Food can containers

Abstract

To provide a food can container capable of suppressing the leaching of microplastics into food. [Solution] A food can container comprises a can body in which food is packed, a can bottom attached to the bottom side of the can body, and a can lid that seals the inside of the can formed by the can body and the can bottom, and the inner surface of at least one of the can body, can bottom, and can lid that is exposed to food is made of stainless steel.

Description

[Technical field]

[0001] The present invention relates to a food can container in which food is packed. [Background technology]

[0002] Food can containers are used for long-term storage of foods containing moisture. One known food can container is that described in Patent Document 1. The food can container of Patent Document 1 allows food to be stored for a long period of time by filling it with food and sealing it. In addition, the food can container of Patent Document 1 prevents the flavor of the food in the food can container from changing and the material of the food can container from corroding by laminating a polyester film to the inner surface of the material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-210363 A Summary of the Invention [Problem to be solved by the invention]

[0004] In food can containers such as those in Patent Document 1, it is believed that the laminated polyester film is hydrolyzed by the moisture in the food. When hydrolyzed, microplastics and nanoplastics are leached into the food. If food is stored in a food can container for a long time, it is believed that more microplastics (or nanoplastics) will leach into the food. Therefore, by eating food packed in a food can container, more microplastics (or nanoplastics) will be exposed to the human body.

[0005] Therefore, an object of the present invention is to provide a food can container that can prevent microplastics from leaching into food. [Means for solving the problem]

[0006] The food can container of the present invention comprises a can body in which food is packed, a can bottom provided on the bottom side of the can body, and a can lid that seals the inside of the can formed by the can body and the can bottom, and the inner surface of at least one of the can body, the can bottom, and the can lid that is exposed to food is made of stainless steel.

[0007] According to the present invention, the inner surface of at least one of the can body, the can bottom, and the can lid that is exposed to food is made of stainless steel. Therefore, the inner surface has corrosion resistance, and therefore the inner surface can be prevented from corroding. In addition, since the inner surface is made of stainless steel, the exposure of plastic to food within the food can container can be prevented. Therefore, the hydrolysis of plastic within the food can container can be prevented. This can prevent microplastics from leaching into food.

[0008] In the above invention, the stainless steel constituting the inner surface preferably has a pitting corrosion index of 15 or more.

[0009] According to the above configuration, the pitting corrosion index of the stainless steel constituting the inner surface is 15 or more. Therefore, the inner surface has high corrosion resistance against food. This makes it possible to prevent food from being stored for a long period of time.

[0010] In the above invention, the pitting corrosion index of the stainless steel constituting the inner surface is preferably 22 or more.

[0011] According to the above configuration, the pitting corrosion index of the stainless steel constituting the inner surface is 22 or more. Therefore, the inner surface has higher corrosion resistance against food. This makes it possible to prevent food from being stored for a longer period of time. Furthermore, by using stainless steel with a pitting corrosion index of 22 or more, it is possible to prevent the occurrence of crevice corrosion, for example, at the joint between the can body and the can lid or the joint between the can body and the can bottom.

[0012] In the above invention, the pitting corrosion index of the stainless steel on the inner surface is preferably 30 or more.

[0013] According to the above configuration, the pitting corrosion index of the stainless steel constituting the inner surface is 30 or more. Therefore, the inner surface is highly resistant to corrosion by food because the occurrence of the inner surface being corroded by food is extremely reduced. This makes it possible to prevent food from being stored for a longer period of time.

[0014] In the above invention, the stainless steel constituting the inner surface is preferably a duplex stainless steel.

[0015] According to the above-mentioned configuration, the stainless steel constituting the inner surface is a duplex stainless steel. Therefore, it is possible to ensure ease of processing while having higher corrosion resistance. As a result, it is possible to easily manufacture a food can container having higher corrosion resistance.

[0016] In the above invention, the stainless steel constituting the inner surface is preferably an austenitic stainless steel.

[0017] According to the above-mentioned structure, the stainless steel constituting the inner surface is an austenitic stainless steel, which ensures ease of processing while providing corrosion resistance, thereby facilitating the manufacture of food can containers made of stainless steel.

