Plant cultivation container

Abstract

This disclosure provides a plant cultivation container that can easily remove attached algae and maintain corrosion resistance. In the plant cultivation container, at least a portion of the container section holding the nutrient solution is made of a coated steel plate 1. The coated steel plate 1 includes a steel plate 2 and a coating layer 3 disposed on the steel plate 2. The coating layer 3 contains a fluorinated polysiloxane (A). The fluorinated polysiloxane (A) is a reaction product containing a fluoropolymer (A1) and a polysiloxane (A2). The fluoropolymer (A1) has a constituent unit (a1) bonded by an amine ester bond, and the constituent unit (a1) includes a constituent unit (a11) having a free radical polymerizable unsaturated bond. The polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain.

Description

[Technical Field]

[0001] This disclosure relates to a coated steel plate and a plant cultivation container. More specifically, this disclosure relates to a coated steel plate and a plant cultivation container, wherein the coated steel plate has a coating film formed by a resin-containing paint. [Previous Technology]

[0002] Patent Document 1 discloses a coated metal plate comprising a metal plate and a coating layer covering the metal plate, the coating layer containing a pyridinethione compound. It also discloses that the coated metal plate has high algae-resistant properties, making it difficult for algae to adhere. [Prior Art Documents] (Patent Documents)

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-90102 [Summary of the Invention]

[0004] It is difficult to completely suppress algae from adhering to the coated metal plate. Moreover, the adhering algae may become attached to the surface of the coated metal plate. Therefore, there is a problem that it is difficult to remove algae that are temporarily attached to the surface of the coated metal plate.

[0005] The problem disclosed herein is to provide a coated steel plate and a plant cultivation container that can easily remove attached algae and maintain corrosion resistance.

[0006] The coated steel sheet disclosed herein comprises a steel sheet and a coating layer disposed on the aforementioned steel sheet. The surface of the aforementioned coating layer has a contact angle of 82° or more and 130° or less with water, and a contact angle of 70° or more and 120° or less with ethylene glycol. The ten-point average roughness of the aforementioned surface is greater than 0 μm and less than 20 μm.

[0007] The coated steel sheet disclosed herein comprises a steel sheet and a coating layer disposed on the steel sheet. The coating layer contains a fluorinated polysiloxane (A). The fluorinated polysiloxane (A) is a reaction product containing a reactive component comprising a fluororesin (A1) and a polysiloxane (A2). The fluororesin (A1) has a constituent unit (a1) bonded by an amine ester bond, and the constituent unit (a1) contains a constituent unit (a11) having a free radical polymerizable unsaturated bond. The polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain.

[0008] The plant cultivation container disclosed herein has a container section for holding the culture medium. At least a portion of the aforementioned container section is made of the aforementioned coated steel plate.

Implementation Method

[0010] [Implementing Forms] This section describes the embodiments of this disclosure. Furthermore, the following embodiments are only a part of the various embodiments of this disclosure. Moreover, the following embodiments can be modified according to various design considerations, etc., as long as the purpose of this disclosure is achieved. Furthermore, the mechanisms of action described below are speculative, and this disclosure is not limited to the explanation of the mechanisms of action below.

[0011] 1. Overview: When cultivating plants, algae may proliferate and hinder plant growth. If algae proliferate in large quantities, the plants may suffer from nutrient deficiency. Therefore, this may lead to problems with inefficient plant growth. Therefore, a method is desired to prevent algae from attaching.

[0012] For example, if a coating containing ingredients that inhibit algae adhesion is formed on the surface of a container used for cultivating plants, algae adhesion can be inhibited. However, it is actually difficult to completely inhibit algae adhesion. Moreover, the attached algae may adhere to the container surface. Therefore, there is a problem that it is difficult to remove algae temporarily attached to the container surface. In addition, when the container is vigorously rubbed in an attempt to remove the algae attached to the container surface, the container may be damaged. Moreover, if chemicals come into contact with these damages, the container may corrode. Therefore, removing algae attached to the container may sometimes impair the container's corrosion resistance. As a result, the inventors repeatedly focused on research and development and completed a coated steel plate 1 that can easily remove attached algae and maintain corrosion resistance, and are considering its application in containers for cultivating plants.

[0013] The inventors discovered that by having a coating layer 3 with a specific surface condition on the coated steel plate 1, algae adhering to the coated steel plate 1 can be removed, and the corrosion resistance of the coated steel plate 1 can be maintained. That is, the inventors completed a coated steel plate 1, which includes a steel plate 2 and a coating layer 3 disposed on the steel plate 2. The surface of the coating layer 3 has a contact angle with water of 82° or more and 130° or less, and a contact angle with ethylene glycol of 70° or more and 120° or less. The ten-point average roughness (Rzjis) of the surface is greater than 0 μm and less than 20 μm.

[0014] Furthermore, the inventors have discovered that by having a coating layer 3 containing specific components in the coated steel plate 1, algae adhering to the coated steel plate 1 can be easily removed, and the corrosion resistance of the coated steel plate 1 can be maintained. That is, the inventors have also completed a coated steel plate 1, which has a steel plate 2 and a coating layer 3 disposed on the steel plate 2. The coating layer 3 contains a fluorinated polysiloxane (A). The fluorinated polysiloxane (A) is a reaction product containing a fluororesin (A1) and a polysiloxane (A2). The fluororesin (A1) has a constitutive unit (a1) bonded by an amine ester bond. The constitutive unit (a1) contains a constitutive unit (a11) with a free radical polymerizable unsaturated bond. The polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain.

[0015] Furthermore, the inventors have also discovered that the coated steel sheet 1 possesses a coating layer 3 that combines the aforementioned surface conditions and composition, which makes it easier to remove algae adhering to the coated steel sheet 1 and better maintains the corrosion resistance of the coated steel sheet 1. Hereinafter, such a coated steel sheet 1 as described in this embodiment will be described.

[0016] 2. Details 2.1 Coated Steel Sheet Figure 1 shows a coated steel sheet 1 according to this embodiment. In this embodiment, the coated steel sheet 1 includes a steel sheet 2 and a coating layer 3 disposed on the steel sheet 2. The surface of the coating layer 3 has a contact angle of 82° or more and 130° or less with water, and a contact angle of 70° or more and 120° or less with ethylene glycol. The ten-point average roughness (Rzjis) of the surface of the coating layer 3 is greater than 0 μm and less than 20 μm. The coating layer 3 contains a fluorinated polysiloxane (A). The fluorinated polysiloxane (A) is a reaction product containing a fluororesin (A1) and a polysiloxane (A2). The fluororesin (A1) has a constitutive unit (a1) bonded by an amine ester bond, and the constitutive unit (a1) contains a constitutive unit (a11) having a free radical polymerizable unsaturated bond. Polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain.

