JP6793587B2 - Easy-to-peel film, lid material, and container - Google Patents

Description

The present invention relates to an easily peelable film, a lid material containing the easily peelable film, and a container provided with the lid material.

Conventionally, a container made of polyester resin has been widely used as a packaging container for filling foods, miscellaneous goods, and the like. These packaging containers are used by heat-sealing the lid material at the filling port and sealing it. However, since the lid material must be peeled off when the package is taken out, the container and the lid material can be stably sealed and sealed. A sealant film with heat-sealing strength that is easy to peel off is required.

As a lid material having such a function, for example, Patent Document 1 describes 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 polyester resin. A film formed by stretching a coextruded film composed of a base material layer is described.

Japanese Unexamined Patent Publication No. 6-143408 (published on May 24, 1994)

However, when the lid material containing the film described in Patent Document 1 is peeled off from the container sealed by the lid material, the seal layer itself of the lid material causes layer cracking and coagulates and breaks. For this reason, the resin of the lid material remains in the container, and further improvement is required in recent years for the aesthetic appearance of the container after the lid material is peeled off.

The present invention has been made in view of the above problems, and an object of the present invention is an easily peelable film that can be suitably formed by a coextrusion film molding method and has easy peelability to a polyester container. It is an object of the present invention to provide an easily peelable film capable of preventing the resin of the sealing layer from remaining on the polyester container after peeling and preventing the peeling surface of the container from being spoiled in appearance.

As a result of diligent studies by the inventors in order to solve the above problems, the following invention has been reached.

That is, the easily peelable film according to one aspect of the present invention is an easily peelable film provided with a seal layer and a base material layer, and the seal layer is made of 100 parts by weight of crystalline polyester (A) and 11. The base material layer contains 100 parts by weight or more of the crystalline polyester (A) and 52 parts by weight or more and 82 parts by weight or less of the olefin resin (B) in the range of 43 parts by weight or less. The crystalline polyester (A) contains the olefin resin (B) within the range of the above, and at least one of the two surface layers of the easily peelable film is the seal layer. It is characterized in that the melting point is in the range of 100 ° C. or higher and 180 ° C. or lower, and the glass transition temperature is 10 ° C. or lower.

Further, in the easily peelable film according to one aspect of the present invention, the seal layer is within the range of 0.05 parts by weight or more and 18 parts by weight or less with respect to 100 parts by weight of the crystalline polyester (A). It is more preferable that the filler (C) is contained.

Further, in the easily peelable film according to one aspect of the present invention, it is more preferable that the olefin resin (B) has a melting point in the range of 100 ° C. or higher and 170 ° C. or lower.

The easily peelable film according to one aspect of the present invention is more preferably a coextruded film.

A lid material containing an easily peelable film according to one aspect of the present invention is also within the scope of the present invention.

A container including a lid material according to one aspect of the present invention and a container body containing polyester is also within the scope of the present invention.

According to the present invention, a coextruded film molding method can be used to form a suitable film, which has easy peelability to a polyester container, and the resin of the sealing layer remains in the polyester container after the lid material is peeled off. It is possible to provide an easily peelable film that can prevent the peeling surface of the container from being spoiled.

Embodiments of the present invention will be described in more detail below.

<Easy-to-peel film>
The easily peelable film according to one embodiment is typically an easily peelable film provided with a seal layer and a base material layer. The easily peelable film may include a layer other than the seal layer and the base material layer, and examples of such a layer include an intermediate layer.

[Seal layer]
The seal layer is at least one of the two surface layers of the easily peelable film, and is heat-sealed to the container when the easily peelable film is used as a lid material of the container. Layer.

