JP6970555B2 - Film for the lid of the packaging container and food packaging package - Google Patents

Description

The present invention relates to, for example, a film for a lid of a packaging container for sealing a container body containing food with a top seal and a food packaging package, and more particularly, it is composed of a laminated film in which at least two or more layers are laminated. Related to the film for the lid of the packaging container and the food packaging package.

Traditionally, for example, foods sold in supermarkets and convenience stores have been stored and sold in thermoplastic resin packaging containers. At this time, the type of packaging container has been selected according to the food and the sales form. For example, packaging containers made of materials with high airtightness and gas barrier properties have been adopted for foods that can be set to have a long best-by date. In such a packaging container, not only the container body for storing food but also the lid for closing the opening portion of the container body has been devised.

For example, the top-seal type lid has a higher advantage than other lids in that the opening portion of the container body can be easily sealed by thermocompression bonding, and the range of utilization has expanded. Furthermore, long-term storage of food has been realized by blocking gas (oxygen in the atmosphere, etc.) that causes deterioration of food that permeates not only the container body but also the lid. However, since the top-seal type lid is in the form of a film having low rigidity, it has a drawback that it is difficult to maintain a desired shape due to the influence of heat shrinkage force, gravity, or other external force.

Therefore, when the density, melt flow rate (MFR), and thickness ratio of the surface layer containing the ethylene-α-olefin copolymer that functions as the sealant layer (sealant layer) are within the predetermined ranges, the layer recovers from deformation. The idea of a film having excellent recoverability such as dents and wrinkles generated when the packaged film is pressed with a finger is disclosed (see, for example, Patent Document 1). Further, as the above-mentioned film, it is preferable that the heat shrinkage of each of MD and TD measured according to the measuring method ASTM-D2327 is 5 to 20% at 100 ° C. and 35% or more at 160 ° C. It has been disclosed.

On the other hand, an idea regarding a biaxially stretched polybutylene terephthalate (PBT) film having excellent dimensional stability when the tensile breaking strength in four directions satisfies a specific value or more is disclosed (see, for example, Patent Document 2). Further, it is also disclosed that the above-mentioned film can be adopted as a film for food packaging or a film for container molding and bonding of foods and the like.

Japanese Unexamined Patent Publication No. 2013-10199 Japanese Unexamined Patent Publication No. 2012-121241

However, in the above-mentioned Patent Document 1, it depends on the shrinkage property of each layer of the laminated film, and there is a possibility that wrinkles and sagging of the surface cannot be eliminated depending on the shrinkage condition. Specifically, if the fused seal repeatedly expands and contracts, the deformation recovery property may decrease due to the deterioration of the sealing function. Further, Patent Document 1 does not describe or suggest that a polyester-based resin containing biaxially stretched polybutylene terephthalate is used for the surface layer, and Patent Document 2 includes a polyester-based resin containing biaxially stretched polybutylene terephthalate. There is no description or suggestion that is adopted for the surface layer of the top-seal type lid.

Therefore, an object of the present invention is to provide a lid film for a packaging container in which the thermoplastic resin film is not easily deformed by a suitable heating temperature range, and a food packaging package using the lid film.

That is, the film for the lid of the packaging container according to the present invention is a film for the lid of the packaging container that seals the opening portion of the container body, and at least the base material layer and the sealing layer are laminated. The base material layer may be characterized in that it is made of a polyester resin and has an MD or TD heat shrinkage rate of 0.5% or more when heated at 90 ° C. in accordance with JIS K 7133.

It is desirable that the polyester resin constituting the base material layer contains polybutylene terephthalate as a main component.

Further, a gas barrier layer having an oxygen permeability of 20 cc / m2 · atm · day or less defined by JIS K 7126 is interposed between the base material layer and the seal layer or in the base material layer. Is desirable.

Further, the food packaging package according to the present invention may be characterized in that the film for a lid is adhered to the flange portion of the container body containing food by thermocompression bonding.

The definition, meaning, or specific example of each requirement constituting the present invention is shown below.

The "opening portion of the container body" may correspond to a portion through which the contents (for example, food) in the molded container body are taken in and out, and the peripheral edge of the above portion constitutes the container body. A part (for example, a flange part) may be provided.

"Sealing" may mean closing the opening portion so that the inside of the container body does not come into contact with the outside air, and specific means for this may be, for example, for the peripheral edge of the opening portion of the container body and the lid. A top-seal type that thermocompression-bonds to the peripheral edge of the film may be adopted.