[0017] As described above, the coating layer 3 has a specific surface state or contains specific components. This allows for easy removal of algae adhering to the coated steel plate 1 and maintains the corrosion resistance of the coated steel plate 1. For example, the coating layer 3 is disposed on the outermost side of the coated steel plate 1. In this case, algae adhering to the coated steel plate 1 can be removed particularly easily. Therefore, in this embodiment, the coating layer 3 is disposed on the outermost side of the coated steel plate 1.

[0018] The method for forming the coating layer 3 is not particularly limited. For example, the coating layer 3 can be formed by applying a resin coating containing a resin component such as fluorinated polysiloxane (A) and baking it to harden it. The maximum plate temperature reached during baking is, for example, 210°C or higher and 250°C or lower, and the time for reaching the maximum plate temperature is, for example, 20 seconds or higher and 60 seconds or lower. As long as there are no defects such as peeling, the thickness of the coating layer 3 is not particularly limited. For example, it is 1 μm or higher and 20 μm or lower. It is preferable to apply the resin coating in a manner within this range and bake it to harden it to form the coating layer 3. Furthermore, if the thickness of the coating layer 3 is within the aforementioned range, the processability of the coated steel sheet 1 can be improved.

[0019] Furthermore, in this embodiment, the coated steel sheet 1 further includes a plating layer 5, which covers the surface of the steel sheet 2 on the side of the coating layer 3. Moreover, the plating layer 5 is located between the steel sheet 2 and the coating layer 3. That is, the steel sheet 2 is a coated steel sheet. The thickness of the plating layer 5 is, for example, 5 μm or more and 30 μm or less. Furthermore, the plating layer 5 contains, for example, at least one selected from the group consisting of zinc and aluminum. In other words, as a coated steel sheet, a hot-dip galvanized steel sheet is preferred; examples of hot-dip galvanized steel sheets include galvanized steel sheets or Zn-Al alloy coated steel sheets.

[0020] Furthermore, in this embodiment, the coated steel sheet 1 further includes an intermediate layer 4 between the steel sheet 2 and the coating layer 3. For example, the intermediate layer 4 can be formed by applying a resin coating to the steel sheet 2. Examples of resin coatings include polyester-based resin coatings and epoxy-based resin coatings. By using the aforementioned resin coating, the adhesion between the intermediate layer 4 and the steel sheet 2 and the coating layer 3 can be improved. Furthermore, in this embodiment, when the coated steel sheet 1 includes the intermediate layer 4, the coating layer 3 can function as a topcoat. In addition, the intermediate layer 4 can consist of one layer or two or more layers. For example, when the intermediate layer 4 consists of only one base coat layer, a primer resin coating (primer coating) is applied to the steel sheet 2 and then baked to harden it. The intermediate layer 4 is formed in this manner. Furthermore, when the intermediate layer 4 consists of both a base coat layer and an intermediate coat layer, a primer coating is applied to the steel sheet 2 and then baked to harden it, thus forming the base coat layer. Next, a resin coating for the intermediate coat (intermediate coat paint) is applied on top of the base coat and baked to harden it, thus forming the intermediate coat. This forms the intermediate layer 4.

[0021] 2.2 Detailed description of the surface condition of the coating layer 3.

[0022] The surface contact angle of the coating layer 3 with water is 82° or more and 130° or less. Algae are readily compatible with water and readily grow in the presence of water. However, if the surface contact angle of the coating layer 3 with water is within the above range, the coating layer 3 is not readily compatible with water, making it difficult for water to penetrate the coating layer 3. In other words, if the surface contact angle of the coating layer 3 with water is within the above range, the coating layer 3 can moderately improve its water repellency. Consequently, algae are less likely to grow by eroding from the surface of the coating layer 3 inwards, thus making it difficult for algae to adhere to the coating layer 3. As a result, even if algae adhere to the surface of the coated steel plate 1, the algae can be easily removed. Furthermore, when removing algae, the adhered algae can be removed without forcefully rubbing the surface of the coated steel plate 1, thus suppressing damage to the surface of the coated steel plate 1. If the coated steel plate 1 is damaged and chemicals come into contact with the damage, corrosion may occur. However, the coated steel plate 1 of this embodiment can suppress such damage, thus reducing the occurrence of corrosion and maintaining corrosion resistance. The contact angle with water is preferably 84° or higher, more preferably 85° or higher, particularly preferably 86° or higher, and even more preferably 90° or higher. The contact angle with water is preferably 120° or lower, more preferably 115° or lower, and particularly preferably 110° or lower. Furthermore, the contact angle of the coating layer 3 with ethylene glycol is 70° or higher and 120° or lower. If the contact angle of the coating layer 3 with ethylene glycol is within the above range, the coating layer 3 can moderately improve its oil-repellent properties. This makes it difficult for algae to adhere to the coating layer 3. As a result, even if algae adhere to the surface of the coated steel plate 1, the algae can be easily removed, and corrosion resistance can be maintained. The contact angle for ethylene glycol is preferably 71° or higher, more preferably 72° or higher, and most preferably 73° or higher. The contact angle for ethylene glycol is preferably 110° or lower, more preferably 100° or lower, and most preferably 93° or lower. Furthermore, the contact angle of water or ethylene glycol droplets can be determined by using a contact angle meter.

[0023] The surface free energy of the coating layer 3 is preferably 5 mJ / m² or more and 23 mJ / m² or less. At this point, algae adhering to the surface of the coated steel plate 1 can be removed more easily, and corrosion resistance can be maintained. This surface free energy is more preferably 8 mJ / m² or more, and even more preferably 11 mJ / m² or more. This surface free energy is more preferably 21.5 mJ / m² or less, and even more preferably 20.5 mJ / m² or less.

[0024] Furthermore, the surface free energy of the coating layer 3 can be calculated based on the measured values ​​of the contact angles of water and ethylene glycol, and on the Owens-Wendt formula and the Young formula.