[0018] In the above invention, the stainless steel constituting the inner surface is preferably a ferritic stainless steel.

[0019] According to the above-mentioned structure, the stainless steel constituting the inner surface is a ferritic stainless steel, which makes it possible to easily manufacture a corrosion-resistant food can container.

[0020] In the above invention, it is preferable that the product further comprises an identification mark indicating that the product is made of recyclable stainless steel.

[0021] According to the above-mentioned configuration, the food can container further includes an identification mark indicating that the food can container is made of recyclable stainless steel, so that the food can container can be easily identified as being made of recyclable stainless steel. Effect of the Invention

[0022] According to the present invention, it is possible to prevent microplastics from leaching into food. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a food can container according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view showing a food can container according to an embodiment of the present invention. [Diagram 3] 1 is a graph showing the PREN of each type of stainless steel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] A food can container (hereinafter referred to as a "can container") 1 according to an embodiment of the present invention will be described below with reference to the drawings mentioned above. Note that the concept of direction used in the following description is used for convenience in the description and does not limit the orientation of the configuration of the invention to that direction. Also, the can container 1 described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the embodiment, and additions, deletions, and modifications are possible within the scope of the invention.

[0025] <Canned food container> The canned food container 1 shown in FIG. 1 is a container used for long-term storage of food F. More specifically, food F is packed and sealed in the canned food container 1. In addition, the food F in the canned food container 1 is subjected to heat sterilization or heat and pressure sterilization. This allows the food F to be stored for a long period of time in the canned food container 1. The food F is, for example, a processed food that mainly contains water and solid substances, but may also be a liquid such as soup that does not contain solid substances. In addition, the canned food container 1 is made of stainless steel having corrosion resistance. This prevents the inner surfaces 11a to 13a of the canned food container 1 from corroding due to chloride substances or acidic substances contained in the food F during long-term storage. The configuration of the canned food container 1 will be described in more detail below.

[0026] As shown in Fig. 2, the can container 1 comprises a can body 11, a can bottom 12, and a can lid 13. More specifically, the can container 1 further comprises an identification mark 14. In this embodiment, the can container 1 is a three-piece can, in which the can body 11 and the can bottom 12 are formed separately, and the can body 15 is formed by combining them. Note that the can container 1 is not necessarily limited to a three-piece can, and may be a can container of another type, such as a two-piece can in which the can body 11 and the can bottom 12 are integrally formed to form the can body 15.

[0027] The can body 11 is a cylindrical member made of stainless steel. More specifically, the can body 11 is formed by rolling a stainless steel strip into a cylindrical shape and welding both circumferential ends. When the can body 11 is formed integrally with the can bottom 12, it is formed by deep drawing a stainless steel plate. The thickness of the can body 11 is, for example, 0.1 mm or more and 0.8 mm or less. However, the thickness of the can body 11 is not limited to the above-mentioned range. In the present embodiment, the inner surface 11a of the can body 11 exposed to the food F is made of stainless steel. More specifically, the food F is packed inside the can body 11, and the inner surface 11a of the can body 11 is exposed to the food F. In the can body 11, the stainless steel is exposed on the inner surface 11a. Although not shown, the outer surface 11b of the can body 11 may be decorated by applying paint or laminating a resin film. However, the outer surface 11b of the can body 11 does not necessarily need to be decorated, and the stainless steel may be exposed.

[0028] In this embodiment, the can body 11 is made of SUS329J4L, which is a duplex stainless steel (i.e., ferritic-austenitic stainless steel). On the other hand, the can body 11 may be made of the following stainless steel. That is, for example, ferritic stainless steel, austenitic stainless steel, and duplex stainless steel are used as the stainless steel for forming the can body 11. For example, SUH409, SUH409L, SUS430, SUS430LX, SUS430J1L, SUS434, SUS436, SUS436L, SUS436J1L, SUS443J1, SUS444, SUS445J1, SUS445J2, SUS447J1, and SUSXM27 (all JIS standards), as well as Sea-Cure (trademark), etc. are used as the ferritic stainless steel.

