JP7801092B2 - Lid, package and wrapping body - Google Patents

Description

The present invention relates to a lid, a package including the lid, and a wrapping body.

Packages that are configured to automatically release water vapor when the pressure in the storage space increases due to heating by a heating means are known. For example, Patent Document 1 discloses a microwave heatable package (9) that includes a container (13) containing a storage space for storing contents, a microwave heatable packaging film (1) that is sealed to the top of the container (13) to close the storage space, and a heat-sealed portion (14) where the top surface and the microwave heatable packaging film (1) are sealed. The microwave heatable packaging film (1) includes a sealing layer that is sealed to the top of the container (13), and a coating layer (3) that is laminated on the sealing layer and generates heat when exposed to microwaves. When the microwave heatable package (9) is heated in a microwave oven, the coating layer (3) generates heat, weakening the heat-sealed portion (14) near the coating layer (3), forming an opening between the microwave heatable packaging film (1) and the container (13), through which water vapor can be released.

Japanese Patent Application Laid-Open No. 2017-159912

In the microwave heating package (9) described above, when the water vapor that passes through the opening and is released is cooled, water droplets may adhere to the microwave heating packaging film (1) and the container (13), blocking the opening. This may prevent the water vapor from being released properly.

(1) The lid of the present invention is a lid attached to a tray including a storage space for storing contents, and comprises a sheet joined to the tray, and a vapor passage portion provided in the sheet so that the sheet can be broken to release water vapor when the pressure in the storage space increases while the sheet is joined to the tray to close the storage space, the vapor passage portion including a plurality of scratch portions that are discontinuous and do not penetrate the sheet, the plurality of scratch portions including thin linear cuts, and the maximum distance between adjacent scratch portions among the plurality of scratch portions is shorter than the length of the shortest scratch portion among the plurality of scratch portions and is within a range of 100 μm or more.
The above-described lid is attached to a tray containing contents in the storage space to produce a package (hereinafter referred to as a "closed package") with the storage space closed. When the closed package is heated by a heating means, the pressure in the storage space increases and the sheet expands. As a result, multiple scratched portions of the vapor passage portion rupture, forming holes in the sheet that communicate the storage space with the outside. This allows water vapor to be appropriately discharged through the holes. Furthermore, during the transport process of the closed package, it is preferable that the sheet does not rupture even when a standard external force is applied to the closed package. On the other hand, when the closed package is heated, it is preferable that the sheet ruptures to allow water vapor to be appropriately discharged. From this perspective, it is preferable that the strength of the portion of the sheet where the vapor passage portion is provided falls within a predetermined range. With the above-described lid, the maximum spacing between adjacent scratched portions among the multiple scratched portions falls within a range of 100 μm or more, so that the strength of the portion of the sheet where the vapor passage portion is provided is unlikely to be excessively reduced. Therefore, the sheet is unlikely to rupture even when an external force is applied to the closed package during the transport process of the closed package. Furthermore, since the maximum distance between adjacent scratched portions among the plurality of scratched portions is shorter than the length of the shortest scratched portion among the plurality of scratched portions, the strength of the portion of the sheet where the vapor passage portion is provided is unlikely to be excessively high. Therefore, when the closed package is heated by a heating means, the sheet breaks and water vapor is appropriately discharged.

(2) In a preferred example, in the lid described in (1), the maximum distance between adjacent scratched portions among the plurality of scratched portions is in the range of 200 μm or more.
The lid described above makes it difficult for the strength of the vapor passage portion to be excessively reduced, and therefore the sheet is less likely to break even if an external force is applied during the process of transporting the package after closing.

(3) In a preferred example, in the lid described in (1) or (2), the maximum distance between adjacent scratched portions among the plurality of scratched portions is within a range of 2000 μm or less.
The lid prevents the strength of the vapor passage portion from becoming excessively high, so that when the closed package is heated by the heating means, the sheet breaks and water vapor is appropriately released.

(4) In a preferred example, in the lid described in (3), the maximum distance between adjacent scratched portions among the plurality of scratched portions is within a range of 1000 μm or less.
The lid prevents the strength of the vapor passage portion from becoming excessively high, so that when the closed package is heated by the heating means, the sheet breaks and water vapor is appropriately released.

(5) In a preferred example, in the lid described in any one of (1) to (4), the sheet includes an innermost layer joined to the tray and an outermost layer laminated on the innermost layer, and the scratched portion penetrates only the outermost layer of the sheet.
The lid allows the sheet to break more appropriately when the closed package is heated by the heating means.

(6) In a preferred example, in the lid described in any one of (1) to (5), the sheet has a rectangular or rectangular shape in a plan view, and the multiple scratched portions are arranged along the short side of the sheet.
The lid allows the sheet to break more appropriately when the closed package is heated by the heating means.

(7) A package according to the present invention comprises the lid described in any one of (1) to (6) above, and the tray to which the lid is joined so as to close the storage space.
According to the above package, the same effect as that of the lid described in any one of (1) to (6) above can be obtained.