[0025] The ten-point average roughness (Rzjis) of the surface of the coating layer 3 is greater than 0 μm and less than 20 μm. At this time, the smoothness of the coating layer 3 is moderately improved, making it difficult for algae to adhere to the coating layer 3. Therefore, algae attached to the surface of the coated steel plate 1 can be removed more easily. The ten-point average roughness (Rzjis) is preferably less than 15 μm, and more preferably less than 7 μm. The ten-point average roughness (Rzjis) can be, for example, greater than 0.5 μm. Furthermore, the ten-point average roughness (Rzjis) at three points on the surface of the coating layer 3 can be measured using a roughness measuring machine according to Japanese Industrial Standard (JIS) B 0601-2001, and the average value of the measurement results is taken as the ten-point average roughness (Rzjis) of the surface of the coating layer 3.

[0026] 2.3 Detailed description of the composition of the coating layer 3.

[0027] The coating layer 3 contains fluorinated polysiloxane (A). This allows for easy removal of algae even if they adhere to the surface of the coated steel sheet 1. Furthermore, the fluorinated polysiloxane (A) imparts resistance to chemicals to the coating layer 3. Therefore, the coated steel sheet 1 with the coating layer 3 containing fluorinated polysiloxane (A) exhibits high corrosion resistance. The content of fluorinated polysiloxane (A) relative to the coating layer 3 is preferably 4% by mass or more and 40% by mass or less. This allows for easier removal of algae adhering to the surface of the coated steel sheet 1. This content is more preferably 10% by mass or more, and even more preferably 30% by mass or more.

[0028] The fluorinated polysiloxane (A) comprises a fluoropolymer (A1) and a polysiloxane (A2) as constituent components. In other words, the fluorinated polysiloxane (A) is a reaction product containing reactive components of the fluoropolymer (A1) and the polysiloxane (A2). For example, the fluorinated polysiloxane (A) can be generated by graft polymerization of the fluoropolymer (A1) and the polysiloxane (A2). In other words, the fluorinated polysiloxane (A) can contain a graft polymer having a main chain derived from the fluoropolymer (A1) and graft chains derived from the polysiloxane (A2). In this case, algae adhering to the surface of the coated steel plate 1 can be removed more easily. While the exact reason is not yet fully understood, it is speculated to be due to the following reasons. That is, by arranging the grafted chains derived from polysiloxane (A2) along the main chain derived from fluororesin (A1), a polymer brush structure with a brush-like shape can be formed. This polymer brush structure formed from polysiloxane (A2) improves the water and oil repellency of the coating layer 3, thereby making it more difficult for algae to adhere to the coated steel plate. As a result, algae adhering to the surface of the coated steel plate 1 can be removed more easily.

[0029] Detailed description of the reactive components used to generate fluorinated polysiloxane (A).

[0030] As described above, the fluorinated polysiloxane (A) includes a fluoropolymer (A1) as a constituent component. The fluoropolymer (A1) has a constituent unit (a1) bonded by an amine ester bond, and the constituent unit (a1) includes a constituent unit (a11) having a free radical polymerizable unsaturated bond. For example, the fluoropolymer (A1) can be obtained by reacting a hydroxyl-containing fluoropolymer (A11) with a free radical polymerizable monomer (A12) having an isocyanate group. In other words, the fluoropolymer (A1) is a reaction product containing a reactive component comprising a hydroxyl-containing fluoropolymer (A11) and a free radical polymerizable monomer (A12) having an isocyanate group. In this case, the free radical polymerizable unsaturated bond of the constituent unit (a11) can originate from the free radical polymerizable unsaturated bond of the free radical polymerizable monomer (A12) having an isocyanate group.

[0031] A fluoropolymer (A11) having hydroxyl groups has, for example, at least one of the constituent units represented by formula (1) and the constituent units represented by formula (2).

[0032]

[0033] When the fluoropolymer (A11) has a plurality of constituent units represented by formula (1), in formula (1), R1 and R2 exist independently in each constituent unit. R1 and R2 are hydrogen atoms, halogen atoms, alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 8 carbon atoms, haloalkyl groups having 1 to 10 carbon atoms substituted with one or more halogen atoms, or haloaryl groups having 6 to 8 carbon atoms substituted with one or more halogen atoms.

[0034]

[0035] When the fluororesin (A11) has a plurality of constituent units represented by formula (2), in formula (2), R3 exists independently in each constituent unit. R3 is a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 8 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms substituted with one or more halogen atoms, or a haloaryl group having 6 to 8 carbon atoms substituted with one or more halogen atoms. When the fluororesin (A11) has a plurality of constituent units represented by formula (2), X exists independently in each constituent unit. X is OR4, CH2OR4, or COOR4. R4 is an alkylene group having 1 to 10 carbon atoms, an cycloalkyl group having 6 to 10 carbon atoms, or an alkylene group having 2 to 10 carbon atoms.

[0036] The hydroxyl value of the fluoropolymer (A11) having hydroxyl groups is 5 mg KOH / g or more and 250 mg KOH / g or less. If the hydroxyl value is 5 mg KOH / g or more, the fluoropolymer (A11) having hydroxyl groups can contain an appropriate amount of hydroxyl groups, thus the reaction between the fluoropolymer (A11) having hydroxyl groups and the free radical polymerizable monomer (A12) having isocyanate groups can proceed efficiently. If the hydroxyl value is 250 mg KOH / g or less, the compatibility between the fluoropolymer (A1) and the polysiloxane (A2) can be improved. Therefore, the polymerization of the fluoropolymer (A1) and the polysiloxane (A2) can proceed efficiently. The hydroxyl value is preferably 10 mg KOH / g or more, more preferably 20 mg KOH / g or more. The hydroxyl value is preferably 200 mg KOH / g or less, more preferably 120 mg KOH / g or less.

[0037] A fluoropolymer (A11) having a hydroxyl group contains, for example, at least one selected from the group consisting of vinyl ether fluoropolymers, allyl ether fluoropolymers, vinyl carboxylate / acrylate fluoropolymers and vinyl ether / vinyl carboxylate fluoropolymers.

