatment was allowed to stand for 24 hours at a temperature of 23 ° C. and a relative humidity of 50% to adjust the state. The heat seal strength after condition adjustment was evaluated by a peel test at a peel rate of 300 mm / min and 180 ° peel, and indicated by a heat seal strength per 15 mm width.
[Deformation resistance under hot water conditions]
The degree of deformation of the lid sample when the heat-sealed sample was immersed in hot water at 85 ° C. for 30 minutes or sterilized at 121 ° C. for 30 minutes was visually observed and evaluated in the following three stages.
○ ... not deformed.
X: Deformed as shrunk.
XX: Solidified in a state where it melted once and partly flowed.
The results of this evaluation are shown as “heat resistance” in Table 2.
[Exfoliation surface appearance]
The peeled surface of the sample A-PET sheet or polycarbonate sheet used for the measurement of the heat seal strength was visually observed and evaluated in the following two stages.
A: The A-PET sheet surface is smooth and no easy-open film remains.
X: There is a portion where the easy-open film remains on the A-PET sheet surface.
□ ... There is a uniform whitened peeling mark on the polycarbonate sheet surface or lid surface.
Δ: There is a portion where the easy-open film remains on the polycarbonate sheet surface in the form of a piece or string.
The evaluation results are shown in Table 2.

As is apparent from Table 2, the easy-open films obtained in Examples 1 to 4 exhibit sufficient heat seal strength even at 130 ° C., and can be heat sealed at a temperature at which the A-PET sheet is not deformed. Has low temperature heat sealability. Further, there was no film residue on the peeled surface, and the appearance was good. Furthermore, these easy-open films did not deform even when placed under hot water conditions and maintained stable heat seal strength. That is, it has heat resistance that does not open under conditions such as warm water.
However, as shown in Table 2, in Comparative Example 1 in which the sealing layer contains a polyolefin resin instead of the polyester resin (B), the heat seal strength after being immersed in hot water at 85 ° C. is 0, and the lid A sample of the material peeled from the A-PET sheet. Further, in Comparative Example 2 in which the support layer did not contain the ethylene copolymer (A), peeling occurred between the seal layer and the support layer in the peeling test, and a film residue was generated in the peeling test.
In Comparative Example 3 in which the support layer did not contain the polyolefin resin (C), remarkable deformation occurred in the evaluation of heat resistance, and the peeled surface appearance was inferior. Comparative Example 4 in which the seal layer does not contain an ethylene-based copolymer (A) and the support layer contains a polyester resin instead of the polyolefin resin (C) has a heat seal strength that is too high and does not exhibit easy-openability. The peeled surface appearance was poor.
The easy-open films obtained in Examples 5 to 7 showed sufficient heat seal strength with respect to the polycarbonate sheet even after the heat sterilization treatment at 121 ° C., and there was no shape deformation. Further, in Examples 5 to 7, a uniform whitened peeling mark is formed on the polycarbonate sheet surface or the lid material surface, the appearance is excellent, and the polycarbonate sheet and the lid material are securely sealed before the lid material is peeled off. It was confirmed that it was done.
On the other hand, in Comparative Example 5 in which the support layer does not contain the ethylene copolymer (A), as in the case of the polyester sheet (Comparative Example 2), peeling occurs between the seal layer and the support layer in the peeling test. A film residue was generated in the peel test.

The easy-open film of the present invention and the lid material using the film are, for example, tofu, tokoroten, yogurt, jelly, coffee beverage, lactic acid beverage, instant noodles, Japanese confectionery, processed meat and other foods, or medicines, medical instruments, inks It is suitable for a container having a cartridge or the like as contents. Especially when an easy-open film is provided with a base material, it is easy to visually recognize the contents by using a transparent base material, and printing, coloring, vapor deposition, etc. are applied to the base material to provide design, barrier properties, and light shielding. Property, pinhole resistance, curl resistance, and the like can be imparted, and can be suitably used for various applications.

Claims (6)

A seal layer, have a the support layer adjacent to the seal layer, an easily openable film is heat sealed to the container body,
The sealing layer contains 40 to 90% by mass of an ethylene copolymer (A) of ethylene and (meth) acrylic acid alkyl ester or vinyl ester, and 60 to 10% by mass of a polyester resin (B). Consists of
The support layer is made of a support material in which the ethylene copolymer (A) is 40 to 90% by mass in a total of 100% by mass of the ethylene copolymer (A) and the polyolefin resin (C). The
An easy-open film, which peels at an interface between the seal layer and the container body .     The easy-open film according to claim 1, wherein the polyester resin (B) has a melting point of 100 to 135 ° C. A lid material using the easy-open film according to claim 1 . A container comprising the lid material according to claim 3 . A container comprising a container body made of polyester and the lid material according to claim 3 . A container comprising a container body made of polycarbonate and the lid material according to claim 3 .