(8) A packaging body according to the present invention comprises a sheet, a sealing portion that seals the sheet to form a storage space capable of accommodating contents, an opening that opens the storage space, a planned sealing portion where a closed seal portion that closes the opening is planned to be formed, and a vapor passage portion that is provided in the sheet so that the sheet can be broken to release water vapor when the pressure in the storage space increases with the closed seal portion formed, wherein the vapor passage portion includes a plurality of scratch portions that are discontinuous and do not penetrate the sheet, the plurality of scratch portions include elongated linear cuts, and the maximum distance between adjacent scratch portions among the plurality of scratch portions is shorter than the length of the shortest scratch portion among the plurality of scratch portions and is within a range of 100 μm or more.
When a package with contents contained in the storage space and a closed seal formed (hereinafter referred to as the "closed package") is heated, the pressure in the storage space increases, causing the sheet to expand. As a result, multiple scratched portions in the vapor passage portion rupture, forming holes in the sheet that connect the storage space to the outside. This allows water vapor to be properly discharged through the holes. Furthermore, during transport of the closed package, it is preferable that the sheet does not rupture even when a standard external force is applied to the closed package. On the other hand, when the closed package is heated, it is preferable that the sheet ruptures to properly discharge water vapor. From this perspective, it is preferable that the strength of the portion of the sheet where the vapor passage portion is provided falls within a predetermined range. According to the above package, the maximum spacing between adjacent scratched portions among the multiple scratched portions falls within a range of 100 μm or more, so that the strength of the portion of the sheet where the vapor passage portion is provided is unlikely to be excessively reduced. Therefore, the vapor passage portion is unlikely to rupture even when an external force is applied to the closed package during transport. Furthermore, since the maximum distance between adjacent scratched portions among the plurality of scratched portions is shorter than the length of the shortest scratched portion among the plurality of scratched portions, the strength of the portion of the sheet where the vapor passage portion is provided is unlikely to be excessively high. Therefore, when the closed package is heated by the heating means, the vapor passage portion breaks, allowing water vapor to be appropriately discharged.

The lid, package, and wrapping body of the present invention allow water vapor to be properly vented.

FIG. 2 is a perspective view of the package according to the first embodiment. FIG. 2 is a plan view of the package of FIG. 1 . FIG. 3 is an enlarged view of the X3 portion of FIG. 2. FIG. 4 is a cross-sectional view taken along line D4-D4 in FIG. 2. 2 is a perspective view of the package of FIG. 1 with the lid broken and a hole formed; FIG. FIG. 6 is a cross-sectional view taken along line D6-D6 in FIG. 5 . 1 is a table showing test conditions and test results for examples and comparative examples of the first embodiment. 1 is a table showing test conditions and test results for examples and comparative examples of the first embodiment. FIG. 10 is a perspective view of a packaging body according to a second embodiment. FIG. 10 is an enlarged view of a portion X10 in FIG. 9 . 10 is a cross-sectional view taken along line D11-D11 in FIG. 9; 10 is a perspective view of the packaging body of FIG. 9 in a state where a sheet is broken and a hole is formed. 13 is a cross-sectional view taken along line D13-D13 in FIG. 12. 10 is a table showing test conditions and test results for examples and comparative examples of the second embodiment. 10 is a table showing test conditions and test results for examples and comparative examples of the second embodiment.

(First embodiment)
FIG. 1 shows an example of a package 1 that can accommodate contents 100 suitable for heating by a heating means and that can exhaust steam generated from the contents 100. An example of the heating means is a microwave oven. The contents 100 are a heated object that generates steam when heated by the heating means. An example of the contents 100 is food. For example, a chilled bento lunch box. Examples of chilled bento lunch boxes are beef bowls, oyakodon (chukadon), Chinese rice bowls, and curry rice. The main elements that make up the package 1 are a tray 10, a lid 20, and a joint 30.

The material constituting the tray 10 can be selected from any material that is resistant to deformation when heated by a heating means. In one example, the material constituting the tray 10 is a mixed resin containing polypropylene and talc. The tray 10 has a bottom wall 11, side walls 12, an opening 13, and a flange 14. The bottom wall 11 and side walls 12 form a storage space 10A that contains the contents 100. The storage space 10A and the opening 13 are closed by a lid 20. The flange 14 is arranged to surround the entire periphery of the opening 13. The shape of the flange 14 can be selected from any shape. In the example shown in Figure 1, etc., the flange 14 is arranged to follow the outer shape of the tray 10.

The dots shown in Figures 1, 2, and 5 indicate the joint 30. The joint 30 is the portion where the top surface 14A of the flange 14 and the innermost layer 21 of the lid 20 are joined (see Figure 4). The method for joining the top surface 14A and the innermost layer 21 can be selected as desired. In a first example, the method for joining the top surface 14A and the innermost layer 21 is sealing using a sealing device. Examples of sealing methods include heat sealing, impulse sealing, high-frequency sealing, and ultrasonic sealing. In a second example, the method for joining the top surface 14A and the innermost layer 21 is adhesive or pressure-sensitive adhesive. In the example shown in Figure 1, etc., the entire top surface 14A and the innermost layer 21 are heat-sealed.

The seal strength of the joint 30 can be selected arbitrarily. In a preferred example, the seal strength of the joint 30 is determined based on the relationship between the difficulty of peeling when a standard external force is applied to the package 1 during transport, etc., and the ease with which a user can peel the lid 20 from the tray 10 after heating of the package 1 by the heating means has finished. An example of the maximum seal strength of the joint 30 is 25 N/15 mm. If the seal strength of the joint 30 is 25 N/15 mm or less, the user can easily peel the lid 20 from the tray 10 after heating of the package 1 by the heating means has finished. An example of the minimum seal strength of the joint 30 is 5 N/15 mm. If the seal strength of the joint 30 is 5 N/15 mm or more, the joint 30 is difficult to peel even when a standard external force is applied to the package 1 during transport, etc., In one example, the seal strength of the joint 30 is 12N/15mm.