[0038] Fluoropolymers (A11) containing hydroxyl groups can be used, for example, commercially available products. Examples of commercially available products include: LUMIFLON (registered trademark) LF-100, LF-200, LF-300, LF-400, LF-554, LF-600, and LF986N manufactured by Asahi Glass Co., Ltd.; CEFRAL COAT (registered trademark) PX-40, A606X, A202B, and CF-803 manufactured by Central Glass Co., Ltd.; ZAFLON (registered trademark) FC-110, FC-220, FC-250, FC-275, FC-310, FC-575, and XFC-973 manufactured by Toa Gosei Co., Ltd.; ZEFFLE (registered trademark) GK-510 manufactured by Daikin Industries, Ltd.; and FLUONATE (registered trademark) K-700, K-702, K-703, K-704, and K-705 manufactured by DIC Co., Ltd.

[0039] The free radical polymerizable monomer (A12) having an isocyanate group contains, for example, at least one of the compounds represented by formula (3) and the compounds represented by formula (4).

[0040]

[0041] In formula (3), R5 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a cycloalkyl group having 3 to 10 carbon atoms. Alkyl groups are, for example, methyl, ethyl, propyl, butyl, pentyl, or hexyl. Alelic groups are, for example, phenyl. Cycloalkyl groups are, for example, cyclohexyl. R6 is an oxygen atom, an alkylene group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an aryl group having 1 to 10 carbon atoms, or an cycloalkyl group having 1 to 10 carbon atoms.

[0042]

[0043] In formula (4), R7 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or a cycloalkyl group having 3 to 10 carbon atoms. Alkyl groups are, for example, methyl, ethyl, propyl, butyl, pentyl, or hexyl. Alelic groups are, for example, phenyl. Cycloalkyl groups are, for example, cyclohexyl. R8 is an oxygen atom, an alkylene group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an aryl group having 1 to 10 carbon atoms, or an cycloalkyl group having 1 to 10 carbon atoms.

[0044] Furthermore, the free radical polymerizable monomer (A12) having an isocyanate group may contain at least one selected from the group consisting of methacryloyl isocyanate, ethyl 2-isocyanate methacrylate, m-isopropenyl-α,α-dimethylbenzyl isocyanate and p-isopropenyl-α,α-dimethylbenzyl isocyanate.

[0045] Preferably, the free radical polymerizable monomer (A12) having isocyanate groups reacts with the fluoropolymer (A11) having hydroxyl groups at a concentration of 0.001 mol or more and 0.1 mol or less per equivalent of hydroxyl groups. If the concentration is 0.001 mol or more, the graft copolymerization of the fluoropolymer (A1) and the polysiloxane (A2) is facilitated. Furthermore, if the concentration is 0.1 mol or less, gelation that occurs during the graft polymerization of the fluoropolymer (A1) and the polysiloxane (A2) can be suppressed.

[0046] As described above, the fluorinated polysiloxane (A) contains a polysiloxane (A2) component as a constituent. The polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain. The free radical polymerizable unsaturated bond is, for example, acrylonitrile, methacrylonitrile, vinyl, or allyl.

[0047] The polysiloxane (A2) contains, for example, at least one of the compounds represented by formula (5) and the compounds represented by formula (6).

[0048]

[0049] In formula (5), R9 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. This hydrocarbon group may be, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, or cyclohexyl. R9 is preferably a hydrogen atom or methyl. Furthermore, R10, R11, R12, R13, and R14 in formula (5) may be the same or different, and are hydrogen atoms or hydrocarbon groups having 1 to 10 carbon atoms. The hydrocarbon group may be, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, or cyclohexyl. R10, R11, R12, and R13 are each preferably methyl or phenyl. R14 is preferably methyl, butyl, or phenyl. Furthermore, in formula (5), n is an integer of 2 or more, preferably an integer of 10 or more, and more preferably an integer of 30 or more.

[0050]

[0051] In formula (6), R15 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The hydrocarbon group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, or cyclohexyl, preferably a hydrogen atom or methyl. R16, R17, R18, R19, and R20 may be the same or different. R16, R17, R18, R19, and R20 are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. The hydrocarbon group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, or cyclohexyl, preferably: R16, R17, R18, and R19 are methyl or phenyl, and R20 is methyl, butyl, or phenyl. Furthermore, p is an integer from 0 to 10, preferably 3. Furthermore, q is an integer greater than 2, preferably greater than 10, and more preferably greater than 30.

[0052] As a polysiloxane (A2), commercially available products can be used. Examples of commercially available products include: Silaplane (registered trademark) FM-0711 (number average molecular weight 1000), FM-0721 (number average molecular weight 5000), and FM-0725 (number average molecular weight 10000) manufactured by Nippon Chip Corporation; and X-22-174DX (number average molecular weight 4600) manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[0053] In addition, the reactive component used to generate the fluorinated polysiloxane (A) may, in addition to the fluoropolymer (A1) and the polysiloxane (A2), include at least one component selected from the group consisting of a monomer (A3) having an alkoxysilyl group, a monomer (A4) having a hydroxyl group, and other monomers (hereinafter referred to as monomer (A5)).

[0054] Examples of monomers having an alkoxysilyl group (A3) include compounds having a dialkoxysilyl group or a trialkoxysilyl group and a free radical polymerizable unsaturated bond. Specifically, the monomer having an alkoxysilyl group (A3) may contain at least one selected from the group consisting of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0055] As a monomer having a hydroxyl group (A4), compounds having a hydroxyl group and a free radical polymerizable unsaturated bond can be listed. Specifically, the monomer having a hydroxyl group (A4) may contain at least one selected from the group consisting of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, and 4-hydroxybutyl methacrylate.

[0056] The monomer (A5) is a monomer that is different from any of the fluoropolymer (A1), polysiloxane (A2), monomer having an alkoxysilyl group (A3), and monomer having a hydroxyl group (A4). The monomer (A5) may, for example, contain at least one selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, and n-butyl methacrylate.

[0057] A fluorinated polysiloxane (A) can be obtained by polymerizing a reactive component comprising the fluoropolymer (A1), polysiloxane (A2), monomer having an alkoxysilyl group (A3), monomer having a hydroxyl group (A4), and monomer (A5) listed above. The content of the fluoropolymer (A1) relative to the reactive component is preferably 2% by mass or more and 70% by mass or less. More preferably, it is 10% by mass or more. More preferably, it is 40% by mass or less. Furthermore, the content of the polysiloxane (A2) relative to the reactive component is preferably 5% by mass or more and 40% by mass or less. More preferably, it is 10% by mass or more. More preferably, it is 30% by mass or less. Furthermore, the content of the monomer having an alkoxy group (A3) relative to the reactive component is preferably 5% by mass or more and 55% by mass or less. More preferably, it is 10% by mass or more. More preferably, it is 40% by mass or less. Furthermore, relative to the reactive component, the content of the monomer with hydroxyl groups (A4) is preferably 3% by mass or more and 50% by mass or less. More preferably, it is 20% by mass or more. More preferably, it is 30% by mass or less. Furthermore, relative to the reactive component, the content of the monomer (A5) is preferably more than 0% by mass and 85% by mass or less. More preferably, it is 30% by mass or less. When these contents are within the above ranges, algae adhering to the coated steel plate 1 can be removed more easily, and the corrosion resistance of the coated steel plate 1 can be improved.