The "base material layer" corresponds to a part of a layer made of a predetermined thermoplastic resin and laminated with another layer (seal layer, gas barrier layer, etc.) to form a laminated film, and corresponds to an opening portion of the container body. It may be located in the outermost layer at the time of sealing, and may have heat resistance suitable for the crimping temperature such as a top seal type.
The thermoplastic resin constituting the "base material layer" may be a polyester-based resin, preferably a polybutylene terephthalate-based resin. Further, it is still preferable that the polybutylene terephthalate resin layer is biaxially stretched. This is because polybutylene terephthalate is not only resistant to deformation due to temperature changes, but also has excellent shrinkage resistance, bending resistance, impact resistance, wear resistance, etc. due to residual heat during thermocompression bonding.
The thickness of the "base material layer" may be 8 to 38 μm, preferably 10 to 30 μm, and more preferably 12 to 25 μm. If the thickness of the base material layer is less than 8 μm, the shape retention and printing pitch stability of the lid are inferior, and if it exceeds 38 μm, the cost becomes high and the manufacturing cost may increase.

The "seal layer" corresponds to another layer (including a part of the other layer) which is made of a predetermined thermoplastic resin and is laminated with a base material layer to form a laminated film, and is an opening portion of the container body. It may be located in the innermost layer at the time of sealing, and may have heat resistance and easy-opening property (easy peeling property) suitable for the crimping temperature such as a top seal type. The "seal layer" may be equivalent to what is generally referred to as a sealant layer.
The thermoplastic resin constituting the "seal layer" may be, for example, a polyolefin resin, and the blending ratio of the polyolefin resin with respect to other thermoplastic resins (for example, polystyrene resin, polyester resin) is 50% or more. It may be a certain composite resin, preferably 70% or more, and more preferably 80% or more.
The thickness of the "seal layer" may be 10 to 100 μm, preferably 20 to 80 μm, and more preferably 30 to 60 μm. If the thickness of the sheet layer is less than 10 μm, the sealing performance is inferior, and if it is more than 100 μm, the manufacturing cost is high, and it is assumed that the tension of the lid is also inferior.

The "atmospheric temperature range" means the temperature range around the laminated film (for example, in the apparatus or in the atmosphere) at the time of thermocompression bonding such as a top seal type, and the range may be 90 ° C to 130 ° C, preferably 90 ° C to 130 ° C. It is 90 ° C. to 100 ° C., and may be included in the "atmospheric temperature range" even when heated at 90 ° C. in accordance with JIS K 7133.
The temperature range at the time of thermal pressure bonding of the top seal or the like may be set as a "heating temperature range", and this "heating temperature range" is the temperature of a heating means (for example, a top sealing device) that touches the laminated film or this heating means. It means the range of temperature of the portion heated by, and the range may be 110 ° C. to 170 ° C.

The "MD or TD heat shrinkage rate" is an MD (Machine Direction, vertical direction) or TD (Transverse Direction, horizontal direction) that changes depending on the "atmospheric temperature range" or "heating temperature range" applied during thermal crimping such as a top seal type. ) May be defined as the shrinkage rate of the laminated film.
The "MD or TD thermal shrinkage stress" is defined as the shrinkage stress of the laminated film in the MD or TD direction that changes depending on the "atmospheric temperature range" or "heating temperature range" applied during thermocompression bonding such as the top seal type. May be good.

The MD or TD heat shrinkage rate in the "atmospheric temperature range" may be 0.5% or more, preferably 1.0 to 2.0%, and more preferably 1.2 to 1.8%. If it is less than 0.5%, the tension of the lid is insufficient, and if it is more than 2.0%, the container will be deformed.

The "gas barrier layer" is included in another layer (including a part of the other layer) or a base material layer having a gas barrier effect, which is made of a predetermined thermoplastic resin and is laminated with the base material layer to form a laminated film. This corresponds to a resin layer that suppresses the permeation of gas in the outside air (for example, oxygen, nitrogen, carbon dioxide, water vapor, etc.) into the container body, and is between the base material layer and the seal layer. Alternatively, it may be located in the base material layer.