In the seal layer, the olefin resin (B) contained in 100 parts by weight of the crystalline polyester (A) is in the range of 11 parts by weight or more and 43 parts by weight or less, and 13 parts by weight or more and 35 parts by weight. It is preferably within the following range. Since the seal layer contains 11 parts by weight or more of the olefin resin (B) contained in 100 parts by weight of the crystalline polyester (A), for example, it is easy for a heat-resistant polyester container which is an adherend. The peelability can be improved. Further, the seal layer contains 43 parts by weight or less of the olefin resin (B) with respect to 100 parts by weight of the crystalline polyester (A), so that, for example, the heat-resistant polyester container which is an adherend is sealed. You can improve your sex. In other words, in the seal layer, the olefin resin (B) contained in 100 parts by weight of the crystalline polyester (A) is contained in the range of 11 parts by weight or more and 43 parts by weight or less, so that the heat-resistant polyester container is used. It is possible to obtain a seal layer having an excellent balance between easy peeling property and sealing property. In the resin composition for forming the seal layer, the content of the crystalline polyester (A) is within the range of 65% by weight or more and 95% by weight or less, assuming that the total weight of the resin composition is 100% by weight. Can be.

The seal layer may further contain a filler (C). From the viewpoint of making it difficult for the seal layer to adhere to the seal layer by a nip roll, a touch roll, or the like during molding, the filler (C) contained in 100 parts by weight of the crystalline polyester (A) in the seal layer is 0.05 weight by weight. It is preferably in the range of parts or more and 18 parts by weight or less, and more preferably in the range of 0.5 parts by weight or more and 10 parts by weight or less.

[Base layer]
The base material layer is a layer that supports a seal layer that is co-extruded with the base material layer when the easily peelable film is molded. Further, as the base material layer, for example, when an easily peelable film is used as a lid material for a container, a plastic film such as a polyethylene terephthalate film is based on the surface of the base material layer on the side facing the seal layer. It is also a layer that is laminated as a material. In this case, the base material layer is interposed between the seal layer and the base material such as polyethylene terephthalate film.

The base material layer contains a crystalline polyester (A) and an olefin resin (B).

In the base material layer, the olefin resin (B) contained in 100 parts by weight of the crystalline polyester (A) is in the range of 52 parts by weight or more and 82 parts by weight or less, and 60 parts by weight or more and 75 parts by weight. It is preferably within the range of less than a part. The base material layer was co-extruded with the seal layer, for example, by containing 52 parts by weight or more of the olefin resin (B) contained in 100 parts by weight of the crystalline polyester (A). Occasionally, it is possible to successfully prevent the base material layer from sticking to a nip roll, touch roll, or the like while successfully supporting the seal layer. Further, if the base material layer contains 82 parts by weight or less of the olefin resin (B) with respect to 100 parts by weight of the crystalline polyester (A), the adhesiveness between the base material layer and the seal layer is lowered. It can be prevented from doing so. Therefore, when the easily peelable film is peeled from the adherend, it is possible to preferably prevent the base material layer from being coagulated and broken or the base material layer and the seal layer from interfacial peeling. it can. In the resin composition for forming the base material layer, the content of the crystalline polyester (A) is in the range of 50% by weight or more and 70% by weight or less, assuming that the total weight of the resin composition is 100% by weight. Can be within. Further, the easily peelable film according to the present invention may contain two or more base material layers. In that case, the resin composition of each resin composition forming the two adjacent base material layers is different.

The base material layer may further contain a filler (C). When the base material layer contains the filler (C), the filler (C) contained in 100 parts by weight of the crystalline polyester (A) in the base material layer has a molding processability of the easily peelable film. From the viewpoint, it is preferably in the range of 0.05 parts by weight or more and 5 parts by weight or less.

[Middle layer]
The easily peelable film according to one embodiment may include an intermediate layer interposed between the seal layer and the base material layer.

In the intermediate layer, the olefin resin (B) contained in 100 parts by weight of the crystalline polyester (A) is preferably in the range of 11 parts by weight or more and 51 parts by weight or less, and 13 parts by weight or more. It is more preferably in the range of 51 parts by weight or less.

The intermediate layer may further contain a filler (C). When the intermediate layer contains the filler (C), the filler (C) contained in 100 parts by weight of the crystalline polyester (A) in the intermediate layer is 0.05 parts by weight or more and 18 parts by weight or less. It is preferably within the range of.

[Crystalline polyester (A)]
The crystalline polyester (A) is a polyester resin produced by polycondensing a polyvalent carboxylic acid and a polyhydric alcohol.