[0058] In addition to the fluorinated polysiloxane (A), the coating layer 3 may also contain a resin different from the fluorinated polysiloxane (A) (hereinafter also referred to as resin (B)). Resin (B) may contain at least one selected from the group consisting of acrylic silicone resin, amine silicone resin, and fluorosiloxane resin. Furthermore, the content of resin (B) relative to the coating layer 3 is preferably set to 30% by mass or less. At this point, algae adhering to the coated steel plate 1 can be removed more easily.

[0059] The coating layer 3 may contain filler. When the coating layer 3 contains filler, it is preferable that the average particle size of the filler is 20 μm or less. This maintains the improved smoothness of the coating layer 3 and improves its durability. The average particle size is more preferably 10 μm or less, further preferably 8 μm or less, and particularly preferably 7 μm or less. The filler may contain at least one selected from the group consisting of silicon dioxide, glass beads, nylon beads, and acrylic beads. Furthermore, the filler content relative to the coating layer 3 is preferably 10% by mass or less. This makes it easier to maintain the improved smoothness of the coating layer 3 surface. This content is more preferably 1% by mass or less. Furthermore, the coating layer 3 is particularly preferably free of filler. This particularly maintains the improved smoothness of the coating layer 3 surface. This makes it difficult for algae to adhere to the coating layer 3.

[0060] 3. Characteristics of the Coated Steel Sheet The coated steel sheet 1 possesses high corrosion resistance. More specifically, the coated steel sheet 1 possesses high acid resistance and high alkali resistance. Corrosion resistance can be confirmed by the following method. First, a 50mm × 120mm test piece is cut from the coated steel sheet 1. Next, the cut end face of the test piece is protected with PTFE tape or the like, and it is immersed in a chemical solution. Then, the corrosion resistance of the coated steel sheet 1 can be confirmed by visually observing the degree of corrosion at this point. Examples of chemical solutions include hydrochloric acid, sulfuric acid, phosphoric acid, or an aqueous solution of sodium hydroxide.

[0061] The coated steel plate 1 can easily remove algae adhering to its surface. As a method to confirm whether algae can be easily removed, i.e., algae removal performance, it can be performed by the following method: First, the coated steel plate 1 is immersed in and exposed to a culture solution for one month, allowing algae to multiply on the surface of the coated steel plate 1. Then, after the algae adhering to the surface dries, it is wiped back and forth once with a cloth. After performing the same operation three times (3 months), the appearance of the wiped area is visually confirmed, and the degree of algae residue is observed, thereby confirming the algae removal performance. Furthermore, the culture solution used can contain at least one component selected from the group consisting of NO3, PO4, SO4, Na, K, Mg, Ca, and NH4.

[0062] 4. Application Example of Coated Steel Sheet The coated steel sheet 1 can easily remove algae adhering to its surface. Therefore, it is suitable for use in manufacturing plant cultivation containers 10 for cultivating plants PL (see Figure 2). When manufacturing the coated steel sheet 1, its size can be appropriately designed. Compared to using resin materials, it is easier to manufacture large-scale products if coated steel sheet 1 is used. Therefore, when manufacturing the plant cultivation container 10, by using the coated steel sheet 1, the plant cultivation container 10 can be made larger or more slender.

[0063] The plant cultivation container 10 has a container section 11 for holding the culture medium 12. That is, the plant cultivation container 10 has a tray-like shape with an opening at the top, which can store and hold the culture medium 12 in the container section 11. In addition, the plant cultivation container 10 may have a lid 14 covering the container section 11, thereby covering the container section 11.

[0064] When the plant cultivation container 10 is used to cultivate the plant PL, the container section 11 can accommodate the plant PL. For example, the plant cultivation container 10 is equipped with a retaining material 13 for holding the plant PL. The retaining material 13 has pores to hold the plant PL, and the plant PL can be held by allowing it to pass through the pores. The retaining material 13 is preferably formed of a flexible and permeable material. Furthermore, the plant cultivation container 10 may not have a retaining material 13. That is, the plant PL can be placed in the plant cultivation container 10 without being held by the retaining material 13.

[0065] Furthermore, at least a portion of the container section 11 is made of coated steel plate 1. For example, the coated steel plate 1 can be bent to have a container section 11 capable of holding the culture medium 12, thereby forming a plant cultivation container 10. Moreover, in this embodiment, the coating layer 3 of the coated steel plate 1 can be exposed on the inner surface of the container section 11, that is, on the surface facing the space holding the culture medium 12.

[0066] When the plant cultivation container 10 is used to cultivate the plant PL, algae may grow in the container section 11. However, since at least a portion of the container section 11 is made of coated steel plate 1, the attached algae can be easily removed by wiping with a cloth or the like. This allows for efficient cultivation of the plant PL. Furthermore, when wiping away the attached algae with a cloth or the like, excessive force is not required, thus preventing damage to the plant cultivation container 10. This maintains the corrosion resistance of the plant cultivation container 10.

[0067] The culture medium 12 is a liquid containing nutrients required for the cultivation of plant PL. For example, the culture medium 12 contains fertilizer. The fertilizer, for example, contains at least one element selected from the group consisting of phosphorus, magnesium, and nitrogen.

[0068] Furthermore, from the viewpoint of plant PL growth management, the pH value of culture medium 12 is preferably maintained at around 5.5 to 7.0. However, during the cultivation of plant PL, the pH value of culture medium 12 sometimes fluctuates within the range of 3 to 9. Therefore, for the purpose of adjusting the pH value, appropriate chemicals can be added to culture medium 12. Chemicals may include, for example, at least one selected from the group consisting of sulfuric acid, phosphoric acid, nitric acid, sodium hydroxide, and potassium hydroxide.