In the film for the lid of the packaging container according to the present invention, at least the base material layer and the seal layer are laminated, and the base material layer is made of a polyester resin and has a temperature of 90 ° C. in accordance with JIS K 7133. Since the MD or TD heat shrinkage rate is 0.5% or more when heated in, there is no wrinkle or slack immediately after the opening of the container body is sealed, and the sealing state is continuously tense. Can be expected to have the effect of maintaining. That is, in the atmospheric temperature range not touched by the heating means of thermal pressure bonding, the heat shrinkage rate of MD or TD of the base material layer is optimized by heating at 90 ° C., and the seal portion is melted at a heating temperature higher than the atmospheric temperature. Since the entire lid film can be maintained in a desired state without destroying the material, the effect of preventing deterioration of the appearance related to quality can be expected.

Further, since the polyester resin constituting the base material layer contains polybutylene terephthalate as a main component, it is possible to prevent the appearance of the lid film from being deteriorated with respect to the temperature at the time of sealing the opening portion of the container body. can.

Further, since the gas barrier layer that suppresses oxygen permeation is interposed between the base material layer and the seal layer or in the base material layer, the thickness can be maintained uniformly without wrinkles or slack due to expansion and contraction. Gases such as oxygen that permeate into the container body through the body film are further suppressed, and long-term storage of the contents can be expected.

Further, in the food packaging package according to the present invention, the film for the lid is adhered to the container body by thermocompression bonding to the flange portion of the container body containing the food, so that the film-shaped lid is wrinkled or slackened. Since it is possible to maintain a tense state, it is possible to produce the desired appearance without distorting the characters and illustrations printed on the surface, and not only to contribute to the improvement of commercial value, but also to provide accurate information to consumers. The effect that can be provided can be expected.

It is a conceptual diagram which shows an example at the time of thermocompression bonding of a film for a lid. It is a partially enlarged sectional view of the film for a lid. It is a conceptual diagram which shows an example of the food packaging package sealed with the film for a lid.

Hereinafter, the outline of the film for the lid (hereinafter, also referred to as “the film for the main lid”) according to the present embodiment will be described with reference to FIGS. 1 and 2.

As shown in FIGS. 1 and 2, the film for the lid is a film 1 for the lid of the packaging container that seals the opening portion of the container body P, and includes at least the base material layer 11 and the seal layer 12. This base material layer is made of a polyester resin and conforms to JIS K 7133, even if the MD or TD heat shrinkage rate is 0.5% or more when heated at 90 ° C. good.

Further, the polyester resin constituting the base material layer 11 may contain polybutylene terephthalate as a main component.

A gas barrier layer 13 having an oxygen permeability of 20 cc / m2 · atm · day or less specified by JIS K 7126 may be contained between the base material layer 11 and the seal layer 12.

Next, the details of the film for the main lid and the container body sealed with the film for the main lid will be described.
In these figures, some of the same parts having a plurality of parts are numbered only in one part. For parts that cannot be confirmed and cannot be seen on the drawing, some parts and leader lines are indicated by broken lines. For the parts that are virtually depicted on the drawing, some parts and leader lines are shown by two-dot chain lines.

The lid film 1 shown in FIG. 1 has a base material layer 11 located on the outermost layer on the side opposite to the container body P side shown in FIG. 2 and a seal layer 12 located on the container body side and the innermost layer. The film was composed of a laminated film in which a gas barrier layer 13 located between the base material layer and the sealing layer was laminated, and the laminated film was cut into a size capable of sealing the opening portion of the container body. It can be a thing. The thickness of the lid film 1 may be 20 to 100 μm.
In addition, other layers such as a printing layer and a dry laminating adhesive layer may be laminated on the laminated film constituting the cover film 1.

The base material layer 11 may be a portion that comes into contact with the thermocompression bonding device H when the opening portion of the container body P is sealed. The thermoplastic resin constituting the base material layer 11 may be, for example, a polyester-based resin, specifically, a polyalkylene allylate-based resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate, or a non-stretched resin. It may be uniaxially or biaxially stretched. The thickness of the base material layer 11 may be 8 to 38 μm. The melting point of the base material layer 11 may be 220 ° C. to 270 ° C.

Further, the base material layer 11 may have an MD or TD heat shrinkage rate of 0.5% or more when heated at 90 ° C. (atmospheric temperature range) in accordance with JIS K 7133. According to this characteristic, the temperature around the base material layer 11 before thermocompression bonding causes the base material layer to shrink to MD or TD, so that the effect of giving tension to the entire cover film 1 can be expected.