[0029] Examples of austenitic stainless steel include SUS201, SUS202, SUS301, SUS301L, SUS301J1, SUS302, SUS302B, SUS303, SUS303Cu, SUS304, SUS304Cu, SUS304L, SUS304N1, SUS304N2, SUS304LN, SUS304J1, SUS304J2, SUS304J3, SUS305, SUS309S, SUS310S, SUS312L, and SUS315J. 1, SUS315J2, SUS316, SUS316L, SUS316N, SUS316LN, SUS316Ti, SUS316J1, SUS316J1L, SUS316F, SUS317, SUS317L, SUS317LN, SUS317J1, SUS317J2, SUS317LMN, SUS321, SUS347, SUS384, SUS836L, SUS890L, SUS904, SUSXM7, and SUSXM15J1 (all JIS standards), etc. are used.

[0030] Furthermore, examples of duplex stainless steel that can be used include SUS323L (name: 2304), SUS329J1, SUS329J4L, SUS329J3L (name: 2205), and SUS327L1 (name: 2507) (all JIS standards). Note that the above-mentioned ferritic stainless steel, austenitic stainless steel, and duplex stainless steel are merely examples, and other stainless steels may also be used.

[0031] Further, stainless steel having a pitting corrosion index (abbreviation: PREN) of 15 or more is used for the can body 11. More preferably, stainless steel having a PREN of 22 or more is used for the can body 11. Even more preferably, stainless steel having a PREN of 30 or more is used for the can body 11. PREN is calculated, for example, as follows. PREN=Weight%Cr+3.3×Weight%Mo+16×Weight%N…(1) Here, wt% Cr is the weight% of chromium contained in the stainless steel, wt% Mo is the weight% of molybdenum contained in the stainless steel, and wt% N is the weight% of nitrogen contained in the stainless steel.

[0032] The PREN is not limited to the value calculated by the above-mentioned formula (1). For example, when the stainless steel contains tungsten and manganese, the PREN may be calculated by the following formula (2), or by other formulas. PREN=Weight%Cr+3.3×{Weight%Mo+0.5weight%W} +16×Weight%N−Weight%Mn…(2) Here, wt% W is the weight% of tungsten contained in the stainless steel, and wt% Mn is the weight% of manganese contained in the stainless steel.

[0033] For example, stainless steels with a PREN of 30 or more include duplex stainless steels, austenitic stainless steels, and ferritic stainless steels. As shown in Fig. 3, general-purpose duplex stainless steels SUS329J4L and SUS329J3L and super duplex stainless steel SUS327L1 are used as duplex stainless steels with a PREN of 30 or more. As austenitic stainless steels with a PREN of 30 or more, SUS317LMN and SUS904 are used. Furthermore, Sea-Cure (trademark) is used as a ferritic stainless steel with a PREN of 30 or more.

[0034] Other examples of austenitic stainless steels with a PREN of 30 or more include SUS312L, SUS836L, and SUS890L. Also, SUS447J1 is used as a ferritic stainless steel with a PREN of 30 or more. However, the materials used as duplex stainless steels, austenitic stainless steels, and ferritic stainless steels with a PREN of 30 or more are not limited to the above-mentioned materials, and any stainless steels may be used as long as the components contained therein give a PREN of 30 or more.

[0035] As stainless steel with a PREN of 22 or more, in addition to the above-mentioned stainless steel with a PREN of 30 or more, for example, the following duplex stainless steel, austenitic stainless steel, and ferritic stainless steel are used. That is, SUS323L is used as lean duplex stainless steel with a PREN of 22 or more, as shown in Figure 3. SUS316 and SUS317L are used as austenitic stainless steel with a PREN of 22 or more. SUS444, for example, is used as ferritic stainless steel with a PREN of 22 or more.

[0036] In addition, SUS821L1 and SUS323L are used as duplex stainless steels with a PREN of 22 or more. SUS309S, SUS310S, SUS316F, SUS316L, SUS316N, SUS316LN, SUS316Ti, SUS317J1, SUS317J2, and SUS317LN are used as austenitic stainless steels with a PREN of 22 or more. SUS445J1, SUS445J2, and SUSXM27 are used as ferritic stainless steels with a PREN of 22 or more. However, the materials used as duplex stainless steels, austenitic stainless steels, and ferritic stainless steels with a PREN of 22 or more are not limited to the above-mentioned materials, and may be any materials that have a PREN of 22 or more due to the components contained in each stainless steel.