[0069] In this way, although the culture medium 12 may contain fertilizers and chemicals, the plant cultivation container 10 is made of coated steel plate 1, which has high chemical resistance. Therefore, even if the plant cultivation container 10 comes into contact with the culture medium 12 containing chemicals such as acids or alkalis, it is not easy to corrode or deteriorate due to corrosion, such as cracking or perforation, which can reduce the burden of long-term algae removal.

[0070] Next, a method for cultivating plant PL using plant cultivation container 10 will be described. First, a culture solution 12 is stored in the container section 11 of plant cultivation container 10. The culture solution 12 is prepared by adding acid or alkali to achieve a predetermined pH value (approximately 5.5 to 7.0 in this embodiment). Furthermore, during the cultivation of plant PL, the pH value of the culture solution 12 may change from the predetermined value. Therefore, the pH value of the culture solution 12 is constantly monitored to maintain it within the predetermined value. If the pH value of the culture solution 12 is found to exceed the range of 5.5 to 7.0, the pH value is maintained within the aforementioned range by appropriately adding the acid or alkali listed above.

[0071] Next, the plant PL is held in the container section 11 of the plant cultivation container 10 such that the roots of the plant PL are immersed in the culture solution 12. The plant PL is not particularly limited, and can be, for example, lettuce, herbs, strawberries, coriander, edible flowers, medicinal plants, spinach, kale, komatsuna, parsley, iceberg lettuce, arugula, celery, or mizuna. As described above, when holding the plant PL in the container section 11, a holding material 13 can be used, preferably in a manner that the plant PL is held through the pores provided by the holding material 13.

[0072] When cultivating plant PL, light is irradiated onto plant PL from light source LS. This promotes the growth of plant PL. Specifically, light source LS is a light-emitting diode (LED) or fluorescent lamp, etc., and is set above plant cultivation container 10. For example, light source LS is sometimes arranged on the side opposite to the side of coated steel plate 1 where the coating layer 3 is disposed (hereinafter also referred to as the back side).

[0073] During the cultivation of plant PL, algae may proliferate in the plant cultivation container 10, which can be removed by wiping with a cloth or similar object. Therefore, keeping the plant cultivation container 10 clean prevents algae from hindering the growth of plant PL. Furthermore, as described above, algae adhering to the plant cultivation container 10 made of coated steel plate 1 can be easily removed. Thus, the time and labor required for algae removal can be reduced.

[0074] By means of this method, plant PL can be cultivated using plant cultivation container 10. For example, plant cultivation container 10 is suitable for use when cultivating plant PL in a plant factory. Furthermore, the above-described plant cultivation method is only one example. That is to say, the method of cultivating plant PL using plant cultivation container 10 is not limited to the above method.

[0075] 5. Variation Example The coated steel sheet 1 listed in the above embodiment further includes a plating layer 5 covering the surface of the coating layer 3 of the steel sheet 2, and the plating layer 5 is located between the steel sheet 2 and the coating layer 3, but it is not limited to this. That is, the coated steel sheet 1 may not have the plating layer 5 covering the surface of the coating layer 3 of the steel sheet 2. In addition, the coated steel sheet 1 may also further include a chemical conversion treatment layer located between the coating layer 3 and the plating layer 5. In this case, the corrosion resistance of the coated steel sheet 1 can be improved.

[0076] In the above embodiment, the coated steel sheet 1 has an intermediate layer 4, but it is not limited to this. That is, the coated steel sheet 1 may not have an intermediate layer 4.

[0077] In the above embodiment, the coated steel plate 1 is used to make plant cultivation container 10, but is not limited thereto.

[0078] 6. As can be seen from the above embodiments, this disclosure includes the following states.

[0079] The first-state coated steel sheet (1) disclosed herein comprises a steel sheet (2) and a coating layer (3) disposed on the steel sheet (2). The surface of the coating layer (3) has a contact angle of 82° or more and 130° or less with respect to water, and a contact angle of 70° or more and 120° or less with respect to ethylene glycol. The ten-point average roughness (Rzjis) of the surface of the coating layer (3) is greater than 0 μm and less than 20 μm.

[0080] Based on this state, it is possible to provide a coated steel sheet (1) that can easily remove attached algae.

[0081] The second-state coated steel sheet (1) disclosed herein is relative to the first-state sample, and the coating layer (3) contains fluorinated polysiloxane (A). The fluorinated polysiloxane (A) is a reaction product containing reactive components of fluororesin (A1) and polysiloxane (A2). The fluororesin (A1) has a constitutive unit (a1) bonded by amine ester bonds, and the constitutive unit (a1) contains a constitutive unit (a11) with free radical polymerizable unsaturated bonds. The polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain.

[0082] The third-state coated steel sheet (1) disclosed herein comprises a steel sheet (2) and a coating layer (3) disposed on the steel sheet (2). The coating layer (3) contains a fluorinated polysiloxane (A). The fluorinated polysiloxane (A) is a reaction product containing a fluoropolymer (A1) and a polysiloxane (A2). The fluoropolymer (A1) has a constituent unit (a1) bonded by an amine ester bond, which contains a constituent unit (a11) having a free radical polymerizable unsaturated bond. The polysiloxane (A2) has a free radical polymerizable unsaturated bond at one end of its molecular chain.

[0083] Based on this state, it is possible to provide a coated steel sheet (1) that can easily remove attached algae.

[0084] The fourth state of the coated steel plate (1) disclosed herein refers to any of the first to third state samples, wherein the coating layer (3) does not contain filler, or the coating layer (3) contains filler and the average particle size of the filler is less than 20 μm.

[0085] The fifth state of the coated steel plate (1) disclosed herein is for any of the first to fourth state samples, and further has an intermediate layer (4) between the steel plate (2) and the coating layer (3).

[0086] The sixth-state coated steel sheet (1) disclosed herein is for any of the first to fifth states, further comprising a plating layer (5) that covers the side of the coating layer (3) of the steel sheet (2). The plating layer (5) is located between the steel sheet (2) and the coating layer (3). The plating layer (5) comprises at least one of zinc and aluminum.

[0087] The seventh-state plant cultivation container (10) disclosed herein includes a container section (11) for holding the culture medium (12). At least a portion of the container section (11) is made of a coated steel plate (1) of any of the first to sixth states. [Example]

[0088] Hereinafter, more specific embodiments of this embodiment will be presented. However, this embodiment is not limited to the following embodiments.