Examples of the polyvalent carboxylic acid include aromatic polyvalent carboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, and trimellitic acid, as well as succinic acid, adipic acid, azelaic acid, and sebacic acid. Examples thereof include aliphatic polyvalent carboxylic acids such as decanoic acid, dimer acid, and cyclohexanedicarboxylic acid.

Examples of polyhydric alcohols include ethylene glycol, propylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyltrimethylene glycol, butanediol, pentanediol, 3-methylpentanediol, hexanediol, and nonane. Examples thereof include polyhydric alcohols such as diol, cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol, pentaethylene glycol, and trimethylolpropane.

The above-mentioned polyvalent carboxylic acid and polyhydric alcohol are used in any combination. Specifically, terephthalic acid / ethylene glycol copolymer, terephthalic acid / ethylene glycol / 1,4-cyclohexanedimethanol ternary copolymer, 2,6-naphthalenedicarboxylic acid / ethylene glycol copolymer, and terphthalic acid. / Isophthalic acid / Butanediol ternary copolymer and the like can be mentioned.

The crystalline polyester (A) preferably has a melting point in the range of 100 ° C. or higher and 180 ° C. or lower, and a glass transition temperature of 10 ° C. or lower from the viewpoint of moldability by the coextrusion molding method. Examples of such crystalline polyesters include resins commercially available under the trade name "Byron" (manufactured by Toyobo Co., Ltd.).

By including the crystalline polyester (A) having a melting point in the range of 100 ° C. or higher and 180 ° C. or lower in the seal layer and the base material layer, the easily peelable film is heated under a temperature condition of about 160 ° C. to 200 ° C. As a result, the easily peelable film can be preferably attached to the adherend. In addition, an easily peelable film that can be suitably coextruded can be formed. Further, by incorporating the crystalline polyester (A) having a glass transition temperature of 10 ° C. or lower in the seal layer and the base material layer, the peelability is excellent in an atmosphere in the temperature range of −20 ° C. to 60 ° C. It is possible to form an easily peelable film.

The melting point and glass transition temperature of the crystalline polyester (A) are measured by using a differential scanning calorimeter (DSC220C manufactured by Seiko Electronics Co., Ltd.) according to the steps (i) to (iii) shown below. In each step, time is plotted on the horizontal axis and heat of fusion is plotted on the vertical axis to obtain a melting curve. The peak observed in step (ii) is measured as a crystallization peak and observed in step (iii). The peak is measured as the melting peak.

(I) Approximately 5 mg of the sample is heated from room temperature to 200 ° C. at a rate of 30 ° C./min, and held for 5 minutes after the temperature rise is completed.

(Ii) Next, the temperature is lowered from 200 ° C. to −100 ° C. at a rate of 10 ° C./min, and the temperature is maintained for 5 minutes after the temperature reduction is completed.

(Iii) Next, the temperature is raised from −100 ° C. to 200 ° C. at a rate of 10 ° C./min.

[Olefin resin (B)]
Examples of the olefin resin (B) include a propylene resin and an ethylene resin.

In the present specification, the propylene-based resin is a propylene homopolymer or a copolymer having a content of a monomer unit derived from propylene of 50% by weight or more. Examples of the copolymer having a monomer unit derived from propylene having a content of 50% by weight or more include a propylene-ethylene random copolymer, a propylene-α-olefin random copolymer, and a propylene-ethylene-α-olefin random. One or more selected from the group consisting of copolymers, "propylene homopolymer component (hereinafter, also referred to as polymer component (I))" and "propylene, ethylene and / or α-olefin having 4 or more carbon atoms". Examples thereof include a propylene-based block copolymer composed of a copolymer component with a comonomer (hereinafter, also referred to as a copolymer component (II)).

Examples of the α-olefin constituting the propylene resin include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. The α-olefin constituting the propylene-based resin has preferably 4 to 20 carbon atoms, and more preferably 4 to 12 carbon atoms.

Examples of the propylene-α-olefin random copolymer include a propylene-1-butene random copolymer and a propylene-1-hexene random copolymer. Examples of the propylene-ethylene-α-olefin random copolymer include a propylene-ethylene-1-butene random copolymer and a propylene-ethylene-1-hexene random copolymer.