[0037] Furthermore, in addition to the above-mentioned stainless steels having a PREN of 22 or more, the following austenitic stainless steels and ferritic stainless steels are used as stainless steels having a PREN of 15 or more. That is, SUS304 is used as an austenitic stainless steel having a PREN of 15 or more, as shown in Figure 3. Also, SUS430, SUS434, and SUS436 are used as ferritic stainless steels having a PREN of 15 or more, for example.

[0038] Other examples of austenitic stainless steels with a PREN of 15 or more include SUS201, SUS202, SUS205, SUS301, SUS301J1, SUS301L, SUS302, SUS302B, SUS303, SUS303Cu, SUS303Se, SUS304Cu, SUS304J1, SUS304J2, SUS304J3, SUS304L, SUS304LN, SUS304N1, SUS304N2, SUS305, SUS315J1, SUS315J2, SUS316J1, SUS316J1L, SUS321, SUS347, SUS384, SUSXM15J1, and SUSXM7. Examples of ferritic stainless steels with a PREN of 15 or more include SUS429, SUS430F, SUS430LX, SUS430J1L, SUS436J1L, SUS436L, and SUS443J1. However, the materials used as duplex stainless steels, austenitic stainless steels, and ferritic stainless steels with a PREN of 15 or more are not limited to the above-mentioned materials, and any stainless steels may have a PREN of 15 or more due to the components contained therein.

[0039] The can bottom 12 is a disk-shaped member made of stainless steel. More specifically, the can bottom 12 is formed by punching a stainless steel plate into a disk by press processing, etc. The can bottom 12 may be formed into a disk shape by cutting the stainless steel plate, etc. The thickness of the can bottom 12 is, for example, 0.1 mm or more and 0.8 mm or less. However, the thickness of the can bottom 12 is not limited to the above-mentioned range. The can bottom 12 is provided on the can body 11 so as to close an opening on one axial side of the can body 11 (i.e., the bottom side of the can body 11). More specifically, the can bottom 12 is seamed around one end of the can body 11 over the entire circumferential direction as shown in FIG. 2. As a result, the can bottom 12 closes the bottom side of the can body 11 and constitutes the bottom of the canned container 1 (i.e., the bottom of the can main body 15). The can bottom 12 may be formed integrally with the can body 11 by additionally drawing the stainless steel plate, as described above.

[0040] In the can bottom 12 thus constructed, the inner surface 12a faces the food F in the can container 1, and the inner surface 12a is exposed to the food F. The inner surface 12a of the can bottom 12 exposed to the food F is made of stainless steel. To explain in more detail, the can container 1 is filled with the food F as described above, and the inner surface 11a of the can bottom 12 is exposed to the food F. In the can bottom 12, the stainless steel is exposed on the inner surface 12a. Note that in this embodiment, the outer surface 12b of the can bottom 12 is also exposed stainless steel. However, the outer surface 12b of the can bottom 12 may be decorated by applying paint or laminating a resin film, or the like.

[0041] The can bottom 12 is made of, for example, the same type of stainless steel as the can body 11. That is, in this embodiment, the can bottom 12 is made of SUS329J4L, which is a duplex stainless steel. The can bottom 12 may be made of a stainless steel different from that of the can body 11. Also, the can bottom 12 may be made of the following stainless steel, like the can body 11. That is, as the stainless steel constituting the can bottom 12, for example, ferritic stainless steel, austenitic stainless steel, and duplex stainless steel may be used. As the ferritic stainless steel, for example, SUH409, SUS430, SUS434, SUS436, SUS444, and Sea-Cure (trademark) are used. As the austenitic stainless steel, for example, SUS304, SUS316, SUS317L, SUS317LMN, and SUS904 are used. As the duplex stainless steel, for example, SUS323L, SUS329J4L, SUS329J3L, and SUS327L1 are used.