As shown in Figures 1 and 2, the lid 20 has a gripping portion 20A that is grasped by the user when peeling the lid 20 from the tray 10 after heating of the package 1 is complete. The gripping portion 20A protrudes outward beyond the outer edge 14B of the flange 14. The lid 20 includes a sheet 20X and a vapor passage portion 40. The lid 20 is attached to a tray 10 containing contents 100 in the storage space 10A to produce a package 1 (hereinafter referred to as the "closed package 1") in which the storage space 10A is closed. When the internal pressure of the tray 10 increases due to heating by a heating means, the portion of the sheet 20X where the vapor passage portion 40 is provided breaks, forming a hole 50 (see Figure 5) that penetrates the sheet 20X, thereby allowing water vapor to automatically escape. The shape of the sheet 20X in a plan view of the lid 20 can be selected as desired depending on the shape of the opening 13. In a first example shown in Figure 2 etc., the shape of the sheet 20X in a plan view of the lid 20 is a rectangle with rounded corners, in other words, a shape similar to a rectangle. In a second example, the shape of the sheet 20X in a plan view of the lid 20 is a rectangle. In a third example, the shape of the sheet 20X in a plan view of the lid 20 is a square, a polygon with pentagons or more sides, or a shape similar to these.

As shown in FIG. 4, the sheet 20X has a two-layer structure, for example, in which an innermost layer 21 and an outermost layer 22 are laminated. The lamination method for each layer 21, 22 is, for example, dry lamination. The innermost layer 21 is laminated on the innermost side. The innermost layer 21 has excellent heat resistance, heat sealability, and impact resistance. An example of a material that constitutes the innermost layer 21 is a mixed resin that has easy-peel properties. An example of a mixed resin is a copolymer of polyethylene and polypropylene. The thickness of the innermost layer 21 can be selected as desired. The thickness of the innermost layer 21 is, for example, in the range of 20 μm to 60 μm. In one example, the thickness of the innermost layer 21 is 30 μm. The outermost layer 22 is laminated on the outermost side. The outermost layer 22 has excellent gas barrier properties, printability, and heat resistance. Examples of materials that can be used to form the outermost layer 22 include polyethylene terephthalate, nylon, biaxially oriented polypropylene, polybutylene terephthalate, and cellophane. The thickness of the outermost layer 22 can be selected as desired. For example, the thickness of the outermost layer 22 is in the range of 9 μm to 25 μm. In one example, the thickness of the outermost layer 22 is 12 μm.

The vapor passage section 40 is a portion of the lid 20 where the strength is partially reduced so that holes 50 (see Figure 5) are formed in the lid 20 for venting water vapor generated from the contents 100. The position of the vapor passage section 40 on the lid 20 can be selected arbitrarily. In a preferred example, the vapor passage section 40 is provided in the portion of the lid 20 where stress is most concentrated when the pressure in the storage space 10A increases due to heating by a heating means. In the example shown in Figure 1 etc., the vapor passage section 40 is provided approximately in the center of the longitudinal direction of the lid 20. The vapor passage section 40 has a plurality of scratched sections 41 that are discontinuous and do not penetrate the sheet 20X. The scratched sections 41 are elongated linear cuts. The arrangement direction of the scratched sections 41 can be selected arbitrarily. In the example shown in Figure 2 etc., the scratched sections 41 are provided along the short direction of the sheet 20X.

When there are three or more scratched portions 41, the spacing between adjacent scratched portions 41 (hereinafter referred to as "spacing LA") can be selected arbitrarily. In a first example shown in FIG. 3, etc., all spacings LA are substantially equal. In a second example, at least two of the multiple spacings LA are different. The shape of the scratched portions 41 can be selected arbitrarily. In a first example shown in FIG. 4, etc., some or all of the multiple scratched portions 41 are arranged so as to penetrate only the outermost layer 22 of the sheet 20X. In a second example, some or all of the multiple scratched portions 41 are arranged only on the outermost layer 22 so as not to penetrate the outermost layer 22. In a third example, some or all of the multiple scratched portions 41 are arranged so as to penetrate only the innermost layer 21. In a fourth example, some or all of the multiple scratched portions 41 are arranged only on the innermost layer 21 so as not to penetrate the innermost layer 21.

The relationship between the lengths (hereinafter referred to as "lengths LB") of the multiple scratched portions 41 can be selected arbitrarily. In the first example shown in Figure 3, etc., the lengths LB of all scratched portions 41 are substantially equal to each other. In the second example, the lengths LB of at least two of the multiple scratched portions 41 are different from each other.

The relationship between the distance LA and the length LB is determined based on the relationship between the resistance of the sheet 20X to breaking when a standard external force acts on the package 1 during transport of the package 1, and the ease with which the sheet 20X breaks when the pressure in the storage space 10A increases. In other words, the relationship between the distance LA and the length LB is determined so that the strength of the portion of the sheet 20X where the vapor passage section 40 is provided falls within a predetermined range.

The maximum distance between adjacent scratched portions 41 (hereinafter referred to as "maximum distance LAX") among the multiple scratched portions 41 is shorter than the length of the shortest scratched portion 41 among the multiple scratched portions 41 (hereinafter referred to as "minimum length LBX"), and is within the range of 100 μm or more. When the maximum distance LAX is within the range of 100 μm or more, the strength of the portion of the sheet 20X where the vapor passage portion 40 is provided is unlikely to become excessively weak. Therefore, even if an external force is applied during the transport process of the closed package 1, the sheet 20X is unlikely to break. When the maximum distance LAX is shorter than the minimum length LBX, the strength of the portion of the sheet 20X where the vapor passage portion 40 is provided is unlikely to become excessively strong. Therefore, when the closed package 1 is heated by a heating means, the sheet 20X breaks, allowing water vapor to be properly released.