In the present specification, the ethylene resin is an ethylene homopolymer or a copolymer having a content of a monomer unit derived from ethylene of more than 50% by weight.

Ethylene-based resins include low-density polyethylene, high-density polyethylene, ethylene-1-butene copolymer, ethylene1-hexene copolymer, ethylene-propylene copolymer, ethylene-methylmethacrylate copolymer, and ethylene-vinyl acetate. Examples thereof include a copolymer and a saponified product of an ethylene-vinyl acetate copolymer.

As the olefin resin (B), two or more kinds of resins may be used, but in that case, it is preferable to select two or more kinds from the same kind of resin, for example, a propylene based resin.

Further, in the easily peelable film according to one aspect of the present invention, the olefin resin (B) is more preferably an olefin resin having a melting point in the range of 100 ° C. or higher and 170 ° C. or lower.

[Filler (C)]
Examples of the filler (C) contained in the seal layer and the base material layer of the easily peelable film include an inorganic filler, and examples of the inorganic filler include calcium carbonate, calcium silicate, silica, kaolin, titanium oxide, and aluminum hydroxide. Examples thereof include, but are not limited to, magnesium hydroxide, magnesium silicate, magnesium sulfate, talc, calcined talc, glass flakes, mica, hydrotalcite, wollastonite, potassium titanate, and carbon black. The inorganic filler may be surface-treated with a surface-treating agent or the like.

[Other ingredients]
Each of the seal layer, the base material layer, and the intermediate layer is a resin other than the crystalline polyester (A) and the olefin resin (B), a compatibilizer, a lubricant, and an antistatic agent, as long as the effects of the present invention are not impaired. , Antioxidant, heat stabilizer, ultraviolet absorber, antibacterial agent, antifogging agent and the like may be contained.

[Manufacturing method of easily peelable film]
A known film forming method can be adopted for producing the easily peelable film. At that time, the resin composition of the seal layer may be prepared in advance before molding the easily peelable film, or the crystalline polyester (A), the olefin resin (B), contained in the resin composition, may be prepared. And the filler (C) or the like may be weighed in a predetermined amount and directly put into the film molding machine. Similarly, a resin composition may be prepared in advance for the base material layer, or a predetermined amount of crystalline polyester (A), olefin resin (B), filler (C) and the like may be weighed and directly formed into a film. You may put it in the machine. The easily peelable films may be separately formed and then bonded together, but when only the seal layer and the base material layer are used, a two-layer structure is used, and when an intermediate layer is provided, a multilayer die having at least a three-layer structure is used. The method by coextrusion molding is preferable.

The coextruded film is produced, for example, by using a three-kind three-layer T-die casting machine. Using three extruders, one extruder to the substrate layer, another extruder to the intermediate layer, and another extruder to the seal layer were laminated with a coextrusion multilayer die. It is extruded into a film from a die and cast-cooled and solidified with a cooling roll to form an easily peelable film. After that, the easily peelable film is conveyed by, for example, a nip roll or a touch roll, and is wound around a take-up roll. Here, as described above, the easily peelable film can be prevented from sticking to the nip roll or the like by providing the base material layer.

By producing the easily peelable film by coextrusion, it becomes easy to finely adjust the thickness of each layer of the produced film. As a result, the balance of the thickness of each layer can be finely adjusted, and a film having excellent peelability can be realized. Therefore, in one embodiment of the present invention, the easily peelable film is a coextruded film formed by a coextrusion molding method. The thickness of the easily peelable film is not particularly limited, but is 10 to 100 μm, and the seal layer is 2 to 80 μm.

<Lid material>
The easily peelable film can be suitably used as a lid material for a container by laminating a base material on the surface of the easily peelable film on the base material layer side. Therefore, a lid material including the easily peelable film according to one embodiment is also within the scope of the present invention. Here, examples of the base material include a plastic film such as a polyethylene terephthalate film, a metal foil such as aluminum, and paper. Such a base material can be laminated on the above base material, for example, by forming an easily peelable film in advance and then using a known adhesive. In order to produce the lid material, the surface of the easily peelable film on the base material layer side may be subjected to surface treatment such as corona discharge treatment. The thickness of the seal layer in the total thickness of the lid material is preferably 2 to 80%, more preferably 10 to 50%, from the viewpoint of the seal strength with respect to the container. The lid material seals the container by attaching the seal layer of the easily peelable film to the container as an adherend by heat sealing.