[0042] Similarly to the can body 11, the can bottom 12 is made of stainless steel having a PREN of 15 or more. More preferably, the can bottom 12 is made of stainless steel having a PREN of 22 or more. Even more preferably, the can bottom 12 is made of stainless steel having a PREN of 30 or more. That is, as shown in FIG. 3, for example, duplex stainless steels such as SUS329J4L, SUS329J3L, and SUS327L1, and austenitic stainless steels such as SUS317LMN and SUS904 are used as stainless steels having a PREN of 30 or more. For example, SUS323L, SUS317L, SUS316, and SUS444 are used as stainless steels having a PREN of 22 or more, in addition to the above-mentioned stainless steels having a PREN of 30 or more. For example, SUS304, SUS430, SUS434, and SUS436 are used as stainless steels having a PREN of 15 or more, in addition to the above-mentioned stainless steels having a PREN of 22 or more. Although not described in detail, the can bottom 12 may be made of any of the various stainless steel materials given as other examples for the can body 11.

[0043] The can lid 13 is a disk-shaped member made of stainless steel. More specifically, the can lid 13 is formed by punching a stainless steel plate into a disk by press processing. The can lid 13 may be formed into a disk shape by cutting the stainless steel plate. The thickness of the can lid 13 is, for example, 0.1 mm or more and 0.8 mm or less. However, the thickness of the can lid 13 is not limited to the above-mentioned range. The can lid 13 is provided on the can body 11 so as to close the opening on the other axial side of the can body 11 (i.e., the ceiling side of the can body 11). More specifically, the can lid 13 is seamed around the other end of the can body 11 over the entire circumference in the circumferential direction as shown in FIG. 2. As a result, the can lid 13 closes the ceiling side of the can body 11 and forms the ceiling part of the canned container 1.

[0044] In the can lid 13 thus constructed, the inner surface 13a faces the food F in the can container 1, and the inner surface 13a is exposed to the food F. The inner surface 13a of the can lid 13, which is exposed to the food F, is also made of stainless steel. To explain in more detail, the can container 1 is filled with food F as described above, and the inner surface 11a of the can lid 13 is exposed to the food F. In the can lid 13, the stainless steel is exposed on the inner surface 13a. Note that in this embodiment, the outer surface 13b of the can lid 13 is also exposed to the stainless steel. However, the outer surface 13b of the can lid 13 may be decorated by applying paint or laminating a resin film, or the like.

[0045] The can lid 13 is made of, for example, the same type of stainless steel as the can body 11. That is, in this embodiment, the can lid 13 is made of SUS329J4L, which is a duplex stainless steel. The can lid 13 may be made of a stainless steel different from that of the can body 11. Also, the can lid 13 may be made of the following stainless steel, like the can body 11. That is, as the stainless steel constituting the can lid 13, for example, ferritic stainless steel, austenitic stainless steel, and duplex stainless steel may be used. As the ferritic stainless steel, for example, SUH409, SUS430, SUS434, SUS436, SUS444, and Sea-Cure (trademark) are used. As the austenitic stainless steel, for example, SUS304, SUS316, SUS317L, SUS317LMN, and SUS904 are used. Furthermore, as the duplex stainless steel, for example, SUS323L, SUS329J4L, SUS329J3L, and SUS327L1 are used.

[0046] Similarly to the can body 11, the can lid 13 is made of stainless steel having a PREN of 15 or more. More preferably, the can lid 13 is made of stainless steel having a PREN of 22 or more. Even more preferably, the can lid 13 is made of stainless steel having a PREN of 30 or more. That is, for example, SUS329J4L, SUS329J3L, and SUS327L1 duplex stainless steels, and SUS317LMN and SUS904 austenitic stainless steels are used as stainless steels having a PREN of 30 or more. For example, SUS323L, SUS317L, SUS316, SUS430, SUS434, SUS436, and SUS444 are used as stainless steels having a PREN of 22 or more, in addition to the above-mentioned stainless steels having a PREN of 30 or more. For example, SUS304, SUS430, SUS434, and SUS436 are used as stainless steels having a PREN of 15 or more, in addition to the above-mentioned stainless steels having a PREN of 22 or more. Although not described in detail, the can lid 13 may also be made of any of the various stainless steel materials given as other examples for the can body 11.