A preferred example of the minimum value of the maximum spacing LAX is 100 μm. When the maximum spacing LAX is in the range of 100 μm or more, the sheet 20X is less likely to break even when a standard external force is applied to the package 1 during the transport process of the package 1. A more preferred example of the minimum value of the maximum spacing LAX is 200 μm. When the maximum spacing LAX is in the range of 200 μm or more, the sheet 20X is less likely to break even when a standard external force is applied to the package 1 during the transport process of the package 1. A preferred example of the maximum value of the maximum spacing LAX is 2000 μm. When the maximum spacing LAX is in the range of 2000 μm or less, the sheet 20X breaks when the closed package 1 is heated by a heating means, allowing water vapor to be properly released. A more preferred example of the maximum value of the maximum spacing LAX is 1000 μm. If the maximum spacing LAX is within the range of 1000 μm or less, the sheet 20X will break when heated by the heating means of the package 1 after closure, allowing water vapor to be more appropriately released. A preferred range for the maximum spacing LAX is 100 μm to 2000 μm. A more preferred range for the maximum spacing LAX is 200 μm to 1000 μm.

A preferred example of the minimum value of the minimum length LBX is 500 μm. If the minimum length LBX is in the range of 500 μm or more, the sheet 20X will break when the closed package 1 is heated by a heating means, allowing water vapor to be properly released. A preferred example of the maximum value of the minimum length LBX is 6900 μm. If the minimum length LBX is in the range of 6900 μm or less, the sheet 20X is less likely to break even if a standard external force is applied to the package 1 during the package 1 transport process. A preferred range for the minimum length LBX is 500 μm to 6900 μm.

The length LC (see Figure 2) of the vapor passage section 40 can be selected arbitrarily. The length LC is the sum of the lengths LB of all scratched sections 41 included in the vapor passage section 40 and all spacings LA. A preferred example of the minimum value of the length LC is 68 mm. A preferred example of the maximum value of the length LC is 70 mm. The preferred range for the length LC is 68 mm to 70 mm.

An example of a method for manufacturing the lid 20 will be described.
The manufacturing method of the lid 20 includes a first step and a second step. In the first step, the innermost layer 21 and the outermost layer 22 are joined together, for example, with an adhesive (not shown). The second step is performed after the first step. In the second step, the sheet 20X is laser-processed using, for example, a laser processing machine, to provide a plurality of discontinuous scratched portions 41.

An example of how to use the package 1 will be described with reference to FIGS.
The closed package 1 is placed in, for example, a microwave oven, and heating of the package 1 begins. As the package 1 is heated in the microwave oven, water vapor is generated from the contents 100. Because the opening 13 of the tray 10 and the storage space 10A are closed by the lid 20, the water vapor generated from the contents 100 remains in the storage space 10A. As the time during which the package 1 is heated increases, the pressure in the storage space 10A gradually increases, causing the sheet 20X to expand. Because the portion of the sheet 20X where the vapor passage portion 40 is provided has lower strength than the other portions, the sheet 20X breaks at the vapor passage portion 40. As shown in FIGS. 5 and 6 , a hole 50 is formed in the lid 20 that penetrates the sheet 20X, connecting the storage space 10A to the outside. As a result, the water vapor that had been remaining in the storage space 10A is released to the outside of the tray 10 through the hole 50. When heating of the package 1 is completed, the package 1 is removed from the microwave oven, the handle 20A is grasped, and the lid 20 is peeled off from the tray 10.

The lid 20 and the package 1 provide the following functions and effects.
When the closed package 1 is heated by a heating means, the sheet 20X expands, causing the multiple scratched portions 41 in the vapor passage portion 40 to break. The broken portions of adjacent scratched portions 41 connect to each other, forming holes 50 in the sheet 20X that connect the storage space 10A to the outside. This allows water vapor to be properly discharged through the holes 50.

(Example of the first embodiment)
The inventors of the present application conducted tests to confirm the relationship between the distance LA and the length LB and various performance characteristics of the package 1 using samples of the example and the comparative example. Figures 7 and 8 show the test conditions and test results for the example and comparative example samples. In the following description, for ease of explanation, the same reference numerals are used for parts of the comparative example samples that are common to the example samples. The example sample is the package 1 according to the first embodiment. The comparative example sample is a package 1 having a different configuration from the example package 1. The comparative example package 1 differs from the example package 1 in that the distance LA is equal to or greater than the length LB and that there is only one scratched portion 41, but otherwise has the same configuration as the example package 1.

The specifications for the samples of each Example and Comparative Example are as follows. The material constituting the innermost layer 21 in the samples of each Example and Comparative Example is a mixed resin with easy-peel properties. The thickness of the innermost layer 21 is 30 μm. The material constituting the outermost layer 22 in the samples of Examples 1 to 10 and Comparative Examples 1 to 6 is polyethylene terephthalate. The thickness of the outermost layer 22 in the samples of Examples 1 to 10 and Comparative Examples 1 to 6 is 12 μm. The material constituting the outermost layer 22 in the samples of Examples 11 to 20 and Comparative Examples 7 to 12 is nylon. The thickness of the outermost layer 22 in the samples of Examples 11 to 20 and Comparative Examples 7 to 12 is 15 μm. In the samples of Comparative Examples 1 and 7, the lid 20 has one scratched portion 41. The spacing LA and length LB in each Example and Comparative Example are substantially equal to each other. In other words, the spacing LA in each Example and Comparative Example is the same as the maximum spacing LAX, and the length LB is the same as the minimum length LBX.

The test confirmed whether the package 1 could be properly steamed when heated by a heating means (hereinafter referred to as "steaming suitability"), and the number of package 1 lids 20 that broke when the package 1 was dropped (hereinafter referred to as "number of breaks upon dropping"). The heating means was a microwave oven.