<Container>
A container comprising the lid material and a container body made of polyester by heat-sealing the seal layer contained in the lid material containing the easily peelable film according to the present invention to a container body made of polyester. Can be formed. Examples of the polyester constituting the container body include crystalline polyester. The container provided with the lid material and the container body made of crystalline polyester can withstand the retort sterilization treatment. Since the lid material according to the embodiment includes the easily peelable film according to the embodiment, the container body made of crystalline polyester is suitably heat-sealed under temperature conditions of 160 ° C. to 200 ° C. be able to. Further, in the container after heat sealing, the lid material has both appropriate sealing property and easy peeling property. Therefore, a container provided with the lid material according to one embodiment is also within the scope of the present invention.

The present invention will be described with reference to examples, but the present invention is not limited thereto.

The laminated films of Examples 1 and 2, and Comparative Examples 1 and 2 were evaluated for film processability, and then for easy peelability.

[Example 1]
100 parts by weight of polypropylene (trade name "Nobrene FL6412", manufactured by Sumitomo Chemical Co., Ltd., MI = 6 g / 10 min) as an olefin resin (B) and talc (trade name "Micron White HS-T") as a filler (C) Hayashi Kasei Co., Ltd., average particle size 4.7 μm)) 150 parts by weight was added, and melt-mixed using a same-direction twin-screw extruder (diameter 45 mm) with the cylinder temperature and die temperature set to 200 ° C. Pellets of the composition (1) were obtained.

As the crystalline polyester (A), 100 parts by weight of Byron GM915 (manufactured by Toyo Spinning Co., Ltd., melting point 139 ° C., glass transition temperature -70 ° C.) and 12.5 parts by weight of polypropylene which is the same as the olefin resin (B). The resin composition (1) was pellet-blended with 12.5 parts by weight to obtain a resin composition (D-1) for forming a seal layer. The composition of the obtained resin composition (D-1) is 17.5 parts by weight of the olefin resin (B) and 7.5 parts by weight of the filler (C) when converted into 100 parts by weight of the crystalline polyester (A). Met.

Further, the resin composition (D-2) for forming the base material layer is the same crystalline polyester (A) and olefin resin (B) as those used for the seal layer, and the crystalline polyester (A) is used. ) 100 parts by weight, 64 parts by weight of the olefin resin (B), and 2.5 parts by weight of the resin composition (1) were pellet-blended. The composition of the obtained resin composition (D-2) is 65 parts by weight of the olefin resin (B) and 1.5 parts by weight of the filler (C) when the crystalline polyester (A) is converted into 100 parts by weight. there were.

Using the above materials, a three-kind three-layer T die-casting machine (extruder A: diameter 40 mm, extruder B: diameter 50 mm, extruder C: diameter 40 mm) is used, and the base material is applied to the extruder A and the extruder B. The resin for the seal layer was put into the layer resin and the extruder C, molded at an extrusion temperature of 180 ° C., and the laminated film of Example 1 was produced in which the base material layer and the seal layer were laminated in this order.

Then, a corona discharge treatment was performed on the surface of the laminated film of Example 1 produced on the substrate layer side so that the wetting tension was 45 dyn / cm. In the laminated film of Example 1, the thickness of the base material layer was 20 μm, the thickness of the seal layer was 10 μm, and the total thickness was 30 μm.