The seal layer 12 may be a portion that comes into contact with the main body flange portion P1 when the opening portion of the container main body P is sealed. The thermoplastic resin constituting the seal layer 12 may be, for example, a polyolefin-based resin, and an easy peel in which a plurality of resins (for example, a polystyrene-based resin or a polyester-based resin) are mixed within a range in which the blending ratio of the polyolefin-based resin is 50% or more. It may be a sex resin. The thickness of the seal layer 12 may be 10 to 100 μm. The melting point of the seal layer 12 may be 100 ° C to 190 ° C.
Specific examples of the thermoplastic resin constituting the seal layer 12 include polyethylene resins (including low-density, linear low-density, and medium-density ones), ethylene-vinyl acetate copolymers, and the like. Ethylene-based resins such as ethylene-α-olefin copolymers and ethylene-methacrylic acid resin copolymers, blended resins of polyethylene and polybutene, homopolypropylene resins, propylene-ethylene random copolymers, propylene-ethylene block copolymers, A polypropylene-based resin such as a propylene-α-olefin copolymer may be used.

The gas barrier layer 13 may be adhered to each of the base material layer 11 and the seal layer 12. The thermoplastic resin constituting the gas barrier layer 13 may be, for example, a resin having an oxygen permeability of 20 cc / m2 · atm · day or less specified by JIS K 7126, and specifically, an ethylene-vinyl alcohol copolymer. (EVOH), MXD6 nylon (MXD6Ny), PVDC, hybrid coat layer may be used.
The thermoplastic resin constituting the gas barrier layer 13 may be a resin having an oxygen permeability according to JIS K 7126 of 25 μm, 20 ml / m2, 24 hr, MPa (75% RH at 20 ° C.) or less, and coextrudable. ..

The laminated structure of the base material layer 11, the seal layer 12, and the gas barrier layer 13 is, for example, the base material layer and the seal layer before laminating via a predetermined adhesive applied and dried on the base material layer before laminating. A dry laminating method may be used in which the gas barrier layer and the gas barrier layer are pressed and bonded with a heating roll.
Considering thermocompression bonding such as a top seal type, the melting point difference between the base material layer 11 and the seal layer 12 may be 50 ° C. or higher, preferably 70 ° C. or higher, and more preferably 80 ° C. or higher. This is because if the melting point difference is 50 ° C. or less, the base material layer may be melted by heating to melt the seal layer.

The container body P is a laminate in which at least a base material layer made of a predetermined thermoplastic resin and another layer including a seal layer (for example, a gas barrier layer arranged between the base material layer and the seal layer) are laminated. The sheet is molded, has appropriate rigidity and heat resistance, has a shape that can store the contents (for example, a shape that includes at least a bottom portion and a side wall portion that stands from the peripheral edge of the bottom portion), and a lid. It may have a shape that can be sealed with the film 1 (for example, a shape in which the upper end edge of the side wall portion corresponds to the opening portion of the container body P and has a flange portion P1 extending outward from the upper end edge thereof).
The base material layer, the seal layer, and the gas barrier layer of the container body P are all or part of the contents described in the base material layer 11, the seal layer 12, and the gas barrier layer 13 of the cover film 1. May be equivalent to.

When the opening portion of the container body P is sealed with the lid film 1, the temperature (for example, 130 ° C. to 150 ° C.) of the lid film is set to a predetermined temperature with respect to the flange portion P1 of the container body. The thermocompression bonding device H may be pressed against it. At this time, the difference between the melting point of the base material layer 11 of the film 1 for the lid, the melting point of the seal layer 12, and the melting point of the seal layer of the container body P allows the base material layer to be left as it is and both seal layers to be melted. Then, the film for the lid may be heat-bonded to the flange portion of the container body.

Here, with reference to FIG. 3, a food packaging package packaged with the cover film (hereinafter, also referred to as “the food packaging package”) will be described.

As shown in FIG. 3, in the food packaging package, the lid film 1 may be adhered to the container body by thermocompression bonding to the flange portion of the container body P containing the food F. At this time, the laminated film constituting the cover film 1 includes a base material layer satisfying the above-mentioned characteristics (MD or TD heat shrinkage rate at atmospheric temperature change during thermocompression bonding is 0.5% or more). Since the base material layer at the opening portion of the container body P does not stretch, the film 1 for the lid is less likely to wrinkle or sag, and may be maintained in a taut state.

Here, a measurement test of the heat shrinkage rate in the base material layer of the cover film common to the examples and the comparative examples will be described.
The description of the measurement test (or calculation method) of the heat shrinkage stress and the rate of change in moisture absorption dimension of the base material will be omitted.