For steam permeability, the samples of Examples 1 to 20 and Comparative Examples 1 to 12 were heated in a microwave oven with contents 100 placed in the storage space 10A and the lid 20 with the joint 30 formed to close the opening 13 and the storage space 10A (hereinafter referred to as the "sealed state"). The contents 100 were curry roux and sterile cooked rice. The curry roux weighed 200 g. The sterile cooked rice weighed 200 g. The microwave oven output was 1000 W. The heating time was 1 minute. After heating, the locations from which steam had been released were visually inspected. The "○" in the steam permeability column shown in Figures 7 and 8 indicates that the portion of the sheet 20X where the steam permeability portion 40 was provided broke, forming holes 50 through which steam was released. The "x" in the steam permeability section shown in Figures 7 and 8 indicates a state in which no hole 50 was formed, and part or all of the bonded portion 30 peeled off, allowing water vapor to escape. The test was conducted five times.

To measure the number of breakages upon drop, sealed samples from Examples 1 to 20 and Comparative Examples 1 to 12 were bundled together in groups of three (hereafter referred to as "bundled groups") and visually inspected to see if the lids 20 broke when they were allowed to drop freely from a height of 80 cm. In the test, 10 bundled groups of each sample from each Example and Comparative Example were allowed to drop freely. The number of breakages upon drop items shown in Figures 7 and 8 is the number of bundles in which the lids 20 of one or more of the three samples included in one bundle broke.

The samples of each example achieved better results in terms of the number of breaks when dropped than the samples of comparative examples 1 and 7. This is thought to be because the strength of the portion of sheet 20X where steam passage portion 40 is provided is not excessively reduced by not providing multiple scratched portions 41 continuously, in other words, by providing multiple scratched portions 41 discontinuously. Furthermore, the samples of each example achieved better results in terms of steam permeability than the samples of comparative examples 2 to 6 and 8 to 12. This is thought to be because the strength of the portion of sheet 20X where steam passage portion 40 is provided is not excessively high when spacing LA is shorter than length LB and falls within the range specified in the embodiment.

Second Embodiment
Figure 9 shows an example of a package 200 that can accommodate contents 300 (see Figure 12) suitable for heating by a heating means and that can expel water vapor generated from the contents 300. An example of the heating means is a microwave oven. The contents 300 are objects to be heated that generate water vapor when heated. An example of the contents 300 is food. An example of the food is frozen fried rice. The contents 300 are placed on a tray (not shown) and stored in the package 200 as needed.

The package 200 is designed to allow for long-term storage while maintaining the quality of the contents 300. The package 200 can take a variety of shapes. Examples of shapes that the package 200 can take are a pillow bag or a pouch. The shape of the package 200 illustrated in Figure 9 is a pillow bag.

The packaging body 200 includes a sheet 210, a sealed portion 220, an opening 230, and a vapor passage portion 240. When the packaging body 200 is heated by a heating means and the pressure in the storage space 200A increases, the portion of the sheet 210 where the vapor passage portion 240 is provided breaks, forming a hole 250 (see Figure 12) that penetrates the sheet 210, thereby allowing water vapor to automatically escape. The dots in Figures 9 and 12 represent the sealed portion 220. The sheet 210 includes a first sheet 211 and a second sheet 212. The first sheet 211 and the second sheet 212 face each other so that the storage space 200A that contains the contents 300 is formed between the sheets 211 and 212. The configuration of the sheet 210 can be selected arbitrarily. In the example shown in Figure 9, etc., the opposing sheets 211 and 212 are formed by folding a single sheet.

As shown in FIG. 11, the sheet 210 has a two-layer structure, for example, in which an innermost layer 210A and an outermost layer 210B are laminated. The lamination method for each layer 210A, 210B is, for example, dry lamination. The innermost layer 210A is laminated on the innermost side. The innermost layer 210A has excellent heat resistance, heat sealability, and impact resistance. One example of a material that constitutes the innermost layer 210A is a mixed resin with easy-peel properties. One example of a mixed resin is a copolymer of polyethylene and polypropylene. The thickness of the innermost layer 210A can be selected as desired. The thickness of the innermost layer 210A is, for example, in the range of 20 μm to 60 μm. In one example, the thickness of the innermost layer 210A is 30 μm. The outermost layer 210B is laminated on the outermost side. The outermost layer 210B has excellent gas barrier properties, printability, and heat resistance. Examples of materials that can be used to form the outermost layer 210B include polyethylene terephthalate, nylon, biaxially oriented polypropylene, polybutylene terephthalate, and cellophane. The thickness of the outermost layer 210B can be selected as desired. For example, the thickness of the outermost layer 210B is in the range of 9 μm to 25 μm. In one example, the thickness of the outermost layer 210B is 12 μm.

The sealed portion 220 shown in FIG. 12 joins the sheets 211, 212 together to prevent them from separating. In one example, the sealed portion 220 joins the innermost layer 210A of the first sheet 211 to the innermost layer 210A of the second sheet 212. Examples of methods for forming the sealed portion 220 include heat sealing, impulse sealing, high-frequency sealing, and ultrasonic sealing. The outer shape of the package 200 when viewed from the front can be selected as desired. In the example shown in FIG. 12, the outer shape of the package 200 is rectangular. The sheet 210 can be divided into a portion surrounded by the sealed portion 220 (hereinafter referred to as the "inner portion 213") and the sealed portion 220. The storage space 200A is a space surrounded by the inner portion 213 of the first sheet 211 and the inner portion 213 of the second sheet 212, and is closed by the sealed portion 220 so as not to communicate with the outside of the package 200.