[Example 2]
The laminated film of Example 2 is a laminated film in which an intermediate layer is provided between a base material layer and a sealing layer. The resin composition for the intermediate layer was obtained by pellet-blending the same crystalline polyester (A), olefin resin (B), and resin composition (1) as those used in Example 1. The composition of the resin composition for the intermediate layer was 42 parts by weight of the olefin resin (B) and 1.3 parts by weight of the filler (C) when converted into 100 parts by weight of the crystalline polyester (A). Using the T-die cast processing machine used in Example 1, the extruder A is a resin composition for a base material layer, the extruder B is a resin composition for an intermediate layer, and the extruder C is a resin composition for a seal layer. Was added to obtain a laminated film of Example 2 in which the base material layer / intermediate layer / seal layer were laminated in this order. Then, in the same manner as in Example 1, the surface of the laminated film of Example 2 on the substrate layer side was subjected to corona discharge treatment. In the laminated film of Example 2, the thickness of the base material layer was 10 μm, the thickness of the intermediate layer was 10 μm, the thickness of the seal layer was 10 μm, and the total thickness was 30 μm.

[Comparative Example 1]
As the resin composition constituting the base material layer, the crystalline polyester (A), the olefin resin (B), and the resin composition (1) used in Example 1 were pellet-blended. Then, a laminated film using a composition consisting of 100 parts by weight of the crystalline polyester (A), 98 parts by weight of the olefin resin (B), and 1.8 parts by weight of the filler (C) was obtained. The base material layer of the laminated film of Comparative Example 1 has a different composition from the base material layer of the laminated film of Example 1, but the production conditions of the seal layer and the laminated film are the same as those of the laminated film of Example 1. is there.

[Comparative Example 2]
As the resin composition constituting the base material layer, the crystalline polyester (A), the olefin resin (B), and the resin composition (1) used in Example 1 are pellet-blended, and the crystalline polyester (A) 100 is blended. A laminated film using a composition consisting of 42 parts by weight of the olefin resin (B) and 1.3 parts by weight of the filler (C) with respect to 100 parts by weight of the crystalline polyester (A) was obtained. Here, the above-mentioned laminated film is the same as that of Example 1 except for the composition.

(Evaluation of film workability)
The evaluation of film workability is based on whether or not the laminated film of Examples and Comparative Examples sticks to and wraps around the nip roll when it passes through the nip roll after being extruded by a T die casting machine. Evaluated as. The case where the laminated film was not wrapped around the nip roll was evaluated as "◯", and the case where the laminated film was wrapped and the film collection became difficult was evaluated as "x". The nip rolls used for the evaluation are as follows.
Roll type: Steel roll (hard chrome plating) and EPT rubber roll Roll diameter: 80 mm in diameter
Roll width: 600mm
Nip load: 9.6 kg

[Evaluation of easy peelability]
In the evaluation of easy peelability, first, a lid material is prepared by attaching a polyester film coated with a coating agent to each of the laminated films of each Example and Comparative Example, and the prepared lid material is used to prepare a peeling strength. The ease of peeling was evaluated by measuring.

(Making lid material)
First, an aliphatic ester coating agent is applied to a polyester film (trade name "Emblet PET-S" (manufactured by Unitika Co., Ltd., thickness 25 μm, width 330 mm)) using a coater (manufactured by Yasui Seiki Co., Ltd.). It was applied. Then, after the surface of the polyester film coated with the aliphatic ester coating agent and the corona discharge-treated surface of the laminated film of Example 1 are pressure-bonded, the surface is heated at 40 ° C. for 24 hours using an oven. , A lid material containing the laminated film of Example 1 was obtained. The aliphatic ester coating agent includes a main agent (“Takelac A-525” (manufactured by Mitsui Chemicals, Inc.)), a curing agent (“Takenate A-52” (manufactured by Mitsui Chemicals, Inc.)), and ethyl acetate. The coating agent is sufficiently mixed with the weight ratio of 10: 1: 15. For the laminated films of Example 2 and Comparative Example 1, lid materials were prepared under the same conditions.