[0047] In this embodiment, the can body 11 and the can lid 13 are made of SUS329J4L, a stainless steel with a PREN of 22 or more. This makes it possible to prevent crevice corrosion from occurring in the portion where the can body 11 and the can lid 13 join together (i.e., the seaming portion 13c). As described above, in this embodiment, the can bottom 12 is also made of SUS329J4L, a stainless steel with a PREN of 22 or more. This makes it possible to similarly prevent crevice corrosion from occurring in the portion where the can body 11 and the can bottom 12 join together (i.e., the seaming portion 12c).

[0048] The identification mark 14 indicates that the can body 11 and the can lid 13 are made of recyclable stainless steel. In this embodiment, the identification mark 14 is a predetermined triangular recess. Such an identification mark 14 is particularly useful when a collector collects canned containers 1 and selects canned containers 1 made of stainless steel. Note that the identification mark 14 does not necessarily have to be a recess, and may be a predetermined mark formed by paint or lamination on the outer surfaces 11b to 13b, as long as it indicates that the canned container 1 contains recyclable stainless steel.

[0049] In the can container 1 configured in this manner, a stainless steel strip is rolled into a cylindrical shape and both circumferential ends are welded to form the can body 11. A stainless steel plate is punched out by a press process to form a disk-shaped can bottom 12. The can bottom 12 is then seamed around one end of the can body 11 over its entire circumference. As a result, one end portion of the can body 11, that is, the bottom of the can body 11 in this embodiment, is sealed by the can bottom 12, and a bottomed, cylindrical can body 15 is formed.

[0050] The food F is filled into the can body 15 from an opening on one side in the axial direction, and then the opening of the can body 15 is closed with the can lid 13. To explain in more detail, like the can bottom 12, the cylindrical can lid 13 is formed by punching out from a stainless steel plate by press working. Then, the can lid 13 is wrapped and seamed around the entire circumference of the opening end of the can body 15 (i.e., the other axial end of the can body 11). As a result, the opening of the can body 15 is closed with the can lid 13, and the food F inside the can body 15 is sealed. In this way, a canned food container 1 is manufactured in which the food F is filled and sealed. Furthermore, the canned food container 1 is subjected to heat sterilization or heat and pressure sterilization to enable long-term storage.

[0051] In the can container 1 of this embodiment, the inner surfaces 11a to 13a of the can body 11, the can bottom 12, and the can lid 13 that are exposed to the food F are made of stainless steel. Therefore, the inner surfaces 11a to 13a have corrosion resistance, and therefore the inner surfaces 11a to 13a can be prevented from corroding. In addition, since the inner surfaces 11a to 13a are made of stainless steel, the exposure of plastic to the food F in the can container 1 can be prevented. Therefore, the hydrolysis of plastic in the can container 1 can be prevented. This can prevent microplastics from seeping into the food F. In particular, when a conventional can container is heated over an open flame, the hydrolysis of plastic in the laminate film progresses at an accelerated rate, and a large amount of microplastics seeps into the food F. However, the can container 1 can prevent such a situation from occurring.

[0052] In the canned food container 1 of the present embodiment, the PREN of the stainless steel constituting the inner surfaces 11a-13a is 15 or more. Therefore, the inner surfaces 11a-13a have high corrosion resistance against the food F. This makes it possible to prevent the food F from being stored for a long period of time.

[0053] Furthermore, in the canned container 1 of this embodiment, the PREN of the stainless steel constituting the inner surfaces 11a-13a is 22 or more. Therefore, the inner surfaces 11a-13a have higher corrosion resistance to the food F. This makes it possible to prevent the food F from being stored for a longer period of time. Furthermore, by using stainless steel with a PREN of 22 or more, it is possible to prevent the occurrence of crevice corrosion, for example, in the seamed portions 12c, 13c.

[0054] Furthermore, in the canned container 1 of this embodiment, the PREN of the stainless steel constituting the inner surfaces 11a-13a is 30 or more. Therefore, the inner surfaces 11a-13a are extremely unlikely to be corroded by the food F, and the inner surfaces 11a-13a have even higher corrosion resistance against the food F. This makes it possible to prevent the food F from being stored for an even longer period of time.