[0089] [Method for Manufacturing Coated Steel Sheets] (Examples 1-10) A polyester resin coating (product number "V-NIT#156N" manufactured by Dai Nippon Paint Co., Ltd.) is applied to the surface of a steel sheet with a thickness of 0.35 mm as a primer coating, and baked at a maximum plate temperature of 200°C for 30 seconds to form a base layer. Next, a polyester resin coating (product number "V-NIT#7520" manufactured by Dai Nippon Paint Co., Ltd., containing a high molecular weight polyester of 12,000) is applied on the base layer as an intermediate coating, and baked at a maximum plate temperature of 220°C for 30 seconds to allow the coating to dry and harden, thereby forming an intermediate coating. An intermediate layer 4 consisting of a primer coating and an intermediate coating is formed in this way. Furthermore, the polyester resin coating contained in the intermediate coating contains fillers as needed.

[0090] Next, a coating containing fluorinated polysiloxane (product number "V-MAGIC#10" manufactured by Dai Nippon Paint Co., Ltd.) is applied as a topcoat to the surface of the intermediate layer 4 (base coat and intermediate coat), and baked at a maximum board temperature of 230°C for 40 seconds to dry and harden it, thereby forming the coating layer 3 (topcoat). The coated steel plate 1 was manufactured in this order.

[0091] Furthermore, in Example 8 only, the coated steel plate 1 was produced without forming an intermediate coating.

[0092] <Preparation method of fluorinated polysiloxane coating> The fluorinated polysiloxane coating (product number "V-MAGIC#10" manufactured by Dai Nippon Paint Co., Ltd.) used as the above-mentioned topcoat coating can be prepared by the following method.

[0093] In a glass reactor equipped with a stirrer, thermometer, condenser, and dry nitrogen inlet, 1554 parts of Ceraful Coat CF-803, 233 parts of xylene, and 6.3 parts of ethyl 2-isocyanate methacrylate were added, and the mixture was heated to 80°C under a dry nitrogen atmosphere. The reaction was carried out at 80°C for 2 hours. After confirming the disappearance of the isocyanate group absorption by infrared absorption spectroscopy of a sample of the reaction solution, the reaction mixture was removed to obtain a component with 50% non-volatile components.

[0094] Next, in a glass reactor equipped with a stirrer, thermometer, condenser, and dry nitrogen inlet, 40 parts of the aforementioned components and 80 parts of butyl acetate were added. After heating to 90°C in a nitrogen atmosphere, a pre-mixed mixture of 20 parts of methyl methacrylate, 7 parts of 2-ethylhexyl methacrylate, 23 parts of 2-hydroxyethyl methacrylate, 10 parts of FM-0721, 20 parts of γ-methacryloxypropyltrimethoxysilane, 2 parts of PERBUTYL O, and 22 parts of xylene was added dropwise over 2 hours at the same temperature. After maintaining the same temperature for 2 hours, 1 part of PERBUTYL O was added, and the mixture was further maintained at 90°C for 5 hours to obtain a solution containing the target fluorinated polysiloxane with 45% non-volatile components and a weight average molecular weight of 58,000.

[0095] Then, for the fluorinated polysiloxane, CORONATE (registered trademark) hx, with a hydroxyl equivalent of 1 equivalent relative to the fluorinated polysiloxane, is added, and further diluted with butyl acetate to make the non-volatile content in the coating 35% by mass. A coating containing the fluorinated polysiloxane is thus prepared. Then, fillers are added to the coating containing the fluorinated polysiloxane as needed to prepare a topcoat coating.

[0096] Furthermore, the materials used in the above preparation method are as follows.

[0097] Fluoropolymer with hydroxyl groups: CEFRAL COAT (registered trademark) CF-803. Manufactured by Central Glass Co., Ltd. Hydroxyl value 60. Number average molecular weight 15000.

[0098] A free radical polymerizable monomer having an isocyanate group: ethyl 2-isocyanate methacrylate.

[0099] Polysiloxane: Silaplane (registered trademark) FM-0721. Manufactured by Nippon Chiso Co., Ltd. Number average molecular weight 5000.

[0100] Free radical polymerization initiator: PERBUTYL (registered trademark) O. Tributyl peroxy-2-ethylhexanoate. Manufactured by Nippon Yushi Co., Ltd.

[0101] Curing agent: CORONATE (registered trademark) HX. A polyisocyanurate based on hexamethylene diisocyanurate. Manufactured by Tosoh Corporation.

[0102] (Example 11) Except for using a fluorinated resin coating (product number "V-FLON#5000" manufactured by Dai Nippon Paint Co., Ltd., containing isocyanate crosslinked trifluorinated (FEVE) fluorinated resin) as the topcoat, the coated steel sheet 1 was produced according to almost the same method as in Example 2. Furthermore, this trifluorinated fluorinated resin does not have polysiloxanes or the like in its functional groups, and is therefore different from the fluorinated polysiloxanes in Example 1, etc.

[0103] (Example 12) Except for using a polyester resin coating (product number "FLC5100" manufactured by Nipponpaint Industrial Coatings) as the topcoat, the coated steel sheet 1 was produced in almost the same manner as in Example 1. Furthermore, the conditions for baking the topcoat to dry and harden it were set to 30 seconds.

[0104] (Comparative Example 1) Except that a polyester resin coating (product number "200HQ" manufactured by Nipponpaint Industrial Coatings) was used as the topcoat and no intermediate coat was provided, the coated steel sheet 1 was produced in almost the same manner as in Example 1. Furthermore, the conditions for baking the topcoat to dry and harden it were set to 30 seconds and a maximum plate temperature of 220°C.

[0105] (Comparative Example 2) Except for using a fluorinated resin coating (product number "DICFlow C", difluorinated type, manufactured by Nipponpaint Industrial Coatings) as the topcoat and not setting an intermediate coating, the coated steel sheet 1 was manufactured in almost the same manner as in Example 1. Furthermore, the conditions for baking the topcoat to dry and harden it were set to 45 seconds and a maximum plate temperature of 250°C. Moreover, this difluorinated fluorinated resin does not have polysiloxanes or the like in its functional groups, and is therefore different from the fluorinated polysiloxanes in Example 1, etc.

[0106] (Comparative Example 3) Instead of using a steel plate with a coating, an acrylic resin plate was used.

[0107] [About the composition] Regarding the composition of the base coat, the resin composition of the coating is shown in Tables 1 to 3.