The sealing portion 220 includes a closing sealing portion 221 (hereinafter referred to as the "first sealing portion 221") that closes the opening 230. In one example, the sealing portion 220 further includes a second sealing portion 222 and a seam sealing portion 223. The first sealing portion 221 is provided at one end of the packaging body 200 in the longitudinal direction, and is arranged along the width direction of the packaging body 200. The second sealing portion 222 is provided at the other end of the packaging body 200 in the longitudinal direction, and is arranged along the width direction of the packaging body 200. The seam sealing portion 223 is provided on the back surface of the packaging body 200, and is arranged along the length direction of the packaging body 200.

The opening 230 shown in Figure 9 is formed at the other longitudinal end of the package 200 so that the contents 300 can be stored in the storage space 200A. In the package 200 shown in Figure 12, the opening 230 is closed by the first seal portion 221.

Figure 9 shows the package 200 before the opening 230 is closed (hereinafter referred to as the "package 200 before closing"). The contents 300 are poured into the storage space 200A through the opening 230 of the package 200 before closing. After the contents 300 are poured, the first seal portion 221 is formed by, for example, heat sealing the intended sealing portion 260 where the first seal portion 221 is to be formed, and the package 200 with the opening 230 closed shown in Figure 12 (hereinafter referred to as the "package 200 after closing") is obtained.

The vapor passage section 240 is a portion of the sheet 210 where the strength is partially reduced so that holes 250 (see Figure 12) are formed in the sheet 210 for venting water vapor generated from the contents 300. The position at which the vapor passage section 240 is provided on the sheet 210 can be selected arbitrarily. In a preferred example, the vapor passage section 240 is provided in the portion of the sheet 210 where stress is most concentrated when the pressure in the storage space 200A increases due to heating by the heating means. In the example shown in Figure 9 etc., the vapor passage section 240 is provided approximately in the center of the first sheet 211 in the longitudinal direction of the package 200.

The vapor passage section 240 has a plurality of scratched sections 241 that are arranged discontinuously and do not penetrate the first sheet 211 or the second sheet 212. The scratched sections 241 are elongated linear cuts. The direction in which the scratched sections 241 are arranged can be selected arbitrarily. In the example shown in Figure 9, the scratched sections 241 are arranged along the short side of the package 200.

When there are three or more scratched portions 241, the relationship between the spacing (hereinafter referred to as "spacing LD") between adjacent scratched portions 241 among the multiple scratched portions 241 can be selected arbitrarily. In a first example shown in FIG. 10 etc., all spacings LD are substantially equal. In a second example, at least two of the multiple spacings LD are different from each other. The shape of the scratched portions 241 can be selected arbitrarily. In a first example shown in FIG. 11 etc., some or all of the multiple scratched portions 241 are arranged so as to penetrate only the outermost layer 210B of the first sheet 211. In a second example, some or all of the multiple scratched portions 241 are arranged only on the outermost layer 210B so as not to penetrate the outermost layer 210B. In a third example, some or all of the multiple scratched portions 241 are arranged so as to penetrate only the innermost layer 210A. In a fourth example, some or all of the multiple scratched portions 241 are arranged only on the innermost layer 210A so as not to penetrate the innermost layer 210A.

The relationship between the lengths (hereinafter referred to as "length LE") of the multiple scratched portions 241 can be selected arbitrarily. In the first example shown in Figure 10, etc., the lengths LE of all scratched portions 241 are substantially equal. In the second example, the lengths LE of at least two of the multiple scratched portions 241 are different from each other.

The relationship between the distance LD and the length LE is determined based on the relationship between the resistance of the sheet 210 to breaking when a standard external force acts on the package 200 during transport, etc., and the ease with which the sheet 210 breaks when the pressure in the storage space 10A increases. In other words, the relationship between the distance LD and the length LE is determined so that the strength of the portion of the sheet 210 where the vapor passage section 240 is provided falls within a predetermined range.

The maximum distance between adjacent scratched portions 241 (hereinafter referred to as "maximum distance LDX") is shorter than the length of the shortest scratched portion 241 (hereinafter referred to as "minimum length LEX"), and is within a range of 100 μm or greater. When the maximum distance LDX is within a range of 100 μm or greater, the strength of the portion of the sheet 210 where the vapor passage portion 240 is provided is unlikely to be excessively reduced. Therefore, even if an external force is applied during the transport process of the closed package 200, the sheet 210 is unlikely to break. When the maximum distance LDX is shorter than the minimum length LEX, the strength of the portion of the sheet 210 where the vapor passage portion 240 is provided is unlikely to be excessively high. Therefore, when the closed package 200 is heated by a heating means, the sheet 210 breaks, allowing water vapor to be properly released.

A preferred example of the minimum value of the maximum spacing LDX is 100 μm. When the maximum spacing LDX is in the range of 100 μm or more, the sheet 210 is less likely to break even when a standard-sized external force is applied to the package 200 during the transport process of the package 200. A more preferred example of the minimum value of the maximum spacing LDX is 200 μm. When the maximum spacing LDX is in the range of 200 μm or more, the sheet 210 is less likely to break even when a standard-sized external force is applied to the package 200 during the transport process of the package 200. A preferred example of the maximum value of the maximum spacing LDX is 2000 μm. When the maximum spacing LDX is in the range of 2000 μm or less, the sheet 210 breaks when the closed package 200 is heated by a heating means, allowing water vapor to be properly released. A more preferred example of the maximum value of the maximum spacing LDX is 1000 μm. If the maximum distance LDX is within the range of 1000 μm or less, the sheet 210 will break when heated by the heating means of the closed package 200, allowing water vapor to be more appropriately released. A preferred range for the maximum distance LDX is 100 μm to 2000 μm. A more preferred range for the maximum distance LDX is 200 μm to 1000 μm.