≪Measurement test of heat shrinkage rate≫
Thermocompression bonding device: SN-2S manufactured by Shinwa Machinery Co., Ltd.
Heating temperature: The sealing portion (the adhesive portion between the flange portion of the container body and the film for the lid) is heated at a heating temperature of 140 ° C. for 1.0 second by a thermocompression bonding device. At the same time, it is assumed that heat of 90 ° C. to 130 ° C. is generated as the atmospheric temperature other than the sealing portion. That is, the crimped portion of the film for the lid is directly heated at 140 ° C. from the thermocompression bonding device, and the state other than this crimped portion is indirectly heated at 90 ° C. to 130 ° C. is formed.

<< Example 1 >>
(Film for lid)
Laminated structure: Base material layer (from above toward the container body) [biaxially stretched polybutylene terephthalate (PBT), thickness 15 μm, melting point 225 ° C], seal layer [polyolefin resin (PP + PE), thickness 50 μm, melting point 130 ° C. ]
Laminating method: Dry laminating method (container body)
Laminated structure: (from the bottom toward the film for the lid) Base material layer [polyester resin (PP, PP + talc, PP), thickness 300 μm], seal layer [gas barrier layer (EVOH), polyolefin resin (PP) , 50 μm]

<< Example 2 >>
(Film for lid)
Laminated structure: Base material layer (from above toward the container body) [biaxially stretched polybutylene terephthalate (PBT), thickness 15 μm, melting point 225 ° C], seal layer [polypropylene (PP), gas barrier layer (EVOH), polyolefin-based Resin (PP + PE), thickness 50 μm, melting point 130 ° C]
Laminating method: Dry laminating method (container body)
Equivalent to Example 1

<< Comparative Example 1 >>
(Film for lid)
Laminated structure: Base material layer (from above toward the container body) [biaxially stretched polyethylene terephthalate (PET), thickness 12 μm, melting point 260 ° C], seal layer [polyolefin resin (PP + PE), thickness 50 μm, melting point 130 ° C]
Laminating method: Dry laminating method (container body)
Equivalent to Example 1

<< Supplement to the test conditions of Examples 1 and 2 >>
The difference between Example 1 and Example 2 is whether or not the gas barrier layer is laminated on the seal layer of the cover film. Example 1 does not have a gas barrier layer, and Example 2 has a gas barrier layer. Are laminated.
<< Supplementary test conditions between Examples 1 and 2 and Comparative Example 1 >>
The difference between Examples 1 and 2 and Comparative Example 1 is whether the substrate layer of the film for the lid is biaxially stretched polybutylene terephthalate (PBT) or biaxially stretched polyethylene terephthalate (PET). 2 is PBT and Comparative Example 1 is PET.

≪Test results≫
The following test results were obtained with the film for the lid of Example 1, Example 2, and Comparative Example 1.
For convenience of reference, the above-mentioned test conditions are described in the upper part.

In Examples 1 and 2, the heat shrinkage rate at an ambient temperature of 90 ° C. was MD = 1.0%, TD = 0.0%, and the heat shrinkage rate at 110 ° C. was MD = 1.4%, TD = 0. The heat shrinkage at 0% and 130 ° C. was MD = 2.0% and TD = 0.0%. That is, since the part other than the crimped portion at the heating temperature of 140 ° C of the thermocompression bonding device shrinks entirely and uniformly at the atmospheric temperature of 90 ° C to 130 ° C, wrinkles and sagging are less likely to occur on the top surface, and the surface is taut (evaluation: 〇). ) Was able to be formed. Further, since the gas barrier layer is laminated on the seal layer, the evaluation of the gas barrier property is higher in Example 2 (evaluation: 〇) than in Example 1 (evaluation: Δ). It was also confirmed that the presence or absence of the gas barrier layer is irrelevant to the evaluation of the condition of the top surface.