(Evaluation of peel strength)
The bottom of a crystalline polyethylene terephthalate container (white) (manufactured by Yoshimura Kasei, container bottom thickness 400 μm) was cut out to 75 × 65 mm and used as an adherend. Then, with respect to the laminated film of Example 1, the seal layer and the adherend are brought into close contact with each other so as to be parallel to the side of the adherend having a width of 75 mm for 1 second under the conditions of a pressure of 0.29 MPa and 160 ° C. Then, it was heat-sealed into a strip having a width of 10 mm. Then, the lid material was cut out at intervals of 15 mm so as to include the seal portion along the direction perpendicular to the band-shaped seal portion. As a result, five test pieces having a size of 15 mm × 65 mm were prepared. Then, using a tensile tester (Autograph AGS10kNG type (manufactured by Toyo Seiki Co., Ltd.)), the peel strength when peeled by 180 degrees at a tensile speed of 300 mm / min in an atmosphere of 23 ° C. was measured. As shown in Table 1, the lid material of Example 1 was evaluated for easy peeling under the same conditions except that the temperature condition of the heat seal was changed to 180 ° C. or 200 ° C. Similarly, the lid materials of Example 2 and Comparative Example 1 were also evaluated for easy peelability.

In the evaluation of easy peeling property, if the peeling strength applied to the test piece having a width of 15 mm is 3N / 15 mm or more and 15N / 15 mm or less, the balance between the sealing strength for the container and the easy peeling property at the time of peeling is excellent. It is judged that there is. In addition, when visually observing the appearance of the adherend after peeling, in the case of interfacial peeling (no film resin piece remains on the adherend), it is judged as "○" because there is no resin residue and it is good. did. In addition, when the lid material was coagulated and peeled off and resin residue was observed on the adherend, it was judged as "x".

〔Evaluation results〕
Table 1 below shows the results of the evaluation of the processability and the easy peelability of the laminated films of Examples and Comparative Examples.

In the easy peelability evaluation, the laminated film of Example 1 was 5.7 N / 15 mm when sealed at 160 ° C, 8.4 N / 15 mm when sealed at 180 ° C, and 200 ° C. Since the peel strength of 9.2 N / 15 mm was obtained, the peel strength was 3 N / 15 mm or more and 15 N / 15 mm or less, so that the balance between the sealing strength for the container and the easy peeling property at the time of peeling was balanced. It was confirmed to be excellent. Further, it was confirmed that the laminated film of Example 2 and the laminated film of Comparative Example 1 also have an excellent balance between the sealing strength against the container and the easy peeling property at the time of peeling.

On the other hand, the laminated film of Comparative Example 2 was found to be wrapped around the nip roll in the evaluation of workability, so that the easy peelability evaluation could not be performed.

Regarding the appearance after peeling, it was confirmed that the laminated films of Examples 1 and 2 were interfacially peeled, and the laminated film of Comparative Example 1 had a resin remaining.

In the evaluation of workability, it was confirmed that the laminated films of Example 1, Example 2 and Comparative Example 1 did not wrap around the nip roll. On the other hand, it was confirmed that the laminated film of Comparative Example 2 was wrapped around the nip roll.

INDUSTRIAL APPLICABILITY The present invention exhibits easy peelability that allows the heat-sealed portion to be easily peeled off at the time of opening while maintaining the sealing property in a package filled with foods, miscellaneous goods, etc. It can be suitably used for an easily peelable film, a lid material using the same, a heat-resistant polyester container, and the like.

Claims (6)

An easily peelable film having a seal layer and a base material layer.
The seal layer contains 100 parts by weight of crystalline polyester (A) and an olefin resin (B) in the range of 11 parts by weight or more and 43 parts by weight or less.
The base material layer contains 100 parts by weight of crystalline polyester (A) and an olefin resin (B) in the range of 52 parts by weight or more and 82 parts by weight or less.
Of the two surface layers of the easily peelable film, at least one surface layer is the seal layer.
The crystalline polyester (A) is an easily peelable film having a melting point of 100 ° C. or higher and 180 ° C. or lower and a glass transition temperature of 10 ° C. or lower. The first aspect of the present invention, wherein the seal layer contains a filler (C) in the range of 0.05 parts by weight or more and 18 parts by weight or less with respect to 100 parts by weight of the crystalline polyester (A). Easy-to-peel film. The easily peelable film according to claim 1 or 2, wherein the olefin resin (B) has a melting point in the range of 100 ° C. or higher and 170 ° C. or lower. The easily peelable film according to any one of claims 1 to 3, which is a coextruded film. A lid material comprising the easily peelable film according to any one of claims 1 to 4. A container comprising the lid material according to claim 5 and a container body containing polyester.