A preferred example of the minimum value of the minimum length LEX is 500 μm. If the minimum length LEX is in the range of 500 μm or more, when the closed package 200 is heated by a heating means, the sheet 210 will break and water vapor can be properly released. A preferred example of the maximum value of the minimum length LEX is 6900 μm. If the minimum length LEX is in the range of 6900 μm or less, the sheet 210 is less likely to break even when a standard external force is applied to the package 200 during transportation. A preferred range for the minimum length LEX is 500 μm to 6900 μm.

The length LF (see Figure 2) of the vapor passage section 240 can be selected arbitrarily. The length LF is the sum of the lengths LE of all scratched sections 241 included in the vapor passage section 240 and all spacings LD. A preferred example of the minimum value of the length LF is 68 mm. A preferred example of the maximum value of the length LF is 70 mm. The preferred range for the length LF is 68 mm to 70 mm.

An example of how to use the packaging body 200 will be described with reference to FIGS.
The closed package 200 is placed in, for example, a microwave oven with the second sheet 212 facing downward, and heating of the package 200 begins. As the package 200 is heated in the microwave oven, water vapor is generated from the contents 300. Because the storage space 200A is closed by the seal portion 220, the water vapor generated from the contents 300 remains in the storage space 200A. As the time during which the package 200 is heated increases, the pressure in the storage space 200A gradually increases, causing the sheet 210 to expand. Because the portion of the sheet 210 where the vapor passage portion 240 is provided is weaker than the other portions, the sheet 210 breaks at the vapor passage portion 240, and as shown in Figures 12 and 13, a hole 250 is formed in the sheet 210, penetrating the sheet 210, connecting the storage space 200A to the outside. As a result, water vapor remaining in storage space 200A is discharged to the outside of package 200 through hole 250. When heating of package 200 is completed, package 200 is removed from the microwave oven, and, for example, first sealed portion 221 or second sealed portion 222 is cut off, and content 300 is removed.

The package 200 provides the following functions and effects.
When the closed package 200 is heated by a heating means, the sheet 210 expands, causing the plurality of scratched portions 241 in the vapor passage portion 240 to break. The broken portions of adjacent scratched portions 241 connect to each other, forming holes 250 in the sheet 210 that connect the storage space 200A to the outside. This allows water vapor to be properly discharged through the holes 250.

(Example of the second embodiment)
The inventors of the present application conducted tests to confirm the relationship between the distance LD and the length LE and various performance characteristics of the package 200 using samples of the example and the comparative example. Figures 14 and 15 show the test conditions and test results for the example and comparative example samples. In the following description, for ease of explanation, the same reference numerals are used for parts of the comparative example samples that are common to the example samples. The example sample is the package 200 according to the first embodiment. The comparative example sample is a package 200 having a different configuration from the example package 200. The comparative example package 200 differs from the example package 200 in that the distance LD is equal to or greater than the length LE and that there is only one scratched portion 241, but otherwise has the same configuration as the example package 200.

The specifications for the samples of each example and comparative example are as follows. The material constituting the innermost layer 210A in the samples of each example and comparative example is a mixed resin with easy-peel properties. The thickness of the innermost layer 210A is 30 μm. The material constituting the outermost layer 210B in the samples of Examples 1 to 10 and Comparative Examples 1 to 6 is polyethylene terephthalate. The thickness of the outermost layer 210B in the samples of Examples 1 to 10 and Comparative Examples 1 to 6 is 12 μm. The material constituting the outermost layer 210B in the samples of Examples 11 to 20 and Comparative Examples 7 to 12 is nylon. The thickness of the outermost layer 210B in the samples of Examples 11 to 20 and Comparative Examples 7 to 12 is 15 μm. In the samples of Comparative Examples 1 and 7, the sheet 210 has one scratched portion 241. The distance LD and length LE in each example and comparative example are substantially equal to each other. In other words, the distance LD in each example and comparative example matches the maximum distance LDX, and the length LE matches the minimum length LEX.

The tests confirmed whether the packaging body 200 could pass steam appropriately when heated by a heating means (hereinafter referred to as "steam passability"), and the number of pieces of the sheet 210 of the packaging body 200 that broke when the packaging body 200 was dropped (hereinafter referred to as "number of breaks upon dropping"). The heating means was a microwave oven.

Regarding steam permeability, the samples of Examples 1 to 20 and Comparative Examples 1 to 12 were heated in a microwave oven with contents 300 placed in the storage space 200A and the seal portion 220 formed to close the opening 230 and the storage space 200A (hereinafter referred to as the "sealed state"). The contents 300 were frozen fried rice. The contents 300 weighed 200 g. The microwave oven was operated at 1000 W. The heating time was 1 minute. After heating, each sample was visually inspected for the location of steam release. In Figures 14 and 15, a "○" in the steam permeability category indicates that the portion of the sheet 210 where the steam permeability portion 240 was located broke, forming a hole 250, and steam was released through the hole 250. In Figures 14 and 15, a "×" in the steam permeability category indicates that no hole 250 was formed and the sheet 210 was ruptured. The test will be conducted five times.

To measure the number of breakages upon drop, sealed bundles of three identical samples from Examples 1 to 20 and Comparative Examples 1 to 12 (hereinafter referred to as "bundled bundles") were visually inspected for breakage of the sheet 210 when allowed to freely drop from a height of 80 cm. In the test, 10 bundles of samples from each Example and Comparative Example were allowed to freely drop. The number of breakages upon drop items shown in Figures 14 and 15 is the number of bundles in which the sheet 210 of one or more of the three samples included in one bundle broke.