[0055] Furthermore, in the can container 1 of this embodiment, the stainless steel constituting the inner surfaces 11a to 13a is a duplex stainless steel. Therefore, it is possible to ensure ease of processing while having higher corrosion resistance. As a result, it is possible to easily manufacture the can container 1 having higher corrosion resistance.

[0056] Furthermore, in the can container 1 of this embodiment, the stainless steel constituting the inner surfaces 11a to 13a may be an austenitic stainless steel. This ensures ease of processing while providing corrosion resistance. This allows the can container 1 made of stainless steel to be easily manufactured.

[0057] In the can container 1 of this embodiment, the stainless steel constituting the inner surface may be a ferritic stainless steel, which makes it possible to easily manufacture a corrosion-resistant food can container.

[0058] Furthermore, the can container 1 of this embodiment further includes an identification mark 14 indicating that it is made of recyclable stainless steel. Therefore, it is easy to identify that the can container 1 contains recyclable stainless steel.

[0059] [Other embodiments] The stainless steels constituting the can body 11, can bottom 12, and can lid 13 of the canned container 1 of this embodiment are not limited to the stainless steels described above, and may be other stainless steels. For example, the austenitic stainless steels are not limited to the above-mentioned SUS304, SUS316, SUS317L, SUS317LNM, and SUS904, and may be other austenitic stainless steels. The same applies to ferritic stainless steels and duplex stainless steels.

[0060] Moreover, the stainless steel with a PREN of 30 or more is not limited to the above-mentioned types of duplex stainless steel and austenitic stainless steel, but may be other types of duplex stainless steel and austenitic stainless steel. Moreover, the stainless steel with a PREN of 30 or more is not limited to duplex stainless steel and austenitic stainless steel, but may be ferritic stainless steel, for example, Sea-Cure (trademark). The same applies to stainless steel with a PREN of 22 or more and stainless steel with a PREN of 15 or more.

[0061] Furthermore, the can container 1 of this embodiment is not limited to a three-piece can as described above, and may be a two-piece can. The shape of the can container 1 is not limited to a cylindrical shape as described above, and may be a rectangular or triangular tubular shape, as long as the food F can be packed in the can container 1. All the inner surfaces 11a to 13a of the can body 11, the can bottom 12, and the can lid 13 do not necessarily have to be made of stainless steel, and at least one of the three inner surfaces 11a to 13a may be made of stainless steel. That is, the inner surface 11a of the can body 11 may be made of stainless steel, and the inner surfaces 12a, 13a of the can bottom 12 and the can lid 13 may be laminated or painted. The can body 11, the can bottom 12, and the can lid 13 may each be made of a different stainless steel. [Explanation of symbols]

[0062] 1 canned food container 11 Can body 11a Inside 12 Can bottom 12a Inside 13 Can Lids 13a Inside 14 Distinguishing marks 15 Can body F Food

Claims

1. A can body in which food is packed; a can bottom provided on a bottom side of the can body; a can lid that seals a can body formed by the can body and the can bottom, At least one of the can body, the can bottom, and the can lid has an inner surface exposed to food made of stainless steel, and the stainless steel is exposed on the inner surface; The pitting corrosion index PREN of the stainless steel constituting the inner surface is PREN=wt%Cr+3.3×wt%Mo+16×wt%N or PREN=wt%Cr+3.3×{wt%Mo+0.5wt%W} +16 x weight %N - weight %Mn A food can container having a mass of 22 or more.

2. 2. The food can container of claim 1, wherein the pitting corrosion index PREN of the stainless steel on the inner surface is 30 or more.

3. 2. The food can container according to claim 1, wherein the stainless steel constituting the inner surface is a duplex stainless steel.

4. 2. The food can container according to claim 1, wherein the stainless steel constituting the inner surface is an austenitic stainless steel.

5. 2. The food can container according to claim 1, wherein the stainless steel constituting the inner surface is a ferritic stainless steel.

6. 2. The food can container according to claim 1, wherein the inner surfaces of the can body, the can bottom, and the can lid that are exposed to food are made of stainless steel and the stainless steel is exposed on the inner surfaces.

Images