[0108] Regarding the components contained in the intermediate coating, the resin components, whether or not there are fillers, the type of fillers, the average particle size of the fillers, and the filler content are shown in Tables 1 to 3.

[0109] Regarding the components contained in the topcoat, the resin components, whether or not there are fillers, the type of fillers, the average particle size of the fillers, and the filler content are shown in Tables 1 to 3.

[0110] [About Characteristics] Regarding the characteristics of the base coating, the film thickness is shown in Tables 1-3.

[0111] Regarding the characteristics of the intermediate coating, the film thickness is shown in Tables 1 to 3.

[0112] The characteristics of the topcoat are shown in Tables 1 to 3, including film thickness, ten-point average roughness (Rzjis), contact angle with water, contact angle with ethylene glycol, and surface free energy.

[0113] In addition, the film thickness, surface roughness (Rzjis), contact angle with water, contact angle with ethylene glycol, and surface free energy were measured by the following methods.

[0114] (Film Thickness) The coated steel sheet 1 is cut along the direction of overlap of each layer. Next, five points are selected at any location on the cross-section of the obtained coated steel sheet 1, and the film thickness of the coating layer 3 is measured at each location using a scanning electron microscope (SEM). The table shows the value calculated by averaging the measurements from the five points.

[0115] (Surface Roughness) The ten-point average roughness Rzjis of the coating layer 3 is measured at 3 points using a roughness measuring machine in accordance with JIS B 0601-2001, and the average value is taken as the ten-point average roughness Rzjis.

[0116] (Contact angle with water) A water droplet was applied to the surface of the coating layer 3, and the contact angle of the coating layer 3 with water was measured using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.).

[0117] (Contact angle with ethylene glycol) Ethylene glycol was dropped onto the surface of the coating layer 3, and the contact angle of the coating layer 3 with ethylene glycol was measured using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.).

[0118] (Surface Free Energy) The surface free energy of coating layer 3 is calculated based on the measured values ​​of the contact angles of water and ethylene glycol, and on the Owens-Wendt formula and the Young formula.

[0119] [Evaluation] (Corrosion Resistance (Chemical Resistance)) A 50mm × 120mm test piece was cut from the coated steel sheet 1. Next, the cut ends of the test piece were protected with polytetrafluoroethylene (PTFE) tape and immersed in a chemical solution for 72 hours. Then, the corrosion resistance of the coated steel sheet 1 was evaluated according to the following criteria by visually confirming the area of ​​coating expansion at this time. Furthermore, 5% hydrochloric acid was used as the chemical.

[0120] A: The coating film in the impregnated portion does not swell, or the swelled area of ​​the coating film in the impregnated portion is less than 10%. B: The swelled area of ​​the coating film in the impregnated portion is more than 10% but less than 50%. C: The swelled area of ​​the coating film in the impregnated portion exceeds 50%.

[0121] (Algae Removal Performance) A plant cultivation container 10, made of a portion of the container section 11 of a coated steel plate 1, was used to cultivate plant PL (spinach) for 30 days. Then, after the algae attached to the plant cultivation container 10 was dried, it was wiped back and forth once with a dry cloth. The same operation was performed three times in the same location (a total of 90 days), and the ease of algae removal and the appearance of the wiped area were visually confirmed on the third wipe (on the 90th day). The degree of algae residue was observed and evaluated according to the following criteria.

[0122] A: No resistance is felt when wiping algae; over 90% of the algae attached to the wiping area can be removed. B: There is resistance, but with slight pressure, over 90% of the algae attached to the wiping area can be removed. C: There is resistance, but with slight pressure, over 70% but less than 90% of the algae attached to the wiping area can be removed. D: There is resistance, but with force, over 70% but less than 90% of the algae attached to the wiping area can be removed. E: There is resistance, but with force, over 40% but less than 70% of the algae attached to the wiping area can be removed. F: Even with forceful wiping, less than 40% of the algae attached to the wiping area can be removed.

[0123] [Table 1]

[0124] [Table 2]

[0125] [Table 3] [Simplified Explanation of the Diagram]

[0009] Figure 1 is a schematic cross-sectional view showing a coated steel sheet of the present disclosure. Figure 2 is a schematic diagram showing a method for cultivating plants using a plant cultivation container made of a coated steel sheet of the present disclosure. [Biomaterial Storage]

[0127] Domestic storage information (please note in order of storage institution, date, and number): None

[0128] Overseas Deposit Information (Please note in the order of deposit country, institution, date, and number) None

Claims

1. A plant cultivation container comprising a container portion for holding a culture medium, at least a portion of the container portion being made of a coated steel plate, the coated steel plate comprising a steel plate and a coating layer disposed on the steel plate, the coating layer containing a fluorinated polysiloxane (A), the fluorinated polysiloxane (A) being a reaction product comprising a reactive component comprising a fluororesin (A1) and a polysiloxane (A2), the fluororesin (A1) having a constitutive unit (a1) bonded by an amine ester bond, the constitutive unit (a1) comprising a constitutive unit (a11) having a free radical polymerizable unsaturated bond, the fluororesin (A1) being a reaction product comprising a fluororesin (A11) having a hydroxyl group and a free radical polymerizable monomer (A12) having an isocyanate group, the polysiloxane (A2) having a free radical polymerizable unsaturated bond at one end of its molecular chain.

2. The plant cultivation container as described in claim 1, wherein, The surface of the aforementioned coating layer has a contact angle of 82° or more and 130° or less with water, and a contact angle of 70° or more and 120° or less with ethylene glycol. The ten-point average roughness of the aforementioned surface is greater than 0 μm and less than 20 μm.

3. The plant cultivation container as described in claim 1 or 2, wherein, The aforementioned coating layer does not contain fillers, or the aforementioned coating layer contains fillers and the average particle size of the aforementioned fillers is less than 20 μm.

4. The plant cultivation container as described in claim 1 or 2, wherein, Furthermore, an intermediate layer is provided between the aforementioned steel plate and the aforementioned coating layer.

5. The plant cultivation container as described in claim 1 or 2, wherein, The aforementioned steel plate further comprises a coating layer covering the side of the aforementioned coating layer of the aforementioned steel plate, and the aforementioned coating layer is located between the aforementioned steel plate and the aforementioned coating layer, and the aforementioned coating layer comprises at least one of zinc and aluminum.

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