The samples of each example achieved better results in terms of the number of breaks when dropped than the samples of comparative examples 1 and 7. This is thought to be because the strength of the portion of the sheet 210 where the vapor passage portion 240 is provided is not excessively reduced by not providing multiple scratched portions 241 continuously, in other words, by providing multiple scratched portions 241 discontinuously. Furthermore, the samples of each example achieved better results in terms of steam permeability than the samples of comparative examples 2 to 6 and 8 to 12. This is thought to be because the strength of the portion of the sheet 210 where the vapor passage portion 240 is provided is not excessively high when the distance LD is shorter than the length LE and is within the range specified in the embodiment.

(Variation)
The above-described embodiments are merely examples of possible forms of the lid, package, and wrapping body of the present invention, and are not intended to limit the forms. The lid, package, and wrapping body of the present invention may take forms different from those illustrated in the embodiments. Examples of such forms include forms in which part of the configuration of each embodiment is replaced, modified, or omitted, or forms in which a new configuration is added to each embodiment. Examples of modified forms of each embodiment are shown below.

- In the first embodiment, the configuration of the vapor passage section 40 can be modified as desired. In a first modified example, the vapor passage section 40 extends along the longitudinal direction of the lid 20 when viewed from above. In a second modified example, the vapor passage section 40 extends so as to intersect the longitudinal and lateral directions of the lid 20 when viewed from above.

- In the first embodiment, the layer of the sheet 20X on which the multiple scratched portions 41 are provided can be selected arbitrarily. In one example, some or all of the multiple scratched portions 41 are provided on an intermediate layer laminated between the innermost layer 21 and the outermost layer 22 of the sheet 20X. The intermediate layer can be made of any material.

- In the second embodiment, the configuration of the vapor passage section 240 can be modified as desired. In a first modified example, the vapor passage section 240 extends along the longitudinal direction of the packaging body 200 when viewed from above. In a second modified example, the vapor passage section 240 extends so as to intersect the longitudinal and lateral directions of the packaging body 200 when viewed from above.

- In the second embodiment, the layer of the sheet 210 on which the multiple scratched portions 241 are provided can be selected arbitrarily. In one example, some or all of the multiple scratched portions 241 are provided on an intermediate layer laminated between the innermost layer 210A and the outermost layer 210B of the sheet 210. The intermediate layer can be made of any material.

1: Package 10: Tray 10A: Storage space 20: Lid 20X: Sheet 21: Innermost layer 22: Outermost layer 40: Steam passage portion 41: Scratched portion 100: Contents 200: Packaging body 200A: Storage space 210: Sheet 220: Sealed portion 230: Opening 240: Steam passage portion 241: Scratched portion 260: Portion to be sealed 300: Contents

Claims (7)

A lid attached to a tray including a storage space for storing contents,
a sheet bonded to the tray;
a vapor passage portion provided in the sheet so as to be able to rupture the sheet and release water vapor when pressure in the storage space increases in a state in which the sheet is joined to the tray so as to close the storage space,
The steam passage portion includes a plurality of scratched portions that are provided discontinuously along the linear direction so as not to penetrate the sheet and so as to be parallel to the linear direction,
The plurality of scratched portions include elongated linear cuts, and the sheet expands with an increase in pressure in the storage space, causing the plurality of scratched portions to break, and the broken portions of adjacent scratched portions to connect with each other, thereby forming holes in the sheet that communicate with the storage space and the outside,
The maximum interval between adjacent scratched portions among the plurality of scratched portions is shorter than the length of the shortest scratched portion among the plurality of scratched portions and is within a range of 100 μm or more;
The maximum distance between adjacent scratched portions among the plurality of scratched portions is within a range of 2000 μm or less. The lid according to claim 1 , wherein the maximum distance between adjacent scratched portions among the plurality of scratched portions is in the range of 200 μm or more. The lid according to claim 1 or 2, wherein the maximum distance between adjacent scratched portions among the plurality of scratched portions is within a range of 1000 μm or less. the sheet includes an innermost layer joined to the tray and an outermost layer laminated on the innermost layer,
The lid according to any one of claims 1 to 3, wherein the scratched portion penetrates only the outermost layer of the sheet. The sheet has a rectangular or rectangular-like shape in plan view,
The lid according to any one of claims 1 to 4, wherein the plurality of scratched portions are provided along the short side direction of the sheet. A lid according to any one of claims 1 to 5;
and the tray to which the lid is joined so as to close the storage space. A seat and
a sealing portion that seals the sheet so as to form a storage space capable of storing contents;
an opening that opens the storage space;
a predetermined seal portion in which a closing seal portion that closes the opening is to be formed;
a vapor passage portion provided in the sheet so that the sheet can be broken to release water vapor when the pressure in the storage space increases with the closed seal portion formed,
The steam passage portion includes a plurality of scratched portions that are provided discontinuously along the linear direction so as not to penetrate the sheet and so as to be parallel to the linear direction,
The plurality of scratched portions include elongated linear cuts, and the sheet expands with an increase in pressure in the storage space, causing the plurality of scratched portions to break, and the broken portions of adjacent scratched portions to connect with each other, thereby forming holes in the sheet that communicate with the storage space and the outside,
The maximum interval between adjacent scratched portions among the plurality of scratched portions is shorter than the length of the shortest scratched portion among the plurality of scratched portions and is within a range of 100 μm or more;
The maximum distance between adjacent scratched portions among the plurality of scratched portions is within a range of 2000 μm or less,
the sheet includes a first sheet and a second sheet facing each other so as to form the storage space capable of storing the contents,
The packaging body, wherein the vapor passage portion is provided in a portion of the first sheet facing the second sheet, or in a portion of the second sheet facing the first sheet.