On the other hand, in Comparative Example 1, the heat shrinkage rate at an ambient temperature of 90 ° C. was MD = 0.2%, TD = 0.2%, and the heat shrinkage rate at 110 ° C. was MD = 0.5%, TD = 0. The heat shrinkage at 1% and 130 ° C. was MD = 0.6% and TD = 0.1%. That is, in Comparative Example 1, it was confirmed that the difference (material of the base material) from Examples 1 and 2 brought about a remarkable difference in the heat shrinkage rate (evaluation = ×). Further, since the gas barrier layer is not laminated on the seal layer, the evaluation of the gas barrier property is the same as that of Example 2 (evaluation: Δ) and Comparative Example 1 (evaluation: Δ), but when the base material layer is different, the above-mentioned case is described. It was also confirmed that the presence or absence of the gas barrier layer is irrelevant to the evaluation of the state of the top surface.
Although the measured values of the heat shrinkage stress and the hygroscopic dimension change are the same between Examples 1 and 2 and Comparative Example 1, there is a substantial difference in view of the remarkable difference in the heat shrinkage rate, and the top surface portion. It was also confirmed that it had a considerable effect on the tension of the body.

Hereinafter, the effects of the film for the lid and the food packaging package will be described with reference to FIGS. 1 to 3 based on the above-described embodiments and examples.

In the cover film 1, at least the base material layer 11 and the seal layer 12 are laminated, and this base material layer is made of a polyester resin and is heated at 90 ° C. in accordance with JIS K 7133. When the heat shrinkage rate of MD or TD is 0.5% or more, it is possible to maintain a suitable sealing state with no wrinkles or slack immediately after sealing the opening portion of the container body P and with continuous tension. The effect can be expected. That is, in the atmospheric temperature range not touched by the thermocompression bonding apparatus H, the heat shrinkage rate of the MD or TD of the base material layer 11 is optimized by heating at 90 ° C., and the seal portion is melted at a heating temperature higher than the atmospheric temperature. Since the entire lid film 1 can be maintained in a desired state without destroying the material, the effect of preventing deterioration of the appearance related to quality can be expected.

Further, since the polyester resin constituting the base material layer 11 contains polybutylene terephthalate as a main component, it is possible to prevent the appearance of the opening portion of the container body P in the cover film 1 from being deteriorated with respect to the temperature at the time of sealing. be able to.

Further, the gas barrier layer 13 that suppresses oxygen permeation is interposed between the base material layer 11 and the seal layer 12 or in the base material layer, so that the gas barrier layer 13 permeates into the container body P via the film for the lid. It can be expected that food F will be stored for a long period of time by further suppressing gas such as oxygen.

Further, in this food packaging package, the lid film 1 is bonded to the container body P by thermocompression bonding to the flange portion of the container body P containing the food F, so that the film-shaped lid is wrinkled or slackened. Since it is possible to maintain a tense state, it is possible to produce the desired appearance without distorting the characters and illustrations printed on the surface, and not only to contribute to the improvement of commercial value, but also to provide accurate information to consumers. The effect that can be provided can be expected.

The container body P in the present embodiment may be formed by thermoforming a synthetic resin sheet by, for example, sheet molding such as vacuum forming, pressure forming, vacuum pressure forming, double-sided vacuum forming, and thermoforming. As deep-drawing packaging, the sheet may be molded into a container shape according to the mold. As the synthetic resin sheet, for example, a polyester resin such as polyethylene terephthalate, a styrene resin such as polystyrene, or an olefin resin such as polypropylene may be used, and a single-layer or multi-layer sheet may be used. As the resin, for example, it is preferable to use a foamed resin because it is lightweight and has heat insulating properties. Further, the front surface or the back surface of the sheet may be covered with a synthetic resin film, and when the front surface is covered, printing may be performed. The thickness of the synthetic resin sheet is not particularly limited, but may be 0.15 to 1.5 mm, preferably 0.20 to 1.2 mm, and more preferably 0.3 to 1.0 mm.

1 Cover film 11 Base material layer 12 Seal layer 13 Gas barrier layer P Container body P1 Flange part H Thermocompression bonding device

Claims (3)

A film for the lid of a packaging container that seals the opening of the container body.
At least the base material layer and the seal layer are laminated,
The base material layer is composed of polybutylene terephthalate and is composed of polybutylene terephthalate.
MD or TD thermal shrinkage rate is 0.5% or more when heated at to 90 ° C. compliant J IS K 7133
A film for a lid of a packaging container, which is characterized by being composed of a biaxially stretched film. Between the base material layer and the seal layer or in the base material layer, as a gas barrier layer , a thermoplastic resin layer having an oxygen permeability of 20 cc / m ² · atm · day or less as defined by JIS K 7126. The film for a lid of a packaging container according to claim 1, wherein the film is intervening. A food packaging package according to claim 1 or 2, wherein the cover film is adhered to the flange portion of the container body containing food by thermocompression bonding.

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